Superior Shoals

Recent work has pointed to lakemounts as potentially critical features in large lake ecosystems, which, like seamounts in ocean environments, appear to be 'hot spots' that play a disproportionately large role in supporting ecosystem biodiversity and production. Further, commercially and recreationally important populations of fish on lakemounts (specifically, the lake trout Salvelinus namaycush) are highly abundant, despite the lack of stocking intervention in these regions which was the primary recovery strategy implemented after the collapse of the Great Lakes fishery in the 1950's and 1960's. As such, lake trout (and perhaps other fishes) at lakemounts may be a refugia for genetically-intact historic strains present prior to fisheries collapse in the Great Lakes, compared to coastal populations of stocked origin. Several mechanistic processes have been reviewed and proposed to be important at lakemounts in driving greater regional production. These processes include upwelling of deep, nutrient-rich hypolimnetic waters against the abupt topographies of lakemounts, both from large-scale currents and internal seiche events during stratification. Lakemounts also provide substrate for benthic organisms in an otherwise pelagic environment. Advective forces due to large-scale currents can also lead to deposition of algae and zooplankton through leeward eddy retention, and the trapping of vertically migrating organisms, making them vulnerable to predation by resident consumers.