Maternal Effects on Embryonic Development and Survival in Walleyes of Lake Nipissing, Ontario

Abstract

AbstractLife history theory predicts that females may increase reproductive allocation with advancing age as the probability for future reproduction diminishes. In iteroparous fishes, increasing age is usually accompanied by increasing fecundity, but evidence of increasing offspring quality is less consistent. We examined the developmental rate and survival of Walleye Sander vitreus embryos with respect to female age, size, condition, and various ova traits in an exploited stock dominated by young spawners. Embryo batches from individual females were collected in the field on multiple dates and reared to hatch under controlled conditions in both flow‐through and static incubation systems. Survival and thermal inputs to hatch (TU50) were analyzed with respect to spawn date, incubation method, and both maternal and ova traits. Spawning date had a relatively strong effect on embryo survival but only a minor effect on TU50, whereas incubation method had a small effect on survival but a stronger effect on TU50. Embryos reared in static incubators required greater thermal inputs to reach hatch. Using a model selection approach to assess the effects of maternal and ova traits, we found that neither maternal age nor size were strong predictors of survival or TU50. Instead, survival was more strongly related to egg size and fatty acid composition, and TU50 was not strongly related to any maternal or ova trait. Our results suggest that the nature and magnitude of maternal effects on early development and survival may vary among Walleye stocks, modified by physical conditions during incubation.