Egg Quality Differences Between Wild and Hatchery-Reared Bloater (Coregonus hoyi)

Abstract

Coregonines are ecologically and culturally important in the Laurentian Great Lakes, and restoration efforts increasingly rely on hatchery propagation to reestablish extirpated populations. However, artificial rearing may alter life history traits that influence recruitment success. We compared maternal traits and egg quality between wild-origin and hatchery-reared Bloater (Coregonus hoyi) from the Lake Michigan source population used in Lake Ontario restoration. Hatchery females were larger and in higher condition but produced smaller eggs (relative to body size) with lower carotenoid concentrations. Although total egg lipid content did not differ, fatty acid profiles diverged: Hatchery eggs contained more monounsaturated fatty acids (MUFAs) and docosahexaenoic acid (DHA), whereas wild eggs were enriched in arachidonic acid (ARA) and eicosapentaenoic acid (EPA), resulting in higher lipid unsaturation. These differences likely reflect dietary mismatches between hatchery feeds and natural prey and may reduce offspring performance in cold, oligotrophic environments. Our findings suggest that improving broodstock diets may be one way to enhance restoration success.