Progress Towards Understanding the Importance of Coastal Wetland Nursery Habitat to Great Lakes Fisheries Support

Great Lakes coastal wetlands provide habitat for Great Lakes fishes of all life stages. A literature review of ichthyoplankton surveys conducted in Great Lakes coastal wetlands found at least 82 species reported to be captured during the larval stage. Twenty of those species are of direct importance to commercial and recreational fisheries. Species richness and composition patterns were most similar among coastal wetlands in Lakes Superior, Huron and Michigan. The relative contribution of fish from coastal wetlands to Great Lakes fisheries is unknown. Many of the coastal wetland-using fish species are captured in the nearshore as adults and juveniles, suggesting exchange between habitats. Stable isotope analysis, used to trace movements of larvae between coastal wetlands and adjacent Lake Superior, revealed that some fishes undertake these exchanges during the larval stage (e.g., Rainbow Smelt, Yellow Perch, and White Sucker). These exchanges between wetlands and the lake were bi-directional. While the data indicate coastal wetlands are an important nursery habitat, and notably so for economically and recreationally important species, the factors influencing exchange between wetlands and other Great Lakes habitats are not well-understood. Approaches to track natal habitat and quantitative larval survey data are necessary to address this knowledge gap.