Lake Whitefish Recruitment
Lake whitefish has been one of the most highly sought commercial fish species in the Great Lakes for well over a century. Like many native fish species, lake whitefish suffered first from habitat loss associated with industrialization and logging practices and overfishing then from introduction of Atlantic Ocean species in to the Great Lakes during the 1930s and 1940s. However, following implementation of the sea lamprey control program, coupled with the initiation of salmon and trout plantings that utilized and reduced alewife as well as rainbow smelt abundance, lake whitefish recovered to historic levels. By the early 1970s, whitefish were the mainstay for the state-licensed commercial fisheries in the three upper Great Lakes, and since the early 1980s, lake whitefish has been the cornerstone for the tribal commercial fishery, composing 60–70 percent of total landings. Strong, consistent reproduction and subsequent recruitment of lake whitefish to the fishable populations in lakes Michigan and Huron—during the late 1990s to the early 2000s—drove commercial yields to levels not seen in either lake since the early 20th century.
Since the early 2000s Lake whitefish populations in the four lower Great Lakes have experienced a steady and substantial decline that continues to the present. Additional research is needed to understand the interactions between physical and biological processes that drive lake whitefish populations or act as bottlenecks to the populations. Understanding the linkage between physical and biological stressors to the populations will help identify potential management solutions.
In February 2018, the GLFT and the Great Lakes Fishery Commission hosted a workshop to understand recent trends in lake whitefish populations across the three upper lakes; engage fishery managers in discussion about importation management risks they face; identify their needs to address those risks; determine information gaps; and develop possible priorities for research and management action. The results of this workshop are summarized in the Developing Research Priorities for Lake Whitefish in the Upper Great Lakes: Results of a Workshop Sponsored by the Great Lakes Fishery Trust and Great Lakes Fishery Commission proceedings document.
The GLFT invites proposal responding to research topics identified in the proceedings document. In 2019, the GLFT’s primary interests in this research theme are:
- Exploring bottlenecks to recruitment: The GLFT invites proposals to develop a synthesis of existing data and research that explores possible mechanisms that explain observed trends in lake whitefish recruitment, including current and historical growth rates and densities, as well as where the recruitment bottleneck(s) may be occurring. The synthesis should examine geospatial differences in whitefish recruitment within and among the Upper Great Lakes. In this research, investigators should explore the conditions that were historically favorable for lake whitefish recruitment and evaluate contributions to the decline in recruitment, including factors such as the role of invasive species and disease—most notably dreissenid mussels, round goby, and viral hemorrhagic septicemia—coupled with ongoing nutrient reductions. The research should also consider how these, and other factors as appropriate, influence recruitment and year-class strength.
- Lake Trout Predation: The GLFT invites proposals to evaluate the impact of lake trout predation on lake whitefish. The study design for this project should be both spatially and temporally explicit to account for variations in location and duration of the diet characterization