Relative influences of microhabitat incubation conditions and genetic parentage effects on lake sturgeon (Acipenser fulvescens) offspring traits during early ontogeny (DATA)

Knowledge on factors influencing traits during critical early growth
periods is essential for predicting population persistence. Genetic
effects and microhabitat stream conditions at female selected oviposition
sites influence larval phenotypes. However, limited work has examined
contributions of both factors across sequential ontogenetic stages for
larvae of wild origin. Using a wild population of lake sturgeon (Acipenser
fulvescens) from Black Lake, Michigan (USA), fertilized eggs were
collected from stream substrate just prior to hatch at one-meter intervals
along seven transect lines at an adult-selected spawning area.
Microhabitat variables (depth, discharge, substrate size) were recorded at
egg collection points. Body length, body area, and yolk-sac area were
quantified for yolk-sac larvae (N = 359) at the time of hatch.
Following the onset of exogenous feeding, larval growth was measured
weekly for four weeks. Parentage was assigned using genetic-based
analysis. Inter-individual variation in phenotypic traits quantified at
hatch were attributed to stream microhabitat variables; mean depth had the
largest influence. No additive genetic effects were detected at hatch.
Post-emergence larval growth significantly varied within and among
half-sibling groups with the greatest range in body size observed at
33 days post-hatch. Additive genetic variance and heritability
increased with age. Results demonstrate that female-selected incubation
habitats influenced traits at hatch for wild-origin fish, but effects do
not persist to a sequential ontogenetic stage. Alternatively, growth after
the onset of exogenous feeding was largely influenced by intrinsic
(genetic) factors which must be considered when designing and implementing
rehabilitation strategies for lake sturgeon and potentially other
threatened riverine fishes.