Hatching success of walleye embryos in relation to maternal and ova characteristics

Abstract – Understanding how maternal and ova traits influence offspring quality is a key issue in both ecological research and fish culture. We examined the survival and size at hatch of walleye embryos in relation to a suite of maternal and ova traits in laboratory incubation trials involving two native walleye populations. Ova were analysed for size, lipid content, fatty acid composition, soluble protein content and size composition, and mineral (Ca, Co, Cu, Fe, Mg, Mn and Zn) content. Embryonic survival (egg hatching success) varied most consistently with respect to spawning date and maternal age. Embryonic survival increased with maternal age, but other indices of maternal health, such as condition (residual mass at length) or somatic lipid content, did not account for significant amounts of variation. Indices of ova total lipid content, fatty acid composition and mineral composition explained significant variation in embryonic survival not accounted for by maternal age and spawning date, whereas indices of protein content and composition generally explained less variance. Both larval mass and length at hatch were primarily determined by ovum size, but length at hatch was also related to some aspects of ova fatty acid and mineral composition.