Maternal input of Striped Bass (Morone saxatilis) : Determining a mother's life history from its progeny in coastal North Carolina

Abstract

Otolith studies have become more prevalent in recent years as use has expanded from ageing to examination of migration patterns and fidelity to natal habitats, and more recently examining otoliths for possible maternal contribution to progeny otoliths. The otoliths of larval Striped Bass, Morone saxatilis (Walbaum; 1792), were used to determine the presence of maternal contribution through three experiments. The first experiment was to examine the formation of larval otoliths to determine if otoliths formed prior to/ during the yolk sac stage when maternal influences are present, and thus if maternal contribution is possible. Two of the three otolith pairs (sagitta and lapillus) are formed during the embryo stage (sagitta) or post hatch (lapillus). The sagittal otoliths are the most often used otolith in microchemical studies; therefore its formation during the embryo stage suggests maternal contribution to progeny otoliths is possible. The second experiment used microchemical analysis of adult Striped Bass soft tissue (muscle, liver, kidney, and gonads) to determine whether adult Striped Bass develop trace elemental signatures similar to the adult otoliths. The gonadal tissues (ovaries and testes) were found to have similar signatures to adult otoliths utilizing a linear discriminate function analysis. As the two previous experiments support the hypothesis of maternal contribution the final step was to run a discriminate function analysis between the progeny and maternal otoliths. Embryo sagittal otoliths correctly identified the maternal clusters 91.67% of the time (n = 12), yolk sac larvae 66.67% of the time (n = 15), and non-yolk sac larvae only 60.94% of the time (n = 64). Progeny otoliths were also able to identify maternal river (Neuse, Roanoke or Tar); embryos classified the river 83.33% of the time (n = 12), yolk sac larvae classified 93.33% of the time (n = 15), and non-yolk sac larvae classified with 44.44% (n = 72) accuracy. Results of this study validate the hypothesis of maternal contribution and support the hypothesis of maternal life history determination from progeny.