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To inform lake trout (Salvelinus namaycush) fishery management in Lake Huron that has undergone rapid ecosystem changes, we quantified lake trout production dynamics by coupling age-structured stock assessment and fish bioenergetics models. Our approach revealed the connection between piscivore production and prey consumption, included growth compensation to reproduction losses, and allowed comparisons between long-term dynamics of fishery harvests and fish production. We found that, despite the collapse of alewives, a major non-native pelagic prey fish, lake trout production appeared to be sustainable. To a certain degree, the effect of recent recruitment declines on lake trout production was offset by the release of harvest pressure from subadult lake trout and reduction in fishing and sea lamprey-induced mortality on adult lake trout. Evidence for sustainability also included the finding that no changes in average ratios of annual production to beginning-of-the-year biomass. Juvenile P:B ratio remained as high as 2.1. The effect of growth declines on adult and subadult production was offset by reduction in population mortality. Body growth and condition did not continue to decline when lake trout became more and more reliant on round goby as food, and the dynamics of total consumption of prey fish continued to be recipient controlled. [ABSTRACT FROM AUTHOR]

Since the 1950s, fishery agencies on Lake Michigan have pursued Lake Trout Salvelinus namaycush rehabilitation through Sea Lamprey Petromyzon marinus control, harvest regulations, and stocking millions of fish annually. Stocking was prioritized at four historically important spawning locations beginning in 1985, and coded wire tags (CWTs) were used to help evaluate performance. We used data from coded‐wire‐tagged fish captured in fishery‐independent surveys from 1998 to 2014 to evaluate relative postrelease survival of Lake Trout, estimated by CPUE and corrected for the number of fish stocked, across 173 CWT lots of the 1994–2003 year‐classes stocked at the four locations. Boosted regression tree models were used to assess the relative influence of four variables on Lake Trout CPUE in two age‐groups (ages 4–5 and ages 6–10) and were paired with ANOVAs to test for statistical significance. Genetic strain (29.1%), stocking location (27.8%), mortality at release (23.1%), and predator density (19.9%) had similar influences on the relative survival of younger fish, whereas the relative survival of older fish was heavily influenced by stocking location (79.8%). Survival of both age‐groups was lowest for fish stocked in the Northern Refuge, where the age structure was truncated due to fishery harvest and Sea Lamprey predation. Survival of stocked fish was higher at the Southern Refuge, Clay Banks, and Julian's Reef, where mortality from Sea Lamprey and harvest was lower and where increases in wild Lake Trout have been observed in recent years. Stocked Lake Michigan remnant genetic strains also appeared to survive better than strains from other lakes at these three locations, but strain effects could not be fully disentangled from the effects of stocking location, and the continued stocking of multiple genetic strains may provide resiliency to future selection pressures. Continued progress toward rehabilitation will require reducing fishing and Sea Lamprey‐induced mortality in northern Lake Michigan to build parental stocks of advanced ages as well as balancing efforts among competing management goals. [ABSTRACT FROM AUTHOR]