Chuck Madenjian, USGS Great Lakes Sc

The burbot recovery in Lake Michigan coincided with a decline in the abundance of deep water sculpin (Myoxocephalus thompsonii). As burbot abundance leveled off during the 1990s, so too did deep water sculpin abundance. Thus, the Great Lakes Science Center bottom trawl survey data suggested a predator-prey link between the burbot and deep water sculpin populations. However, bioenergetics modeling has not been applied to the burbot population in Lake Michigan to estimate annual consumption of deepwater sculpins by burbot. In addition, the round goby (Neogobius melanostomus) is slowly spreading into the main basin of Lake Michigan. Bioenergetics model applications to the burbot population would be useful in estimating annual consumption of round gobies by burbot. In this way, the role of burbot within the Lake Michigan food web becomes better defined.

Specifically, the objectives of this study are to: (1) compare diet, growth, maturity, fecundity, thiamine levels in eggs, annual survival, and sea lamprey mortality of lake trout at various stocking sites in Lake Michigan, (2) compare growth and survival of various strains of lake trout stocked into Lake Michigan, (3) use the above-mentioned research findings to improve the lake trout rehabilitation effort in Lake Michigan, (4) survey the lake trout population in Lake Michigan for evidence of natural reproduction, (5) use the results of this surveillance for management recommendations concerning lake trout rehabilitation in Lake Michigan, (6) use the spring LWAP survey results to characterize the population dynamics of burbot in Lake Michigan, and (7) apply bioenergetics modeling to the burbot population to estimate annual consumption of various prey fishes.