Assessment of family-derived metabolic traits for the conservation of an ancient fish

Physiological and behavioral traits of aquatic organisms are often highly dependent on environmental conditions, but genetic (family) effects often contribute to phenotypic variation. In this study, a series of physiological indices were used to assess the variability that exists among progeny of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) produced from eight different families. We designed a controlled experiment aimed to evaluate metabolic performance of age-0 lake sturgeon where growth, energy density, survival, metabolic rate, volitional swimming performance, and critical thermal maxima were quantified for fish reared under the same environmental conditions. We found a strong family effect for most metrics that were quantified and primarily influenced by the female. Furthermore, poor growth and survival within families were strongly correlated to low energy density levels and depressed routine metabolic rates at the yolk sac stage. Lastly, the quantification of energy density at the onset of exogenous feeding appeared to be an excellent predictor of future growth and survival. Our results suggest that the choice of female for production of progeny in conservation hatcheries will have significant impacts on the success of stock enhancement as a conservation strategy for lake sturgeon. -- Keywords : lake sturgeon ; Acipenser fulvescens ; respirometry ; early life history ; conservation aquaculture ; critical thermal maxima