Lake Huron has a history of overfishing, habitat degradation, and introductions of non-native species that have resulted in a dynamic ecosystem with a prey base of primarily non-native species. In the mid-2000s, a massive shift in the ecosystem occurred when Alewife and Chinook Salmon populations collapsed. This led to an increase in native Lake Trout and Walleye populations, despite the continued low prey biomass. Alternative prey such as non-native Round Goby and Rainbow Smelt have supported predator foraging, but it is unclear if current prey biomass levels can support the continued expansion of Lake Trout and Walleye populations. I conducted a comprehensive diet study of angler-caught predators in 2017 and 2018 to evaluate current spatial and temporal trends in the diets of the major predators of Lake Huron within the context of historical foraging conditions. I observed several prominent spatiotemporal trends for the majority of Lake Huron predator diets, including a shift in consumption from Round Goby to Rainbow Smelt between spring and summer, and an overall reduced consumption of Round Goby in Saginaw Bay compared to the main basin. I also found an increased reliance on Round Goby by native Walleye and Lake Trout compared to previous studies while Chinook Salmon continued to rely upon Rainbow Smelt and Alewife. Evidence from gut fullness indices and size distributions of consumed prey indicate that forage conditions in Lake Huron continue to decline. Overall, the predator community continues to be reliant on non-native prey, and forage conditions may be indicative of prey limitation for the foreseeable future.
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