ABUNDANCE AND VIABILITY OF STRIPED BASS EGGS
 SPAWNED IN THE ROANOKE RIVER, NORTH CAROLINA,
 IN 1991
 By
 Roger A. Rulifson
 Institute for Coastal and Marine Resources, and
 Department of Biology
 East Carolina University
 Greenville, North Carolina 27858
 olJ
 (ICMR Contribution Series, No. ICMR-93-tj(L)
 The research on which the report is based was financed by the United States Environmental
 Protection Agency and the North Carolina Department of Environment, Health, and Natural
 Resources, through the Albemarle-Pamlico Study.
 Contents of the publication do not necessarily reflect the views and policies of the United States
 Environmental Protection Agency, the North Carolina Department of Environment, Health, and
 Natural Resources , nor does mention of trade names or commercial products constitute their
 endorsement by the United States or North Carolina Government.
 Report No. APES 93-04
 May 1993
EXECUTIVE SUMMARY
 Striped bass spawning activity in the Roanoke River, North Carolina, was documented in
 1991 by sampling for eggs at Barnhill's Landing (River Mile 117), which is just downstream of
 the spawning grounds between the towns of Halifax (RM 120) and Weldon (RM 130). Egg
 sampling was conducted every four hours near the surface and bottom from 15 April to 14 June.
 Water quality and changes in instream flow caused by water releases from Roanoke Rapids
 Reservoir at RM 137 also were monitored every four hours. Results were compared to similar
 studies funded by the Albemarle-Pamlico Estuarine Study during the springs of 1988, 1989, and
 1990. Objectives were: 1) to continue the uninterrupted egg study data base of W.W. Hassler
 beginning in 1959; 2) to identify potential sources of bias in Hassler's egg production estimates;
 and 3) relate striped bass spawning activity to operation of the Roanoke Rapids hydroelectric
 dam upstream.
 EGG PRODUCTION. The estimated number of striped bass eggs spawned in the
 Roanoke River in 1991 was 1.835 billion ±65.787 million from a total of 10,467 eggs collected
 in surface nets . Spawning prior to 15 April, or after 14 June, was not monitored. The 1991
 estimate is the highest observed at Barnhill's Landing since 1975. Estimated egg viability for the
 season was 55.4%, with no seasonal trend in viability evident. Most eggs drifting past Barnhill 's
 Landing were less than 10 hours old.
 SPAWNING EVENT MILESTONES. A 57-day spawning window was observed in
 1991. The continuous spawning period of 41 days was longer than in 1988 (27 days) and 1989
 (23 days), but shorter than 1990 (50 days) . Eggs first appeared on 17 April. Seasonal egg
 production was 50% completed by 13 May, 75% completed by 15 May, and 90% completed by
 25 May. The last eggs were collected on 12 June. Three spawning peaks were observed: .8-9
 May (20% of total eggs), 11-12 May (17%), and 14 May (19%).
 USING RIVER VOLUME TO ESTIMATE EGG PRODUCTION. Hassler's daily
 egg production estimates were made by a mathematical formula that used the average cross 
sectional area of the river and average number of eggs collected every three hours in surface
 waters within five minutes. Daily egg production estimates also were calculated substituting
 river volume for cross-sectional area so that the two methods could be compared. Substituting
 river volume for cross-sectional area may be valuable only when major spawning activity occurs
 during high instream flow periods. Under these conditions, Hassler's method may underestimate
 the number of eggs produced. To perform this substitution requires additional measurements of
 environmental conditions, and several assumptions about the nature of these variables. Since an
 unquantifiable number of eggs is transported to the floodplain under flooding conditions, either
 method will underestimate egg production during the flooding event.
 EFFECTS OF SAMPLING LOCATION. Since 1959, four sampling locations were
 used in the Hassler studies: Palmyra (RM 78.5), Halifax (RM 121), Barnhill 's Landing (RM
 117), and Johnson's Landing (RM 118). Results of the 1991 Barnhill's Landing study and a.
 ii
concurrent study at Jacob's Landing (RM 102) indicate that annual egg production estimates
 will be statistically similar within a 20-mile reach downstream of the spawning grounds, but egg
 viability estimates will be different at each sampling location. Sampling too close to, or too far
 away from, the spawning grounds will overestimate egg viability. The best location to estimate
 overall egg viability is the Barnhill's Landing area.
 WATER TEMPERATURES AND SPAWNING. Water temperatures on the spawning
 grounds can be lowered by naturally-occurring cold fronts, but also by man-caused water
 releases from Roanoke Rapids Reservoir. -Major spawning activity begins after water
 temperatures reach 18°C. Early season water releases from the reservoir can delay spawning.
 Cold fronts or water releases occurring after spawning is initiated can cause spawning to cease if
 water temperatures drop below 18°C for prolonged periods; spawning activity resumes after the
 river returns to at least 18°C. The resulting pattern of springtime water temperatures dictates the
 period of peak spawning. The second week in May is the usual expectation of peak spawning
 activity, but the peak can be earlier or as late as Memorial Day.
 WATER QUALITY AND EGG VIABILITY. Egg viability observed at Barnhill's
 Landing does not appear to be a function of environmental conditions in general, so other factors
 may be involved in influencing egg viability. Water quality farther downstream may play an
 important role in hatching success and larval survival.
 MANAGEMENT IMPLICATIONS. Striped bass spawning activity can be
 man ipulated by water releases from Roanoke Rapids Reservoir upstream. The spawning
 window is much longer than is currently considered by the power company, the U.S. Army
 Corps of Engineers, and the North Carolina Wildlife Resources Commission for management
 purposes. No information is available concerning which spawning period(s) make the greatest
 contribution to successful hatching and subsequent recruitment of young-of-year. Therefore,
 instream flow should be managed to mimic the historical flows as much as possible over the
 longest period of time possible (first of April to end of June) . This management action includes
 providing adequate instream flows during the pre-spawning season (late March through April) to
 prevent downstream water temperatures from warming too quickly, and to provide attracting
 flows for the spawning population . Also, adequate and relatively stable flows should be
 maintained after the peak spawn, since spawning continues through mid-June. Moderate
 seasonal flows are associated with the highest juvenile abundance indices in Albemarle Sound.
 Moderate flow regime guidelines recommended by the Roanoke River Water Flow Committee,
 and implemented by the Corps and power company during the 1988-1991 study, should continue
 to be used.
 iii
TABLE OF CONTENTS
 Page
 EXECUTIVE SUl\flv1ARY ii
 TABLE OF CONTENTS iv
 LIST OF FIGURES v
 LIST OF TABLES vii
 LIST OF APPENDIX TABLES........................................................................................ ix
 IN1RODUCTION 1
 STUDY SITE DESCRIP110N 3
 METHODS 3
 RESULTS............... ........................................................................... ................................ 5
 Egg Production and Viability for 1991...................................................................... 5
 Vertical Heterogeneity 8
 Estimating Egg Production on a Per Trip Basis......................................................... 9
 Estimating Egg Production by Volume 9
 Differences in Egg Production by Location............................................................... 10
 DISCUSSION 12
 Substituting Volume for River Cross-section 12
 Effects of Sampling Location 12
 Comparisons Among Years 1988-1991......... ............................................................ 15
 MANAGEMENT IMPLICATIONS 17
 SUMMARY AND CONCLUSIONS 18
 ACKNOWLEDGMENTS 20
 REFERENCES.......................................... ................................. ....................................... 21
 APPENDIX _............................................... 72
 iv
LISTOF FIGURES
 Figure Page
 1. Drainage area of the Roanoke River Basin................................................................ 26
 2. Roanoke River watershed downstream of Roanoke Rapids Reservoir showing
 the historical sampling stations for striped bass eggs: Palmyra (1959-60),
 Halifax (1961-74), Barnhill's Landing (1975-81,1989-1991), Johnson's
 Landing (1982-87), and Pollock's Ferry (1988) ........................................................ 27
 3. Estimated daily production of striped bass eggs in the Roanoke River
 based on samples collected at Barnhill's Landing, NC, for the period 16
 April to 14 June 1991................................................................................................. 28
 4. Estimated production of striped bass eggs in the Roanoke River based on
 samples collected at BamhilJ's Landing, NC, in 1991, presented as
 percentage of total production 28
 5. Daily viability estimates of striped bass eggs in the Roanoke River
 based on samples collected at Barnhill's Landing, NC, in 1991 ............................... 29
 6. Number of striped bass eggs collected in all nets during each trip, and
 corresponding water temperatures rC) at Barnhill's Landing, NC, for the
 period 15 April to 14 June 1991 30
 7. Air temperature (DC) measured at Barnhill's Landing, NC, for the period
 15 April to 14 June 1991............................................................................................ 31
 8. Hourly record of Roanoke River instream flow (cfs) downstream of the
 Roanoke Rapids Reservoir (USGS data), April-June 1991.... ................................... 31
 9. Relative change in river height (ft) and corresponding surface water
 velocity at Barnhill's Landing, Roanoke River, NC, for the period 15 April to
 14 June 1991 32
 10. Depth (em) of secchi disk visibility in the Roanoke River at Barnhill's
 Landing, NC, for the period 15 April to 14 June 1991. Unfilled bars indicate
 no information available 33
 I I. Changes in conductivity UiS) of Roanoke River waters at Barnhill's Landing,
 NC, for the period 15 April to 14 June 1991 33
 v
LIST OF FIGURES (continued)
 Figure Page
 12. Changes in dissolved oxygen (mg/L) of Roanoke River waters at Barnhill's
 Landing, NC, for the period 15 April to 14 June 1991.............................................. 34
 13. Changes in pH of Roanoke River surface waters at Barnhill's Landing, NC,
 for the period 15 April to 14 June 1991..................................................................... 34
 vi
LISTOF TABLES
 Table Page
 1. Sniped bass daily egg production in the Roanoke River, NC, 1991 estimated
 by the Hassler method and by river discharge five hours previous to sample
 collection... ................................................................................................................. 35
 2. Estimated number of sniped bass eggs spawned in the Roanoke River,
 NC, and the corresponding egg viability, 1959-1987 (Hassler reports),
 1988-1990 (Rulifson reports), and 1991 (this study)................................................. 37
 3. Sniped bass daily egg viability at Barnhill's Landing, Roanoke River,
 NC, 1991 38
 4. Sniped bass egg viability at Barnhill's Landing, Roanoke River, NC, 1991,
 relative to water temperature 40
 5. Sniped bass egg viability at Barnhill's Landing, Roanoke River, NC,
 1991, relative to surface water velocity 40
 6. Sniped bass egg viability at Barnhill's Landing, Roanoke River, NC, 1991,
 relative to time of day 41
 7. Sniped bass egg viability at Barnhill's Landing, Roanoke River, NC,
 1991, relative to dissolved oxygen (mg/L) 41
 8. Sniped bass egg viability at Barnhill's Landing, Roanoke River, NC,
 1991, relative to pH.................................................................................................... 42
 9. Raw data and egg production estimates by nip for sniped bass egg
 samples taken at Barnhill's Landing, Roanoke River, NC, in 1991.. ........................ 43
 10. Daily egg production of sniped bass at Barnhill's Landing, Roanoke River,
 NC, in 1991, estimated by two methods and two depths........................................... 57
 II. Results of statistical analyses (NPARIWAY, SAS 1985) on log-transformed
 data testing whether significant differences exist in the 1991 yearly egg
 production estimates calculated by the Hassler method and nip method using
 cross-sectional area of the river or discharge from the dam five hours
 previous, and surface and oblique sampling techniques 60
 vii
LIST OF TABLES (continued)
 Table Page
 12. Striped bass spawning in the Roanoke River, NC, estimated from surface
 samples by the Hassler and trip methods, and by cross-sectional area (Hassler)
 and river discharge five hours previous, 1991...................... ........................... .......... 61
 13. Summary of striped bass spawning activity in the Roanoke River observed
 at Barnhill's Landing (River Mile 117) and Jacob's Landing (RM 102) from
 15 April to 14 June 1991.............................................................................. .............. 64
 14. Description of variables used in the Jacob's Landing instantaneous egg
 production analysis 66
 15. Results ofregression analyses (PROC REG, SAS Institute 1985) predicting
 instantaneous egg production estimates at Jacob's Landing (RM 102) based
 on egg production estimates from Barnhill's Landing (RM 117) four, eight,
 and 12 hours earlier................. ................................................................................... 67
 16. Results of regression analyses (pROC REG, SAS Institute 1985) predicting
 adjusted instantaneous egg production estimates at Jacob's Landing (RM102)
 (by subtracting Jacob's stage 1 eggs) based on egg production estimates
 from Barnhill's Landing (RM 117) four, eight, and 12 hours earlier 68
 17. Summary of striped bass spawning activity in the Roanoke River observed
 at Pollock's Ferry (RM 105) in 1988, and Barnhill's Landing (RM 117),
 1989-1991 .................................................................................................................. 69
 viii
Table
 LIST OF APPENDIX TABLES
 Page
 A-I. List of counties enumerated in Figure 1................................................................ 73
 A-2. Location of the historical sampling locations used by W.W. Hassler
 and co-workers (1959-1987) and Rulifson (l988-present)................................... 73
 A-3. Hourly sample grid for the 1991 sniped bass egg study at Barnhill's
 Landing, Roanoke River, NC................................................................................ 74
 A-4. Water quality data collected at Barnhill's Landing, Roanoke River, North
 Carolina, from 15 April to 14 June 1991 76
 A-5. Sniped bass egg enumeration and stage of development data collected
 at Barnhill's Landing, Roanoke River, North Carolina, from 15 April
 to 14 June 1991 88
 A-6. Surface net egg collections, Barnhill's Landing, Roanoke River, North
 Carolina in 1991.................................................................................................... 100
 A-7. Oblique net egg collections, Barnhill's Landing, Roanoke River, North
 Carolina in 1991.................................................................................................... 102
 A-8. Number of eggs in all nets, Barnhill's Landing, Roanoke River, North
 Carolina in 1991.. 104
 A-9. Normal and observed rainfall (inches) for the Roanoke River basin
 downstream of Kerr Reservoir (RM 178.7), and basinwide, for April-
 June 1982-1991 (U.S. Army Corps of Engineers data) 106
 ix
INTRODUCTION
 Striped bass (Marone saxatilisi inhabiting Albemarle Sound and its tributaries support
 important recreational and commercial fisheries in coastal North Carolina (Johnson er al. 1986,
 USDOI and USDOC 1986). The major spawning area for Albemarle Sound striped bass is
 located in the Roanoke River, which discharges through several channels into the western end of
 Albemarle Sound (Figure 1). Since the mid-1970s, these fisheries have suffered due to reduced
 numbers of harvestable adults. Population decline may be caused by a number of factors such as
 reduced egg viability (Hassler et al. 1981), poor survival of eggs and larvae due to less than
 optimal stream flow (Hassler reports, Rulifson reports), poor food availability for larvae
 (Rulifson et al. 1992a, 1992b), poor survival of juveniles on the nursery grounds of the western
 Sound, and intense fishing pressure (Rulifson and Manooch 1991).
 Studies on egg abundance and viability have been conducted each year since the mid 
1950s by Dr. W.W. Hassler and co-workers from North Carolina State University in Raleigh.
 These daily records have been an extremely important source of information for reconstructing
 the historical spawning record in relation to exploitation, changes in fishing regulations, and
 man-induced changes in the flow regime and water quality for the Roanoke River watershed.
 Funds provided by the Albemarle-Pamlico Estuarine Study (APES) to East Carolina University
 in the spring of 1988 allowed the continuation of the study. This manuscript follows information
 obtained during the 1988-1990 spawning seasons (Rulifson 1989, 1990, 1992a), and summarizes
 the results of the 1991 striped bass spawning season.
 The manner in which water is released from dams in this watershed, and the subsequent
 physiological and behavioral effects on spawning striped bass, has been scrutinized closely at
 various times since initiation of John H. Kerr Reservoir construction in 1950. This concern was
 one of the reasons for forming a Steering Committee for Roanoke River Studies in 1955. The
 Committee was composed of state, federal, and private agencies and interests whose objective
 was to conduct a comprehensive study of the river in order to minimize multiple use conflicts
 (Hassler and Taylor 1986). The findings of the Committee were discussed in detail by Fish
 (1959). The cooperative Roanoke-Albemarle Striped Bass Studies were initiated in 1955 as part
 of the Steering Committee studies. Original support for these efforts was provided by the
 National Council for Stream Improvement, Weyerhaeuser Company, and Albemarle Paper
 Manufacturing Company. Weyerhaeuser Company continued its support of the studies after
 1958 when the Steering Committee studies were terminated; cooperative field work was resumed
 in 1975 with the U.S. Fish and Wildlife Service (FWS) and North Carolina Division of Marine
 Fisheries (NCDMF) under the auspices of the Anadromous Fish Conservation Act (pL 89-304).
 In the mid-1980s, water quality and watershed management of the lower Roanoke River
 basin were again key issues for several reasons : the initiation of the Albemarle-Pamlico
 Estuarine Study; the controversy over interbasin transfer of water for municipal use by the City
 of Virginia Beach; the establishment of the Roanoke National Wildlife Refuge within the
 floodplain of the lower Roanoke River; relicensing of Roanoke and Gaston Dams (license
expiration in year 2(01); and the continued decline of the Roanoke/Albemarle striped bass stock.
 These events all had the common concern of how the flow regime is managed by the system of
 reservoirs located in the Piedmont region of the watershed, especially during the spring spawning
 season.
 In 1988, an ad hoc group was formed to investigate the modification of Roanoke River
 instream flow below Roanoke Rapids Dam for striped bass and other downstream resources.
 The Roanoke River Water Flow Committee (Flow Committee) was comprised of 20
 representatives of State and Federal agencies and university scientists. The purpose of the
 Committee was to gather information on all resources of the lower watershed and recommend a
 flow regime that was beneficial to the downstream resources and their users. Striped bass as a
 resource received the most attention because of its great social and economic importance t~ this
 region, and because of the extensive data base established by Dr. Hassler. Detailed descriptions
 of the Flow Committee findings were presented elsewhere (Manooch and Rulifson 1989;
 Rulifson and Manooch 1990a, 1991).
 Also in 1988, a North Carolina Striped Bass Study was authorized by the U.S. Congress
 in the reauthorization of the Atlantic Striped Bass Conservation Act (p.L. 100-589) to conduct a
 study of factors affecting the decline of striped bass in the Albemarle Sound and Roanoke River
 basin. In 1989, a North Carolina Striped Bass Study Management Board was formed to
 undertake these studies, develop management recommendations, and submit the study results and
 recommendations to Congress and the States of North Carolina and Virginia (North Carolina
 Striped Bass Study Management Board 1991) . Findings of substantial habitat degradation,
 especially water quality, led to recommendations of a moratorium on any additional wastewater
 discharges or consumptive water withdrawal until a basin-wide comprehensive water study can
 be completed (USFWS 1992).
 At the present time, the manner in which waters are released from Roanoke Rapids Dam
 is governed by a tri-party agreement involving the U.S. Army Corps of Engineers (Corps) ,
 Virginia Power (VEPCO), and the North Carolina Wildlife Resources Commission (NCWRC).
 Provisions for minimum flows from the reservoir were established by the Memorandum of
 Understanding (MOU) signed in 1971. In the original agreement, no guidelines were given for
 maximum flows or for the manner in which the average daily discharge is derived. For example,
 under present guidelines the dam operator can double or cut in half the rate of discharge through
 the turbines every hour to optimize on-demand hydropower generation. A discharge of 5,000 cfs
 (cubic feet per second) can increase to 10,000 cfs in an hour, and then to 20 ,000 cfs after two
 hours . These sudden changes in the flow regime result in dramatic changes in water temperature
 and water depth on the spawning grounds within a several-hour period. The effects of reservoir
 discharge on striped bass spawning activity have been documented (Rulifson and Manooch
 1990b, Zincone and Rulifson 1991). In 1989, the Corps agreed to a four-year trial period of
 modified flows from 1 April to 15 June as per the recommendations of the Flow Committee
 (Manooch and Rulifson 1989), after which the effects of the modified flow regime on striped
 bass and other natural resources downstream would be assessed.
 2
The study described herein was undertaken with several objectives: 1) to continue the
 data base established by Dr. Hassler; 2) to identify potential sources of bias in Hassler's
 methodology in estimating egg production and viability; and 3) to determine the relationship
 between intensity of striped bass spawning (as measured by egg production) and water releases
 from the Roanoke Rapids Reservoir. Results of the 1991 study are compared with those
 obtained in the first three years of the study. Management implications and recommendations
 are presented.
 STUDY SITE DESCRIPTION
 The Roanoke River is a major coastal floodplain river originating in the Appalachian
 Ridge in Virginia and discharging into the western end of Albemarle Sound in North Carolina
 (Figure 1). The watershed encompasses 9,666 square miles (25,033 km2) , making it the largest
 basin of any North Carolina estuary (Giese et al. 1985). Waters descend 2,900 feet from the
 origin to the estuary, a distance of 410 miles.
 Instream flow of the Roanoke River is highly regulated by a number of reservoirs
 upstream: in Virginia, Smith Mountain Lake, Philpott Lake, Leesville Lake, John H. Kerr
 Reservoir, and Lake Gaston; and Lake Gaston and Roanoke Rapids Lake in North Carolina. Of
 these, the Roanoke Rapids Reservoir located at River Mile (RM) 137 exerts direct influence on
 instream flow of the lower river; approximately 87% of the flow to the coastal watershed is
 provided by its discharge (Giese et al, 1985). Average annual discharge of the river at Weldon,
 North Carolina (USGS gage), is 8,120 ±8.622 cfs (1912-1990, Rulifson et a!. 1992b). The
 watershed itself contributes approximately 50% of the freshwater input to Albemarle Sound, and
 therefore has a major impact on the coastal zone of northeastern North Carolina.
 The primary spawning ground for Albemarle striped bass is located in the Roanoke River
 between Halifax (RM 120) and Weldon (RM 130), North Carolina. The historical spawning
 grounds farther upstream were blocked by construction of the Roanoke Rapids Dam (RM 137) in
 1955 (McCoy 1959). Spawning activity begins in April and is completed by mid-June (Hassler
 et al. 1981). Once spawned. the fertilized eggs develop to the hatching stage as they are
 transponed downstream by currents. After hatching, the larvae are transported through the
 distributaries of the delta into the historical nursery grounds of western Albemarle Sound
 (Rulifson et al, 1992a).
 METHODS
 The field station in 1991 was located at Barnhill's Landing (RM I17), the site of W.W.
 Hassler's sampling efforts during the period from 1975 to 1981 and the 1989 and 1990 egg
 studies (Rulifson 1990, 1992a). This area is located (Appendix Table A-2) approximately three
 3
miles below the historical spawning grounds and about 12 river miles upstream of the Pollock's
 Ferry site used in the 1988 (Rulifson 1989) study (Figure 2). Sampling was initiated on 15 April
 and was terminated on 14 June 1991.
 Procedures for field sampling and sample workup were similar to those used by W.W.
 Hassler to ensure compatibility of the data sets. Many of the tables and figures presented in my
 study are similar to Hassler's for purposes of comparison.
 Sampling for striped bass eggs was conducted six times daily at four-hour intervals
 (0200, 0600, 1000, 1400, 1800, and 2200 hours) by trailing paired lO-inch diameter nets
 constructed of 500-um nitex mesh (6:1 tail-to-mouth ratio) from a small aluminum boat anchored
 in mid-stream. A solid sample jar attached to the tail of each net was used to retain collected
 eggs. Two sample efforts of five-minute duration were made: the first sample six inches below .
 the surface (Hassler's method), and the second sample near the bottom. This procedure alJowed
 comparisons of egg density at the surface with the abundance of eggs near the bottom. A
 flowmeter with slow speed propeller was attached to the bongo frame to estimate the theoretical
 volume of water filtered, This methodology produced two estimates of egg production: 1) an
 estimate of egg density per unit of water filtered: and 2) an estimate of total eggs in the cross 
sectional area of the river (Hassler's method). The cross-sectional area of the river at the
 sampling site was determined for the range of water levels encountered during the study. River
 stage, air and water temperatures, dissolved oxygen, conductivity, pH, total dissolved solids, and
 water velocity were recorded for each sample. Instruments used to measure environmental
 parameters were calibrated periodically according to U.S. Environmental Protection Agency
 (USEPA) standard methods. Secchi visibility depth was recorded for all samples taken during
 daylight hours.
 The unpreserved samples were returned to the field station for immediate examination.
 Eggs collected by both nets were enumerated and averaged for each surface tow and each bottom
 tow. For each sample, all eggs were examined to determine viability and stage of development.
 Egg viability was determined as described by Hassler et al. (1981): each was examined to
 determine the status of the embryo (development), yolk and oil globules (intact), perivitelline
 space (cloudy or clear), and whether the chorion was broken or intact. Viable eggs were staged
 under a dissecting microscope using the criteria established by Bonn et al. (1976) . Stage 1
 included eggs less than 10 hours old. Stage 2 eggs were those 10 to 18 hours old. Stage 3 eggs
 were 20 to 28 hours old, and Stage 4 eggs were 30 to 38 hours old. Stage 5 were eggs 40 hours
 and older, and newly-hatched larvae. Stage of development was based on an assumed water
 temperature of 17°C since this is the only published photographic and written description
 available. Eggs spawned at water temperatures greater than this value will develop faster and
 hatch earlier (Shannon 1970).
 Data were entered into the mainframe computer at East Carolina University and analyzed
 using the Statistical Analysis System, Version 5 (SAS 1985). The estimated number of striped
 bass eggs passing the sampling station was calculated on a daily basis using the equation
 4
developed by Hassler:
 (I) N = 514.29 XY,
 where N = the estimated number of striped bass eggs spawned during the 24-hour period; X =
 the mean number of striped bass eggs collected per surface sample during the 24-hour period (12
 samples maximum); and Y = the cross-sectional area of the river in square feet for mean river
 stage during the 24-hour period. The constant 514.29 was derived from the number of five 
minute intervals in a 24-hour period (288) multiplied by the relationship of 1.0 f~ of river area to
 the mouth opening of the l O-inch diameter egg net (0.56 f~, equaling a ratio of 1:1.785714).
 Only surface samples were used in the daily egg production estimates so that data were
 comparable to Hassler's database.
 Statistical analysis of the egg count data was performed using the SAS UNIVARIATE
 procedure to determine distribution of the data. Normal probability plots indicated that
 transformation of the count data was required; natural log transformation reduced skewness and
 kunosis better than square root transformation.
 In 1991, a concurrent egg study was conducted downstream at Jacob's Landing (RM 102)
 just upstream of the Highway 258 bridge to provide information about the possible effect of
 sampling location on egg production estimates and egg viability. Methods were identical to
 those described for Barnhill's Landing. Results were described in detail previously (Rulifson
 1992b); however, a brief summary of the results is presented in this report.
 RESULTS
 About 95% of the possible samples (1,382 of 1,448) were examined in 1991. The
 remainder were not collected because of inclement weather or equipment failure.
 Egg Production and Viability for 1991
 The estimated number of striped bass eggs produced in 1991 was 1,837,208,211 (n=6I,
 S.D. 65,787,080) from a total of 10,467 eggs collected in surface nets. Samples were first taken
 on 15 April; the first eggs appeared in Barnhill samples on I7 April (Table 1). Whether spawning
 occurred earlier than 15 April is unknown. Considering only the data obtained for the sampling
 period, spawning activity in 1991 appeared to start later than that observed in 1988 (12 April)
 and 1989 (16 April), and but earlier than 1990 (24 April). Spawning activity continued through
 12 June 1991 for a 57-day spawning window; sampling was terminated on 14 June so any
 spawning in late June was not monitored. This late spawning activity was prolonged compared
 to 1988 (2 June) and 1989 (9 June), but similar to 1990 (12 June). In 1991, there were 41
 consecutive days of spawning activity, a longer period than that observed in 1988 (27 days) and
 1989 (23 days), but shorter than 1990 (50 days).
 5
During the 1991 spawning season, there were three major and several minor spawning
 events. The three major events occurred near mid-May: 8-9 May, 11-12 May, and 14 May
 (Figure 3). Approximately 50% of the yearly egg production estimate was reached by 13 May,
 75% of the total by 15 May, and 90% of the total by 25 May (Table I, Figure 4).
 The egg viability estimate for 1991 was 55.36%, the third highest estimate obtained at
 Barnhill's Landing and the sixth highest since 1974 (Table 2). No seasonal trend in egg viability
 was evident (Table 3, Figure 5), and vertically there was <1% difference in surface and bottom
 viability estimates.
 Relationships between surface egg viability and various environmental parameters were
 determined using several statistical procedures. Striped bass eggs were collected in surface nets
 of 191 trips. Egg viability data from those trips were not normally distributed (Kolmogorov-D
 statistic, SAS 1985). Data were transformed using an arcsin square root function, then subjected
 to a correlation analysis to determine those environmental variables significantly related (alpha
 0.05) to egg viability. Appropriate environmental variables and egg viability were subjected to a
 weighted least squares analysis, with the analysis weighted by the number of eggs in the sample. .
 Results indicated that none of the environmental variables explained much of the variability in
 viability of eggs collected at the surface or by oblique tows. For surface egg viability, surface
 water velocity and dissolved oxygen were significant contributors to a linear model (df=2, 189;
 F=17.45; P=O.OOOl; R2=0.16; Mallow's statistic=4.ll). Variability in oblique egg viability was
 partially explained by an inverse relationship with dissolved oxygen and river stage (df=2, 206;
 F=14.88 ; P=O.OOOl; R2=0.13; Mallow's statistic=3.61). Poor predictability of viability based on
 environmental factors was expected since water quality and instream flow were quite stable
 during the major egg production period.
 A total of 9,593 eggs was examined throughout the season to determine stage of
 development; nearly all examined were in the early developmental stages. Approximately 62%
 of the eggs were less than 10 hours old. An additional 38% were 10-18 hours old, and only nine
 eggs (0.09%) were 20-28 hours into their development. No post-hatch striped bass larvae were
 observed in the samples.
 Water temperatures were quite warm throughout the spring spawning activity (Figure 6)
 caused by the record-breaking hot weather prevailing at the time (Figure 7). One striped bass
 egg was collected from a single sample at the Scotland Neck bridge (NC Hwy. 258) while
 training the field crew prior to 15 April. At that time, the water temperature was 17°C. During
 the actual sampling season, water temperatures ranged from 12.0 to 26.0° C during the study. As
 in years previous, the major spawning activity was initiated after water temperatures reached
 18°C (Figure 6). Approximately 94% of all eggs were collected in waters between 18°C and
 21.9°C (Table 4). Daily water temperatures averaged above 18°C after 25 April. Environmental
 data suggest that river temperature was stabilized b.y reservoir discharge while daily air
 temperatures exhibited typical diurnal variability. The correlation coefficient for the water
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 temperature-air temperature relationship was 0.59 (n=358; P=O.OOOI). No trend in egg viability
 related to water temperature was evident.
 Surface water velocities ranged from a high of 123 em/second on 17 April to a low of 49
 em/second on 11 June corresponding to changes in river depth at Barnhill's Landing (Figure 9).
 A high positive correlation coefficient of 0.88 (n=347; P=O.OOOI) between river stage and water
 velocity was evident. The moderate instream flow conditions that prevailed during the major
 period of spawning activity resulted in 92% of the eggs collected at surface water velocities of
 60-79 cm second (Table 5). An additional 3.8% of the eggs were collected at velocities of 40-59
 em/second, and less than one percent of the eggs were caught in velocities of 100 em/second or
 greater.
 Seasonal changes in the water release schedule at Roanoke Rapids Dam influenced
 changes in surface water velocities and surface water temperatures. Heavy basinwide spring
 rains in March 1991 (3.4 inches above normal) resulted in high inflow to Kerr Reservoir, and
 increased water releases downstream. Reduced inflow to Kerr Reservoir in early April allowed
 the Corps to reduce flows downstream beginning 20 April, 20 days after the Negotiated Flow
 Regime of the Flow Committee should have been implemented. The Negotiated Flow Regime
 provides a step-down flow range from 1 April to 15 June designed to more closely represent the
 historial river flow prior to impoundment (Kerr Reservoir construction was initiated in 1950).
 The Corps of Engineers was able to provide an appropriate water release schedule to allow
 Virginia Power Company to maintain water releases from Roanoke Rapids Reservoir within the
 Flow Committee guidelines beginning 21 April (Figure 8). The moderated instream flow
 resulted in downstream water temperatures reaching 18°C early in April and remaining at or
 above this temperature during May and June (Figure 7).
 Initially, the depth of secchi disk visibility was low concordant with high reservoir
 discharge. Lowest values (30 em) were obtained on 15 April, after which visibility increased to
 70-80 em (Figure 10). Low values indicated increased turbidity, a result of changing water level
 in the river. Although low visibility values corresponded with river fluctuation events, the
 overall correlation coefficients indicated a significant inverse relationship between secchi
 visibility and river stage (n=288, r=-0.29), and secchi and water velocity (n=228, r=-0.27).
 Conductivity of Roanoke River waters flowing past Barnhill's Landing was low
 throughout the study, ranging between 7 and 10 mS (Figure 11).
 Egg distribution patterns in samples indicated a diurnal spawning pattern. Egg
 abundance was lowest in afternoon and evening samples , and highest between 0200 and 1000
 hours (Table 6). Pinpointing the exact upstream location of major spawning activity is difficult.
 However, a general estimation can be made using the stage of egg development and water
 velocity. Nearly 62% of the eggs were <10 hours old (assuming a water temperature of 17°C),
 and an additional 38% were 10-18 hours old. About 9.2% of the eggs were collected in water
 velocities of 60-80 em/second, The mean water velocity for most of the spawning activity was
 7
approximately 70 em/second (2.3 ft/second). Thus, major spawning occurred from about RM
 132 near Weldon to just upstream of Barnhill's Landing, perhaps RM 119.
 Dissolved oxygen levels in Roanoke River waters remained above 7.0 mgIL for most of
 April and May, but in general exhibited a decreasing trend during the season to a level between
 6.0 and 7.0 mg/L in June (Figure 12). Most (96%) of the eggs were collected at dissolved
 oxygen levels of 7.0-8.9 mgIL (Table 7).
 The pH of Roanoke River waters remained above 7.0 for most of the study (Figure 13).
 Nearly 85% of the eggs were collected in waters of 7.74 pH or higher, and more than 33% were
 collected at pH values 8.0 and greater (Table 8).
 Vertical Heterogeneity
 During each sampling trip , paired-net egg samples were taken both at the surface and
 near the bottom for five-minute periods so that differences in the vertical distribution of eggs
 could be quantified. Egg production for each trip was calculated by using the ratio of the
 opening of the egg net to the estimated cross-sectional area of the river multiplied by the average
 number of eggs caught in either the surface nets or bottom-towed nets in five minutes.
 Sample replications (net A, net B) were tested to determine normality of the data and
 ascertain whether both samples collected similar numbers of eggs. A total of22,108 eggs was
 collected in all nets: 10,467 eggs in surface tows, and 11,641 in oblique tows. Surface net A
 collected 5,250 eggs (n=346; mean=15.17; S.D.=38.45), and surface net B collected 5,217 eggs
 (n=346; mean=15.08; S.D.=41.36). The seasonal difference between surface net collections was
 only 33 eggs . A similar pattern was observed for bottom tows. Net A collected 6,055 eggs
 (n=345; mean=17.55; S.D.=49.30) compared to 5,586 eggs for net B (n=345; mean=16.19;
 S.D.=39.69). The seasonal difference between paired bottom collections was 469 eggs.
 No significant diffferences were observed between replicate surface samples, or between
 bottom replicate samples . The actual difference in numbers of eggs between the paired surface
 nets A and B was subjected to the UNIVARIATE procedure; results indicated non-normal
 distribution of the data. Data transformation reduced kurtosis of the data from 37.3 (raw data) to
 1.4 (log values) . A similar procedure was used for bottom sample data. Differences in the log 
catches of the two surface nets were not significant (n=346; S=122176; P>IZI=0.31); a similar
 result was obtained for bottom catches (n=345; S=119098; P>IZI=0.97).
 Differences between paired observations of surface and bottom egg collections were not
 significant. Results using log-transformed data indicated that egg collections of bottom net A
 and surface net A were similar (n=345, 346; S=-120545; P>IZI=0.65); the same result was
 observed for the B nets (n=345, 346; S=123220; P>IZI=0.13). Overall , the average numbers of
 eggs in bottom nets and surface nets were statistically similar (n=345 , 346; S=121846;
 P>IZI=O.34).
 8
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 Estimating EggProduction on a Per TripBasis
 The original Hassler method of estimating daily egg production (Equation 1 above)
 produced a point value but no estimate of data variability. The trip method of calculating egg
 production was performed by estimating the number of eggs in the river at the time the sample
 was collected, then averaging the expanded numbers over the 24-hour period to estimate daily
 production. The result of this method is a daily egg production estimate and an estimate of
 variability for the number.
 Egg production estimates on a per trip basis were calculated for surface samples, oblique
 samples, and all samples combined, then compared statistically to those values obtained using
 the Hassler (daily) averaging method. Table 9 lists the estimated egg abundance (in a five  
minute period) for the six sampling periods each day. Table 10 presents the estimated daily egg
 production for surface, oblique, and all samples calculated by the Hassler and trip methods. As
 expected, results of analyses (UNIVARIATE) using the paired daily egg production estimates in
 Table 10 were not significantly different. However, in this instance we are particularly
 concerned with whether the yearly egg production estimates are significantly different from one
 another. The daily egg production estimates were analyzed using NPARIWAY. Results
 indicated that the yearly egg production estimates for 1991, calculated by the Hassler and trip
 methods, using surface, oblique, and combined egg data, were not significantly different (Table
 11).
 Estimating Egg Production by Volume
 Estimates of striped bass daily egg production can be calculated substituting volume for
 cross-sectional area of the river, and knowing the water velocity at the time of sample collection.
 The equation is
 (river discharge x 24 hrs x 60 min x 60 sec)
 (2) Daily egg production =sample eggs x _
 (water velocity x 0.9) x net area x 300 sec
 where
 river discharge =ftJ/sec, recorded upstream several hours previous to sample collection;
 average water velocity = ft/sec x 0.9 (to correct for surface measurement); and
 net area = 0.56 fro
 A data set of hourly instream flow records from the USGS gage was merged with the egg
 collection data so that each trip had seven possible values of flow : the actual flow measured at
 the time and date of the trip (FLOW), flow recorded one hour previous to the trip (FLOWLl),
 and so on through flow recorded six hours previous to an egg collection trip (FLOWL6) .
 9
Correlation analysis was used to determine which record of flow had the highest linear
 correlation with water velocity measured at the surface during sampling, and river stage at
 Barnhill's Landing. In 1991, water velocity was highly correlated with discharge, ranging from a
 low Pearson r value of 0.908 for FLOW, to 0.912 for FLOWL5; the value for river stage and
 FLOWL5 was r=O.970. Thus, instream flow measured five hours previous to sample collection
 was used in volumetric egg production estimates.
 In 1991, the Hassler estimate of yearly egg production by cross-sectional area (1.837
 ±0.062 billion eggs) was not significantly different (Table 11) from the Hassler estimate by
 volume (2.082 ±0.07l billion). Table 12 provides a daily comparison of both egg production
 estimates. The two estimates are never the same except in cases where no eggs were collected
 over the 24-hour period. Table 12 also lists the mean daily values of river characteristics used in
 estimating egg production by cross-section and by volume. Yearly egg production estimates
 calculated by the trip method (Table 12) were statistically similar (Table II) to the Hassler
 method estimates.
 Differences in Egg Production by Location
 Statistical analyses were conducted on natural log-transformed data to ascertain how
 sampling location relative to striped bass spawning activity might influence the yearly egg
 production and egg viability estimates . Table 13 compares the results of egg monitoring at
 Barnhill's Landing to results of a similar study at Jacob's Landing 15 river miles downstream.
 Note that the total number of eggs counted at each location was similar; the yearly egg
 production estimates were not significantly different. This phenomenon is interesting
 considering that the number of days of continuous spawning activity downstream was 10 days
 longer than upstream, and the egg viability estimate was nearly 70% compared to the upstream
 estimate of 55 %. It seems reasonable 10 suspect that some unknown amount of spawning
 activity was occurring between the two sampling locations. This hypothesis is supported by the
 presence of eggs <10 hours in development, while most viable eggs examined at the Jacob's
 Landing site downstream were over 10 hours old (Table 13).
 To interpret the Jacob's Landing egg production estimate, several assumptions were
 required. It was necessary to assume that any relationships between egg production estimates for
 Barnhill's Landing (RM 117) and Jacob's Landing (RM 102) represented some constant mean
 process. Egg production estimates for each location were reduced 10 the smallest units so that
 each unit could be accounted for in the analyses . For example, the instantaneous egg production
 estimate at Barnhill's Landing was made up of all the dead eggs in the sample, plus four live-egg
 categories: Stages 1-4 (Table 14). The various units contributing to the Jacob's Landing
 instantaneous egg production estimate were unknown . Also, the egg transport time between the
 two sites was not known, so three separate analyses were performed using travel times of 4, 8
 and 12 hours .
 Regression analyses used the Jacob 's Landing instantaneous egg production estimate
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 (lJIPROD) as the dependent variable. Stage 1 eggs collected at Jacob's Landing (USTl) were
 assumed to originate from spawning activity between the two sites. The remainder of the
 Jacob's egg production estimate was assumed to be made up of eggs spawned above Barnhill's
 Landing: Stage 1 eggs (LBSTl), Stage 2 eggs (LBST2), Stage 3 eggs (LBST3), Stage 4 eggs
 (LBST4), and dead eggs (LBDPROD). Dead eggs collected at Jacob's Landing originated from
 upstream of Barnhill's Landing and between the two sites. Since there was no way to estimate
 the number of dead eggs from each location, the dead eggs collected at Jacob's (LJDPROD)
 were assumed to originate from spawning activity downstream of Barnhill's Landing.
 Initial regression analyses used the full data set. Approximately one-half of the records
 could not be used because of zero eggs collected at one or both stations. Visual examination of
 plots of residual vs. predicted values identified outliers in the data set In all cases these outliers
 were caused by very low (less than 10) eggs in Jacob's Landing samples, or no eggs collected at
 Barnhill's Landing. These observations were removed from the data set, and the data set was
 reanalyzed.
 The resultant fun regression analyses accounted for 88% of the variability in the Jacob's
 Landing egg production estimates (Table 15). Interestingly, the full models of alI three analyses
 for the 4, 8, and 12-hour travel times indicated that egg production between the two sites is not
 significant, and dead eggs at Barnhill 's Landing do not contribute significantly to the Jacob's
 estimated egg production. Also, the number of Stage 3 eggs (20-28 hours old) found at
 Barnhill's Landing are few and do not contribute to an overall egg production rate at Jacob's
 Landing (Table 15). The 8-hour egg transport time resulted in an intercept closest to zero;
 significant contributors to the model included Barnhill Stage 1 and Stage 2 eggs along with dead
 eggs produced between the two sampling sites. For a 4-hour egg travel time , significant
 contributors to the analysis included Barnhill Stage 2 eggs and dead egg production between the
 two sites. However, the Durbin-Watson statistic to determine autocorrelation of the data was
 close to the 0.05 significance level (P=0.067), suggesting that the 4-hour lag time may be
 inappropriate. Results of the 12-hour egg transport analysis were similar to those of the 8-hour
 egg transport model (Table 15). A reduced model using only Jacob's Stage 1 eggs and the
 Barnhill total instantaneous egg production estimate was not a good predictor of Jacob's egg
 production estimates.
 Since Stage I eggs coIIected at Jacob's Landing did not contribute significantly to any of the
 full analyses, the Jacob's egg production estimates were adjusted by subtracting the Jacob 's
 Stage 1 eggs. Results of the Jacob's adjusted instantaneous egg production estimates indicated
 that both the 8-hour and 12-hour models were similar (Table 16). The few Stage 3 eggs from
 upstream did not contribute significantly to downstream egg production estimates. The 12-hour
 model indicated that dead eggs from upstream were important contributors to the downstream
 estimate, but upstream dead eggs were not significant in the 8-hour model.
 Examination of the residuals indicated the possibility of other variables (e.g., water
 temperature) not accounted for in the full model. These additional variables remain to be
 11
In 1981, Hassler (Hassler, Luempert and Mabry 1982) sampled from 29 April to 29 May and
 reponed an egg viability of 73.7% (Table I). Kornegay 's efforts one mile downstream began on
 21 April and ended 15 May, resulting in an egg viability estimate of 69%. These two egg
 viability estimates were within five percent and so appeared similar. The similarity was not so
 striking when daily viability estimates were examined. With one exception, daily egg viability
 estimates for Johnson's Landing in 1981 were consistently higher than for the downstream
 Barnhill's Landing site. These results supported the egg viability bias hypothesis described
 above. However, the daily egg production data were very similar and showed peak spawning
 activity around 29 April and again around 9-15 May. Coincidentally, spawning activity peaks in
 1981 occurred just after sudden changes in river flow: a 4,000 cfs increase on 22-24 April and a
 similar decrease on 7-8 May. Minor spawning peaks in mid and late May of 1981 exhibited this
 similar pattern.
 In 1982, Hassler (Hassler and Taylor 1984) sampled at Johnson's Landing from 3 May to
 2 June; spawning activity had started prior to sampling efforts. Hassler's egg viability estimate
 for 1982 was 71.93% (Table 1). Thirteen miles downstream at Pollock's Ferry, Kornegay (1983)
 sampled from 20 April to 14 May and obtained an egg viability estimate of 76.47%, a value
 within five percent of the Hassler estimate. Again, the lower value obtained at Johnson's
 Landing and the higher value estimated downstream at Pollock's Ferry supported the sampling
 location bias hypothesis.
 The 1982 egg viability estimates calculated on a daily basis indicated a high degree of
 similarity between the two stations. Even though the sites were 13 miles apart, egg transport
 time may be as short as 7.6 hours assuming a uniform water velocity of 2.5 feet/sec (75 em/sec).
 Thus , egg viability estimates calculated on a daily, rather than per sample, basis may not be
 adequate to determine egg viability differences between the two sites. Both daily egg production
 estimates for 1982 revealed similar patterns in spawning activity: peak spawning occurred
 approximately 9-11 May just after river flow dropped from 11,600 cfs to about 6,300 cfs on 7-8
 May. Kornegay (1983) attributed the spawning peak to increases in water temperature to 18AaC.
 In 1983, Hassler (Hassler and Taylor 1984) sampled at Johnson's Landing from 6 May to
 12 June and estimated the overall egg viability as 33.29% (Table 2). Kornegay and Mullis
 (1984) sampled at Pollock's Ferry from 24 April to 31 May and reponed egg viability at 40.48%.
 Again, the higher egg viability estimate downstream supported the sampling location bias
 hypothesis.
 Trends in daily egg viability data for 1983 were obscured because of extensive spring
 flooding , although higher daily egg viability later in the season seemed to coincide with lower
 river flow. Row models developed by the COIPS show that the lower watershed will flood under
 prolonged periods of 8,000 cfs river flow or more (M. Grimes, Wilmington District, Corps of
 Engineers, personal communication).
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 Similar to the 1981 and 1982 spawning seasons, peaks in the 1983 striped bass spawning
 activity coincided with changes in river flow. During the latter half of April and early May,
 instream flow approached 26,000 cfs, then dropped to about 20,000 cfs on 7 May. The first ,
 though minor, spawning peak was observed on 9 May. A second., slightly larger, spawning peak
 occurred on 15-17 May during a rather stable period of river flow. A third, larger peak on 24-26
 May coincided with dropping water levels initiated on 25 May. The major peak spawn, which
 occurred on 30 May, coincided with lowest water levels of the season established two days
 earlier.
 Comparisons Among Years 1988-1991
 The four years of striped bass spawning studies conducted for the Albemarle-Pamlico
 Estuarine Study documents the predictability of striped bass spawning activity. Although the
 actual timing of peak spawning activity is variable from year to year, the sequence of spawning
 events related to water temperature and river flow is similar among years. Table 17 summarizes
 the major aspects of spawning in the lower Roanoke River watershed.
 The number of spring days used by striped bass for spawning (the spawning window) is
 longer than generally acknowledged by state fishery agencies, the Corps, and Virginia Power
 Company. In my studies, egg sampling was initiated each year in mid-April, and eggs first
 appeared in samples within one week. Hassler's egg sampling schedule was variable each year
 (Table 2) , depending on the movement of adults upstream from Albemarle Sound. This
 sampling design resulted in 14 years in which Hassler collected eggs on the fITSt day of sampling
 (Manooch and Rulifson 1989, Appendix Table B-8). Also, Hassler's reports indicated that egg
 sampling was terminated after five consecutive days of no eggs in the samples, but the data for
 10 of those years ended with no "zero catches", indicating that spawning activity was still
 occurring at termination of sampling. This assumption is reasonable considering that spawning
 activity occurred through 12 June in 1990 and 1991. Hassler 's studies, combined with results
 from 1988-1991, indicate that striped bass spawning encompasses at least 50 days, with
 additional sporadic spawning by a few individuals prior to mid-April and after mid-June.
 Major spawning activity is initiated after water temperatures reach 18°C, but limited
 spawning activity occurs at water temperatures as low as 14°C. Most eggs are collected between
 18°C and 21.9°C. The exception to' this trend appears to be in those years in which water
 temperatures increase rapidly while the spawning run of adult striped bass is still far
 downstream. When water temperatures increase gradually, major spawning activity occurs
 within days after reaching 18°C.
 Water temperatures on the spawning grounds can be lowered by naturally-occurring cold
 fronts but also by man-caused water releases from Roanoke Rapids Dam, thus affecting
 spawning activity. Water temperatures may reach 18°C early in the season, and spawning
 activity may commence, but passing cold fronts or reservoir releases of cold water may rapidly
 lower spawning grounds water temperatures below 18°C, causing cessation of spawning. This
 15
same phenomenon has been documented for striped bass spawning in the Annapolis River,
 Nova Scotia; rapid temperature drops to IS-16°C caused spawning to cease (Williams 1978).
 The resulting pattern of springtime water temperatures directly affects the period of peak
 spawning. The third week in May is the usual expectation of peak spawning activity; however,
 the peak can be as early as the second week in May (1988, 1991) or as late as Memorial Day
 weekend (1989). In 1988, water temperatures were warm earlier in the season due to low flow
 conditions in late March and early April. In 1989, flooding conditions caused water
 temperatures to increase late in the season.
 Water quality near the spawning grounds is not a problem for egg viability, but may play
 an important role farther downstream. Most eggs appeared in river waters with pH values of 7.0
 or higher (Table 17). Roanoke River waters become more acidic farther downstream, especially
 during periods of flooding , caused by flushing and/or draining of backwater sloughs and
 floodplain areas. The 1988 Pollock's Ferry data collected at RM 105 indicate how pH values
 decrease in downstream areas . Acidic waters cause egg and larval mortality; the presence of
 high levels of aluminum characteristic of North Carolina coastal streams seems to hasten death
 (Dorton 1991). Dissolved oxygen levels are adequate downstream of the spawning grounds, but
 may be a problem farther downstream when swamp waters high in organic matter are flushed
 into the system. Most eggs are collected in waters of dissolved oxygen content between 7.0 and
 8.9 mgIL; however, in 1988 most eggs collected at Pollock's Ferry were in waters between 5.0
 and 7.9 mgIL (Table 17). Low dissolved oxygen values during spawning have been documented
 for the lower river, delta, and western Albemarle Sound (Rulifson et al1992a).
 Egg viability observed at Barnhill's Landing does not appear to be a function of
 environmental conditions in general, so other factors may be involved in influencing observed
 egg viabilities . One possibility concerns whether females are producing less viable eggs due to
 poor environmental quality as the eggs are forming in the ovaries. This hypothesis is known as
 "habitat squeeze", first proposed by Coutant (1985) for Tennessee reservoirs . Sampling in
 Albemarle Sound during summer indicates that most areas of the Sound exceed the preferred
 tolerance levels of striped bass. A second possibility is that hourly shifts in egg viability reflect
 the age structure of the spawning population. Considerable controversy exists about whether
 first-time spawning females can produce eggs of the same quality as females weighing 10
 pounds or more. If viability is correlated with fish age, then lower egg viability would suggest
 younger females participating in the spawning act; higher viability would suggest older females
 releasing eggs. NCRWC personnel believe that younger females come upstream earlier to
 spawn, followed by older females later in the season (K. Nelson, personal communication). If
 egg viability was related to the age distribution of the spawning population, then a seasonal
 progression of lower to higher egg viability should be observed. No such trend was apparent in
 the 1988-1991 studies.
 Although "rock fights" -- the spawning act -- are observed throughout the day, most egg
 deposition occurs in the evening. This aspect is reflected in the sampling times at which most
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 eggs are collected at Barnhill"s Landing: 0200-1000 (Table 17). Eggs spawned in rock fights
 observed just downstream of the Weldon landing near dusk, and transported at an average rate of
 70 em/second (2.3 feet/second, or 1.5 miles/hour) should appear at Barnhill's Landing within
 eight hours (i.e., 0200-0600 hours). Eggs spawned upstream of Weldon at the same time would
 arrive at the collection site later (e.g., 1000), and would be 10-18 hours old in development.
 Management Implications
 Striped bass spawning activity in the lower Roanoke River can be manipulated by water
 releases from Roanoke Rapids Reservoir upstream. The spawning window is much longer than
 is currently considered by VEPCO, the Corps, and the NCWRC for management purposes.
 However, there is little evidence to ascertain which period(s) of the spawning season makes the
 greatest contribution to successful hatching and subsequent recruitment of young-of-year striped
 bass to the year class forming in Albemarle Sound. YOY recruitment may be: (I) from the
 relatively few numbers of surviving eggs spawned throughout the season; (2) from the
 tremendous number of eggs released during the peak spawn period; or (3) from the progeny of
 only several females spawned at a fortuitous time (i.e., "optimal conditions") in the season.
 Since what constitutes "optimal conditions" is not known, the Roanoke River instream flow
 should be managed to mimic the historical river flows as much as possible over the longest
 period of time possible (first of April to end of June) . Moderate flows result in the highest
 juvenile abundance indices in Albemarle Sound (Hassler et al , 1981, Rulifson and Manooch
 1990b). This management action includes providing adequate instream flows during the pre 
spawning season (late March through April) to prevent downstream water temperatures from
 warming too quickly and to provide attracting flows for the spawning population. Also ,
 adequate flows should be maintained after the peak spawn, since spawning continues through
 mid-June. Typically in late May and June, hydroelectric activity by the power company to meet
 peak electrical demands results in downstream flows fluctuating between 2,000 and 20,000 cfs
 within hours . Moderated hydroelectric activities are recommended to provide a more stable
 environment downstream. Moderate flow regime guidelines as recommended by the Roanoke
 River Water Flow Committee, and implemented by the Corps and VEPCO during the study
 period (1988-1991), should continue to be used.
 17
SUMMARY AND CONCLUSIONS
 1. The estimated number of striped bass eggs produced in the Roanoke River for 1991 was
 1.837 billion ±65.787 million from a total of 10,467 eggs collected in surface nets during
 the period 15 April to 14 June. Spawning prior to 15 April , and after 14 June, was
 undetermined.
 2. A 57-day spawning window was observed in 1991 ; the 41-day continuous spawning
 window was longer than in 1988 (27 days) and 1989 (23 days) , but shorter than 1990 (50
 days) .
 3. Eggs first appeared in surface samples on 17 April. Seasonal egg production was 50%
 complete by 13 May, 75% complete by 15 May, and 90% complete by 25 May. The last
 eggs were collected on 12 June.
 4. Three spawning peaks , all early in the season, were observed in 1991: 8-9 May (20% of
 total egg production), 11-12 May (17%), and 14 May (19%).
 5. Major egg deposition occurred after water temperatures reached 18°C, a phenomenon
 observed in 1988, 1989, and 1990.
 6. Egg viability for 1991 was 55.4% . The difference between egg viability of surface and
 bottom samples was less than one percent.
 7. No seasonal trend in egg viability was evident; only a small portion of data variability
 was explained by dissolved oxygen and water velocity (R2=0.16). Poor predictability of
 viability based on environmental factors was expected since water quality and instream
 flow were quite stable during the major egg production period.
 8. Most eggs (62%) passing Barnhill 's Landing were less than 10 hours old. An additional
 38% were 10-18 hours old, and only nine eggs were 20-28 hours in development.
 9. The est imation of annual egg viability is probably influenced by location in the river at
 which the sampling was conducted. Sample location does not significantly change the
 annual egg production estimate.
 10. Abou t 94% of all eggs were collected at water temperatures 18.0-21.9°C. The range of
 temperatures during the study was 12.0-26.0°C.
 1J. Most eggs (92%) were collected at surface water velocities of 60-79 em/second. Water
 velocities ranged from 49 em/second to 123 em/second, with a seasonal mean of 74
 em/second.
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 12. Changes in secchi disk visibility coincided with changes in river level, ranging from 30
 cm to 85 cm.
 13. Most eggs (96%) were collected at dissolved oxygen levels between 7.0 and 8.9 mg/L; a
 seasonal decrease in dissolved oxygen was observed, from a high of 10.0 mg/L in April
 to a low of 5.2 mg/L in June .
 14. Most eggs (85%) were caught in waters of pH 7.74 or greater.
 15. In 1991, there were no significant differences in the number of eggs collected in surface
 or bottom samples.
 16. In 1991, the daily estimates of egg production calculated by the Hassler (daily averaging)
 method and by the trip method were not statistically different. The trip method produces
 a daily egg estimate with an estimate of data variability; the Hassler daily estimate is a
 single point value with no estimate of variability.
 17. In 1991, the daily egg production estimates calculated by cross-sectional area of the river,
 and by volume, were not significantly different. However, in some years (e.g., 1990) the
 cross-sectional area calculations (Hassler's method) may underestimate the number of
 eggs in the river during high flow years if major spawning activity occurs during high
 flows .
 18. From the results of the independent studies conducted by Hassler and the NCWRC in
 1981,1982, and 1983, and the 1988-1991 egg studies by Rulifson, it is clear that
 spawning activity of Roanoke River striped bass is affected by reservoir discharge. The
 relationship of egg viability to successful juvenile recruitment to the year class is unclear.
 19. The value of the annual egg studies is the documentation of striped bass spawning
 activity relative to changing environmental conditions, especially human-related activities
 such as hydroelectric generation upstream. The annual studies should be regarded as an
 imponant relative index of striped bass activity among years, and daily activity within the
 season and should be continued to provide critical data for renewal of the dam licences by
 the Federal Energy Regulatory Commission.
 19
ACKNOWLEDGMENTS
 This project could not have been accomplished without the dedicated field effons of Mark
 Bowers, Drew Bass, and Brian Cook at Barnhill's Landing, and Richard Hedgepeth and Jeff
 Gearhan at Jacob's Landing. Thanks go to Institute staff Scott Wood, David Knowles, and Mary
 Johnson for taking samples when the field crew attended classes at ECU. Special thanks go to
 Mr. Paul Hale, Sr. for use of Barnhill 's Landing, and to Mr. Gene Bennett for use of his property
 at Jacob's Landing. The field crew for 1988 included Todd Ball, Jose Escorriola-Giovannini
 ("Nacho"), Andrew Tate , and Scott Wood. The 1989 field crew was Stuart Laws and Mark
 Bowers ; the 1990 field crew was Mark Bowers and Drew Bass. We all greatly appreciated the
 assistance of North Carolina Wildlife Resources Commission personnel for help with logistics
 and moral suppon, especially Fred Harris , Kent Nelson, Bob Curry, and others who assisted at
 the Weldon Hatchery during spawning season. Dr. Charles S. Manooch of the National Marine
 Fisheries Service, Beaufort Laboratory, provided assistance and support at critical times, and his
 efforts were much appreciated. Marsha E. Shepherd of the Academic Computing Center at East
 Carolina University was instrumental in writing the programs for the computer analyses. John E.
 Cooper of ECU's Institute for Coastal and Marine Resources drew several of the figures . The
 studies were funded by several sources: the U.S. Fish and Wildlife Service through the North
 Carolina Wildlife Resources Commission with Wallop-Breaux funding; the North Carolina
 Striped Bass Study Management Board (congressional funds) ; and the Albemarle-Pamlico
 Estuarine Study, which is a cooperative state-federal initiative of the North Carolina Department
 of Health, Environment, and Natural Resources, and the U.S. Environmental Protection Agency.
 20
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 REFERENCES
 Bonn, E.W., W.M. Bailey, J.D. Bayless, K.E. Erickson, and R.E. Stevens. 1976. Guidelines for
 striped bass culture. American Fisheries Society, Bethesda, Maryland; USA.
 Coutant, C.C. 1985. Striped bass, temperature, and dissolved oxygen: a speculative hypothesis
 for environmental risk. Transactions of the American Fisheries Society 11 :31-61.
 Dorton, P.E 1991. Aluminum and acid pH effects on larval striped bass (Marone saxatilisy
 epithelium determined by scann ing electron microscopy. M.S. Thesis, East Carolina
 University, Greenville, NC. 56 p.
 Fish, EE 1959. Report of the steering committee for Roanoke River studies, 1955-58. U.S.
 Public Health Service, Raleigh, NC. 279 p.
 Giese, G.L., H.B. Wilder, and G.G. Parker, Jr. 1985. Hydrology of major estuaries and sounds
 in North Carolina. Reston, VA: U.S. Geological Survey, Water Supply Paper No. 2221.
 Hassler, W.W., B.B. Brandt, J.T. Brown, and P.R. Cheek. 1961. Status of the striped bass in the
 Roanoke River, North Carolina, for 1960. Department of Zoology, North Carolina State
 University, Raleigh, Mimeo Report. 38 p. + Appendices.
 Hassler, W.W., W.L. Trent, and W.E. Gray. 1963. The status and abundance of the striped bass
 in the Roanoke River, North Carolina, for 1963. Department of Zoology, North Carolina
 State University, Raleigh, Mimeo Report. 43 p. + Appendices.
 Hassler, W.W., W.L. Trent, and B.M. Florence. 1965. The status and abundance of the striped
 bass in the Roanoke River, North Carolina, for 1964. Department of Zoology, North
 Carolina State University, Raleigh, Mimeo Report 45 p. + Appendices.
 Hassler, W.W., W.L. Trent, and B.M. Florence. 1966. The status and abundance of the striped
 bass in the Roanoke River, North Carolina, for 1965. Department of Zoology, North
 Carolina State University, Raleigh, Mimeo Report 53 p. + Appendices.
 Hassler, W.W., W.T. Hogarth, and H.L. Liner;III. 1967. The status and abundance of the
 striped bass in the Roanoke River, North Carolina, for 1966. Department of Zoolog y,
 North Carolina State University, Raleigh, Mimeo Report. 53 p. + Appendices.
 Hassler, W.W., W.T. Hogarth, H.L. Liner, III and H.S. Millsaps. 1968. The status and
 abundance of the striped bass in the Roanoke River, North Carolina, for 1967 .
 Department of Zoology, North Carolina State Universi ty, Raleigh, Mimeo Report . 72 p.
 + Appendices.
 21
Hassler, W.W., W.T. Hogarth, C.R. Stroud, Jr., and H .S. Millsaps. 1969. The status and
 abundance of the striped bass in the Roanoke River, North Carolina, for 1968.
 Department of Zoology, North Carolina State University, Raleigh, Mimeo Report. 71 p.
 + Appendices.
 Hassler, W.W., and W.T. Hogarth. 1970. The status, abundance, and exploitation of striped
 bass in the Roanoke River and Albemarle Sound, North Carolina, and the spawning of
 striped bass in the Tar River, North Carolina. Department of Zoology, North Carolina
 State University, Raleigh, Mimeo Report. 64 p. + Appendices.
 Hassler, W.W., W.T. Hogarth, and C.S. Manooch. 1971. The status, abundance, and
 exploitation of striped bass in the Roanoke River and Albemarle Sound, North Carolina,
 1970. Department of Zoology, North Carolina State University, Raleigh, Mimeo Report.
 82 p. + Appendices.
 Hassler, W.W., W.T. Hogarth, C.S. Manooch, and N.L. Hill. 1973. The status, abundance, and
 exploitation of striped bass in the Roanoke River and Albemarle Sound, North Carolina,
 1972. Department of Zoology, North Carolina State University, Raleigh, Mimeo Report.
 75 p. + Appendices.
 Hassler, W.W., and N.L. Hill. 1975. The status, abundance, and exploitation of striped bass in
 the Roanoke River and Albemarle Sound, North Carolina, 1973. Department of Zoology,
 North Carolina State University, Raleigh, Mimeo Report. 64 p. + Appendices.
 Hassler, W.W., and N.L. Hill. 1976. The status, abundance, and exploitation of striped bass in
 the Roanoke River and Albemarle Sound, North Carolina, 1974. Department of Zoology,
 North Carolina State University, Raleigh, Mimeo Report. 80 p. + Appendices.
 Hassler, W.W., and N.L. Hill. 1976. The status, abundance, and exploitation of striped bass in
 the Roanoke River and Albemarle Sound, North Carolina, 1975. Department of Zoology,
 North Carolina State University, Raleigh, Mimeo Report. 87 p. + Appendices.
 Hassler, W.W., and N.L. Hill. 1978. The status, abundance, and exploitation of striped bass in
 the Roanoke River and Albemarle Sound, North Carolina, 1976. Department of Zoology,
 North Carolina State University, Raleigh , Mimeo Report. 117 p. + Appendices.
 Hassler, W.W., and N.L. Hill. 1979. The status, abundance, and exploitation of striped bass in
 the Roanoke River and Albemarle Sound, North Carolina, 1977. Department of Zoology,
 North Carolina State University, Raleigh, Mimeo Report. 118 p. + Appendices.
 Hassler, w.w., and N.L. Hill. 1980. The status, abundance, and exploitation of striped bass in
 the Roanoke River and Albemarle Sound, North Carolina, 1979. Department of Zoology,
 North Carolina State University, Raleigh, Mimeo Report. 82 p.
 22
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 Hassler, W.W., N.L. Hill, and J.T. Brown. 1981. The status and abundance of striped bass in
 the Roanoke River and Albemarle Sound, North Carolina 1956-1980. North Carolina
 Department of Natural Resources and Community Development, Division of Marine
 Fisheries, Special Scientific Report No. 38.
 Hassler, W.W., L.G. Luernpert, and J.w. Mabry. 1982. The status, abundance, and exploitation
 of striped bass in the Roanoke River and Albemarle Sound, North Carolina, 1981.
 Department of Zoology, North Carolina State University, Raleigh, Mimeo Report, 55 p. +
 Appendices.
 Hassler, W.W., and S.D. Taylor. 1984. The status, abundance, and exploitation of striped bass
 in the Roanoke River and Albemarle Sound, North Carolina, 1982 and 1983. Department
 of Zoology, North Carolina State University, Raleigh, Mimeo Report. 67 p. +
 Appendices.
 Hassler, W.W., and S.D. Taylor. 1986. The status, abundance, and exploitation of striped bass
 in the Roanoke River and Albemarle Sound, North Carolina, 1985. Department of
 Zoology, North Carolina State University, Raleigh, Mimeo Report, 47 p. + Appendices.
 Johnson, J.C., P. Fricke, M. Hepburn, J. Sabella, W. Still, and C.R. Hayes. 1986. Recreational
 fishing in the sounds of North Carolina: a socioeconomic analysis. Volume I. UNC Sea
 Grant Publication UNC-SG-86-12.
 Kornegay, J.W. 1981. Investigations into the possible causes of the decline of Albemarle Sound
 striped bass. Final Report for 1 April to 30 September 1981, Jobs 2 and 3. North
 Carolina Wildlife Resources Commission, Raleigh. 16 p.
 Kornegay, J.W. 1983. Coastal fisheries investigations. Study VIII: Investigations into the
 decline in egg viability and juvenile survival of Albemarle Sound striped bass (Morone
 saxatilisi, Jobs 1-4. Federal Aid in Fish Restoration Project F-22, Final Report for period
 1 April 1982 - 1 January 1983. North Carolina Wildlife Resources Commission, Raleigh.
 13 p.
 Kornegay, J.W. and A.W. Mullis. 1984. Investigations into the decline in egg viability and
 juvenile survival of Albemarle Sound striped bass (Morone saxatilis). Final Report on
 Project F-22, Study VIII. North Carolina Wildlife Resources Commission, Raleigh. 13
 p.
 Manooch, C.S ., III and R.A . Rulifson (eds.). 1989. Roanoke River Water Flow Committee
 Report: A recommended water flow regime for the Roanoke River, North Carolina, to
 benefit anadromous striped bass and other below-dam resources and users. NOAA
 Technical Memorandum NMFS-SEFC-216, 224 p.
 23
McCoy, E.G. 1959. Quantitative sampling of striped bass, Roccus saxatilis (Walbaum), eggs in
 the Roanoke River, North Carolina. M.S . Thesis, North Carolina State University,
 Raleigh, NC, 136 p.
 North Carolina Striped Bass Study Management Board. 1991. Report on the Albemarle Sound 
Roanoke River stock of striped bass. U.S. Fish and Wildlife Service, Atlanta GA. 56 p. +
 Appendices.
 Rulifson, R.A. 1989. Abundance and viability of striped bass eggs spawned in the Roanoke
 River, North Carolina, in 1988. A1bemar1e-Pamlico Estuarine Study, Raleigh, NC,
 Project No. APES 90-03. 76 p.
 Rulifson, R.A. 1990. Abundance and viability of striped bass eggs spawned in the Roanoke
 River, North Carolina, in 1989. A1bemarle-Pamlico Estuarine Study, Raleigh, NC,
 Report No. APES Project 90-11. 96 p.
 Rulifson, R.A. 1992a. Abundance and viability of striped bass eggs spawned in the Roanoke
 River, North Carolina, in 1990. A1bemar1e-Pamlico Estuarine Study, Raleigh, NC,
 Report No. APES 92-23, 87 p.
 Rulifson, R.A. 1992b . Striped bass egg abundance and viability at Scotland Neck, Roanoke
 River, North Carolina, for 1991. North Carolina Wildlife Resources Commission,
 Raleigh, Completion Report for Project F-27, Study 2. 48 p. + 2 appendices.
 Rulifson, R.A., and C.S. Manooch, ill. 1990a. Roanoke River Water Flow Committee report for
 1988 and 1989. NOAA Technical Memorandum NMFS-SEFC-256, 209 p.
 Rulifson, R.A., and C.S. Manooch, III. 1990b. Recruitment of juvenile striped bass in the
 Roanoke River, North Carolina, as related to reservoir discharge. North American
 Journal of Fisheries Management 10:397-407.
 Rulifson, R.A., and C.S. Manooch, ill. 1991. Roanoke River Water Flow Committee report for
 1990. NOAA Technical Memorandum NMFS-SEFC-291, 433 p.
 Rulifson, R.A., J.E. Cooper, D.W. Stanley, M.E. Shepherd, S.F. Wood, and D.D. Daniel. 1992a.
 Food and feeding of young striped bass in Roanoke River and western Albemarle Sound,
 North Carolina, 1984-1991. North Carolina Wildlife Resources Commission, Raleigh,
 Completion Report for Project F-27.
 24
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 Rulifson, R.A., J.E. Cooper, D.W. Stanley, ME. Shepherd, S.F. Wood, and D.D. Daniel. 1992b.
 Food and feeding of young striped bass in Roanoke River and western Albemarle Sound,
 North Carolina, 1990-1991. North Carolina Wildlife Resources Commission, Raleigh,
 and North Carolina Striped Bass Study Management Board, Completion Report for
 Projects 90-2 and 91-2, 62 p.
 SAS Institute. 1985. SAS User's Guide: Statistics, Version 5 Edition. SAS Institute, Inc., Cary,
 NC 584p.
 Shannon, E.H. 1970. Effect of temperature changes upon developing striped bass eggs and fry.
 Proceedings of the 23rd Annual Conference of Southeastern Fish and Game
 Commissioners 1969:265-274.
 Tarplee, W.H., W.T. Bryson, and R.G. Sherfinski. 1979. Portable pushnet apparatus for
 sampling ichthyoplankton. Ptogressive Fish Culturist 41:213-215.
 USDOI and USDOC (U.S. Department of the Interior and U.S. Department of Commerce) .
 1986. Emergency striped bass research study. 1985 Annual Report. Washington,
 District of Columbia, USA.
 USFWS (U.S. Fish and Wildlife Service). 1992. Report to the Congress for the North Carolina
 Striped Bass Study, Albemarle Sound and Roanoke River Basin. U.S. Fish and Wildlife
 Service in consultation with the National Oceanic and Atmospheric Administration,
 Washington, D.C., 8 p.
 Williams, R.R.G . 1978. Spawning of the striped bass, Morone saxatilis (Walbaum), in the
 Annapolis River, Nova Scotia. M.Sc. Thesis, Acadia University, Wolfville, Nova Scotia.
 Zincone, L.H., Jr., and R.A. Rulifson. 1991. Instream flow and striped bass recruitment in the
 lower Roanoke River, North Carolina. Rivers 2:125-137.
 25
,,- 71' .,.-
 11-
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 Figure 1. Drainage area of the Roanoke River Basin. Dashed line indicated approximate location of the Fall
 Line; diamonds-locations of USGS water quality and gaging stations; inverted triangle=USGS water
 quality station; Teupstream limit of tidal influence; S2=mean upstream intrusion limit of saltwaterfront
 (200 mg/L chloride); Sm=maximum upstream intrusion of saltwater front (Giese et al. 1985). Counties
 containing Roanoke watershed are enumerated and listed in Appendix Table A-I.
Figure 2. Roanoke River watershed downstream of Roanoke Rapids Reservoir showing the
 historical sampling stations for striped bass eggs: Palmyra (1959-60), Halifax
 (1961-74), Barnhill's Landing (1975-81, 1989-1991), Johnson's Landing (1982 
87), and Pollock's Ferry (1988).
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 NORTHAMPTON
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 27
6/146/1
 Daily egg
 production
 5/1 5/15
 Time in Days
 4/15
 350..,...---------:----------,
 300
 250
 -~ 200o
 ~ 150
 ..........
 100
 50
 Figure 3. Estimated daily production of striped bass eggs in the Roanoke River
 based on samples collected at Barnhill 's Landing, NC, for the period
 15 April to 14 June 1991.
 100
 90 Cumulative
 80 eggproduction70
 ~ 60c(J)
 o 50~(J) 40a,
 30
 20
 1
 4/15 5/1 5/15 6/1 6/14
 Time in Days
 Figure 4. Estimated production of striped bass eggs in the Roanoke River based
 on samples collected at Barnhill'S Landing, NC, in 1991, presented as
 percentage of total production .
 28
6/146/15/1 5/15
 Time in Days
 4/15
 Daily viabili ty est imates of striped bass eggs in the Roanoke River
 based on samples collected at Barnhill's Landing, NC, in 1991.
 90~------------------.
 80
 70
 ...... 60
 c~ 50
 Q) 40
 a,
 30
 20
 10
 Figure 5.
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6/146/15/15
 Time (4-hr intervals)
 - ------------------------- -----
 5/1
 28......-------------------,
 26 Water temperature
 24
 o 22
 ID 2
 CD
 0, 18
 CD
 Cl 16
 14
 12
 1 /15
 6/145/1 5/15 6/1
 Time (4-hrintervals)
 /15
 1200
 Egg counts 17951000
 C/} all nets
 0> 8000>CD
 '+-0
 L- 600CD
 .0
 E 400::J
 Z
 200
 Figure 6. Number of striped bass eggs collected in all nets during each trip, and
 corresponding water temperatures (0C) at Barnhill's Landing, NC, for
 the period 15 April to 14 June 1991.
 30
Air temperature
 35,-r-----------------,
 30-
 Figure 8. Hourly record of Roanoke River ins tream flow (cfs) downstream of the
 Roanoke Rapids Reservoir (USGS data), April-June 1991.
 6/14
 6/145/1 5/15 6/1
 Time (hourly intervals)
 5/1 5/15 6/1
 Time (4-hr intervals)
 Air temperature (DC) measured at Barnhill's Landing, NC, for the
 period 15 April to 14 June 1991.
 '- -.'"
 ... -
 l-
 . ,
 T I
 .. ... J\
 LY ... ' ~
 .0 25-
 enQ)~ 2D- l
 ~ 15- ~
 10-
 Figure 7.
 31
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 8 20
 .,.-
 X 18
 $ 16
 ~ 14
 ~ 12
 ~ 10~ 8
 ~ 6
 en
 c ~/15
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5/1 5/15 6/1
 Time (4-hr intervals)
 6/14
 __r---._~
 Relative change in
 river heightl
 \~
 lr~1
 8
 18
 16
 CD 14
 Lf 12
 6/14
 Surface water velocity
 ~1 ~15 6~
 Time (4-hr intervals)
 130~------------------'
 120
 110
 "'0 100
 c
 8 90
 CJ.)
 ~ 8
 o 70
 6
 5
 4 /15
 Figure 9. Relative change in river height (ft) and corresponding surface water
 velocity at Barnhill's Landing, Roanoke River, NC, for the period 15
 April to 14 June 1991.
 32
6/145/1 5/15 6/1
 Time (4-hr intervals)
 Secchi visibility depth
 1201...----- - - - - - - - - - - - - - - - --,
 110
 -E 100
 o
 ~ 9
 ~ 8
 ·en
 .>:::. 7
 8 6
 IJ5 50
 4
 3 \-1-------.1.
 (
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 1
 Figure 10. Depth (ern) of secchi disk visibility in the Roanoke River at Barnhill's
 Landing, NC, for the period 15 April to 14 June 1991. Unfilled bars
 indicate no information available.
 11~-------------------,
 Conductivity!
 I
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 -(J)
 :::J
 ---~
 .>
 "c:5 8
 :::J
 -0
 C 7o
 o
 6
 ..........uULi UU "",UI....JW L....-lUL,fUliill..lUUUUU ~
 33
 Figure 11. Changes in conductivity (~S ) of Roanoke River waters at Barnhill 's
 Landing, NC, for the period 15 April to 14 June 1991.
 \
 l
 I
 ~/15 5/1 5/15 6/1
 Time (4-hr intervals)
 6/14
11.,......-------------------,
 Dissolved oxygen
 1
 ~ 8E
 7
 6
 6/14~/15 5/1 5/15 6/1
 Time (4-hr intervals)
 Figure 12. Changes in dissolved oxygen (mg/L) of Roanoke River waters at
 Barnhill's Landing, NC, for the period 15 April to 14 June 1991.
 Surface water pH
 7 ------- --------------
 8
 8.5
 (])
 =>
 eu
 > 7.5
 :c
 0..
 6.5
 5/1 5/15 6/1
 Time (4-hr intervals)
 6/14
 Figure 13. Changes in pH of Roanoke River surface waters at Barnhill 's
 Landing, NC, for the period 15 April to 14 June 1991.
 34
Table 1 . Striped bass daily egg production in the Roanoke River, NC, 1991, estimated by the Hassler
 method and by river discharge five hours previous to sample collection.
 River Mean Estimated % of Cumulative Estimated % of Cumulative
 Number flow eggs/ eggs/day total percent eggs/day total percent
 Date samples (cfs) net (Hassler) (Hassler) (Hassler) (Volume) (Volume) (Volume)
 910415 10 20,055 0 0 0.0 0 .0 0 0.0 0 .0
 910416 12 20,139 0 0 0.0 0.0 0 0 .0 0 .0
 910417 12 20,004 0 349,644 0 .0 0.0 266,415 0 .0 0 .0
 910418 12 20,052 0 0 0.0 0.0 0 0 .0 0.0
 910419 10 20,083 0 0 0 .0 0 .0 0 0.0 0.0
 910420 12 20,020 0 0 0.0 0.0 0 0 .0 0.0
 910421 12 15,836 0 0 0 .0 0 .0 0 0 .0 0.0
 910422 10 11,297 0 0 0.0 0 .0 0 0 .0 0 .0
 910423 12 10,825 0 476,091 0.0 0 .0 425,162 0.0 0.0
 910424 12 10,791 0 886,916 0.0 0.1 792,839 0 .0 0.1
 910425 10 10,808 1 3,039,676 0.2 0.3 3,042,206 0 .1 0.2
 w 910426 10 10,860 0 2 47 ,741 0 .0 0.3 271,327 0 .0 0.2U1 910427 12 8,085 0 0 0.0 0.3 0 0.0 0.2
 9104·28 12 7 ,810 2 3 ,777,979 0 .2 0 .5 3,993,722 0 .2 0. 4
 910429 12 7,771 4 8,742 ,234 0 .5 1.0 9,177,152 0 .4 0.9
 910430 10 8,181 2 4,765,173 0 .3 1.2 4 ,753,955 0 .2 1 .1
 910501 12 9,165 2 4,924,741 0.3 1.5 4,746,864 0.2 1.3
 910502 12 9,511 20 42,272 ,152 2.3 3 .8 41,299,676 2.0 3.3
 910503 10 9 ,500 8 16,686,391 0 .9 4.7 16,783,198 0 .8 4 .1
 910504 10 9,511 1 2 ,600,477 0.1 4 .8 3,053,943 0 .1 4 . 3
 910505 12 9,462 7 14 , 099 , 1 35 0.8 5.6 15,767,393 0.8 5.0
 910506 10 9,494 19 40,636,743 2 .2 7 . 8 44,507,797 2.1 7.2
 910507 12 9,511 13 28,376,626 1.5 9.4 32,707,375 1.6 8 .7
 910508 12 9,483 118 252 ,225,065 13.7 23.1 290 ,064,227 13 .9 22 .7
 910509 1 2 9 ,511 56 118,391,049 6 .4 29.5 130,578,718 6 .3 28.9
 910510 12 9,402 13 26,382,648 1.4 31.0 29,834 ,214 1.4 30 .4
 910511 12 9,250 52 1 07 , 006 , 692 5 .8 36.8 128,512,164 6 .2 36 .5
 91 0512 12 9 ,239 98 202,652,419 11.0 47 .8 233,208,626 11.2 47 .7
 910513 12 9,239 45 91,28 4,628 5.0 52 .8 105,307,107 5 .1 52 .8
 910514 12 9,272 168 344,834,188 18 .8 71. 6 395,191,853 19 .0 71 .8
 910515 12 9, 293 29 59 ,300,32 6 3.2 74.8 68 ,247,098 3.3 7 5. 1
 910516 12 9,293 29 58,865,042 3 .2 78.0 67,004,766 3 .2 78 .3
 910517 12 9,277 24 50,259,042 2 .7 80.7 56,132,930 2 .7 81.0
Table 1. Continued .
 River Mean Estimated % of Cumulative Estimated % of Cumulative
 Number flow eggs/ eggs/day total percent eggs/day total percent
 Date samples (cfs) net (Hassler) (Hassler) (Hassler) (Volume) (Volume) (Vo1.ume)
 910518 12 9,271 35 73,051,127 4 .0 84.7 82,063,464 3 .9 84 .9
 910519 12 9,293 17 34,377,001 1 .9 86.6 41,227,980 2 .0 86 .9
 910520 12 7,081 4 6 ,503,436 0 .4 86.9 6,597,644 0 .3 87 .2
 910521 12 9,174 7 12,704,913 0.7 87.6 15,795,023 0 .8 88.0
 910522 12 9,180 10 19,901,131 1 .1 88 .7 22,392,820 1.1 89.0
 910523 12 9,110 6 12,090,546 0 .7 89 .4 13,050,179 0.6 89.7
 910524 12 9,244 14 28,081,642 1.5 90.9 31,864,449 1.5 91.2
 910525 10 9,298 12 25,317,723 1.4 92.3 27 ,914,144 1.3 92 .5
 910526 12 9,347 20 40,970,399 2 .2 94.5 46,222,310 2 .2 94.8
 910527 10 9,315 12 24,377,387 1 .3 95.8 27,048,083 1 .3 96.1
 910528 10 9,320 9 19,082,707 1.0 96 .9 19,521,860 0 .9 97.0
 910529 12 9,272 8 16,179,281 0.9 97.7 16,992,567 0 .8 97.8Ul
 0, 910530 12 9,315 7 14,113,840 0.8 98 .5 15,070,058 0 .7 98.5
 910531 12 9,304 4 7,229,040 0 .4 98 .9 7,939,350 0.4 98 .9
 910601 10 9,315 3 6,196,320 0.3 99.2 6 ,805,535 0.3 99 .3
 910602 8 9,255 2 4,097,040 0 .2 99 .5 4,418,486 0 .2 99.5
 910603 10 9,298 1 2,048,520 0.1 99 .6 2,140,231 0.1 99.6
 910604 12 9 ,331 2 3,089,700 0 .2 99 .7 3,522,916 0.2 99 .7
 910605 12 9,309 0 514,950 0 .0 99.8 556,507 0.0 99.8
 910606 12 9,298 1 1,024,260 0 .1 99.8 1,151,233 0.1 99 .8
 910607 12 9,320 1 1,198,260 0 .1 99.9 1,372,851 0.1 99 .9
 910608 10 9,336 0 0 0.0 99.9 0 0.0 99 .9
 910609 12 9,336 0 171,650 0 .0 99.9 190,826 0 .0 99 .9
 910610 12 7,425 0 613,608 0.0 99.9 661,019 0 .0 99.9
 910611 12 6,691 0 367,777 0.0 100.0 464,619 0.0 99 .9
 910612 12 6,655 1 823,137 0 .0 100 .0 1,076,238 0.1 100.0
 910613 12 6,618 0 0 0 .0 100.0 0 0.0 100 .0
 910614 6 6,573 0 0 0 .0 100.0 0 0.0 100.0
 1991 egg production estimate : 1,837,208,211 2,081,731,118
 ± 61,787,080 ± 70,953,356
I
 r Table 2. Estimated number of striped bass eggs spawned in the Roanoke River, NC, and the
 I
 corr esponding egg viability, 1959- 1987 (Hassler reports), 1988-1990 (Rulifson
 reports), and 1991 (this study).
 [ Estimated Egg via- Site of eggYear Sampling period number of eggs bility (%) collection
 i 1959 300,000,000 92.88 Palmyra (RM 78.5)1960 23 Apr-8 Jun 740,000,000 92.88 Palmyra
 1961 2,065,232,519 79.74 Halifax (RM 121)
 I 1962 1,088,076,294 86.22 Halifax1963 18 Apr-8 Jun 918,652,436 79.94 Halifax
 1964 24 Apr-27 May 1,285,351,276 95.77 Halifax
 I 1965 21 Apr-28 May 823,522,540 95.91 Halifax1966 26 Apr-31 May 1,821,385,754 94.51 Halifax1967 21 Apr-11 Jun 1,333,312,869 96.20 Halifax
 1968 24 Apr-4 Jun 1,483,102,338 86.20 Halifax
 I 1969 27 Apr-6 Jun 3,229,715,526 89.86 Halifax1970 30 Apr-l Jun 1,464,841,490 89.23 Halifax
 1971 2,833,119,620 80.81 Halifax
 1972 2 May-28 May 4,932,000,707 90.51 Halifax
 1973 29 Apr-3 Jun 1,501,498,887 87.21 Halifax
 1974 1 May-2 Jun 2,163,239,468 87.31 Halifax
 1975 7 May-2Jun 2,193,008,096 55.69 Barnhill 's (RM 117)
 I 1976 1 May-30May 1,496,768,659 50.73 Barnhill's Landing1977 29 Apr-31 May 1,775,957,318 52.72 Barnhill's Landing
 1978 1,691,227,585 37.72 Barnhill 's Landing
 I 1979 10 May-11 Jun 1,613,382,382 43.62 Barnhill 's Landing1980 1 May-l Jun 870,322,832 43.39 Barnhill 's Landing1981 29 Apr-29 May 344,364,065 73.70 Barnhill's Landing
 I 1982 3 May-2Jun 1,698,888,853 71.93 Johnson's (RM 118)1983 6 May- 12 Jun 1,352,611,202 33.29 Johnson's Landing1984 9 M!ly-9 Jun 703,879,559 22.73 Johnson's Landing
 1985 23 Apr-23 May 600,562,645 72.21 Johnson' s Landing
 I 1986 2,279,071,483 51.10 Johnson's Landing1987 1,382,496,006 42.87 Johnson's Landing
 1988 10 Apr-7 Jun 2,082,130,728 89.00 Pollock's Ferry
 j (RM 105)1989 16 Apr- 15 Jun 637,919,162 41.80 Barnhill's Landing
 1990 16 Apr- 15 Jun 964,791,625 58.00 Barnhill ' s Landing
 1991 15.Apr-14 Jun 1,837,208,211 55.36 Barnhill's Landing
 ! 15 Apr-14 Jun 2,068,304,334 69.51 Jacob's Landing(RM 102)
 [
 I
 ,
 I
 l 37
Table 3. Striped bass daily egg viability at Barnhill's
 Landing, Roanoke River, NC , 1991.
 Number Number Number Percentage
 of non-viable viable viable
 Date samples eggs e gg s eggs
 910415 10 0 0
 910416 12 0 0
 91041 7 12 1 0 0 .00
 910418 12 0 0
 910419 10 0 0
 910420 12 0 0
 910421 12 0 0
 910422 10 0 0
 910423 12 1 1 50 .00
 910424 12 2 2 50.00
 910425 10 5 7 58.33
 910426 10 1 0 0.00
 910427 12 0 0
 910428 12 4 19 82.61
 910429 12 11 42 79.25
 910430 10 6 18 75 .00
 910501 12 11 17 60 .71
 910502 12 98 137 58.30
 910503 10 33 44 57.14
 910504 10 8 4 33.33
 910505 12 33 46 58 .23
 910506 10 73 116 61.38
 910507 12 43 116 72.96
 910508 12 621 796 56.18
 910509 12 323 343 51.50
 910510 12 68 82 54.67
 910511 12 286 334 53.87
 910512 12 622 557 47.24
 910513 12 238 296 55.43
 910514 12 981 1,039 5 1. 44
 910515 12 147 198 57 .39
 910516 12 150 192 56.14
 910517 12 130 162 55 .48
 910518 12 182 243 57 .18
 910519 12 92 108 54.0 0
 910520 12 16 27 62 . 79
 910521 12 27 51 65.38
 910522 12 41 78 65 .55
 910523 12 33 39 54.17
 910524 12 61 1 06 63.47
 910525 10 41 83 66.94
 910526 12 86 154 64.17
 910527 10 52 67 56. 30
 38
[
 I
 I
 Table 3 . Continued.
 Number Number Number Percentage
 I of non-viable viable viableDate samples eggs eggs eggs
 I 910528 10 27 66 70.97910529 12 25 69 73.40
 910530 12 31 51 62 .20
 1
 910531 12 21 21 50.00
 910601 10 11 19 63.3 3
 91060 2 8 8 8 50.00
 910 60 3 10 2 8 80. 00
 910604 12 7 11 61.11
 910605 12 2 1 33.3 3
 910606 12 1 5 83.33
 910607 12 2 5 71. 43
 910608 10 0 0
 910609 12 0 1 0.00
 910610 12 2 2 50.00
 910611 12 2 1 33 .33
 91061 2 12 4 3 42.86
 910613 12 0 0
 910614 6 0 0I
 I
 I
 I
 )
 I
 I
 I
 (
 l 39
Table 4. St r i p e d bass egg viabi l ity at Barnhill's La nd i ng ,
 Roanoke River, NC, 1991, r e l a ti v e to water
 temperature.
 Temperature
 range
 ( C)
 missing
 12 .0-13.9
 14.0-15.9
 16.0-17.9
 18.0-19 .9
 20.0-21.9
 22.0-23.9
 24.0-25 .9
 >=26.0
 Number
 non-viable
 eggs
 o
 1
 69
 918
 1 ,861
 1,647
 170
 6
 =====
 4,672
 Numbe r
 viable
 eggs
 o
 1
 96
 1,428
 1 ,874
 2 ,081
 309
 6
 -----
 - - -
 5,795
 Percent
 viable
 eggs
 0 . 00
 50 .00
 58 .18
 60.87
 50.1 7
 55.82
 64.51
 50 .00
 Percent of
 all eggs
 collected
 0 .000
 0.019
 1 .576
 22.413
 35.684
 35 .617
 4.576
 0 .115
 =======
 100.000
 Table 5 . Striped bass egg viability at Barnhill's Landing,
 Roanoke River, NC, 1991, relative to surface water
 velocity.
 Water
 velocities
 (cs /second)
 Number
 non-viable
 eggs
 Number
 viable
 eggs
 Percent
 viable
 eggs
 Percent of
 all eggs
 collected
 missing
 40 .0-59 .9
 60.0-79.9
 80 .0-99 .9
 10 0 .0-119 .9
 120.0-139.9
 94 308 76.62 3 .841
 4,410 5,254 54.37 92 .328
 165 233 58 .54 3.802
 3 0 0 .00 0.029
 0 0 0 .00 0.000
 :::;:==== ===== =======
 4, 672 5,7 95 100 .000
 40
Striped bass egg viability at Barnhill's Landing,
 Roanoke River, NC, 1991, relative to time of day .
 [
 I
 I
 I
 I
 I
 ,
 I
 Table 6.
 Time of
 collection
 0200
 0600
 1000
 1400
 1800
 2200
 Number
 non-viable
 eggs
 1,169
 629
 1,428
 398
 687
 361
 =====
 4,672
 Number
 viable
 eggs
 1,188
 1,563
 1,092
 595
 662
 69 5
 =====
 5,795
 Percent
 viable
 eggs
 50.40
 71. 30
 43.33
 59 .92
 49 .07
 65.81
 Percent of
 all eggs
 collected
 22.518
 20.942
 24.076
 9 .487
 12.88 8
 10 .089
 =======
 100 .000
 I
 I
 I
 I
 j
 I
 [
 I
 I
 l
 Table 7. Striped bass egg viability at Barnhill 's Landing,
 Roanoke River, NC, 1991, relative to dissolved
 oxygen.
 Dissolved Numbe r Number Percent Percent of
 oxygen non-viable v i a b l e viable all eggs
 values eggs eggs eggs collected
 missing 43 46 51. 69 0 .850
 5 . 0- 5 . 9 5 8 61.54 0.124
 6 .0-6.9 92 2 13 69 .84 2.914
 7.0-7.9 3,188 3 ,908 55.07 67.794
 8.0-8 .9 1,329 1 ,597 54.58 27 .955
 9 .0-9 .9 15 23 60 .53 0.363
 10 .0-10.9 0 0 0 .00 0.000
 ===== ===== =======
 4, 672 5 ,795 100 .000
 41
Table 8. Striped bass egg viability at Barnhill's Landing,
 Roanoke River, Ne, 1991, relative to pH.
 Range of Number Number Percent Percent of
 pH values non-viable viable viable all eggs
 eggs eggs eggs collected
 missing 3 30 90.91 0.315
 6.50-6.74 4 9 69.23 0.124
 6.75-6.99 0 0 0.000
 7.00-7.24 65 114 63.69 1. 710
 7.25-7.49 26 73 73.74 0.946
 7.50-7.74 497 753 60.24 11. 942
 7.75-7.99 2,786 2,620 48.46 51. 648
 8.0 OR MORE 1,291 2,196 62.98 33.314
 ===== ===== =======
 4,672 5,795 100.000
 42
Table 9 . Raw data and egg production esti mates by t rip for striped b a ss eggs samples taken at Barnhill' s
 Landing, Roanoke Rive r , North Carolina, in 1991. Combined production is the average of surface and
 oblique samples.
 Egg count Egg count Egg count Egg count River Crcss- Egg pro- Egg pro- Egg pro-
 Surface Su rface Oblique Oblique stage sect ion duction duction duction
 Date Time (rep A) (rep B) (rep A) (rep B) (feet) (sq.ft .) Surface Oblique Combined
 910415 600 0 0 0 0 19 .9 8,203 0 0 0
 1000 0 0 0 0 19 .9 8,203 0 0 0
 1400 0 0 0 0 19.9 8,203 0 0 0
 1800 0 0 0 0 19.9 8,203 0 0 0
 2200 0 0 0 0 19.9 8 , 203 0 0 0
 910416 200 0 0 0 0 19.9 8,203 0 0 0
 600 0 0 0 0 20.0 8,248 0 0 0
 "'"
 1000 0 0 0 0 19. 9 8,203 0 0 0
 ....,
 1 400 0 0 0 0 19.8 8,158 0 0 0
 1800 0 0 0 0 19 .8 8,158 0 0 0
 22 00 0 0 0 0 19 .8 8,158 0 0 0
 910417 200 0 0 0 0 19.8 8,158 0 0 0
 600 0 0 0 0 19 .8 8,158 0 0 0
 1000 0 0 0 1 19 .8 8,158 0 7 ,284 3, 64 2
 1400 0 0 0 0 19 .8 8,158 0 0 0
 1800 0 0 0 0 19 .8 8,158 0 0 0
 2200 1 0 0 0 19 .8 8,158 7, 2 84 0 3 ,642
 910418 200 0 0 0 0 19 .8 8,158 0 0 0
 600 0 0 0 0 19. 8 8,158 0 0 0
 1000 0 0 0 1 19 .8 8,158 0 7,284 3,642
 1400 0 0 0 0 19. 7 8,113 0 0 0
 1800 0 0 0 0 19 .7 8,113 0 0 0
 2200 0 0 0 0 19.7 8,113 0 0 0
Table 9. Continued .
 Egg count Egg count Egg count Egg count River Cros,s- Egg pro- Egg pro- Egg pro-
 Surface Surface Oblique Oblique stage section duction duction duction
 Date Ti:me (rep A) (rep B) (rep A) (rep B) (feet) (sq.ft .) Surface Oblique Combined
 910419 200 0 0 0 0 19 .7 8,113 0 0 0
 600 0 0 0 0 19 .7 8,113 0 0 0
 1000
 1400 0 0 0 0 19.7 8,113 0 0 0
 1800 0 0 0 0 19 .8 8,158 0 0 0
 2200 0 0 0 0 19.8 8,158 0 0 0
 910420 2 00 0 0 0 0 19 .8 8, 158 0 0 0
 600 0 0 0 0 19 .8 8,158 0 0 0
 1000 0 0 0 0 19.8 8 ,158 0 0 0
 1400 0 0 0 0 19 .8 8,158 0 0 0
 1 800 0 0 0 0 19 .8 8,158 0 0 0
 2200 0 0 0 0 19 .8 8,158 0 0 0
 910 421 200 0 0 0 0 19 .4 7 ,979 0 0 0
 600 0 0 0 0 18 .8 7 ,709 0 0 0
 1000 0 0 0 0 19 .4 7,979 0 0 0
 1400 0 0 0 0 18 .7 7,665 0 0 0
 1 800 0 0 0 0 18.0 7,350 0 0 0
 22 00 0 0 0 0 16.9 6,875 0 0 0
 910422 200
 600 0 0 0 0 15.9 6,475 0 0 0
 1000 0 0 0 0 15.6 6,357 0 0 0
 1400 0 0 0 0 14 .8 6,042 0 0 0
 1800 0 0 0 0 14.7 6,003 0 0 0
 2200 0 0 0 0 14.3 5,848 0 0 0
 910423 2 00 0 0 0 0 13 .8 5,656 0 0 0
 600 0 0 0 0 13.8 5 ,656 0 0 0
Table 9. Continued.
 Egg count Egg count Egg count Egg count River Cro3s- Egg pro- Egg pro- Egg pro-
 Surface Surface Oblique Oblique stage section duction duction duction
 Date Time (rep A) (rep B) (rep A) (rep B) (feet) (sq . ft.) Surface Oblique Combined
 1000 0 0 0 0 13.7 5,618 0 0 0
 1400 0 0 0 0 13.7 5,618 0 0 0
 1800 0 0 0 0 13 .2 5,428 a 0 0
 2200 1 1 0 0 1 3 . 0 5,352 9,557 0 4, 778
 910424 200 0 0 1 0 12.8 5,278 0 4,713 2,356
 600 0 0 0 0 12 .7 5 ,241 0 a 0
 1000 0 0 1 1 12 .8 5,278 0 9,425 4, 713
 1400 2 0 0 0 12 .4 5,131 9,162 0 4 ,581
 1800 2 0 2 2 12.3 5 ,094 9,096 18,192 13,644
 .I>- 2200 0 0 0 0 12 .1 5,020 0 0 0
 Ul
 910425 200 0 1 2 0 12.0 4 ,983 4,449 8,898 6,674
 600
 1000 6 4 6 7 11.9 4,947 44,170 57, 421 50,795
 1400 0 0 0 0 11.9 4,947 0 0 0
 1800 1 0 0 1 11.8 4,911 4,385 4 , 385 4,385
 2200 0 0 0 0 11.6 4,839 0 0 0
 910426 200 0 1 0 1 11.6 4,839 4,320 4, 32 0 4,320
 600 0 0 0 0 11 .6 4 ,839 0 0 0
 1000 0 0 0 0 11.6 4,839 0 0 0
 1400 0 0 0 0 11.5 4,803 0 0 0
 1800 0 0 0 1 11 .4 4,767 0 4, 256 2, 128
 2200
 910427 200 0 0 0 0 10.6 4 ,485 0 0 0
 600 0 0 0 0 9.7 4,181 0 0 0
 1000 0 0 0 0 9 .7 4,181 0 a 0
 1400 0 0 0 0 9 .6 4,148 a 0 0
Table 9. Continued.
 Egg count Egg count Egg count Egg count River Cr08:1- Egg pro- Egg pro- Egg pro-
 Surface Surface Oblique Oblique stage section duction duction duction
 Date Time (rep A) (rep B) (rep A) (rep B) (feet) (sq.ft.) Surface Oblique Combined
 1800 0 0 0 0 9 .6 4 ,148 0 0 0
 2200 0 0 0 0 8.7 3,854 0 0 0
 910428 200 0 0 1 0 8.6 3,822 0 3,412 1,706
 600 1 2 3 4 8 .4 3,758 10,066 23,486 16,776
 1000 1 5 4 5 8.7 3,854 20,647 30 ,970 25,809
 1400 5 2 1 4 8.7 3,854 24,088 17,206 20,647
 1800 3 2 2 3 8.7 3,854 17,206 17,206 17,206
 2200 1 1 1 5 8.7 3,854 6,882 20,647 13,765
 ~ 910429 200 4 2 6 5 8.7 3,854 20,647 37,853 29,250
 0\ 600 12 14 24 12 8 .7 3,854 89,470 123,882 106,676
 1000 3 6 8 8 8 .6 3,822 30,712 54,600 42,656
 1400 4 1 1 7 8 .7 3,854 17,206 27,529 22 ,368
 1800 1 0 0 0 8 .7 3,854 3,441 0 1,721
 2200 4 2 2 0 8 .7 3,854 20,647 6,882 13,765
 910430 200
 600 0 2 1 3 8.6 3,822 6,825 13,650 10,237
 1000 9 6 6 4 8 .5 3,790 50,758 33,838 42,298
 1400 2 2 0 1 8 .6 3,822 13,650 3,412 8,531
 1800 0 1 1 0 8.8 3,886 3,470 3,470 3,470
 2200 2 0 0 0 9.1 3,983 7,113 0 3,556
 910501 200 2 1 3 1 9.2 4,016 10,757 14,343 12,550
 600 5 3 3 2 9 .4 4,082 29,157 18,223 23,690
 1000 6 4 4 5 9 .5 4,115 36,740 33,066 34,903
 1400 0 0 0 0 9 .5 4,115 0 0 0
 1800 0 1 0 0 9 .5 4 ,115 3,674 0 1,837
 2200 3 3 0 2 9.7 4,181 22,397 7,466 14,931
Table 9. Continued.
 Egg count Egg count Egg count Egg count River Cross- Egg pro- Egg pro- Egg pro-
 Surface Surface Oblique Oblique "tage section duction duction duction
 Date Time (rep A) (rep B) (rep A) (rep B) (feet) ("q.ft .) Surface Oblique Combined
 910502 200 27 35 39 48 9.7 4,181 231,432 324,751 278,091
 600 31 10 39 29 9 .7 4,181 153,043 253,828 203,436
 1000 59 51 67 62 9 .7 4 ,181 410,604 481,527 446,066
 1400 1 6 6 2 9 .8 4 ,214 26,336 30,098 28 ,217
 1800 1 0 2 6 9.8 4,214 3,762 30,098 16,930
 2200 8 6 18 25 9 .8 4,214 52,671 161,776 107,224
 910503 200 19 23 31 26 9.8 4,214 158,014 214,447 186,230
 600 3 2 4 1 9 .8 4,214 18,811 18,811 18,811
 1000 17 9 17 12 9.8 4,214 97,818 109,105 103,461
 1400 0 0 0 5 9 .8 4,214 0 18,811 9,406
 ..,.
 1800 2 2 10 5 9.8 4,214 15,049 56,433 35,741
 -.J
 2200
 910504 200
 600 2 3 4 6 9.8 4,214 18,811 37,622 28,217
 1000 0 1 5 5 9.8 4,214 3,762 37,622 20,692
 1400 2 0 1 1 9.8 4,214 7,524 7,524 7,524
 1800 0 2 5 3 9.8 4,214 7,524 30,098 18,811
 2200 1 1 2 1 9.8 4,214 7,524 11,287 9,406
 910505 200 6 10 12 7 9 .8 4,214 60 ,196 71,482 65,839
 600 4 4 10 5 9.6 4,148 29,627 55,551 42,589
 1000 8 10 14 9 9.6 4,148 66,661 85,178 75,920
 1400 7 6 0 3 9 .7 4,181 48,526 11,198 29,862
 1800 8 6 10 9 9 .6 4 ,148 51,847 70,364 61,106
 2200 8 2 1 1 9.6 4,148 37,034 7,407 22,220
 910506 200
 600 16 3 20 13 9 .7 4,181 70,923 123,181 97,052
Table 9 . Continued.
 Egg count Egg count Egg count Egg count Ri.ver Cross- Egg pro- Egg pro- Egg pro-
 Surface Surface . Oblique Oblique stage section duction duction duction
 Date TiJDe (rep A) (rep B) (rep A) (rep B) (feet) (sq. ft.) Surface Oblique Combined
 1000 66 77 68 90 9 .7 4 ,181 533 ,786 589,777 561,781
 1400 13 3 3 9 9 .7 4 , 1 81 59 ,724 44 ,793 52,259
 1800 2 0 0 5 9.7 4,181 7,466 18 ,664 13,065
 2200 2 7 9 1 9 .7 4 ,181 33,595 37 ,328 35,461
 910507 200 9 4 10 9 9 .6 4,148 48 ,144 70 ,364 59 ,254
 600 16 8 19 46 9 .6 4 ,148 88,881 240,720 164,801
 1000 1 1 5 5 9 .6 4 , 1 4 8 7,407 37 ,034 22,220
 1400 8 3 2 11 9.7 4,181 41,060 48,526 44,793
 1800 15 17 11 8 9.7 4,181 119,449 70,923 95,186
 2200 47 30 21 44 9 .7 4,181 287,423 242,630 265,026
 01>-
 00
 910508 200 37 26 49 24 9 .6 4,148 233,314 270,348 251,831
 600 173 180 170 89 9 .6 4,148 1,307,297 959,179 1, 1 33 , 23 8
 1000 119 105 57 107 9.7 4 ,181 836,140 612,174 724,157
 1400 179 243 453 253 9 .6 4,148 1,562,832 2,614,595 2,088 ,713
 1800 83 95 120 98 9 .6 4,148 659 ,204 807 ,340 733,272
 2200 117 60 101 103 9 .6 4 ,148 655,500 755,492 705,496
 910509 200 83 92 120 101 9 .6 4,148 648 ,094 818,450 733,272
 600 144 114 223 181 9.6 4,148 955,475 1,496,170 1, 225,823
 1000 78 97 70 73 9.6 4,148 648,094 529,585 598,839
 1400 16 1 7 5 9.6 4,148 62,958 44,441 53,699
 1800 13 22 17 8 9.6 4,148 129 ,619 92,585 111,102
 2200 2 4 1 9 9 .6 4,148 22,220 37,034 29,627
 910510 200 26 19 36 41 9.6 4 , 148 166,653 285,161 225,907
 600 5 7 8 11 9.5 4,115 44,088 69,806 56,947
 1000 25 18 28 23 9.5 4 , 115 157,983 187,375 172,679
 1400 6 2 1 10 9 .5 4, 115 29,392 40,414 34,903
Table 9 . Continued.
 Egg count Egg count Egg count Egg count River Cross- Egg pro- Egg pro- Egg pro-
 Surface Surface Oblique Oblique stage section duction duction duction
 Date Time (rep A) (rep B) (rep A) (rep B) (feet) (sq.ft .) Surface Oblique Combined
 1800 5 12 10 8 9.4 4,082 61,959 65,604 63,781
 2200 15 10 9 27 9.3 4,049 90,382 130,150 110,266
 910511 200 21 18 31 27 9 .3 4,049 140,995 209,686 175,340
 600 78 43 60 43 9 .3 4,049 437,447 372,373 404,910
 1000 79 107 76 81 9 .2 4,016 666,959 562,971 614,965
 1400 20 15 34- : 20 9 .2 4,016 125,";;03 193,633 159,568
 1800 38 41 57 47 9.2 4,016 283,278 372,924 328,101
 2200 81 79 94 88 9.2 4,016 573,728 652,616 613,172
 .j>. 910512 200 131 107 121 117 9.2 4,016 853,421 853,421 853,421
 '0 600 98 113 157 104 9.2 4,016 756,604 935,895 846,250
 1000 224 301 209 235 9.2 4,016 1,882,547 1,592,097 1,737,322
 1400 26 48 8 3 9.2 4,016 265,349 39,444 152,397
 1800 53 73 51 69 9.2 4,016 451,811 430,296 441,054
 2200 3 2 8 19 9.1 3,983 17,782 96,024 56,903
 910513 200 57 83 48 59 9.1 3,983 497,900 380,538 439,219
 600 26 15 8 31 9 .1 3,983 145,814 138,701 142,257
 1000 42 37 58 60 9 .1 3,983 280,958 419,659 350,308
 1400 18 24 25 10 9 .2 4,016 150,604 125,503 138,053
 1800 61 89 75 82 9.1 3,983 533,464 558,359 545,912
 2200 19 63 58 29 9.1 3,983 291,627 309,409 300,518
 910514 200 389 427 526 453 9 .1 3,983 2,902,045 3,481,743 3,191,894
 600 316 204 315 198 9.1 3,983 1,849,343 1,824,448 1,836,895
 1000 154 264 138 114 9.1 3,983 1,486,587 896,220 1,191,403
 1400 23 18 36 43 9.1 3,983 145,814 280,958 213,386
 1800 64 79 59 68 9.1 3,983 508,569 451,666 480,118
 2200 41 41 71 77 9.1 3,983 291,627 526,351 408,989
Table 9 . c ontinued .
 Egg c ount Egg count Egg count Egg count River Cro:5s - Egg pro- Egg pro- Egg pro-
 Surface Surface Oblique Oblique s t a ge section duction duction duction
 Date TiJne (rep A) (re p B) (rep A) (rep B) (feet) (sq. f t.) Surface Oblique Combined
 910515 200 97 81 109 90 9 .1 3 ,983 633,044 707,729 670 ,387
 600 26 45 38 71 9.2 4 , 01 6 25 4 , 592 390,853 322 ,722
 1000 14 12 24 7 9.2 4,016 93,231 111,160 102 ,195
 1400 12 2 13 14 9.2 4,016 50 ,201 96 ,817 73 ,509
 1800 16 12 13 5 9 .2 4,016 100 , 402 64,544 82,473
 2200 16 12 11 17 9 .2 4,016 100,402 100,402 100,402
 910516 200 1 9 2 6 23 38 9. 2 4 ,016 161,361 218, 734 190,048
 600 50 41 30 47 9.2 4 ,016 326,308 276,107 301,207
 1000 15 18 23 1 7 9.2 4,016 118,331 143,432 1 30,882
 Ul 1400 12 19 26 20 9.2 4,016 111,160 164,947 138,053
 0 1800 34 46 68 47 9 .2 4,016 2 86, 8 64 412 ,367 349,616
 2200 20 42 47 43 9.2 4 ,016 222, 320 322,722 272 ,521
 910517 200 49 38 33 28 9.2 4,016 311,965 218,734 265 ,349
 600 63 67 38 26 9.2 4 , 01 6 466,154 229 ,491 347,823
 1000 10 8 18 14 9.2 4 , 01 6 64,544 114,746 89,645
 1400 5 3 2 2 9 .2 4,016 28,686 14,343 21 ,515
 1800 10 12 11 1 4 9 .2 4,016 78 ,888 89,645 84,266
 2200 16 11 23 17 9 .2 4,016 96,817 143 , 432 120,124
 910518 2 00 21 29 17 18 9.2 4,016 179,290 125,503 152,397
 600 39 13 44 37 9 .2 4,016 186,462 290, 450 238, 456
 1000 65 41 43 52 9.2 4 ,016 380 ,095 340,651 360,373
 1400 33 34 12 15 9 .2 4 ,016 240,249 96,817 168,533
 1800 73 44 86 109 9 .2 4,016 419 ,539 699,232 559,385
 22 00 9 24 10 10 9 .1 3,983 117,362 71,129 94,245
 910519 200 1 4 12 1 0 8 9.2 4 ,016 93,231 64,544 78,888
 600 1 8 2 13 13 9.2 4 ,016 71,716 93 , 231 82, 473
Table 9. Continued.
 Egg count Egg count Egg count Egg count River Cross- Egg pro- Egg pro- Egg pro-
 Surface Surface Oblique Oblique stage section duction duction duction
 Date Time (rep A) (rep B) (rep A) (rep B) (feet) (sq. ft.) Surface Oblique Combined
 1000 50 46 48 59 9.2 4,016 344,237 383,681 363,959
 1400 5 8 7 2 9.2 4 ,016 46,615 32,272 39,444
 1800 21 18 8 23 9.2 4,016 139,846 111,160 125,503
 2200 1 5 5 6 9 .1 3 ,983 21,339 39,121 30 , 23 0
 910520 200 17 9 14 12 9.0 3,950 91,703 91,703 91,703
 600 1 3 3 3 7.9 3,598 12,850 19,275 16,062
 1000 1 4 3 4 7.1 3,346 14,937 20,911 17,924
 1400 0 3 2 0 6.7 3,081 8,252 5,502 6 ,877
 1800 1 0 1 1 7 .3 3,409 3,044 6 ,087 4 ,565
 2200 3 1 12 5 8. 5 3,790 13,535 57,525 35,530
 Ul
 - 910521 200 4 7 3 5 8 .5 3,790 37,222 27,071 32 ,146
 600 10 5 4 1 8.4 3,758 50,328 16,776 33,552
 1000 10 8 9 4 8.5 3,790 60,909 43,990 52,450
 1400 5 5 3 4 8.5 3,790 33,838 23,687 28,763
 1800 4 4 3 2 8.5 3,790 27,071 16,919 21,995
 2200 9 7 3 8 8 .8 3,886 55,516 38,167 46,841
 910522 200 11 14 10 12 8.8 3,886 86,743 76,334 81,539
 600 9 3 2 8 8.8 3,886 41,637 34,697 38,167
 1000 14 9 36 54 8.8 3,886 79,804 312,276 196,040
 1400 14 7 8 11 9 .0 3,950 74,068 67,014 70,541
 1800 17 10 21 14 8.8 3,886 93,683 121,441 107,562
 2200 9 2 12 2 8.9 3,918 38,482 48,977 43,730
 910523 2 00 3 2 4 6 8.9 3,918 17,492 34,984 26 ,238
 600 1 0 4 7 8 .9 3,918 3 ,498 38 ,482 20,990
 1000 8 6 7 11 8 .9 3,918 4 8 , 977 62 ,971 55,974
 1400 8 1 5 2 8 .9 3,918 31 ,486 24 , 489 27,987
Table 9. Continued.
 Egg count Egg count Egg count Egg count River Cross- Egg pro- Egg pro- Egg pro-
 Surface Surface Oblique Oblique stage 15e c t i on duction duction duction
 Date T.ime (rep A) (rep B) (rep A) (rep B) (feet) (sq. ft . ) Surface Oblique Combined
 1800 13 4 12 11 8.9 3 ,918 59, 473 80,463 69,968
 2200 12 14 19 12 8.9 3, 918 90,958 108,450 99,704
 910524 200 21 17 25 20 8 .9 3,918 132,939 157,428 145,183
 600 19 28 17 23 8 .9 3,918 1 64 , 424 139,936 152,180
 1000 9 12 17 14 8 .9 3 ,918 73, 466 108,450 90 ,958
 1400 9 5 3 4 8.9 3,918 48,977 24,489 36,733
 1800 10 8 9 12 8 .9 3,918 62,971 73,466 68,219
 2200 11 18 15 20 9.0 3,950 102,285 123,447 112,866
 910525 200
 Ut 600 11 5 1 7 9.0 3,950 56,433 28,216 42,325IV
 1000 7 6 9 8 9 .0 3,950 45,852 59,960 52,906
 1400 4 6 11 5 9 .1 3,983 35,564 56,903 46,234
 1800 18 23 37 23 9 .1 3,983 145,814 213,386 179,600
 2200 23 21 18 7 9.1 3,983 156,483 88,911 122,697
 910526 200 19 21 31 26 9.1 3 ,983 142,257 202,716 172, 487
 600 3 5 4 24 9.1 3,983 28 ,451 99,580 64,016
 1 0 00 16 32 29 50 9 .1 3,983 170 , 709 280,958 225,833
 1400 19 13 5 18 9.1 3,983 113,806 81,798 97,802
 1800 34 40 78 64 9.1 3,983 263,176 505,013 384,094
 2200 12 26 10 30 9.1 3 ,983 135,144 142,257 138,701
 910527 200 16 12 21 26 9.1 3,983 99,580 167,152 133,366
 600 19 1 2 20 14 9.1 3,983 110,249 120,919 115,584
 1000 11 14 17 19 9.1 3,983 88,911 128,031 108, 471
 1400 7 9 10 11 9.1 3,983 56,903 74 ,685 65,794
 1800 8 11 18 11 9.1 3,983 67,572 103,136 85,354
 2200 9 .1 3,983
Table 9. Continued.
 Egg count Egg count Egg count Egg count River Cross- Egg pro- Egg pro- Egg pro-
 Surface Surface Oblique Oblique stage section duction duction duction
 Date Time (rep A) (rep B) (rep A) (rep B) (feet) (sq.ft.) Surface Oblique Combined
 910528 200 13 7 13 8 9.1 3,983 71,129 74,685 72,907
 600 3 1 12 9 9 .1 3,983 14,226 74,685 44,455
 1000 23 7 8 8 9.1 3,983 106,693 56,903 81,798
 1400
 1800 8 9 9 .1 3,983 60,459 60,459
 2200 11 11 18 8 9.2 4,016 78,888 93,231 86,059
 910529 200 22 13 7 15 9.2 4,016 125,503 78,888 102,195
 600 6 4 2 3 9.2 4,016 35,858 17,929 26,894
 1000 3 3 6 4 9 .2 4,016 21,515 35,858 28,686
 1400 13 3 3 4 9.2 4,016 57,373 25,101 41,237
 lJl 1800 8 4 4 3 9.2 4,016 43,030 25,101 34,065
 w 2200 11 4 9 12 9.2 4,016 53,787 75,302 64,544
 910530 200 19 23 26 29 9.2 4,016 150,604 197,219 173,911
 600 4 2 6 5 9.2 4,016 21,515 39,444 30,479
 1000 7 7 10 11 9 .2 4,016 50,201 75,302 62,752
 1400
 °
 2 1 5 9.2 4,016 7,172 21,515 14,343
 1800 4 6 9 10 9 .2 4,016 35,858 68,130 51,994
 2200 5 3 4 2 9.2 4,016 28,686 21,515 25,101
 910531 200 7 5 9 12 9.2 4,016 43,030 75,302 59,166
 600 2 1 1 1 9.2 4,016 10,757 7,172 8,965
 1000 4 3 6 5 9.2 4,016 25,101 39,444 32,272
 1400 2
 °
 3 2 9.2 4,016 7,172 17,929 12,550
 1800 6 5 7 4 9.2 4,016 39,444 39,444 39,444
 2200 4 3 8 5 9.2 4,016 25,101 46,615 35,858
 910601 200 2 7 9 9 9.2 4,016 32,272 64,544 48,408
 600 5 3 4 6 9.2 4,016 28,686 35,858 32,272
Table 9 . Continued .
 Egg count Egg count Egg count Egg count River Cro,ss- Egg pro- Egg pro- Egg pro-
 Surface Surface Oblique Oblique stage section duction duction duction
 Date Time (rep A) (rep B) (rep A) (rep B) (feet) (sq.ft .) Surface Oblique Combined
 1000 5 0 2 5 9 .2 4,016 17,929 25,101 21,515
 1400 6 1 1 1 9.2 4,016 25,101 7,172 16,136
 1800 1 0 2 1 9.2 4,016 3,586 10,757 7,172
 2200
 910602 200 4 2 2 3 9.1 3,983 21,339 17,782 19,560
 600
 1000 1 2 3 3 9 .1 3,983 10,669 21,339 16,004
 1400 0 2 3 1 9 .1 3,983 7,113 14,226 10,669
 1800
 2200 1 4 1 2 9.1 3 ,983 17,782 10,669 14,226
 U1
 .I>-
 910603 200 6 2 1 4 9.1 3,983 28,451 17,782 23,117
 600 0 1 1 1 9.1 3,983 3,556 7,113 5,335
 1000 0 0 1 0 9.1 3,983 0 3,556 1,778
 1400 1 0 5 0 9.1 3,983 3,556 17,782 10,669
 1800
 2200 0 0 0 0 9 .1 3,983 0 0 0
 910604 200 0 0 0 0 9.1 3,983 0 0 0
 600 0 2 1 1 9.1 3,983 7,113 7,113 7,113
 1000 3 0 0 2 9 .2 4,016 10,757 7,172 8,965
 1400 1 0 2 0 9 .2 4,016 3,586 7,172 5,379
 1800 7 3 5 6 9 .2 4,016 35,858 39,444 37,651
 2200 2 0 0 0 9 .2 4 ,016 7,172 0 3,586
 910605 200 1 0 0 0 9 .2 4,016 3,586 0 1,793
 600 0 0 1 1 9 .2 4 ,016 0 7 ,172 3,586
 1000 1 0 2 0 9 .2 4,016 3,586 7,172 5,379
 1400 0 0 0 0 9 .2 4,016 0 0 0
Table 9. Continued.
 Egg count Egg count Egg count Egg count River Cros.s- Egg pro- Egg pro- Egg pro-
 Surface Surface Oblique Oblique stage s e c tion duction duction duction
 Date Time (rep A) (rep B) (rep A) (rep B) (feet) (sq. f t.) Surface Oblique Combined
 1800 1 0 1 0 9 .1 3,983 3,556 3,556 3 ,556
 2200 0 0 1 1 9 .1 3,983 0 7,113 3,556
 910606 200 2 1 2 1 9 .1 3,983 10,669 10,669 10,669
 600 0 2 1 1 9 .1 3,983 7 ,113 7 ,113 7 ,113
 1000 0 0 2 1 9.0 3,950 0 10, 5 81 5 ,291
 1400 1 0 0 1 9.1 3 ,983 3,556 3 ,556 3,556
 1 800 0 0 1 0 9.2 4,016 0 3,586 1,793
 2200 0 0 1 0 9 . 1 3, 983 0 3,556 1, 778
 910607 200 0 1 1 2 9.1 3,983 3,556 10,669 7 ,113
 Ul 600 0 0 0 1 9 .1 3,983 0 3,556 1 ,778
 Ul 1000 0 2 2 2 9 .2 4,016 7 ,172 14,343 10,757
 1400 0 0 0 0 9 .1 3 ,983 0 0 0
 1800 0 0 1 1 9 .2 4 ,016 0 7, 172 3 ,586
 2200 3 1 2 1 9 .1 3,983 14,226 10,669 12 , 447
 910608 200
 600 0 0 0 0 9 .1 3,983 0 0 0
 1000 0 0 1 3 9.1 3,983 0 1 4,226 7 ,113
 1400 0 0 1 0 9.1 3,983 0 3,556 1,778
 1800 0 0 0 0 9. 1 3,983 0 0 0
 2200 0 0 0 0 9.1 3,983 0 0 0
 910609 200 0 0 0 0 9 .1 3 ,983 0 0 0
 600 0 1 0 0 9 .2 4 ,016 3,586 0 1,793
 1000 0 0 0 0 9 .2 4 ,016 0 0 0
 1400 0 0 0 0 9 .2 4,016 0 0 0
 1800 0 0 0 0 9 .1 3 ,983 0 0 0
 2200 0 0 2 1 9.2 4 ,016 0 10, 757 5, 37 9
Table 9. Continued .
 Egg count Egg count Egg count Egg count River Cross- Egg pro- Egg pro- Egg pro-
 Surface Surface Oblique Oblique stage section duction duction duction
 Date T:i.me (rep A) (rep B) (rep A) (rep B) (feet) (sq. ft.) Surface Oblique Combined
 910610 200 0 0 0 0 9 .9 3,919 0 0 0
 600 0 0 0 0 9 .5 3,790 0 0 0
 1000 1 1 0 0 9 .9 3 ,996 6,939 0 3, 470
 1400 1 1 1 0 7.3 3,409 6,097 3,044 4 , 5 65
 1900 0 0 0 0 7.0 3,314 0 0 0
 2200 0 0 0 0 6.9 3 ,159 0 0 0
 910611 2 00 1 0 0 0 6.5 2,925 2,612 0 1,306
 600 0 0 1 0 6.5 2,925 0 2,612 1 ,306
 1000 0 0 0 0 6.5 2 ,925 0 0 0
 lJl 1400 1 0 0 0 6.4 2,949 2 ,542 0 1 ,271
 0'1 1900 0 0 0 0 6 .3 2,770 0 0 0
 22 00 1 0 1 0 6.3 2,770 2,473 2 , 473 2,473
 910612 200 0 0 1 0 6.3 2,770 0 2,473 1,236
 600 0 0 0 0 6 .3 2,770 0 0 0
 1000 1 0 2 1 6.3 2,770 2 ,473 7,419 4,946
 1400 3 1 0 1 6 .2 2 ,692 9,614 2,403 6,009
 1900 1 1 0 5 6.2 2 ,692 4 ,907 12,017 9,412
 2200 0 0 0 1 6.3 2 ,770 0 2,473 1,236
 910613 200 0 0 0 0 6 .2 2 ,692 0 0 0
 600 0 0 0 0 6.2 2,692 0 0 0
 1000 0 0 3 1 6.2 2 ,692 0 9,614 4 , 907
 1400 0 0 0 0 6 .1 2,614 0 0 0
 1900 0 0 0 0 6.1 2,614 0 0 0
 2200 0 0 0 0 6.1 2,614 0 0 0
 910614 200 0 0 0 0 6 .1 2,614 0 0 0
 600 0 0 0 0 6.2 2,692 0 0 0
 1000 0 0 0 0 6. 1 2,614 0 0 0
-
 Table 10 . Daily egg production of striped bass at Barnhill's Landing, Roanoke River, North Carolina, in
 1991 estimated by two methods and two depths.
 Total eggs Total eggs Total eggs Total eggs Total eggs Total eggs
 No. of .surface only oblique only all depths surface only oblique only all depths
 Date samples (trip method) (trip method) (trip method) (Hassler) (Hassler) (Hassler)
 910415 20
 ° ° ° ° ° °910416 24
 ° ° ° ° ° °910417 24 349,644 349,644 349,644 349,644 349,644 349,644
 910418 24
 °
 349,644 174,822
 °
 348,682 174,341
 910419 20
 ° ° ° ° ° °910420 24
 ° ° ° ° ° °910421 24
 ° ° ° ° ° °910422 20
 ° ° ° ° ° °910423 24 458,738
 °
 229,369 476,091
 °
 238,046
 lJl 910424 24 876,376 1,551,832 1,214,104 886,916 1,552,103 1,219,509
 -.J 910425 20 3,053,031 4,072,565 3,562,798 3,039,676 4,052,901 3,546,289
 910426 20 248,855 493,996 371,425 247,741 495,481 371,611
 910427 24
 ° ° ° ° ° °910428 24 3,786,692 5,420,578 4,603,635 3,777,979 5,420,578 4,599,278
 910429 24 8,742,004 12,035,916 10,388,960 8,742,234 12,041,190 10,391,712
 910430 20 4,712,594 3,131,774 3,922,184 4,765,173 3,176,782 3,970,977
 910501 24 4,930,858 3,508,739 4,219,799 4,924,741 3,517,672 4,221,207
 910502 24 42,137,087 61,540,246 51,838,666 42,272,152 61,699,354 51,985,753
 910503 20 16,686,391 24,054,408 20,370,399 16,686,391 24,054,408 20,370,399
 910504 20 2,600 ,477 7,151 ,310 4,875,893 2,600,477 7,151,310 4,875,893
 910505 24 14,106,902 14,456,803 14,281,853 14,099,135 14,456,075 14,277,605
 910506 20 40,636,743 46,872,010 43,754,376 40,636,743 46,872,010 43,754,376
 910507 24 28,433,731 34,089,760 31,261,746 28,376,626 34,087,645 31,232,135
 910508 24 252,207,910 288,920,528 270,564,219 252,225,065 289,070,929 270,647,997
 910509 24 118,391,049 144,877,936 131,634,493 118,391,049 144,877,936 131,634,493
 910510 24 26,422,129 37,368,787 31,895,458 26,382,648 37,287,476 31,835,062
 910511 24 106,940,691 113,482,666 110,211,678 107,006,692 113,565,166 110,285,929
 910512 24 202,922,437 189,466,056 196,194,246 202,652,419 189,245,389 195,948,904
 910513 24 91,218,357 92,744,877 91,981,617 91,284,628 92,823,133 92,053,880
 910514 24 344,834,188 358,149 ,567 351,491,878 344,834,188 358,149,567 351,491,878
Table 10. Continued.
 Total eggs Total eggs Total eggs Total eggs Total eggs Total eggs
 No . of e:urface only oblique only all depths surface only oblique only all depths
 Date samples (trip method) (trip method) (trip method) (Hassler) (Hassler) (Hassler)
 910515 24 59,130,420 70,632,850 64,881,635 59,300,326 70,816,622 65,058,474
 910516 24 58,865,042 73,839,482 66,352,262 58,865,042 73,839,482 66,352,262
 910517 24 50,259,042 38,899,121 44,579,081 50,259,042 38,899,121 44,579,081
 910518 24 73,104,472 77,942,162 75,523,317 73,051,127 77,863,907 75,457,517
 910519 24 34,415,541 34,752,731 34,584,136 34,377,001 34,720,771 34,548,886
 910520 24 6,927,486 9,648,265 8,287,875 6,503,436 9,074,561 7,788,998
 910521 24 12,714,530 7,997,330 10,355,930 12,704,913 7,981,292 10,343,102
 910522 24 19,892,189 31,715,759 25,803,974 19,901,131 31,774,915 25,838,023
 910523 24 12,090,546 16,792,426 14,441,486 12,090,546 16,792,426 14,441,486
 910524 24 28,083,247 30,106,592 29,094,920 28,081,642 30,099,484 29,090,563
 910525 20 25,352,579 25,769,051 25,560,815 25,317,723 25,726,074 25,521,898
 lJl 910526 24 40,970,399 62,991,988 51,981,193 40,970,399 62,991,988 51,981,19300
 910527 20 24,377,387 34,210,283 29,293,835 24 ,377,387 34,210,283 29,293,835
 910528 18 19,088,460 21,564,450 19,911,252 19,082,707 21,544,992 20,177,056
 910529 24 16,179,281 12,392,640 14,285,960 16,179,281 12,392,640 14,285,960
 910530 24 14,113,840 20,310,161 17,212,001 14,113,840 20,310,161 17,212,001
 910531 24 7,229,040 10,843,560 9,036,300 7,229,040 10,843,560 9,036,300
 910601 20 6,196,320 8,261,760 7,229,040 6,196,320 8,261,760 7,229,040
 910602 16 4,097,040 4,609,170 4,353,105 4,097,040 4,609,170 4,353,105
 910603 20 2,048,520 2,663,076 2,355,798 2,048,520 2,663,076 2,355,798
 910604 24 3,095,340 2,923,220 3,009,280 3,089,700 2,918,050 3,003,875
 910605 24 514,950 1,200,610 857,780 514,950 1,201,550 858,250
 910606 24 1,024,260 1,874,990 1,449,625 1,024,260 1,877,810 1,451,035
 910607 24 1,197,790 2,227,690 1,712,740 1,198,260 2,225,340 1,711,800
 910608 20 0 1,024,260 512,130 0 1,024,260 512,130
 910609 24 172,120 516,360 344,240 171,650 514,950 343,300
 910610 24 625,291 146,097 385,694 613,608 153,402 383,505
 910611 24 366,110 244,073 305,092 367,777 245,185 306,481
 910612 24 810,911 1,285,721 1,048,316 823,137 1,293,501 1,058,319
Table 10 . Continued.
 Total eggs Total eggs Total eggs Total eggs Total eggs Total eggs
 No. of s urfac e only oblique only a l l depths surface only oblique only all depths
 Date samples (trip method) (trip method) (trip method) (Hassler) (Hassler) (Hassler)
 910613 24
 °
 461 ,472 230,736
 °
 454,804 227,402
 910614 12
 ° ° ° ° ° °
 Tot al eggs: 1,837,639,036 2,051,936,992 1 ,944,372 ,811 1 ,837,208 ,211 2,051 ,620,568 1 ,944,277,596
 S .D . ± 61,792,545 ± 65,745,038 ± 63,678 ,774 ± 61,787,080 ± 65 ,754,219 ± 63,679,706
Table 11. Results of statistical analyses (NPARIWAY, SAS 1985) on log-transformed data
 testing whether significant differences exist in the 1991 yearly egg production
 estimates calculated by the Hassler method and trip method using cross-sectional
 area of the river or discharge from the dam five hours previous, and surface and
 oblique sampling techniques. Significance tests with 2 df =Kruskal-Wallis with chi 
square statistic; 1 df = Wilcoxon signed-rank with Z statistic.
 Class Comparison n df Statistic Pe-statistic
 River cross-section only
 Hassler Surface, Oblique, All 61 2 0.26 0.8770
 Trip Surface , Oblique, All 61 2 0.27 0.8755
 All samples Hassler, Trip 61 1 0.00 0.9980
 Oblique Hassler, Trip 61 1 0.00 0.9980
 Surface Hassler, Trip 61 1 0.00 0.9898
 Cross-section vs volume
 (surface samples only)
 Hassler Xsect, Volume 61 1 -0.0437 0.9652
 Trip Xsect, Volume 61 1 0.0103 0.9918
 Volume Hassler, Trip 61 1 0.1977 0.8433
 Xsect Hassler, Trip 61 1 0.1566 0.8755
 60
Table 12. Striped bass spawninq in the Roanoke River, NC. estimated from surface sample. by the Ba.sler and trip
 methods, and by cross-sectional area (Hassler) and river discharge five hours previous, 1991.
 Mean
 Number Hean Mean Hean Mean Mean volume Daily 8ggs- by trip Daily eggs - a.s.ler
 of river Burface X-section river eggs/ filtered
 Date samples stage velocity (sq .!t. ) discharge day (ets) x-eect , FlowlS x-eeee . FlowlS
 910415 20 19 .9 3 .5 8,203 20,055 0 593 0 0 0 0
 910416 24 19 .9 3.5 8,188 20.139 0 590 0 0 0 0
 910417 24 19 .8 3.6 8,158 20,004 0 601 349,644 280 ,733 349,644 266,415
 910418 24 19.7 3.5 8,136 20,052 0 584 0 0 0 0
 910419 20 19 .7 3.4 8.131 20,083 0 570 0 0 0 0
 910420 24 19.8 3 .5 8,158 20,020 0 588 0 0 0 0
 910421 24 18 .5 3.0 7,593 15,836 0 498 0 0 0 0
 910422 20 15.1 2.4 6,145 11.297 0 405 0 0 0 0
 910423 24 13.5 2.4 5.554 10,825 0 407 458,738 432,721 476.091 425,1620\
 ...... 910424 24 12. 5 2 .6 5.174 10,791 0 436 876,376 705,096 886.916 792,839
 910425 20 11.8 2.4 4,925 10,809 1 409 3,053,031 2,949,890 3,039,676 3,042,206
 910426 20 11.5 2.3 4,817 10 ,860 0 384 248,855 262,064 247 ,741 271.327
 910427 24 9.6 2.2 4,1.66 8.085 0 369 0 0 0 0
 910428 24 8.6 2.1 3,833 7,B10 2 360 3,786,692 4,096,235 3,777,979 3.993.722
 910429 24 8.7 2.1 3,849 7.771 4 359 8,742,004 9,053,264 8,742,234 9,177,152
 910430 20 8.7 2.4 3,861 8,181 2 396 4,712 ,594 4,589,164 4,765,173 4,753,955
 910501 24 9.5 2.6 4 ,104 9,165 2 433 4,930,858 4 ,689,638 4,924,741 4,746,864
 910502 24 9.7 2.6 4,197 9,511 20 433 42,137,087 39,079,500 42,272,152 41,299,676
 910503 20 9 .8 2.5 4,214 9,500 8 418 16,686,391 15,345,593 16,686,391 16,783,198
 910504 20 9.8 2.1 4,214 9,511 1 359 2,600,477 3,001 ,748 2,600,477 3 ,053,943
 910505 24 9 .6 2.3 4,164 9,462 7 379 14,106,902 15,887,918 14,099,135 15,767,393
 910506 20 9.7 2.3 4,181 9,494 19 387 40,636,743 42,815,923 40,636,743 44,507,797
 910507 24 9.6 2.2 4,164 9,511 13 370 28,433,731 32, 449,·2-~2 28,376,626 32,707,375
 910508 24 9.6 2.2 4,153 9.483 118 371 252,207,910 298,989 ,699 252.225.065 290,064,227
 910509 24 9.6 2 .3 4,148 9.511 56 388 118,391,049 132.622 .304 118,391,049 130,578,718
 910510 24 9.5 2.3 4,104 9 ,402 13' 378 26,422,129 29.781.761 26,382,648 29,834,214
Table 12. Continued.
 Mean
 Number Hean Hean Mean Mean Mean volume Daily e g g s - by trip Daily eggs - Has.ler
 of river surface X-section river eggs/ filtered
 Da t e samples stage velocity ( 0 '1' ft .) discharge day (cfa) x-eeee , Flo.lS X-seet . Fl o . lS
 910511 24 9.2 2 . 1 4 , 0 27 9,250 52 35 7 106,940,6 91 128,029,1519 107, 006,692 1 29 .51 2 , 1 6 4
 910512 24 9 .2 2 .2 4.011 9,239 98 374 202,922,437 224.205 .849 202,652,419 233 ,208,626
 910513 24 9 .1 2.2 3.989 9,239 45 375 91 .218.357 1 0 4,468,886 91,284,628 105,307 .101
 91 0514 24 9 . 1 2.3 3 ,983 9,272 168 379 344,834,188 396,253.553 344,834,188 395,191 ,853
 910515 24 9. 2 2 .2 4, 011 9 ,293 29 376 59,130,420 68, 656,539 59,300,326 68,24 7 ,098
 910516 24 9 .2 2.3 4.016 9,293 29 379 58 .965,042 6 6 , 851 , 91 8 58 , 86 5,042 67,004,766
 910517 24 9 .2 2 . 3 4,016 9,277 24 386 50,259,042 56,512,309 50 ,259,042 56, 132 ,930
 910518 24 9 .2 2.3 4,011 9 , 271 35 384 73,104,472 81,980,151 73 ,051,127 82,063,464
 910519 24 9 .2 2 .1 4,011 9,293 17 361 34 ,415,541 40 ,410,730 34,377 , 001 41,227,980
 910520 24 7 . 7 2 .2 3,529 7, 0 81 4 369 6,927 ,48 6 7,763,489 6,503,436 6,597,644
 910521 24 8 .5 2 .2 3,801 9 ,174 7 362 12, 71 4, 5 3 0 15.835.787 12,704 ,913 15 .795,023
 '"tv 910522 24 8 .8 2 .3 3 ,902 9,180 10 390 19 ,892 . 189 22,396.011 19,901,131 22,392,820
 91 0523 24 8.9 2.4 3,918 9 ,110 6 402 12,0 90 ,546 13 ,149,964 12 , 090 ,546 13,050,179
 910524 24 8.9 2 .3 3,924 9,24 4 14 388 28 ,083,247 31 , 7 71 , 8 6 6 28 ,081,642 31,864,449
 910525 2 0 9 .1 2 .4 3,970 9,298 12 397 25,352,579 27, 722 , 131 25 ,317 ,723 2 7 ,914 ,144
 910526 24 9.1 2.3 3 , 9 83 9 ,34 7 20 388 40,910,399 45,654, 715 40,970,399 46 .222,310
 910527 22 9 .1 2.3 3 ,983 9,315 12 393 24,377,387 27,069,730 24 ,377,387 27,048, 083
 910528 20 9.1 2 .5 3,990 9,320 9 426 19 ,088 ,460 19,448,728 19 ,082, 107 19 ,521 ,860
 910529 24 9.2 2.4 4,016 9 ,212 8 410 16,179,281 16,758,331 16,179,281 rs, 992 , 567
 91 0530 24 9 .2 2 .4 4, 016 9 ,315 7 405 14, 113, 840 15 ,205,814 14 ,113,84 0 15,070 ,058
 910531 24 9.2 2 .3 4,016 9,304 4 394 7,229,040 1 , 90 6 , 5 67 7,229,04 0 7 , 93 9 ,35 0
 910601 20 9 .2 2 .3 4,016 9,315 3 394 6,196,320 6,726,519 6,196 ,320 6 ,805,535
 910602 16 9.1 2 .4 3,983 9,255 2 402 4 ,097,040 4,484,298 4, 097 ,040 4,418,486
 910603 20 9.1 2.5 3 ,983 9,298 1 417 2,~4B,520 2, 148 .570 2,048,520 2,140,231
 910604 24 9.2 2 .3 4,005 9,331 2 381 3,095,340 3,506,112 3, 089,700 3,522,916
 910605 24 9.2 2 .4 4,005 9,309 0 401 514,·950 569 ,640 514,950 556, 501
 910606 24 9. 1 2 .3 3 ,983 9,298 1 388 1 ,024,260 1,142,441 1 .024,260 1 ,151,233
 910607 24 9.1 2 .3 3.994 9 ,320 1 380 1 , 197 , 7 90 1 ,373,954 1 ,198,260 1,372,851
Table 12 . Continued.
 Mean
 Number Hean Hean Mean Kean Mean volume Daily eggll- by trip Da i l y egga - Baa.ler
 of river aurface X-section river f!JgglIl filtered
 Date lIamplea atag_ velocity (sq. ft.) di.charge day (efs) x-eece , Flo.15 X-aect. Flo.IS
 910609 20 '.1 2.4 3 ,993 9,336 0 3•• 0 0 0 0
 91060 9 24 ' .2 2 .3 4,005 9 ,336 0 3.1 1 72 ,120 18 7 ,'15 171,650 190 ,826
 910610 24 7.' 2 .1 3, 57' 7, 425 0 35. 625,291 590,057 613 ,600 661,01 9
 910611 24 ' .4 2.1 2 ,860 6,691 0 3 • • 366.110 499,141 367,777 464 ,619
 910612 24 ' . 3 2 .1 2,744 6,655 1 3" B10 ,911 1,031,121 823, 137 1, 076,238
 910613 24 '.1 1.. 2,'53 6,618 0 32' 0 0 0 0
 910 61 4 12 ' .1 2. 0 2 ,640 6,573 0 33. 0 0 0 0
 Total egg production ••tlmat. for the season : 1,937 ,639,03 6 2, 077,392 .576 1 . B37, 208, 211 2 , 081.731.118
 Standard deviation: ± 61 .792,545 ± 71 , 1 95 . 920 ± 61, 787, 080 ± 70,953 ,356
 0\
 W
Table 13. Summary of striped bass spawning activity in the Roanoke River observed at
 Barnhill's Landing (River Mile 117) and Jacob's Landing (RM 102) from 15 April
 to 14 June 1991.
 Barnhill's Jacob's
 Landing Landing
 1,382 1,386
 10,467 10,644
 11,641 12,878
 22,108 23,522
 1,837,208,211 2,068,304,334
 2,051,620,568 2,499,322,372
 1,944,277,596 2,283,054,389
 55.36 69.51
 56.32 71.84
 55.87 70.78
 17 April 25 April
 12 June 14 June
 57 51
 41 51
 Activity
 Total number of samples examined
 Total number of eggs collected:
 surface
 bottom
 total
 Egg production estimate (Hassler method):
 surface
 bottom
 average of combined samples
 Egg viability estimate (%):
 surface
 bottom
 average of combined samples
 Date of first egg:
 Date of last egg:
 Days within spawning window :
 Number of days of continuous spawning
 Dates of peak spawning activity and percent
 of total eggs collected:
 first peak
 second peak
 third peak
 Date at which egg production was:
 50% complete
 75% complete
 90% complete
 Percent of all viable eggs (17° C criteria):
 less than 10 hours
 10 to 18 hours
 20 to 28 hours
 30 hours and older
 newly-hatched larvae
 64
 8-9 May (20%)
 11-12 May (17%)
 14 May (19%)
 13 May
 15 May
 25 May
 62.29
 37.61
 0.09
 0.00
 0.00
 8-9 May (17%)
 11-12 May (15%)
 14 May (20%)
 14 May
 18 May
 26 May
 2.92
 26.05
 68.30
 2.68
 0.05
Table 13 (continued).
 Barnhill's Jacob's
 Activity Landing Landing
 Egg collection water temperatures (e):
 most eggs 20-23.9 (71%) 20-23.9 (70%)
 minimum temperature 14-15.9 «1%) 14-15.9 «1 %)
 maximum temperature 26.0+ «1%) 26.0+ «1%)
 I Surface water pH:most eggs 7.75+ (85%) 7.5-7.99 (90%)
 minimum pH 6.5-6.74 «1%) 5.75-5.99 «1 %)
 [
 maximum pH 8.0+ (33%) 8.0+ (4%)
 Dissolved oxygen (mg/L):
 most eggs 7-8.9 (95%) 7-8.9 (69%)
 I minimum DO 5-5.9 «1%) 4-4.9 «1%)
 Surface water velocity (em/second):
 !
 most eggs 60-79.9 (92%) 60-79.9 (96%)
 minimum velocity 40-59.9 (4%) 40-59 .9 «1 %)
 maximum velocity 100-119.9 «1%) 80-99.9 (3%)
 I Time of collection (percent of total eggs caught) :0200 22.5 11.3
 0600 20.9 16.7
 1000 24.1 21.6
 1400 9.5 24.6
 1800 12.9 14.6
 2200 10.1 11.2
 J
 J
 I
 i
 l 65
Table 14. Description of variables used in the Jacob 's Landing instantaneous egg production
 analyses.
 Variable name
 Barnhill 's Landing:
 Variable description
 BIPROD
 BDPROD
 BSTI
 BST2
 BST3
 BST4
 Jacob's Landing:
 JIPROD
 JDPROD
 JSTI
 instantaneous egg production estimate
 number of dead eggs in BIPROD
 number of live Stage 1 eggs (0-8 hours) in BIPROD
 number of live Stage 2 eggs (10-18 hours) in BIPROD
 number of live Stage 3 eggs (20-28 hours) in BIPROD
 number of live Stage 4 eggs (30+ hours) in BIPROD
 instantaneous egg production estimate
 number of dead eggs in JIPROD
 number oflive Stage 1 eggs (0-8 hours) in JIPROD
 Variable name additions:
 L prefix indicating natural log transformed data of the variable
 L4 suffix indicating data record 4 hours earlier than the matching record
 downstream
 L8 suffix indicating data record 8 hours earlier than the matching record
 downstream
 L12 suffix indicating data record 12 hours earlier than the matching record
 downstream
 66
67
Table 16. Results ofregression analyses (PROC REG, SAS Institute 1985) predicting adjusted
 instantaneous egg production estimates at Jacob's Landing (RM 102) (by subtracting
 Jacob 's stage 1 eggs) based on egg production estimates from Barnhill's Landing
 (RM 117) four, eight, and 12 hours earlier. Variable definitions in Table 14.
 Dependent Independent Parameter Durbin
 variable DF F P R2 variables estimate P>T Watson P
 Four-hour egg transport:
 LAJIPROD 1,170 120.668 0.0001 0.42 IN1ERCEPT 10.394 0.0001 1.197 0.440
 LBIPROD4 0.408 0.0001
 LAJIPROD 5,153 40.619 0.0001 0.57 IN1ERCEPT 10.533 0.0001 1.570 0.317
 LBSTIL4 0.082 0.0001
 LBSTZL4 0.057 0.0001
 LBSTIL4 0.035 0.2250
 LBDPROD4 0.042 0.0300
 LJDPROD 0.261 0.0001
 Eight-hour egg transport:
 LAJIPROD 1,170 294.383 0.0001 0.63 INTERCEPT 5.661 0.0001 1.916 0.136
 LBIPROD8 0.685 0.0001
 LAJIPROD 5,152 233.102 0.0001 0.88 IN1ERCEPT 3.082 0.0001 1.601 0.174
 LBSTIL8 0.065 0.0001
 LBSTZL8 0.033 0.0001
 LBSTIL8 -0.014 0.2931
 LBDPROD8 0.001 0.3668
 LJDPROD 0.787 0.0001
 12-hour egg transport:
 LAJIPROD 1,170 36.635 0.0001 0.18 IN1ERCEPT 13.832 0.0001 0.895 0.590
 LBIPRODI2 0.205 0.0001
 LAJIPROD 5,150 192.209 0.0001 0.86 IN1ERCEPT 3.178 0.0001 1.557 0.224
 LBSTlL12 0.042 0.0034
 LBSTZL12 0.033 0.0001
 LBSTIL12 -0.004 0.7650
 LBDPRODI2 0.Q25 0.0211
 LJDPROD 0.789 0.0001
 68
Table 17. Summary of striped bass spawning activity in the Roanoke River observed at Pollock's Ferry (RM 105) in 1988,
 and Barnhill's Landing (RM I 17), 1989-1991.
 Activity
 Number of samples examined:
 surface
 bottom
 total
 Number of eggs collected:
 surface
 bottom
 total
 Hassler egg production estimate:
 surface
 bottom
 average of combined samples
 Egg viability estimate:
 Date of first egg:
 Date of last egg:
 Days within spawning window:
 Number of days of
 continuous spawning:
 Major spawning activity and percent
 of total eggs collected:
 first peak
 second peak
 third peak
 fourth peak
 1988
 625
 624
 1,249
 20,144
 21,575
 41,719
 2.082 billion
 2.277 billion
 2.178 billion
 89.0%
 12 Apr
 2 Jun
 52
 27
 11-12 May (38%)
 15-16 May (22%)
 20 May (13%)
 23-24 May (13%)
 1989
 688
 678
 1,366
 4,722
 5,107
 9,829
 0.638 billion
 0.720 billion
 0.677 billion
 41.8%
 16Apr
 9 Jun
 55
 23
 23-24 May (27%)
 26-27 May (33%)
 31 May-I Jun (26%)
 1990
 698
 696
 1,394
 5,309
 6,630
 11,939
 0.965 billion
 1.26I billion
 1.114 billion
 58.5%
 24 Apr
 12 Jun
 50
 50
 2-3 May (7%)
 7 May (15%)
 10 May (20%)
 1991
 692
 690
 1,382
 10,467
 11,641
 22,108
 1.837 billion
 2.052 billion
 1.944 billion
 55.4%
 17 Apr
 12 Jun
 57
 41
 8-9 May (20%)
 11-12 May (17%)
 14 May (19%)
Table 17. Continued .
 Activity 1988 1989 1990 1991
 Date at which egg production was:
 50% complete 15 May 26 May 10 May 13 May
 75% complete 20 May 27 May 14 May 15 May
 90% complete 24 May 31 May 20 May 25 May
 Percent of all staged viable eggs
 (17° C criteria):
 less than 10 hours <1 77 71 62
 10 to 18 hours 13 5 29 38
 20 to 28 hours 72 19 <1 <1
 30 hours and older 14 <1 <1 0
 newly-hatched larvae 0 0 0 0
 Percent of all eggs collected at
 water temperature ("C):
 --.J 12-13.9 <1 0 0 0
 0 14-15.9 <1 <1 0 <1
 .16-17.9 2 3 <1 2
 18-19.9 43 40 48 22
 20-21.9 36 48 48 36
 22-23.9 16 8 3 36
 24-25.9 4 <1 0 5
 26+ 0 0 0 <1
 Percent of all eggs collected at
 surface water pH:
 5.50-5.74 0 0 0 0
 6.00-6.24 <1 0 0 0
 6.25-6.49 2 0 0 0
 6.50-6.74 2 <1 0 <1
 6.75-6.99 4 1 1
 7.00-7.24 67 1 12 2
 7.25-7.49 8 3 24 <1
 7.50-7.74 14 6 52 12
 7.75-7 .99 <1 38 6 52
 8.0+ 0 47 3 33
 not recorded 3 3 1 <1
Table 17. Continued.
 Activity 1988 1989 1990 1991
 Percent of all eggs collected at
 surface dissolved oxygen (mg/L):
 5-5.9 6 0 0 <1
 6-6.9 53 0 3 3
 7-7.9 32 28 47 68
 8-8.9 8 72 46 28
 9-9.9 <I <1 3 <1
 10-10.9 <I 0 0 0
 not recorded <I <1 <1 <I
 Percent of all eggs collected at
 surface water velocity (cm/second) :
 40-59.9 0 7 2 4
 60-79.9 30 22 66 92
 -..J 80-99.9 69 9 26 4
 - 100-119.9 <I 58 7 <I
 .120-139.9 0 5 0 0
 not recorded <I <I 0 0
 Percent of all eggs collected
 at time:
 0200 5 18 28 23
 0600 15 28 42 21
 1000 18 22 12 24
 1400 19 II 6 9
 1800 27 6 4 13
 2200 16 15 7 10
APPENDIX
 72
Table A-I. List of Counties Enumerated in Figure 1.
 (
 I
 1
 r
 I
 I
 Virginia
 1. Roanoke
 2. Frankl in
 3. Patrick
 4. Henry
 5. Bedford
 6. Pittsylvania
 7. Campbell
 8. Halifax
 9. Charlotte
 10. Lunenburg
 11. Mecklenburg
 12. Brunswick
 North carolina
 13. Stokes
 14. Rockingham
 15. Caswell
 16. Person
 17. Granville
 18. Vance
 19. Warren
 20. Halifax
 21. Northampton
 22. Bertie
 23. Martin
 24. Washington
 Halifax 120 77°35'5"E 36°20'6"N
 Johnson's Landing 118.5 77°18'23"E 36°33'20"N
 Barnhill 's Landing 117 77°18'23"E 36°32'15"N
 Pollock' Ferry 105 77°24'30"E 36°15'30"N
 Jacobs Landing 102 77022'30''E 36014'57''N
 Palmyra 78.5 77°19'30"E 36°4'32"N
 Location of the historical sampling locations used by W.W. Hassler and co 
workers (1959-1987) and Rulifson (l988-present).
 I
 I
 I
 !
 (
 I
 I
 1
 j
 L
 Table A-2.
 Location River mile
 73
 Latitude Longitude
Table A-3. Hourly sample grid for the 1991 striped bass egg study at Barnhill's
 Landing, Roanoke River, NC.
 Day Date 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Total
 0 910415 4 4 4 4 4 20
 1 910416 4 4 4 4 4 4 24
 2 910417 4 4 4 4 4 4 24
 3 910418 4 4 4 4 4 . . 4 24
 4 910419 4 4 4 4 4 20
 5 910420 4 4 4 4 4 4 24
 6 910421 4 4 4 4 4 4 24
 7 910422 4 4 4 4 4 20
 8 910423 4 4 4 4 4 4 24
 9 910424 4 4 4 4 4 4 24
 10 910425 4 4 4 4 4 20
 11 910426 4 4 4 4 4 20
 -.) 12 910427 4 4 4 4 4 4 24
 .". 13 910428 4 4 4' 4 4 4 24
 14 910429 4 4 4 4 4 4 24
 15 910430 4 4 4 4 4 20
 16 910501 4 4 4 4 4 4 24
 17 910502 4 4 4 4 4 4 24
 18 910503 4 4 4 4 4 20
 19 910504 4 4 4 4 4 20
 20 910505 4 4 4 4 4 4 24
 21 910506 4 4 4 4 4 20
 22 910507 4 4 4 4 4 4 24
 23 910508 4 4 4 4 4 4 24
 24 910509 4 4 4 4 4 4 24
 25 910510 4 4 4 4 4 4 24
 26 910511 4 4 4 4 . . 4 4 24
 27 910512 4 4 4 4 4 4 24
 28 910513 4 4 4 4 4 4 24
 29 910514 4 4 4 4 4 4 24
Table A-3 . Continued
 Day Date 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Total
 30 910515 4 4 4 4 4 4 24
 31 910516 4 4 4 4 4 4 24
 32 910517 4 4 4 4 4 4 24
 33 910518 4 4 4 4 4 4 24
 34 910519 4 4 4 4 4 4 24
 35 910520 4 4 4 4 4 4 24
 36 910521 4 4 4 4 4 4 24
 37 910522 4 4 4 4 4 4 24
 38 910523 4 4 4 4 4 4 24
 39 910524 4 4 4 4 4 4 24
 40 910525 4 4 4 4 4 20
 41 910526 4 4 4 4 4 4 24
 42 910527 4 4 4 4 4 20
 43 910528 4 4 4 2 4 18
 -..I 44 910529 4 4 4 4 4 4 24u.
 45 910530 4 4 4 4 4 4 24
 46 91 0531 4 4 4 4 4 4 24
 47 910601 4 4 4 4 4 20
 48 91 0602 4 4 4 4 16
 49 91 0603 4 4 4 4 4 20
 50 91 0604 4 4 4 4 4 4 24
 51 910605 4 4 4 4 4 4 24
 52 910606 4 4 4 4 4 4 24
 53 910607 4 4 4 4 4 4 24
 54 910608 4 4 4 4 4 20
 55 910609 4 4 4 4 4 4 24
 56 910610 4 4 4 4 4 4 24
 57 910611 4 4 4 4 4 4 24
 58 910612 4 4 4 4 4 4 24
 59 910613 4 4 4 4 4 4 24
 60 910614 4 4 4 12
Table A-4. Water quality data collected at Barnhill 's Landing, Roanoke River ,
 North Carolina, from 15 April to 14 June 1991.
 PAGE DATE TIME ATEMP WTEMP PH DO TDS SECCHI WVEL RSTAGE XSECT SREVS OREVS
 1 9104 15 600 13.5 15.0 7.8 9.2 2 .0 113.5 19.9 8203.2 6818 7361
 2 910415 1000 15.5 15 . 0 7 .7 9 .4 4 .0 97.4 19 .9 8203.2 6226 6082
 3 910415 1400 28 .0 15 .0 7.9 8.9 4 .0 30.0 109.4 19.9 8203 .2 2472 7113
 4 910415 1800 21.0 16 .0 8.0 8 .8 4.0 40.0 107 .2 19 .9 8203 .2 6115 6364
 5 910415 2200 20.0 16.0 8 .3 9 .0 4 .0 110 .0 19.9 8203.2 7410 7044
 6 910416 200 18.0 15.0 7 .9 8.6 3.0 109.4 19.9 8203.2 6780 6890
 7 910416 600 18.0 15 .0 7 .8 8.9 4 .0 45.0 110.0 20.0 8248 .1 7180 747 7
 8 910416 1000 18 .0 15 .0 7.9 9.0 4.0 70 .0 107.8 19 .9 8203 .2 6630 6577
 9 910416 1400 26.0 16 .0 8 .2 8.9 4 .0 80 .0 103.6 19 .8 8158.3 7585 7058
 1 0 910416 1800 24.0 16.5 8 .8 8 .7 4.0 75.0 105.6 19.8 8158.3 7001 68 74
 11 910416 2200 20.0 16.5 7.9 8.1 4 .0 105.6 19.8 8158.3 7074 8156
 12 910417 200 16.0 17.0 7 .8 8.8 4 .0 104.6 19.8 8158.3 682 7 6925
 -.J 13 910417 600 13.0 15 .0 8.4 9.0 4.0 80.0 123.3 19.8 8158.3 7554 6741
 0\ 14 910417 1000 20 .0 16 .0 7 .9 7 . 0 4 .0 60 .0 111.1 19.8 8158.3 7 42 9 5633
 15 910417 1400 24 .0 16 .0 8.1 8 .5 3.0 75 .0 104 .1 19.8 8158.3 7 038 6814
 16 910417 1800 27 .0 16.0 8.0 8.4 4.0 80.0 106.7 19.8 8158.3 7287 7484
 17 910417 2200 22.0 17.5 8.1 8.4 4.0 104.1 19 .8 8158.3 6637 7726
 18 910418 200 18.0 17.0 8.1 9.2 4.0 104.1 19 .8 8158.3 ·71 17 6800
 19 910418 600 15.0 16 .0 7.9 9.5 4.0 75 . 0 101.1 19 .8 8158.3 6799 6506
 20 910418 1000 17.0 16.5 8.3 8.9 4 .0 60.0 102.1 19.8 8158 .3 6962 6332
 21 910418 1400 22.0 16.5 8 .3 8.9 4 .0 70 .0 108 .3 19 .7 8113.4 7098 6774
 22 910418 1800 19 .0 16.0 8.2 8.9 4.0 70.0 109.4 19 .7 8113 .4 7492 7079
 23 910418 2200 17.0 17.0 8.2 8.5 4 .0 111.1 19 .7 8113'.4 7273 6985
 . . . 24 910419 200 14 .0 15.5 8.1 8.8 4.0 107 .8 19 .7 . 811 3 . 4 6852 6910
 .; ' .. 25 910419' 600 13.0 15.5 8.0 8 :5 5.0 100.2 19.7 <81.i3.4 .7276 69,05
 • 26 910419 1000 14.0 16.0 8.2 4.0 .
 27 910419 1400 16.0 16.0 . 8 .0 8 .4 4 .0 65 .0 104 .1 19'.7 :.jji i3 . 4 6854 6901
 28 910'~i9 1800 15 .0 15.5 7.9 8.6 4 .0 75.0 101. 6 19.8 8158 .3 6512 6978
 29 910419 2200 14.0 15 .5 8.1 9.0 4 .0 103.6 19.8 8158.3 6844 6962
 30 910420 200 13.0 15.5 8.3 9.2 5 .0 103.1 19.8 8158 .3 6903 6512
~
 I
 Table A-4. Continued .
 PAGE DATE TIME ATEMP WTEMP PH DO TDS SECCHI WVEL RSTAGE XSECT SREVS OREVS
 31 910420 600 13.0 15 .0 8 .4 9.2 5.0 105.6 19 .8 8158 .3 6988 6844
 32 910420 1 00 0 15.0 15.0 8 .3 9.2 5.0 75.0 106 .7 19.8 8158.3 6826 6673
 33 910420 1400 16 .0 14.0 8.7 9.8 4.0 50.0 107 .8 19.8 8158 .3 6794 71 2 0
 34 910420 18 0 0 17.0 15 .0 8 .3 9.8 4 .0 111.1 19.8 8158 .3 6946 6833
 35 910420 2200 16.0 14.5 8.3 9 .0 4 .0 106 .1 19 .8 8158.3 6943 693 1
 36 910421 200 13.0 14.5 7 .8 9.4 5.0 101 .6 19 .4 7978.7 6647 686537 910421 600 16 .0 13.0 8 .5 9.0 4 .0 97 .4 18.8 7709.3 7520 6011
 38 910421 1000 15 .0 14.0 8 .1 9.8 4.0 65 .0 80.5 19.4 7978 .7 5351 5407
 39 910421 1400 16 .0 14 .0 8 .0 9 .8 5 .0 70.0 87 .8 18.7 7 6 64 . 5 6523 6210
 40 910421 1800 16 .0 14 .5 7.8 9.8 4 .0 70 .0 85.0 18 .0 7350.3 5723 4812
 41 910421 2200 14.0 13.0 7.7 9.0 90 .0 16.9 6875.4 6036 5851
 42 910422 200
 43 910422 600 12 .0 12.0 7 . 7 10.0 70. 0 81.1 15.9 64 75.2 504 7 5093
 44 910422 1000 12.0 13.5 9.1 80 .0 77 .0 15 .6 6356.8 3866 5451...,
 45 910422 1400 18 .0 15 .0 9 .1 80.0 72.8 14 .8 6042.2 4825 4608...,
 46 910422 1800 16 .0 15 .0 7. 8 9.0 3.0 70 .0 76.2 14.7 6003.4 4775 4381
 47 910422 2200 12.0 15.0 7.9 9.5 3.0 60.1 14.3 5848.0 4614 4440
 48 910423 200 12.0 15.0 8.0 9.9 4.0 76.2 13.8 5655 .6 4916 4278
 49 910423 600 6 .0 15.0 8.1 8.9 4.0 80.0 67 .7 13.8 5655.6 4546 4923
 50 910423 10 0 0 14 .0 15.0 8.0 9.4 4 .0 70 .0 66 .9 13.7 5617 . 6 4798 4834
 51 910423 1400 20.0 15.0 8.0 9.1 70.0 78.4 13.7 5617.6 5207 5068
 52 910423 1800 20.0 15.0 8.1 8 .3 80 .0 82 .4 13 .2 5427.8 5133 4408
 53 910423 2200 15.0 15 .0 9.4 9 .4 4 .0 71.8 13.0 5351.9 5886 5494
 54 910424 200 12.0 15.5 7.9 10 .0 5.0 72 .1 12.8 5278 . 1 5252 52 10
 55 910424 600 12.0 15.0 7.3 8 .8 70.0 73.3 12.7 5 2 41. 3 5295 4965
 56 910424 1000 17 .0 15 .0 7.8 9.2 80 ; .0 69.7 12.8 5278.1 3458 5063
 57 910424 1400 23.0" 16.0 7.9 8.1 60 '"<T 102.1 12.4 5130.6 5192 474058 910424 1800 2'4 .0 16.0 7.8 8 .5 60.0 78.4 12.3 5093.7 4880 4364
 59 910424 2200 15 .0 '16 .5 7 .9 9 .4 78.4 12 .1 5020 .0 5151 498 1
 60 910425 20 0 13:0 16.0 7.8 9.8 75.9 12.0 4983.1 4099 4918
 61 910425 600 8.0 16.0 8 .1 8 .6
 62 910425 1000 18.0 16.0 8.3 9.0 70.0 77.6 11. 9 4947 .0 4697 5026
 63 910425 1400 21.0 16.0 8.1 8.1 60.0 70.9 11.9 4947.0 5225 4722
Table A-4. Continued .
 PAGE DATE TIME ATEMP WTEMP PH DO TDS SECCHI WVEL RSTAGE XSECT SREVS OREVS
 64 910425 1800 20.0 16 .0 8.1 8.8 70.0 69 .3 11. 8 4910.9 5190 4991
 65 910425 2200 16 .0 17.0 8 .1 8.9 77.6 11. 6 4838.8 5207 4826
 66 910426 200 15 .0 17 .0 7.9 9.4 72.3 11.6 4838.8 5445 5235
 67 910426 600 12 .0 16.0 8.4 9.0 70.0 75 .9 11. 6 4838.8 5500 4962
 68 910426 1000 20 .0 16 .0 7 .0 8.4 80.0 65.0 11. 6 4838.8 4388 3592
 69 910426 1400 26.0 16.0 8.2 8.2 70.0 67 .7 11.5 4802.7 5148 4152
 70 910426 1800 20.0 16.0 8.2 8.2 70 .0 67.5 11. 4 4766.6 4965 4679
 71 910426 2200 19.0 17.0 8.0 8.9
 72 910427 200 18.0 17.0 8.2 8.8 67 .9 10.6 4485.2 5209 5167
 73 910427 600 16.0 16 .0 8.6 8.1 80.0 67.9 9.7 4180.7 4364 1248
 74 910427 1000 20 .0 16 .0 8.3 8.9 75.0 66.1 9.7 4180.7 4574 4239
 75 910427 1400 23.0 16.5 8.4 8.6 75.0 67.5 9.6 4147.8 4507 4323
 76 910427 1800 24 .0 17.0 8 .3 8.9 70.0 66 .9 9.6 4147.8 4429 4392
 77 910427 2200 20.0 18.0 8.2 9.0 65 .8 8.7 3854 .1 4230 4138
 -.I 78 910428 200 18.0 18.0 7.9 9.2 68.4 8.6 3822.0 4312 423500 79 910428 600 18 .0 18.0 7.8 9.2 64.8 8.4 3757.8 4591 4373
 80 910428 1000 21.0 18.0 8.7 8.2 50.0 58.6 8.7 3854.1 3935 4574
 81 910428 1400 23.0 18 .0 8.4 8.0 50 .0 65.3 8.7 3854.1 4209 5127
 82 910428 1800 22.0 18.0 8.2 7.9 50.0 67.5 8.7 3854 .1 4302 4043
 83 910428 2200 19.0 18.0 8.2 7.9 67.1 8.7 3854.1 4590 4306
 84 910429 200 18.0 18.0 8.1 7.9 66.3 8.7 3854.1 5185 4440
 85 910429 600 19.0 17.0 8.2 8.2 60 .0 67.9 8.7 3854.1 4504 4470
 86 910429 1000 22.0 17.0 8.2 7.4 80 .0 66.3 8.6 3822.0 1652 3375
 87 910429 1400 25.0 18.0 8.2 7.3 75.0 62 .6 8.7 3854.1 4125 . 3483
 88 910429 1800 24.0 18.0 8.3 7.3 80.0 64.3 8.7 3854.1 4420 4035
 89 910429 2200 20.0 18.0 8.3 8.8 63.5 8.7 3854.1 4773 4562
 90 910430 200 19.0 18.0 7.8 9.0
 91 910430 600 19.0 17.0 7.9 8.8 70.0 64.6 8.6 3822.0 5205 4253
 92 910430 1000 22.0 18.0 . 8 . 2 9.8 70.0 72.6 8.5 3789.9 4681 4371
 93 910430 1400 23.0 18.0 8.2 7.4 60.0 73.6 8.6 3822.0 4646 4328
 94 910430 1800 24.0 18.0 8.0 7.9 65 .0 69.3 8 .8 3886 .1 4210 4320
 95 910430 2200 20.0 18 .5 8.1 8.2 79.6 9.1 3983.2 5009 5067
 96 910501 200 18.0 18.5 8.0 8 .4 79.3 . 9.2 4016.1 4877 4673
Table A-4. Continued.
 PAGE DATE TIME ATEMP WTEMP PH DO TDS SECCHI WVEL RSTAGE XSECT SREVS OREVS
 97 910501 600 18 .0 19.0 8 .3 8 .4 65.0 78.4 9.4 4082.0 5309 5186
 98 910501 1000 22 .0 19.0 7.9 7.9 70.0 78 .1 9 .5 4114.9 5123 5032
 99 910501 1400 25.0 1-8.5 8 .1 7 .8 70.0 82.1 9 .5 4114.9 5023 4923
 100 910501 1800 24 .0 19.0 8 .0 7.8 75.0 72.3 9 .5 4114.9 4692 4667
 101 910501 2200 22.0 20 .0 8.6 8 :0 80.5 9 .7 4180 .7 5492 4656
 102 910502 200 1 6 . 0 19.0 8.0 8.4 84 .0 9.7 4180.7 5842 5821
 103 910502 600 15.0 18.0 8.4 7.4 60.0 80.8 9.7 4180.7 54 74 5379
 104 910502 1000 22.0 17 .5 8.2 7.9 75 .0 84 .3 9.7 4180.7 4622 4652
 105 910502 1400 26 .0 20.0 8.2 7.4 68 .0 72 .6 9 .8 4213. 7 5234 3434
 106 910502 1800 17.0 19 .0 8.3 7.6 70.0 72.8 9.8 4213. 7 4895
 107 910502 2200 12.0 20.0 7.9 8.3 7 6 . 8 9.8 4213.7 4957 4930
 108 910503 200 10.0 19.0 7.7 8.4 83.7 9.8 4213 .7 5123 4820
 109 91 0503 600 10.0 19.0 7.8 7.9 65.0 65.4 9 .8 4213.7 4693 4715
 -../ 110 910503 1000 21.0 19.0 7.7 8.1 70 .0 89 .3 9 .8 4213.7 5156 4463
 '0 111 910503 1400 25.0 21.0 7.9 7.8 65 .0 68.6 9.8 4213.7 4946 4884
 112 910503 1800 24.0 19.0 7.9 7.6 75 .0 72 .6 9 .8 42 13.7 5301 5309
 113 910503 2200 19 .0 20 .0 7.9 8 .6
 114 910504 200 15.0 18.5 7 .0 8 .8
 115 910504 600 14 .0 18 .0 7.7 9.4 69.9 9.8 4213 .7 4475 5041
 116 910504 1000 16.0 18.0 7.8 9.2 70. 0 64.6 9 .8 4213.7 4621 4699
 117 910504 1400 22.0 20.0 7 . 6 8.2 7 0 . 0 61.5 9.8 4213.7 5016 5048
 118 910504 1800 23.0 19.5 7.9 7.8 75.0 67 .5 9.8 4213.7 4820 4642
 119 910504 2200 18.0 19.0 7.6 8.0 61. 8 9.8 4213.7 4381 4862
 120 910505 200 17 .0 19.5 7.9 8.3 67.3 9.8 4213 .7 4832 3521
 121 910505 600 16.0 18.0 7.8 8 .0 68.0 77 .6 9.6 414 7.8 5265 6352
 122 910505 1000 20.0 18 .5 7 .9 8.2 75.0 70.9 9.6 4147 .8 4915 5012
 123 910505 1400 22.0 19.0 7.7 8.2 75 .0 67.1 9.7 4180.7 49.10 4862
 124 910505 1800 24 .0 20 .0 7 .9 8.0 80.0 67.9 9 .6 4i47.8 44 _46 50 77
 125 910505 2200 20.0 20.0 7.9 7.4 62.0 9.6 .~ 14 7.8 4i15 4700
 126 910506 200 18.0 19.0 7.9 7 .7
 127 910506 600 20 .0 19.0 8 .0 7.5 65.0 59.6 9.7 4180.7 4400 5252
 128 910506 1000 21.0 19 .0 7.9 8.4 70.0 75.9 9.7 4180.7 4856 4701
Table A-4 . Continued.
 PAGE DATE TIME ATEMP WTEMP PH DO TDS SECCHI WVEL RSTAGE XSECT SREVS OREVS
 129 91 0506 1400 21.0 22 .0 8 .0 7.6 70. 0 74 .3 9 .7 41 80. 7 4818 5414
 130 91 05 0 6 180 0 22 .0 20.5 8 .0 7 .8 65 .0 75 .4 9. 7 418 0 . 7 43 85 4929
 131 910506 220 0 20.0 20 .0 7. 8 7.8 65 .8 9 . 7 41 80.7 4410 4494
 132 91050 7 200 1 8. 0 20 .0 7. 9 8 .4 65.3 9.6 4147.8 4880 4623
 133 910507 600 18 .0 19.5 8.0 7 . 2 60.0 71. 4 9.6 4147.8 49 00 5003
 134 9105 07 1000 21.5 19 .5 8.0 7. 2 80.0 64 . 1 9.6 4147.8 549 1 1788
 135 910507 1400 24.0 21.5 7 .8 6 .8 80.0 68.2 9. 7 4180 .7 5732 4849
 136 91 0507 1800 20 .0 20 . 0 8.0 7. 6 70.0 66 .1 9. 7 4180 . 7 4395 4193
 137 910507 2200 15 .0 20.0 8.0 7 .6 67 . 7 9.7 4180 .7 4628 3504
 138 910508 200 15.0 19 .0 8.0 7 .6 66.1 9.6 4147 .8 4314 4951
 139 910508 600 13 .0 19 .0 8 .2 7.4 73 .0 54.7 9.6 4147 .8 4569 3103
 140 9105 08 1000 20 .0 19 .5 7.8 7.6 70. 0 71.1 9. 7 4180 . 7 4632 4489
 14 1 910508 140 0 22. 0 20.0 7.8 8 .1 80 .0 68.6 9.6 414 7.8 4733 4625
 ex>
 142 910508 1800 20 .0 20 .5 7.9 8 .4 75 .0 72 . 1 9.6 414 7 . 8 4735 48 75
 0 143 91 0508 2200 17 .0 21.0 8.0 8. 6 70 .9 9 .6 4147 .8 4951 4620
 144 9105 09 200 12.0 2 0 .0 7 . 9 8 .3 70 .4 9.6 414 7.8 446 1 4752
 145 910509 600 15 .0 19 .0 7.6 8 .7 7 0. 0 67 . 7 9 .6 414 7 .8 4931 470 1
 146 910509 1000 19 .0 19 .0 7 .5 8.2 70 .0 69 .9 9 . 6 4147.8 4695 45 80
 147 9105 09 1400 20 .0 20 .0 8. 1 7 .6 70.0 70. 6 9.6 414 7 .8 46 45 4977
 148 910509 1800 22 .0 20 .0 8.0 7 .8 80 .0 71.4 9.6 4147 .8 4522 4572
 149 9105 09 2200 18.0 19.5 8 .3 8.2 72 .3 9.6 4147.8 4383 4400
 150 91 0510 200 15.0 19.0 8.1 8 .4 68.8 9.6 4147 .8 4533 4620
 151 910510 600 _1 8 . 0 19 .0 8 .0 7,4 7 0. 0 69.0 9.5 4114.9 44 75 3958
 152 910510 1000 21.0 19.5 7 . 9 7.8 75. 0 72 .6 9 .5 4114.9 4828 5 049
 153 910 51 0 1400 29.0 20.0 7 .8 7.2 70 .0 69.5 9.5 4114.9 4859 5175
 154 91051 0 18 00 22.0 20.0 8 .1 8.4 80.0 68.6 9.4 4082 .0 4793 47 87
 155 910510 2200 19 .0 20.0 8.3 7 .4 .. 63 .1 9.3 4049 .1 4591 4352
 156 910511 200 17 .0 19 .5 8.1 7. 8 65.3 9 .3 4049.1 4436 4662
 157 91 0511 600 16 .0 2 0 . 0 8 .3 7.2 70 . o. 61.5 9.3 4049.1 4588 42 50 '
 158 910511 1 000 20 .0 20 . 0 7.8 7 . 6 80 .0 67.3 9 .2 4016.1 4985 4599
 159 910511 1400 22 .0 22 .0 8.1 7 .4 80 .0 64.3 9 . 2 4016 .1 4254 4165 :
 160 910511 1800 24 .0 20 .0 7.9 7.4 80.0 65 .0 9 .2 4016 .1 4324 4465
-l
 Table A-4 . Continued.
 PAGE DATE TIME ATEMP WTEMP PH DO TDS SECCHI WVEL RSTAGE XSECT SREVS OREVS
 161 nOSH 2200 17.0 19.5 7.9 8 .4 65.3 9.2 4016 .1 394 0 3516
 162 910512 200 15.0 19 .0 7 .8 8.0 66.5 9 .2 4016.1 4278 4730
 163 910512 600 17 .0 19 .0 7.8 7 .8 70 .0 67 .9 9.2 4016.1 4426 4612
 164 910512 1000 21. 0 20 .0 7.8 7.9 80.0 74 .0 9 .2 4016.1 4409 4836
 165 910512 1400 29 .0 23.0 7 .7 7 .8 70.0 67.7 9.2 4016.1 4727 4346
 166 910512 1800 26.0 21.0 8.1 7.9 80 .0 68 .4 9.2 4016.1 4688 5010
 167 910512 2200 21. 0 21.0 8.1 7.6 62.2 9.1 3983.2 4056 4418
 168 910513 200 22 .0 21.0 8 .0 7.9 70.9 9.1 3983.2 5109 5090
 169 910513 600 20.0 21.0 8 .2 7 .8 70.0 63.3 9.1 3983.2 4545 3741
 170 910513 1000 25.0 21.5 7.8 7 .6 80.0 73.3 9.1 3983.2 4756 477 7
 171 910513 1400 25 .0 23 .0 7.9 7.6 70.0 68.6 9.2 4016.1 4600 4290
 172 910513 1800 26.0 22.5 8.2 7.4 80.0 69 .5 9.1 3983 .2 4855 4593
 173 910513 2200 22.0 22.0 8.2 8.0 62 .4 9.1 3983 .2 3726 3778
 174 910514 200 21.0 22.0 7.9 7.8 69.5 9 .1 3983.2 4779 4717
 00 175 910514 600 21. 0 22.0 8.3 7.8 65 .0 63.3 9.1 3983.2 4724 4149
 - 176 910514 1000 25 .0 22 .0 7.8 7.9 75.0 70.6 9 .1 3983.2 4541 4583
 177 910514 1400 27.0 22 .0 8 .5 7 .6 75.0 67 .9 9.1 3983.2 4637 5344
 178 910514 1800 24.0 22 .0 7.9 7.5 70.0 70.9 9 .1 3983.2 4913 5012
 179 910514 2200 22.0 22.5 8.0 8 .3 70 .4 9.1 3983.2 4844 4960
 180 910515 200 20.0 21.5 7.8 7 .9 69.3 9.1 3983.2 4651 4721
 181 910515 600 21. 0 22.0 8.0 7.6 70.0 63.1 9.2 4016.1 4603 4137
 182 910515 1000 22.0 22.0 7.6 6.8 70 .0 69 .7 9 .2 4016.1 4293 3734
 183 9105 15 1400 24.0 23.0 7 .7 7.2 70 .0 71.8 9.2 4016.1 4122 4234
 184 910515 1800 22.0 22.0 7.0 7.2 70.0 64.3 9.2 4016.1 3196 3689
 185 910515 2200 22 .0 23.0 8.1 7.6 70 .9 9.2 4016.1 3551 4682
 186 910516 200 17 .0 22.0 7 .6 70.9 9 .2 4016 .1 4417 4633
 187 910516 600 20 .0 21.0 7 .0 8.0 65.0 68 .2 9 .2 4016. 1 4012 4044
 188 910516 1000 23 .0 21.0 7.8 7 .8 75 .0 67.3 9.2 4016.1 4422 4188 ,
 189 910516 1400 . 2£ .0 23.0 8.0 .7.5 75.0 69.0 9.2 ·: .:4016.1 4222 4157
 190 910516 1800 25.0 22.5 7.6 8.0 70 .0 69 .5 9.2 '. :' 4016 .1 4582 5656
 191 910516 2200 22 .0 22.5 ~.4 8.2 68.2 9.2 4016.1 4968 4476
 192 910517 200 19.0 21.0 7 .8 7.9 69.0 9.2 4016.1 4410 4101
Table A-4. Continued .
 PAGE DATE TIME ATEMP WTEMP PH DO TDS SECCHI WVEL RSTAGE XSECT SREVS OREVS
 193 91051 7 600 20 .0 21.5 7.8 7 .4 68 .6 9.2 4016.1 5069 4031
 194 910517 1000 21.0 22 .0 7.8 7.0 70.0 68 .8 9.2 4016 .1 4703 4245
 195 910517 1400 23.0 22 .5 7.5 7.4 75.0 73 .1 9 .2 4016 .1 5039 4265
 196 910517 1800 26 .0 23.0 7.5 7.8 75.0 68.4 9 .2 4016 .1 4727 3541
 197 91051 7 2200 23.0 23 .0 7.6 7 . 6 72.3 9.2 4016 .1 5853 5024
 198 910518 200 20.0 22 .0 7.8 7.5 70.2 9.2 4016.1 4121 4213
 199 910518 600 23 .0 22. 0 8.6 6.8 65 .0 73.1 9 .2 4016.1 4636 4652
 200 910518 1000 25.0 23.0 8.2 7 . 2 75.0 70.2 9 .2 4016.1 47 09 5038
 201 910518 1400 26 .0 24 .0 8 .4 7 .0 70.0 70 .4 9.2 40 16.1 4156 4471
 202 910518 1800 22 .0 24.0 7.6 8 .4 70.0 69 .0 9 .2 4016.1 491 7 4890
 203 910518 2200 17.0 22.0 7.6 65 .3 9.1 3983 .2 4873 4343
 204 910519 200 15.0 22.0 8 .5 7.8 66.5 9.2 4016.1 4412 4127
 205 910519 600 16.0 21.0 8.0 7.6 70.0 54.3 9.2 4016.1 3866 4295
 206 910519 1000 14 .0 20.0 8 .0 7 .9 65 .0 69 .3 9 .2 4016.1 5152 490200 207 910519 1400 15 .0 20.0 6 .6 7 .8 70 .0 64 .5 9 .2 4016.1 4830 3415tv
 208 910519 1800 13.0 21.0 7 .1 8.1 70 .0 68 .8 9 .2 4016.1 4934 4830
 209 910519 2200 14 .0 20 .0 7 .5 7 .6 69 .3 9.1 3983 .2 4966 4716
 210 910520 200 13.0 20.0 7 .8 7 .4 66 .3 9 .0 3950 .3 4212 4159
 211 910520 600 14.0 20 .0 7.4 8.0 75.0 83 .3 7.9 3598.0 3701 3522
 212 910520 1000 16.0 21.0 7. 1 8.4 60.0 62 .6 7.1 3345 .8 3641 3586
 213 910520 1400 17 .0 21.0 7 . 6 7.8 70.0 58.6 6.7 3080 .9 3709 3455
 214 910520 1800 17.0 21. 0 7. 6 7.4 70.0 62.9 7.3 3408.9 4407 3836
 215 910520 2200 16.0 20.0 7.6 8.0 68.2 8.5 3789.9 4557 1141
 216 910521 200 15.0 20.0 7.7 7 .8 64.5 8.5 3789.9 8331 5374
 217 910521 600 17.0 20.0 7.4 7.6 70 .0 65.0 8.4 3757.8 5384 4480
 218 910521 1000 21.0 20.0 7.4 8.0 75.0 69.5 8 .5 3789.9 4753 4582
 219 910521 1400 21.0 21.0 7.7 7. 6 75 .0 64.5 8 .5 3789 .9 4793 4612
 220 910521 1800 22 .0 21.0 7 .8 7.5 75 .0 69 .0 8.5 3789.9 4411 4213
 221 910521 2200 19.0 . 21.0 7 .9 7-.6 62.0 8 .8 3886.1 4152 4301
 222 910522 200 17.0 21.0 7.9 '7.8 67 .1 8.8 3886.1 4310 4126
 223 910522 600 - 16 .0 20 .0 7.5 6.0 70.0 66.5 8.8 3886.1 5161 4248
 224 910522 1000 21.0 20.0 7 .5 8.0 75.0 70.2 8 .8 3886.1 4704 4443
-
 Table A-4. Cont inued.
 PAGE DATE TIME ATEMP WTEMP PH DO TD S SECCHI WVEL RSTAGE XSECT SREVS OREVS
 22 5 9105 22 1400 24 .0 2 0 . 0 7.6 7 .8 70.0 76. 2 9 .0 3950 . 3 47 76 5082
 226 9105 22 1800 23.0 21.0 7 . 8 7 . 8 70.0 72. 3 8 .8 3886.1 477 3 4834
 22 7 91052 2 2200 20.0 2 0 . 0 7 . 6 7.2 72 .6 8. 9 3918.2 4279 45 38
 22 8 910523 200 17.0 21. 0 8.0 8. 3 69.0 8. 9 3918. 2 4021 4317
 229 91 052 3 600 18 .0 2 0. 0 7 . 9 7. 2 70 .0 72 .8 8 . 9 3918.2 48 08 4678
 23 0 91052 3 1000 22 .0 2 0. 0 7 .8 7. 6 80.0 69 .0 8. 9 3 91 8. 2 48 34 4795
 23 1 9105 23 14 00 24.0 21. 0 8.0 7 . 2 80 .0 80.8 8 . 9 391 8. 2 5137 4884
 2 3 2 910523 1800 25.0 22 . 0 8.1 7.0 80.0 74 .6 8.9 3 91 8.2 5180 4654
 2 33 9105 23 22 00 21.0 22 .5 8 .0 7. 5 71.4 8.9 3918.2 4682 4455
 2 3 4 9105 24 200 17 . 0 21. 0 7. 9 7 .4 69 .5 8. 9 3918. 2 4312 445 2
 235 9105 24 600 17 .0 2 0. 0 7.8 7. 2 70 .0 72.3 8 .9 3918 .2 4760 4393
 236 91 052 4 1000 22.0 2 0 . 0 8 .1 7.7 75.0 71.1 8. 9 3918. 2 4303 4526
 237 910524 1400 24.0 2 1. 0 7.8 7.9 80.0 69 .9 8. 9 3918 . 2 4608 4189
 238 910524 1800 25.0 22.0 8 .0 8.1 80.0 70.6 8 .9 3918 . 2 42 31 430600 23 9 910524 22 00 20 .0 22 . 0 7 . 9 7. 6 75 .0 68.4 9 .0 3950 .3 5263 5270w
 24 0 910525 200
 241 910525 600 18.0 20.0 7 . 2 7.6 75.0 69.7 9. 0 3950.3 4964 4 62 9
 2 42 9105 25 1000 2 3. 0 21. 0 7.8 7.6 75.0 71.4 9.0 3950 .3 4636 4654
 24 3 910525 1400 28.0 22 . 0 7 .8 7.0 80 .0 72.6 9.1 3983 .2 5209 4555
 2 44 910525 1800 25.0 22 . 5 7. 9 7.4 80 .0 70.2 9 . 1 3983 .2 4257 4915
 245 9105 25 22 00 24 . 0 22 . 0 7.7 6.0 75. 9 9 .1 3983 .2 5450 5080
 246 910526 200 18 .0 21. 0 7.8 7 .2 69 . 9 9.1 3983 . 2 421 5 4371
 247 9105 26 600 2 1. 0 22 . 0 7.8 7. 2 75.0 65 . 3 9 . 1 3983. 2 5709 5330
 248 910526 1000 23 .0 22 . 0 7.8 7.9 85.0 81.1 9 .1 3983.2 5440 5165
 24 9 9105 2 6 1400 28.0 23 . 0 7.8 7.8 80.0 61.5 9.1 3983.2 4890 4 691
 25 0 910526 1800 2 6.0 23 . 0 7 .7 7.4 80.0 70 .8 9.1 3983. 2 5255 4954
 25 1 910526 2200 25.0 22 . 0 7.7 7.0 7 4 :1 9.1 3983.2 4927 43 89
 252 910527 200 18.0 22 . 5 8.1 7 .5 68 .0 9.1 3983.2 4402 45 21
 25 3 910527 600 20.0 21. 0 7.8 7. 7 72.8 9.1 3983.2 4121 4571
 254 9105 27 1000 25.0 22.0 7. 9 7. 2 80.0 72 .8 9 . 1 3983 .2 5107 4 92 1
 255 910527 1400 2 6 . 0 22. 5 7.6 7. 8 80.0 70 . 6 9 . 1 3983 .2 48 23 45 62
 256 910527 1800 26.0 23 . 0 7.7 7. 9 75.0 72 . 1 9 . 1 39 83.2 510 2 47 01
Table A-4. Continued .
 PAGE DATE TIME ATEMP WTEMP PH DO TDS SECCHI WVEL RSTAGE XSECT SREVS OREVS
 257 910527 2200 22 .0 23.0 7.6 7 .5 71. 8 9.1 3983.2 4720 4522
 258 910528 200 24.0 23.0 8 .0 7.8 80 .8 9.1 3983 .2 4907 4618
 259 910528 600 24.0 24 .0 8.0 7. 6 75.0 77.6 9.1 3983.2 3830 4697
 260 910528 1000 25 .0 24.0 7.8 7.6 80.0 80.8 9.1 3983.2 45 77 4275
 261 910528 1400 25.0 23 .0 8.4 7.0
 262 910528 1800 27.0 25.0 8 .3 7.2 75.0 72.6 9.1 3983.2 5855
 263 910528 2200 24.0 25 .0 8 .1 7.0 74.9 9.2 4016.1 5202 4781
 264 910529 200 23.0 24.0 7.9 7 .2 75.9 9 .2 4016.1 4214 4376
 265 910529 600 22 .0 24.0 8.1 7.6 70 .0 71.1 9 .2 4016.1 4792 44 78
 266 910529 1000 26.0 25 .0 8.2 6.8 75.0 70 .9 9 .2 4016 .1 3815 4436
 267 910529 1400 29 .0 25.0 8.0 7.0 70.0 79.0 9.2 4016 .1 5102 5238
 268 910529 1800 27 .0 25.0 8. 1 7 .0 70.0 74.9 9.2 4016.1 5021 538 7
 269 910529 2200 25.0 25.0 8.2 6.9 74 .8 9.2 4016.1 4999 4965
 270 910530 200 21.0 22.5 7.8 73.6 9.2 4016.1 4678 4765
 00 271 910530 600 22 .0 24.0 7.9 7 .4 70 .0 79.6 9.2 4016 .1 4962 4522.j>.
 272 910530 1000 25 .0 23.5 8.0 7.2 85.0 72 .1 9.2 4016.1 5053 4715
 273 910530 1400 28.0 24 .0 8.0 6 .8 80 .0 74.6 9.2 4016.1 5269 4885
 274 910530 1800 27.0 25.0 7 .9 6.9 80 .0 7 0. 9 9.2 4016 .1 5234 4967
 275 910530 2200 24.0 25 .0 8.4 6.4 70.6 9.2 4016.1 5211 3633
 276 910531 200 20.0 23.0 7. 7 6 .8 71. 6 9.2 4016. 1 4856 4623
 277 91 0531 600 24.0 24.0 8.1 6 .8 80.0 67.9 9.2 4016.1 4860 4869
 278 910531 1000 25.0 24.0 7 .7 7.1 80.0 72.3 9.2 4016.1 5 120 4856
 279 910531 1400 28.0 24.0 7.8 7.0 85 .0 72.3 9 .2 4016.1 4963 4712 .
 280 91 0531 1800 27.0 25.0 8.1 6 .9 85.0 71. 8 9.2 4016.1 4766 4681
 281 910531 2200 22 .0 25.0 7.8 6 .6 72 .6 9.2 4016.1 4867 4511
 282 910601 200 20.0 24.0 7.8 6 .8 71. 6 9.2 4016.1 4901 4706
 283 910601 600 21.0 24.0 8.1 6.8 70 .0 71. 1 9.2 4016.1 4788 4~23
 284 910601 1000 29.0 25 .0 8.4 5 .2 80.0 73.9 9 .2 4016.1 4452 5028
 285 910601 · 1400 30.0 26 .0 8 .0 5.6 80 .0 75.1 9.2 4016. 1 4974 ·4 68 8
 286 910601 1800 30.0 26 .0 8.0 5.6 75 .0 65 .8 9.2 4016.1 5395 ·3 640
 287 910601 2200 21.0 25 .0 7.6 6 .0
 288 910602 200 20 .0 24 .0 7.9 6.3 69.9 9 .1 3983 .2 4930 4461
Table A-4. Continued .
 PAGE DATE TIME ATEMP WTEMP PH DO TDS SECCHI WVEL RSTAGE XSECT SREVS OREVS
 289 910602 600
 290 910602 1000 26.0 24 .0 7.8 6.5 70 .0 70 .6 9 .1 3983 .2 5113 5140
 291 910602 1400 29.0 26.0 8.0 6.2 70.0 78.4 9 .1 3983.2 5046 5055
 292 910602 1800 26.0 25.0 7 .6 6.6
 293 910602 2200 23 .0 25 .0 8.1 6.0 72.8 9.1 3983 .2 4069 5067
 294 910603 200 22 .0 25.0 7.9 6 .6 75.1 9 .1 3983.2 5253 4700
 295 910603 600 22 .0 25.0 8.4 6.4 70.0 76.5 9.1 3983.2 4814 4559
 296 910603 1000 25.0 25 .0 7.9 6.4 70 .0 71. 8 9.1 3983.2 4716 4654
 297 910603 1400 31.0 25 .0 8 .0 6.0 80 .0 7 6 . 5 9 .1 3983.2 4475 5286
 298 910603 1 80 0 25.0 25 .0 8.1 6 .4
 299 910603 2200 24.0 25.0 7 . 9 6.5 78. 4 9. 1 3983 .2 4796 4876
 300 910604 200 20.0 24.5 7.7 6 .3 72 .1 9.1 3983 .2 4861 4678
 301 . 910604 600 22 .0 24.0 8.4 6.6 70.0 64.5 9.1 3983.2 5512 5171
 302 910604 1000 24.0 24 .0 8.0 6 .4 70.0 68.6 9 .2 4016. 1 5053 450300 303 910604 1400 26 .0 24 .0 8.4 6.4 70 .0 73 . 3 9.2 4016 .1 4867 4964u.
 304 910604 1800 22 .0 25.0 7. 8 6 .2 7 0 . 0 70.9 9 .2 4016.1 4491 4732
 305 910604 2200 21.0 24 .0 8.1 65,8 9.2 4016.1 4449 3977
 306 910605 200 18 .0 23 .0 8.0 6.5 70.6 9 .2 4016.1 4407 4601
 307 910605 600 20 .0 21. 0 8.2 6.8 80.0 76.2 9.2 4016.1 4330 4027
 308 910605 1000 22.0 22 .0 8.1 6.9 75.0 72 .3 9.2 4016.1 4401 4665
 309 910605 1400 23.0 22.0 7.9 6.7 75 . 0 69 .0 9.2 4016.1 45 12 4233
 310 910605 1800 21.0 22.0 8.1 7.3 70.0 70 .6 9.1 3983 .2 4221 457 7
 311 910605 2200 18.0 22 .0 8 .1 6 .0 78.1 9.1 3983 .2 4240 4518
 312 910606 200 17 .0 22 .0 7. 9 6.2 70.9 9.1 3983.2 4458 4123
 313 910606 600 14.0 22.0 8.0 6.6 7 0 . 0 69.9 9 .1 3983.2 5108 5192
 314 910606 1000 19 .0 22.0 7.8 6 .4 75.0 71.1 9.0 3950.3 5151 5045
 315 910606 1400 24 .0 23 .0 7.9 6 .6 80.0 72.8 9 .1 3983.2 5398 4612
 316 910606 1800 22 .0 24.0 7.8 6.9 70.0 69 .9 9.2 401'6. 1 5144 4952
 317 910606 2200 19.0 22 .0 8 .0 6.0 67.3 9.1 3983.2 4590 4094
 318 910607 200 17.0 22 .0 7.8 6 .2 69.9 9.1 3983.2 4122 4212
 319 910607 600 22.0 15.0 7.9 6.8 70.0 69.5 9.1 3983.2 4468 3955
 320 910607 1000 21.0 23 .0 7.7 6.6 80.0 69.7 9 .2 4016 .1 5309 4684
Table A-4. Continued .
 PAGE DATE TIME ATEMP WTEMP PH DO TDS SECCHI WVEL RSTAGE XSECT SREVS OREVS
 32 1 910607 1400 24 .0 22 .0 7 .8 6.4 80 .0 65.6 9.1 3983 .2 4755 5184
 322 910607 1800 22.0 24 .0 7.7 6.9 70.0 70.4 9.2 4016 .1 4826 4627
 323 910607 2200 19.0 22.0 7 .8 6.0 68.6 9.1 3983.2 4729 4313
 324 910608 200
 325 910608 600 1 9 . 0 21.0 7 .6 7 . 2 70.0 78.4 9 .1 3983.2 4447 5523
 326 910608 1000 19 .0 23.0 7 .8 6.9 75 .0 70.9 9.1 3983.2 4853 4569
 327 910608 1400 3 0.0 22.0 7.8 6.8 80.0 72 .6 9 .1 3983 .2 4399 4412
 328 910608 1800 23.0 23 .0 7.9 6.2 75.0 69.3 9 .1 3983 .2 4475 4560
 329 910608 2200 20 .0 23.0 7. 6 6.6 75 .0 70.9 9 .1 3983 .2 4475 4560
 330 910609 200 18 .0 22.0 7 . 8 6.2 71.1 9 .1 3983.2 4487 4326
 331 910609 600 18.0 22.0 7 .9 6.2 70.0 71.4 9 .2 4016 .1 4655 4578
 332 910609 1000 24.0 23.0 7.8 7.0 75. 0 72 .6 9 .2 4016.1 5061 4931
 333 910609 1400 25 .0 23 .0 7 .9 6.8 80 .0 70.6 9.2 4016 .1 4688 4258
 334 910609 1800 23 .0 23 .0 7 . 6 7.0 70 .0 69.5 9 .1 3983 .2 4033 396800 335 910609 2200 22.0 23.0 8.5 7.4 70.9 9 .2 40 16 .1 4665 46680\
 336 910610 200 18 .0 22.0 8.0 6.5 68 .4 8. 9 3918 .2 4718 4424
 337 910610 600 17.0 22 .0 8.3 6 .8 70.0 68 .8 8.5 3789.9 4428 4312
 338 910610 1000 24.0 23.0 7 .9 7 .0 80.0 67.9 8.8 3886.1 4233 3915
 339 910610 1400 29.0 24.0 8.9 6.4 80 .0 62.4 7.3 3408 .9 4011 4659
 340 910610 1800 26 .0 24 .0 8.3 7 .4 80.0 64.6 7.0 3314 .3 4016 4197
 341 910610 2200 21.0 23.0 8.0 6 .2 59 .1 6.8 3158.7 3777 3767
 342 910611 200 19.0 23 .0 8.2 6 .8 65.0 6 .5 2925.3 3423 3366
 343 910611 600 19.0 22 .0 8.0 7 .0 70.0 67 .7 6.5 2925.3 4386 4233
 344 910611 1000 24.0 23 .0 7 . 9 7 .3 75 .0 67.9 6.5 2925 .3 4003 3861
 345 910611 1400 30.0 23 .0 . 8.0 7 . 0 80.0 69.0 6 .4 2847.5 4392 4055
 346 910611 1800 25.0 24 .0 8 .2 7 .2 80 .0 57.3 6 .3 2769 .7 4101· 428 7
 347 910611 2200 25.0 24.0 7.8 6.8 49.1 6 .3 2769.7 4325 · 4518
 348 910612 200 19.0 23.0 e.O 6.4 58.3 6.3 2769 .7 3866' 3601
 349 910612 600 22:0 23.0 ·8 .3 6 .8 7.0 . '0 58.3 6 .3 2769.7 4518 3641
 350 910612 1000 26.0 24.0 8 .1 6.5 '70.0 65 .8 6.3 2769 .7 4050 4084
 351 910612 1400 30 .0 24.0 8.4 6.8 80.0 65.0 6.2 2691.9 3880 3710
 352 910612 1800 29 .0 26 .0 8.5 6 .0 80.0 66.7 6.2 2691.9 4271 4248
-
 Table A-4 . Continued .
 PAGE DATE TIME ATEMP WTEMP PH DO TDS SECCHI WVEL RSTAGE XSECT SREVS OREVS
 353 910612 22 00 25.0 25 .0 8 .2 6 .2 62.8 6 .3 2769.7 40 05 42 00
 354 910613 200 20.0 24 . 0 8.0 6 .1 59.1 6 .2 2691. 9 411 7 4375
 355 910613 60 0 24 .0 24 .0 8 .3 6 .4 75. 0 57 .0 6.2 2691. 9 4002 3965
 356 91 0613 10 00 24.0 25.0 8 .0 6 .8 80 .0 58 .9 6 .2 2691 .9 4012 4007
 357 910613 1400 28.0 25.0 7 . 8 7 .2 80 .0 58.8 6 .1 2614. 1 4021 3871
 358 9106 13 1800 27.0 25.0 8 .2 7. 1 85 .0 58 .3 6 .1 2614.1 3987 3655
 359 910 613 2200 22.0 24 .0 7. 7 6.8 62 .4 6 . 1 2614 .1 4184 42 75
 360 910614 200 20 .0 24.0 7 .9 6 .6 61. 7 6. 1 2614.1 4099 4233
 361 91 0614 60 0 21.0 24.0 7.6 6.4 75. 0 59.6 6 .2 2691. 9 42 04 4007
 362 910614 1000 23 .0 24.0 8 .3 6.9 70.0 60 .4 6 .1 2614 . 1 4112 4055
Table A-5. Striped bass egg enumeration, v iabi lity , and s tage of development
 collected at Barnhill's Landing , Roanoke River, North Carolina , from 15
 April to 14 June 1991.
 PAGE DATE TIME ASURF BSURF AOBL BOBL ASVIA BSVIA AOVIA BOVIA ST1 ST2 ST3 ST4 HATCH
 1 9104 15 600 0 0 0 0
 2 9104 15 1 000 0 0 0 0
 3 9104 15 1400 0 0 0 0
 4 910415 180 0 0 0 0 0
 5 910415 2200 0 0 0 0
 6 910416 200 0 0 0 0
 7 910416 600 0 0 0 0
 8 910416 1000 0 0 0 0
 9 910416 1400 0 0 0 0
 10 910416 1800 0 0 0 0
 11 910416 2200 0 0 0 0
 12 910417 200 0 0 0 0
 00 13 910417 600 0 0 0 000 14 910417 1000 0 0 0 1 0 0 0 0
 15 910417 1400 0 0 0 0
 16 910417 1800 0 0 0 0
 17 91041 7 220 0 1 0 0 0 0 0 0 0
 18 910418 200 0 0 0 0
 19 910418 600 0 0 0 0
 20 910418 1000 0 0 0 1 0 0 0 0
 21 910418 1400 0 0 0 0
 22 910418 1800 0 0 0 0
 23 910418 2200 0 0 0 0
 24 910419 200 0 0 0 0
 25 910419 600 0 0 0 0
 26 910419 1000
 27 910419 1400 0 0 0 0
 28 910419 1 800 0 0 0 0
 29 910419 2200 0 0 0 0
 30 910420 200 0 0 0 0
Table A-5. Continued .
 PAGE DATE TIME ASURF BSURF AOBL BOBL ASVIA BSVIA AOVIA BOVIA STl ST2 ST3 ST4 HATCH
 31 91 0420 600 0 0 0 0
 32 910420 1000 0 0 0 0
 33 910420 1400 0 0 0 0
 34 910420 1800 0 0 0 0
 35 910420 2200 0 0 0 0
 36 910421 200 0 0 0 0
 37 910421 600 0 0 0 0
 38 910421 1000 0 a a a
 39 910421 1400 a 0 a a
 40 910421 1800 a 0 0 a
 41 910421 2200 a a 0 a
 42 910422 200
 43 910422 600 a a a a
 44 910422 1000 a a a a
 45 910422 1400 0 0 a 0
 0Cl 46 910422 1800 a 0 0 0\0
 47 910422 2200 a a 0 a
 48 910423 200 a a 0 a
 49 910423 600 a a 0 a
 50 910423 1000 a a 0 a
 51 910423 1400 0 0 0 0
 52 910423 1800 a a 0 a
 53 910423 2200 1 1 a a 1 a a a 1 0 a 0 0
 54 910424 200 a a 1 a a a a a
 55 910424 600 0 0 a a
 56 910424 1000 0 0 1 1 0 a 1 a 1 0 0 0 0
 57 910424 140 0 2 a 0 0 a a a a
 58 910424 1800 2 a 2 .2 2 a 2 1 5 a 0 a a
 59 910424 2200 a a 0 a
 60 910425 200 a 1 2 a a 1 1 a 2 0 0 0 a
 61 910425 600
 62 910425 1000 6 4 6 7 5 0 4 5 14 0 0 a 0
Table A-5. Continued.
 PAGE DATE TIME ASURF BSURF AOBL BOBL ASVIA BSVIA AOVIA BOVIA ST1 ST2 ST3 ST4 HATCH
 63 910425 1400 0 0 0 0
 64 910425 1800 1 0 0 1 1 0 0 1 0 2 0 0 0
 65 910425 2200 0 0 0 0
 66 910426 200 0 1 0 1 0 0 0 0
 67 910426 600 0 0 0 0
 68 910426 1000 0 0 0 0
 69 910426 1400 0 0 0 0
 70 910426 1800 0 0 0 1 0 0 0 0
 71 910426 2200
 72 910427 200 0 0 0 0
 73 910427 600 0 0 0 0
 74 910427 1000 0 0 0 0
 75 910427 1400 0 0 0 0
 76 910427 1800 0 0 0 0
 \0 77 910427 2200 0 0 0 0
 0 78 910428 200 0 0 1 0 0 0 0 0
 79 910428 600 1 2 3 4 1 1 1 3 6 0 0 0 0
 80 910428 1000 1 5 4 5 1 5 3 5 14 0 0 0 0
 81 910428 1400 5 2 1 4 5 2 1 3 11 0 0 0 0
 82 910428 1800 3 2 2 3 3 1 2 2 8 0 0 0 0
 83 910428 2200 1 1 1 5 0 0 1 4 0 5 0 0 0
 84 910429 200 4 2 6 5 4 2 5 3 0 14 0 0 0
 85 910429 600 12 14 24 12 11 13 21 9 0 54 0 0 0
 86 910429 1000 3 6 8 8 1 3 6 6 16 0 0 0 0
 87 910429 1400 4 1 1 7 3 1 1 5 0 10 0 0 0
 88 910429 1800 1 0 0 0 1 0 0 0 0 1 0 0 0
 89 910429 2200 4 2 2 0 1 2 1 0 2 2 0 0 0
 90 910430 200
 91 910430 600 0 2 --I 3 0 2 0 2 4 0 0 0 0
 92 910430 1000 9 6 6 4 8 5 5 3 0 21 0 0 0
 93 910430 1400 2 2 0 1 1 1 0 1 0 3 0 0 0
 94 910430 1800 0 1 1 0 0 1 0 0 0 1 0 0 0
Table A-5. Continued.
 PAGE DATE TIME ASURF BSURF AOBL BOBL ASVIA BSVIA AOVIA BOVIA ST1 ST2 ST3 ST4 HATCH
 95 910430 2200 2 0 0 0 0 0 0 0
 96 910501 200 2 1 3 1 1 0 1 1 3 0 0 0 0
 97 910501 600 5 3 3 2 3 1 0 1 4 1 0 0 0
 98 910501 1000 6 4 4 5 4 3 2 3 7 5 0 0 0
 99 910501 1400 0 0 0 0
 100 910501 1800 0 1 0 0 0 1 0 0 1 0 0 0 0
 101 910501 2200 3 3 0 2 2 2 0 2 6 0 0 0 0
 102 910502 200 27 35 39 48 20 16 12 30 77 1 0 0 0
 103 910502 600 31 10 39 29 23 6 31 23 79 4 0 0 0
 104 910502 1000 59 51 67 62 30 27 42 27 54 3 0 0 0
 105 910502 1400 1 6 6 2 0 5 6 1 9 3 0 0 0
 106 910502 1800 1 0 2 6 0 0 1 4 5 0 0 0 0
 107 910502 2200 8 6 18 25 5 5 8 13 27 4 0 0 0
 108 910503 200 19 23 31 26 12 17 19 16 58 6 0 0 0
 '0 109 910503 600 3 2 4 1 3 1 1 1 1 5 0 0 0
 - 110 910503 1000 17 9 17 12 7 2 5 3 15 2 0 0 0
 111 910503 1400 0 0 0 5 0 0 0 2 2 0 0 0 0
 112 910503 1800 2 2 10 5 1 1 6 1 9 0 0 0 0
 113 910503 2200
 114 910504 200
 115 910504 600 2 3 4 6 1 0 2 3 5 1 0 0 0
 116 910504 1000 0 1 5 5 0 0 4 2 6 0 0 0 0
 117 910504 1400 2 0 1 1 0 0 1 1 2 0 0 0 0
 118 910504 1800 0 2 5 3 0 1 2 2 5 0 0 0 0
 119 910504 2200 1 1 2 1 1 1 1 1 4 0 0 0 0
 120 910505 200 6 10 12 7 1 6 8 4 19 0 0 0 0
 121 910505 600 4 4 10 5 2 2 10 3 17 0 0 0 0
 122 910505 1000 8 10 14 9 4 6 6 5 21 0 0 0 0
 123 910505 1400 7 6. 0 3 6 6 0 ' 2 14 0 0 0 0
 124 910505 1800 8 6 10 9 3 3 5 6 17 0 0 0 '0
 125 910505 2200 8 2 1 1 6 1 1 0 8 0 0 0 0
 126 910506 200
Table A-5. Continued.
 PAGE DATE TIME ASURF BSURF AOBL BOBL ASVIA BSVIA AOVIA BOVIA STl ST2 ST3 ST4 HATCH
 127 910506 600 16 3 20 13 13 3 15 5 36 0 0 0 0
 128 910506 1000 66 77 68 90 34 44 41 42 138 23 0 0 0
 129 910506 1400 13 3 3 9 11 3 2 8 24 0 0 0 0
 130 910506 1800 2 0 0 5 0 0 0 1 1 0 0 0 0
 131 910506 2200 2 7 9 1 2 6 3 0 11 0 0 0 0
 132 910507 200 9 4 10 9 3 1 4 6 14 0 0 0 0
 133 910507 600 16 8 19 46 11 6 9 29 55 0 0 0 0
 134 910507 1000 1 1 5 5 1 0 4 3 8 0 0 0 0
 135 910507 1400 8 3 2 11 6 2 1 10 19 0 0 0 0
 136 910507 1800 15 17 11 8 8 9 8 7 32 0 0 0 0
 137 910507 2200 47 30 21 44 43 26 16 26 111 0 0 0 0
 138 910508 200 37 26 49 24 29 18 32 17 96 0 0 0 0
 139 910508 600 173 180 170 89 129 135 129 39 126 132 0 0 0
 \0 140 910508 1000 119 105 57 107 66 46 25 66 69 22 0 0 0
 tv 141 910508 1400 179 243 453 253 80 129 148 106 201 27 0 0 0
 142 910508 1800 83 95 120 98 37 49 48 39 80 17 0 0 0
 143 910508 2200 117 60 101 103 53 25 43 50 79 24 0 0 0
 144 910509 200 83 92 120 101 29 47 58 44 70 17 0 0 0
 145 910509 600 144 114 223 181 105 54 110 80 133 31 0 0 0
 146 910509 1000 78 97 70 73 37 49 39 31 66 14 0 0 0
 147 910509 1400 16 1 7 5 6 0 5 5 15 1 0 0 0
 148 910509 1800 13 22 17 8 5 7 6 5 23 0 0 0 0
 149 910509 2200 2 4 1 9 1 3 0 6 10 0 0 0 0
 150 910510 200 26 19 36 41 12 8 19 18 48 9 0 0 0
 151 910510 600 5 7 8 11 4 7 7 7 25 0 0 0- 0
 152 910510 1000 25 18 28 23 15 7 9 16 35 12 0 0 0
 153 910510 1400 6 2 1 10 6 2 0 6 14 0 0 0 0
 154 910510 1800 5 12 10 8 2 4 4 2 9 3 . 0 0 0
 155 910510 2200 15 10 9 27 9 6 6 21 42 0 0 0 - 0
 156 910511 200 21 18 31 27 10 8 12 12 34- 8 0 0 0 -,
 157 910511 600 78 43 60 43 56 36 41 32 128 37 0 0 0
 158 910511 1000 79 107 76 81 30 42 37 32 67 74 0 0 0
Table A-5. Continued.
 PAGE DATE TIME ASURF BSURF AOBL BOBL ASVIA BSVIA AOVIA BOVIA STl ST2 ST3 ST4 HATCH
 159 910511 1400 20 15 34 20 12 9 1B 14 41 12 0 0 0
 160 910511 1BOO 3B 41 57 47 19 17 20 17 52 21 0 0 0
 161 910511 2200 B1 79 94 BB 52 43 55 5B 202 6 0 0 0
 162 910512 200 131 107 121 117 7B 54 71 66 130 19 0 0 0
 163 910512 600 9B 113 157 104 63 75 95 75 124 34 0 0 0
 164 910512 1000 224 301 209 235 B5 103 177 134 145 92 0 0 0
 165 910512 1400 26 4B B 3 16 35 4 3 32 26 0 0 0
 166 910512 1BOO 53 73 51 69 24 23 21 1B 50 36 0 0 0
 167 910512 2200 3 2 B 19 0 1 5 14 11 9 0 0 0
 16B 910513 200 57 B3 4B 59 2B 35 26 30 103 16 0 0 0
 169 910513 600 26 15 B 31 22 9 4 19 43 11 0 0 0
 170 910513 1000 42 37 5B 60 1B 16 26 29 26 63 0 0 0
 171 910513 1400 1B 24 25 10 1B 21 17 5 40 21 0 0 0
 172 910513 1BOO 61 B9 75 B2 31 29 34 3B 51 B1 0 0 0
 \0 173 910513 2200 19 63 5B 29 14 55 36 16 53 6B 0 0 0
 w 174 910514 200 3B9 427 526 453 206 175 275 251 114 312 0 0 0
 175 910514 600 316 204 315 19B 244 147 239 141 BO 305 0 0 0
 176 910514 1000 154 264 13B 114 41 79 79 49 5 113 2 0 0
 177 910514 1400 23 1B 36 43 20 13 21 27 5B 23 0 0 0
 17B 910514 1BOO 64 79 59 6B 29 40 30 31
 179 910514 2200 41 41 71 77 25 20 34 46 67 5B 0 0 0
 1BO 910515 200 97 B1 109 90 43 40 42 36 103 5B 0 0 0
 1B1 910515 600 26 45 3B 71 16 39 26 60 101 40 0 0 0
 1B2 910515 1000 14 12 24 7 14 7 1B 4 1B 35 0 0 0
 1B3 910515 1400 12 2 13 14 B 0 11 . 5 7 17 0 0 0
 1B4 910515 1BOO 16 12 13 5 12 6 9 5 9 23 0 0 0
 1B5 910515 2200 16 12 11 17 7 6 B B 11 1B 0 0 0
 1B6 910516 200 19 26 23 3B 11 11 10 1B 19 31 0 0 0
 1B7 910516 600 50 41 30 47 3B 27 2B 35 4B BO 0 0 0
 1BB 910516 1000 15 1B 23 17 7 B 10 9 B 26 0 0 0
 1B9 910516 1400 12 19 26 20 4 6 11 13 13 21 0 0 0
 190 910516 1BOO 34 46 6B 47 19 17 3B 31 19 B6 0 0 0
Table A-5 . Continued.
 PAGE DATE TIME ASURF BSURF AOBL BOBL ASVIA BSVIA AOVIA BOVIA STI ST2 ST3 ST4 HATCH
 191 910516 2200 20 42 47 43 1 8 26 32 15 29 62 a a a
 192 910517 200 49 38 33 28 21 17 20 16 43 31 a a a
 193 910517 600 63 67 38 26 34 42 27 1 9 83 39 a a a
 194 9105 17 1000 10 8 18 14 5 4 10 8 7 20 a a a
 195 910517 1400 5 3 2 2 3 1 a 2 4 2 a a a
 196 91051 7 1800 10 12 11 14 5 7 5 6 3 20 a a a
 197 910517 2200 16 11 23 17 14 9 19 13 25 30 a a a
 198 910518 200 21 29 17 18 11 12 10 9 24 18 a a a
 199 910518 600 39 13 44 37 29 10 35 25 55 44 a a a
 200 910518 1000 65 41 43 52 20 18 16 30 33 49 2 a a
 201 910518 1400 33 34 12 15 27 26 10 13 32 42 2 a a
 202 910518 1800 73 44 86 109 36 24 52 70 130 52 a a a
 203 910518 2200 9 24 10 10 9 21 7 7 27 17 a a a
 \0 204 910519 200 14 12 10 8 8 8 5 4 15 10 a · 0 a.j>.
 205 9105 19 600 18 2 13 13 16 2 6 11 8 27 a a a
 206 910519 1000 50 46 48 59 24 21 37 32 92 21 1 a a
 207 9105 19 1400 5 8 7 2 3 6 1 2 8 4 a a a
 208 910519 1800 21 18 8 23 9 8 5 13 22 13 a a a
 209 910519 2200 1 5 5 6 a 3 4 5 9 3 a a a
 210 910520 200 17 9 14 12 9 5 6 4 17 7 a a a
 211 910520 600 1 3 3 3 1 3 2 2 4 4 a a a
 212 910520 1000 1 4 3 4 a 2 1 1 a 4 a a a
 213 910520 1400 a 3 2 a a 3 2 a 3 2 a a a
 214 910520 1800 1 a 1 1 1 a 1 1 1 . 2 a a a
 215 910520 2200 3 1 12 5 2 1 8 4 12 3 a a a
 216 910521 200 4 7 3 5 3 4 2 2 7 4 a a a
 217 910521 600 10 5 4 1 7 5 3 1 7 9 a a a
 218 910521 1000 10 8 9 4. 6 7 9 4 20 6 a a a . .. ,-
 219 910521 1400 °S 5 3 4 ° 2 3 2 1 6 2 a a a
 220 910521 1800 4 4 3 2 2 1 1 2 5 1 a a a
 221 910521 2200 9 7 3 8 6 5 3 7 15 6 a a a
 222 910522 200 11 14 10 12 5 5 6 4 13 7 a a a
Table A-5. Continued.
 PAGE DATE TIME ASURF BSURF AOBL BOBL ASVIA BSVIA AOVIA BOVIA ST1 ST2 ST3 ST4 HATCH
 223 910522 600 9 3 2 8 9 3 2 5 16 3 0 0 0
 224 910522 1000 14 9 36 54 8 6 21 30 61 4 0 0 0
 225 910522 1400 14 7 8 11 9 5 7 6 23 4 0 0 0
 226 910522 1800 17 10 21 14 12 6 14 9 24 17 0 0 0
 227 910522 2200 9 2 12 2 8 2 11 1 10 12 0 0 0
 228 910523 200 3 2 4 6 2 1 2 3 6 2 0 0 0
 229 910523 600 1 0 4 7 1 0 4 7 12 0 0 0 0
 230 910523 1000 8 6 7 11 3 3 4 5 5 10 0 0 0
 231 910523 1400 8 1 5 2 7 1 2 0 2 8 0 0 0
 232 910523 1800 13 4 12 11 8 1 12 8 16 13 0 0 0
 233 910523 2200 12 14 19 12 5 7 9 7 18 10 0 0 0
 234 910524 200 21 17 25 20 11 10 14 9 32 12 0 0 0
 235 910524 600 19 28 17 23 13 21 11 16 54 7 0 0 0
 236 910524 1000 9 12 17 14 6 9 9 6 19 11 0 0 0\0 237 910524 1400 9 5 3 4 4 3 2 2 8 3 0 0 0Ul
 238 910524 1800 10 8 9 12 6 4 6 7 14 9 0 0 0
 239 910524 2200 11 18 15 20 9 10 14 14 28 19 0 0 0
 240 910525 200
 241 910525 600 11 5 1 7 8 4 1 7 13 7 0 0 0
 242 910525 1000 7 6 9 8 4 3 6 4 12 5 0 0 0
 243 910525 1400 4 6 11 5 4 3 9 2 13 5 0 0 0
 244 910525 1800 18 23 37 23 12 10 28 17 34 33 0 0 0
 245 910525 2200 23 21 18 7 21 14 12 6 36 17 0 0 0
 246 910526 200 19 21 31 26 10 12 18 18 41 17 0 0 0
 247 910526 600 3 5 4 24 0 3 4 14 7 14 0 0 0
 248 910526 1000 16 32 29 50 10 18 19 29 60 16 0 0 0
 249 910526 1400 19 13 5 18 10 10 3 16 29 10 0 O· 0
 250 910526 1800 34 40 78 64 26 21 40 33 39 51 0 0 · 0
 251 910526 2200 12 26 10 ;30 9 25 4 22 24 36 0 '0 0
 252 910527 200 16 12 21 26 9 9 12 14 32 12 0 '0 . 0
 253 910527 600 19 12 20 14 8 7 9 8 22 10 0 0 0
 254 910527 1000 11 14 17 19 6 8 11 9 27 7 0 0 0
Table A-5. Continued.
 PAGE DATE TIME ASURF BSURF AOBL BOBL ASVIA BSVIA AOVIA BOVIA ST1 ST2 ST3 ST4 HATCH
 255 910527 1400 7 9 10 11 4 4 6 7 12 9 0 0 0
 256 910527 1800 8 11 18 11 5 7 11 8 21 10 0 0 0
 257 910527 2200
 258 910528 200 13 7 13 8 9 6 6 5 5 21 0 0 0
 259 910528 600 3 1 12 9 2 1 6 7 6 10 0 0 0
 260 910528 1000 23 7 8 8 9 5 6 8 14 14 0 0 0
 261 910528 1400
 262 910528 1800 8 9 8 8 7 9 0 0 0
 263 910528 2200 11 11 18 8 8 10 4 5 18 9 0 0 0
 264 910529 200 22 13 7 15 17 9 7 9 27 15 0 0 0
 265 910529 600 6 4 2 3 6 3 1 1 8 3 0 0 0
 266 910529 1000 3 3 6 4 2 2 3 4 9 4 0 0 0
 267 910529 1400 13 3 3 4 6 2 3 1 7 5 0 0 0
 268 910529 1800 8 4 4 3 6 3 4 2 5 11 0 0 0
 'l:> 269 910529 2200 11 4 9 12 10 3 7 11 15 16 0 0 0
 0\ 270 910530 200 19 23 26 29 11 12 17 14 33 21 0 0 0
 271 910530 600 4 2 6 5 4 2 6 3 5 10 0 0 0
 272 910530 1000 7 7 10 11 6 5 6 7 11 13 1 0 0
 273 910530 1400 0 2 1 5 0 0 0 4 2 2 0 0 0
 274 910530 1800 4 6 9 10 3 3 6 7 5 14 0 0 0
 275 910530 2200 5 3 4 2 2 3 3 2 8 2 0 0 0
 276 910531 200 7 5 9 12 3 3 6 7 12 7 0 0 0
 277 910531 600 2 1 1 1 1 1 1 0 2 1 0 0 0
 278 910531 1000 4 3 6 5 2 1 4 3 4 6 0 0 0
 279 910531 1400 2 0 3 2 1 0 2 2 4 1 0 0 0
 280 910531 1800 6 5 7 4 3 3 4 2 3 9 0 0 0
 281 910531 2200 4 3 8 5 2 1 5 2 2 8 0 0 0
 282 910601 200 2 7 9 9 2 5 5 4 6 10 0 0 0 .'
 283 910601 600 5 3 4 6 3 1 2 3 1 8 0 0 0
 284 910601 1000 5 0 2 5 4 0 1 5 8 2 0 0 0
 285 910601 1400 6 1 1 1 2 1 0 1 4 0 0 0 0
 286 910601 1800 1 0 2 1 1 0 2 1 3 1 0 0 0
Table A-5. Continued.
 PAGE DATE TIME A5URF B5URF AOBL BOBL A5VIA B5VIA AOVIA BOVIA 5Tl 5T2 5T3 5T4 HATCH
 287 910601 2200
 288 910602 200 4 2 2 3 2 1 2 1 4 2 0 0 0
 289 910602 600
 290 910602 1000 1 2 3 3 0 0 1 1 1 1 0 0 0
 291 910602 1400 0 2 3 1 0 2 1 0 2 0 1 0 0
 292 910602 1800
 293 910602 2200 1 4 1 2 1 2 0 2 4 1 0 0 0
 294 910603 200 6 2 1 4 5 2 0 3 7 3 0 0 0
 295 910603 600 0 1 1 1 0 0 0 1 0 1 0 0 0
 296 910603 1000 0 0 1 0 0 0 0 0
 297 910603 1400 1 0 5 0 1 0 5 0 6 0 0 0 0
 298 910603 1800
 299 910603 2200 0 0 0 0
 \0 300 910604 200 0 0 0 0
 -.I 301 910604 600 0 2 1 1 0 1 1 1 1 2 0 0 0
 302 910604 1000 3 0 0 2 1 0 0 1 2 0 0 0 0
 303 910604 1400 1 0 2 0 1 0 1 0 1 1 0 0 0
 304 910604 1800 7 3 5 6 4 3 4 5 2 14 0 0 0
 305 910604 2200 2 0 0 0 1 0 0 0 1 0 0 0 0
 306 910605 200 1 0 0 0 0 0 0 0
 307 910605 600 0 0 1 1 0 0 0 1 0 1 0 0 0
 308 910605 1000 1 0 2 0 1 0 1 0 2 0 0 0 0
 309 910605 1400 0 0 0 0
 310 910605 1800 1 0 1 0 0 0 1 0 0 1 0 0 0
 311 910605 2200 0 0 1 1 0 0 1 1 1 1 0 0 0
 312 910606 200 2 1 2 1 1 1 0 1 0 3 0 0 0
 313 910606 600 0 2 1 1 0 2 1 0 3 0 0 0 0
 314 910606 1000 0 0 2 1 0 0 1 0 0 1 0 0 0
 315 910606 1400 1 0 0 1 1 . 0 0 1 0 2 0 0 0
 316 910606 1800 0 0 1 0 0 .. 0 0 0
 •317 910606 2200 0 0 1 0 0 0 1 0 1 0 0 0 0
 318 910607 200 0 1 1 2 0 1 0 1 0 2 0 0 0
Table A-5. Continued.
 PAGE DATE TIME ASURF BSURF AOBL BOBL ASVIA BSVIA AOVIA BOVIA STI ST2 ST3 ST4 HATCH
 319 910607 600 0 0 0 1 0 0 0 1 1 0 0 0 0
 320 910607 1000 0 2 2 2 0 1 0 1 0 2 0 0 0
 321 910607 1400 0 0 0 0
 322 910607 1800 0 0 1 1 0 0 1 1 0 2 0 0 0
 323 910607 2200 3 1 2 1 2 1 2 1 4 2 0 0 0
 324 910608 200
 325 910608 600 0 0 0 0
 326 910608 1000 0 0 1 3 0 0 0 1 0 1 0 0 0
 327 910608 1400 0 0 1 0 0 0 1 0 0 1 0 0 0
 328 910608 1800 0 0 0 0
 329 910608 2200 0 0 0 0
 330 910609 200 0 0 0 0
 331 910609 600 0 1 0 0 0 1 0 0 0 1 0 0 0
 'D 332 910609 1000 0 0 0 0
 00 333 910609 1400 0 0 0 0
 334 910609 1800 0 0 0 0
 335 910609 2200 0 0 2 1 0 0 2 1 2 1 0 0 0
 336 910610 200 0 0 0 0
 337 910610 600 0 0 0 0
 338 9106 10 1000 1 1 0 0 1 1 0 0 0 2 0 0 0
 339 910610 1400 1 1 1 0 0 0 0 0
 340 910610 1800 0 0 0 0
 341 910610 2200 0 0 0 0
 342 910611 200 1 0 0 0 0 0 0 0
 343 910611 600 0 0 1 0 0 0 0 0
 344 910611 1000 0 0 0 0
 ..
 345 910611 1400 1 0 0 0 0 0 .. 0 0
 346 910611 1800 0 0 0 0 . "
 347 910611 2200 1 0 1 0 1 o • 1 0 1 1 0 0 0
 348 910612 200 0 0 1 0 0 0 0 0
 349 910612 600 0 0 0 0
 350 910612 1000 1 0 2 1 0 0 0 1 1 0 0 0 0
Table A-5 . Cont i nue d .
 PAGE DATE TIME ASURF BSURF AOBL BOBL ASVIA BSVIA AOVIA BOVIA ST1 ST2 ST3 ST4 HATCH
 351 910612 1400 3 1 0 1 2 1 0 0 2 1 0 0 0
 352 910612 1800 1 1 0 5 0 0 0 3 2 1 0 0 0
 353 910612 2200 0 0 0 1 0 0 0 1 1 0 0 0 0
 354 910613 200 0 0 0 0
 355 910613 600 0 0 0 0
 356 910613 1000 0 0 3 1 0 0 1 0 0 1 0 0 0
 357 910613 1400 0 0 0 0
 358 910613 1800 0 0 0 0
 359 910613 2200 0 0 0 0
 360 910614 200 0 0 0 0
 361 910614 600 0 0 0 0
 362 910614 1000 0 0 0 0
 -e
 -o
Table A-6. Surface net egg collections, Barnhill's Landing,
 Roanoke River, North Carolina in 1991.
 Day Date 0200 0600 1000 1400 1800 2200 Total
 0 910415 0 0 0 0 0 0
 1 910416 0 0 0 0 0 0 0
 2 910417 0 0 0 0 0 1 1
 3 910418 0 0 0 0 0 0 0
 4 910419 0 0 0 0 0 0
 5 910420 0 0 0 0 0 0 0
 6 910421 0 0 0 0 0 0 0
 7 910422 0 0 0 0 0 0
 8 910423 0 0 0 0 0 2 2
 9 910424 0 0 0 2 2 0 4
 10 910425 1 10 0 1 0 12
 11 910426 1 0 0 0 0 1
 12 910427 0 0 0 0 0 0 0
 13 910428 0 3 6 7 5 2 23
 14 910429 6 26 9 5 1 6 53
 15 910430 2 15 4 1 2 24
 16 910501 3 8 10 0 1 6 28
 17 910502 62 41 110 7 1 14 235
 18 910503 42 5 26 0 4 77
 19 910504 5 1 2 2 2 12
 20 910505 16 8 18 13 14 10 79
 21 910506 19 143 16 2 9 189
 22 910507 13 24 2 11 32 77 159
 23 910508 63 353 224 422 178 177 1417
 24 910509 175 258 175 17 35 6 666
 25 910510 45 12 43 8 17 25 150
 26 910511 39 121 186 35 79 160 620
 27 910512 238 211 525 74 126 5 1179
 28 910513 140 41 79 42 150 82 534
 29 910514 816 520 418 41 143 82 2020
 30 910515 178 71 26 14 28 28 345
 31 910516 45 91 33 31 80 62 342
 32 910517 87 130 18 8 22 27 292
 33 910518 50 52 106 67 117 33 425
 34 910519 26 20 96 13 39 6 200
 35 910520 26 4 5 3 1 4 43
 36 910521 11 15 18 10 8 16 78
 37 910522 25 12 23 21 27 11 119
 38 910523 5 1 14 9 17 26 72
 39 910524 38 47 21 14 18 29 167
 40 910525 16 13 10 41 44 124
 41 910526 40 8 48 32 74 38 240
 42 910527 28 31 25 16 19 119
 43 910528 20 4 30 17 22 93
 44 910529 35 10 6 16 12 15 94
 45 910530 42 6 14 2 10 8 82
 100
I
 r Table A-6 . Continued.
 I Day Date 0200 0600 1000 1400 1800 2200 Total
 r
 46 910531 12 3 7 2 11 7 42
 47 910601 9 8 5 7 1 . 30
 48 910602 6 . 3 2 5 16
 I 49 910603 8 1 0 1 . 0 1050 910604 0 2 3 1 10 2 18
 51 910605 1 0 1 0 1 0 3
 I 52 910606 3 2 0 1 0 0 653 910607 1 0 2 0 0 4 754 910608 0 0 0 0 0 0
 I 55 910609 0
 1 0 0 0 0 1
 56 910610 0 0 2 2 0 0 4
 57 910611 1 0 0 1 0 1 3
 58 910612 0 0 1 4 2 0 7
 I 59 910613 0 0 0 0 0 0 060 910614 0 0 0 0
 I
 I
 I
 I
 I
 I
 I
 I
 I
 [
 l 101
Table A-7. Oblique net egg collections, Barnhill's Landing,
 Roanoke River, North Carolina in 1991.
 Day Date 0200 0600 1000 1400 1800 2200 Total
 0 910415 0 0 0 0 0 0
 1 910416 0 0 0 0 0 0 0
 2 910417 0 0 1 0 0 0 1
 3 910418 0 0 1 0 0 0 1
 4 910419 0 0 . 0 0 0 0
 5 910420 0 0 0 0 0 0 0
 6 910421 0 0 0 0 0 0 0
 7 910422 0 0 0 0 0 0
 8 910423 0 0 0 0 0 0 0
 9 910424 1 0 2 0 4 0 7
 10 910425 2 13 0 1 0 16
 11 910426 1 0 0 0 1 2
 12 910427 0 0 0 0 0 0 0
 13 910428 1 7 9 5 5 6 33
 14 910429 11 36 16 8 0 2 73
 15 910430 4 10 1 1 0 16
 16 910501 4 5 9 0 0 2 20
 17 910502 87 68 129 8 8 43 343
 18 910503 57 5 29 5 15 111
 19 910504 10 10 2 8 3 33
 20 910505 19 15 23 3 19 2 81
 21 910506 33 158 12 5 10 218
 22 910507 19 65 10 13 19 65 191
 23 910508 73 259 164 706 218 204 1624
 24 910509 221 404 143 12 25 10 815
 25 910510 77 19 51 11 18 36 212
 26 910511 58 103 157 54 104 182 658
 27 910512 238 261 444 11 120 27 1101
 28 910513 107 39 118 35 157 87 543
 29 910514 979 513 252 79 127 148 2098
 30 910515 199 109 31 27 18 28 412
 31 910516 61 77 40 46 115 90 429
 32 910517 61 64 32 4 25 40 226
 33 910518 35 81 95 27 195 20 453
 34 910519 18 26 107 9 31 11 202
 35 910520 26 6 7 2 2 17 60
 36 910521 8 5 13 7 5 11 49
 37 910522 22 10 90 19 35 14 190
 38 910523 10 11 18 7 23 31 100
 39 910524 45 40 31 7 21 35 179
 40 910525 8 17 16 60 25 126
 41 910526 57 28 79 23 142 40 369
 42 910527 47 34 36 21 29 167
 43 910528 21 21 16 26 84
 44 910529 22 5 10 7 7 21 72
 45 910530 55 11 21 6 19 6 118
 102
I
 I Table A-7. Continued.
 I Day Date 0200 0600 1000 1400 1800 2200 Total
 , 46 910531 21 2 11 5 11 13 63
 47 910601 18 10 7 2 3 40
 I
 48 910602 5 6 4 3 18
 49 910603 5 2 1 5 0 13
 50 910604 0 2 2 2 11 0 17
 51 910605 0 2 2 0 1 2 7
 I 52 910606 3 2 3 1 1 1 1153 910607 3 1 4 0 2 3 1354 910608 0 4 1 0 0 5
 I
 55 910609 0 0 0 0 0 3 3
 56 910610 0 0 0 1 0 0 1
 57 910611 0 1 0 0 0 1 2
 58 910612 1 0 3 1 5 1 11
 ! 59 910613 0 0 4 0 0 0 460 910614 0 0 0 0
 [
 I
 I
 I
 I
 I
 I
 I
 I
 [
 l~ 103
Table A-8. Number of eggs in all nets, Barnhill's Landing,
 Roanoke River, North Carolina in 1991.
 Day Date 0200 0600 1000 1400 1800 2200 Total
 0 910415 0 0 0 0 0 0
 1 910416 0 0 0 0 0 0 0
 2 910417 0 0 1 0 0 1 2
 3 910418 0 0 1 0 0 0 1
 4 910419 0 0 0 0 0 0
 5 910420 0 0 0 0 0 0 0
 6 910421 0 0 0 0 0 0 0
 7 910422 0 0 0 0 0 0
 8 910423 0 0 0 0 0 2 2
 9 910424 1 0 2 2 6 0 11
 10 910425 3 23 0 2 0 28
 11 910426 2 0 0 0 1 3
 12 910427 0 0 0 0 0 0 0
 13 910428 1 10 15 12 10 8 56
 14 910429 17 62 25 13 1 8 126
 15 910430 6 25 5 2 2 40
 16 910501 7 13 19 0 1 8 48
 17 910502 149 109 239 15 9 57 578
 18 910503 99 10 55 5 19 188
 19 910504 15 11 4 10 5 45
 20 910505 35 23 41 16 33 12 160
 21 910506 52 301 28 7 19 407
 22 910507 32 89 12 24 51 142 350
 23 910508 136 612 388 1128 396 381 3041
 24 910509 396 662 318 29 60 16 1481
 25 910510 122 31 94 19 35 61 362
 26 910511 97 224 343 89 183 342 1278
 27 910512 476 472 969 85 246 32 2280
 28 910513 247 80 197 77 307 169 1077
 29 910514 1795 1033 670 120 270 230 4118
 30 910515 377 180 57 41 46 56 757
 31 910516 106 168 73 77 195 152 771
 32 910517 148 194 50 12 47 67 518
 33 910518 85 133 201 94 312 53 878
 34 910519 44 46 203 22 70 17 402
 35 910520 52 10 12 5 3 21 103
 36 910521 19 20 31 17 13 27 127
 37 910522 47 22 113 40 62 25 309
 38 910523 15 12 32 16 40 57 172
 39 910524 83 87 52 21 39 64 346
 40 910525 24 30 26 101 69 250
 41 910526 97 36 127 55 216 78 609
 42 910527 75 65 61 37 48 286
 43 910528 41 25 46 17 48 177
 44 910529 57 15 16 23 19 36 166
 45 910530 97 17 35 8 29 14 200
 104
I
 I Table A-8 . Continued.
 I Day Date 0200 0600 1000 1400 1800 2200 Total
 I 46 910531 33 5 18 7 22 20 10547 910601 27 18 12 9 4 . 70
 48 910602 11 . 9 6 8 34
 I 49 910603 13 3 1 6 . 0 2350 910604 0 4 5 3 21 2 35
 51 910605 1 2 3 0 2 2 10
 I 52 910606 6 4 3 2 1 1 1753 910607 4 1 6 0 2 7 2054 910608 . 0 4 1 0 0 5
 55 910609 0 1 0 0 0 3 4
 I 5 6 910610 0 0 2 3 0 0 557 910611 1 1 0 1 0 2 5
 58 910612 1 0 4 5 7 1 18
 I 59 910613 0 0 4 0 0 0 460 910614 0 0 0 0
 I
 I
 I
 I
 [
 I
 I
 I
 I
 l 105
Table A-9. Normal and observed rainfall (inches) for the Roanoke River basin downstream of
 Kerr Reservoir (RM 178.7), and basinwide, for April-June 1982-1991 (U.S. Army
 Corps of Engineers data).
 Below Kerr Dam Basinwide
 Normal Observed Normal Observed
 Year Apr May Jun Apr May Jun Apr May Jun Apr May Jun
 1963 3.37 4.02 3.91 1.55 2.83 2.59
 1964 3.26 4.02 3.91 2.20 1.30 2.45
 1965 3.26 3.77 3.78 2.04 1.98 8.30
 1966 3.16 3.62 4.16 1.49 6.38 3.55
 1967 3.03 3.84 4.11 1.88 3.24 2.39
 1968 2.95 3.79 3.99 3.21 5.20 3.05
 1969 2.95 3.79 3.99 3.05 3.24 4.12
 1970 2.95 3.79 3.99 4.09 2.36 3.12
 1971 2.95 3.79 3.99 2.57 6.36 3.41
 1972 2.95 3.79 3.99 2.32 5.03 4.52
 1973 2.95 3.79 3.99 4.62 4.53 5.95
 1974 2.95 3.79 3.99 2.56 5.68 2.65
 1975 2.95 3.79 3.99 2.23 3.23 2.27
 1976 2.95 3.79 3.99 0.85 3.73 4.39
 1977 2.95 3.79 3.99 2.66 5.44 3.69
 1978 2.90 4.08 3.87 4.94 4.85 5.60
 1979 2.98 4.11 3.94 4.30 6.09 5.87
 1980 2.98 4.11 3.94 3.15 2.85 2.84
 1981 2.98 4.11 3.94 1.41 4.96 3.10
 1982 2.98 4.11 3.94 3.04 2.56 4.83
 1983 2.98 4.11 3.97 5.99A 3.99 2.48
 1984 2.98 4.11 3.97 4.59 6.83 2.49
 1985 3.13 4.19 3.88 1.13 3.03 3.32
 1986 3.13 4.19 3.88 1.40 1.98 0.32B
 1987 3.13 4.19 3.88 5.53 2.21 3.44
 1988 3.01 4.09 3.75 4.67 3.87 3.68
 1989 3.01 4.09 3.75 6.41 5.16 8.41 3.36 3.89 3.84 4.02 5.76 7.95
 1990 3.22 4.06 3.87 3.37 5.83 2.34 3.40 3.87 3.83 3.51 7.55 1.76
 1991 3.22 4.06 3.87 2.62 1.46 2.86 3.40 3.87 3.83 2.94 3.08 2.68
 A Maximum observed April rainfall since 1952.
 B Record low observed June rainfal l.
 106