Effects of delayed fertilization on embryo viability in walleye Sander vitreus (Mitchill): the role of maternal effects

The effects of delayed fertilization on embryonic viability in walleye Sander vitreus were examined using laboratory fertilization and incubation trials. Both fertilization success (survival to 10 h post‐fertilization) and embryonic survival (from 10 to 168 h post‐fertilization) generally declined with increasing ova storage time but trends varied significantly among females. Embryonic survival of individual egg batches was positively related to fertilization success. The slope of the relationship between fertilization success and ova storage time was negatively related to maternal fork length indicating that ova quality declined more rapidly with storage time for larger females than for smaller females. In contrast, the slope of the early embryonic survival v. ova storage time relationship was not significantly related to maternal size.