Lake Trout Egg Fatty Acid Signature Variability in the Great Lakes

Prey fish assemblages vary substantially among the Great Lakes as each ecosystem constitutes an inimitable community and has management strategies adapted to the particulars of its fisheries and conservation needs. Within each system there are also considerable temporal fluctuations in prey assemblage as native and nonnative species undergo sizable abundance oscillations. Predators’ tissues, including eggs, can reflect such changes related to nutrient intake. In the Great Lakes, lake trout populations have been suppressed by overharvest and sea lamprey predation while lack of their recovery has been linked to prey driven nutrient deficiencies. We assessed fatty acid signatures of lake trout eggs from multiple Great Lakes in a single year and from Lake Michigan in multiple years to document the amount of variability one can expect on the spatial and temporal scales, respectively. Eggs from various lakes could be readily distinguished based on their fatty acid signatures, although the degree of difference varied among systems. These results are indicative of large variation in lake trout egg fatty acid signatures among and within the Great Lakes and can affect lake trout egg quality with implications for successful restoration of this valuable native top predator.