Genetic and environmental components of phenotypic and behavioral trait variation during lake sturgeon (Acipenser fulvescens) early ontogeny

Quantifying the relative contributions of genetic and environmental effects and their interaction on phenotypic variation is vital to understand how populations respond to their environment. Adults can plastically respond to environmental conditions by selecting breeding and egg incubation locations that affect offspring traits during embryonic and larval development. Environmental conditions during incubation can also affect traits during later ontogenetic stages (i.e., ontogenetic contingency). Using a well-studied population of lake sturgeon (Acipenser fulvescens) from Black Lake, Michigan, eggs were reared from full and half-sibling families at two spawning locations and in a common garden experiment consisting of three water velocity treatments: high, low, and variable. Larvae reared within the stream varied significantly between spawning sites for traits quantified at hatch including body length, body area, and yolk-sac area. Estimates of trait heritabilities ranged from 0.42-0.48. Growth from hatch to 2-3 weeks post hatch when larvae emerged from the substrate to begin exogenously feeding varied among families reared at the spawning locations due to a genotype-by-environment (G-by-E) interaction. In the common garden experiment, phenotypic variation among families was greatest for larvae reared under high velocity and a significant G-by-E was detected for body length, body area, and head area. Growth also varied among velocity treatments, but did not vary between families. Overall, results indicate that adult-selected spawning and rearing locations as well as genetic effects influence offspring phenotypic trait variation. Importantly, egg incubation conditions can also affect trait variation during sequential ontogenetic stages potentially affecting larval survival and population levels of recruitment.