Spawning Habitat for Muskellunge Is Far More Variable than Expected: A Review of over 20 Years of Research

摘要

We synthesize results from a number of studies to determine if Muskellunge Esox masquinongy spawning habitat is predictable. Specific objectives are to (1) evaluate characteristics of spawning habitat in a number of different systems; (2) determine ifspawning habitat can be predicted from data on land cover, geology, and physical characteristics in the lake or river; and (3) compare spawning habitat in inland lakes and some Great Lakes locations. In inland lakes, Muskellunge preferred to spawn overfine sediments near emergent and submersed vegetation in protected bays or shorelines, but bay and calm shoreline habitat is not always available and may be degraded, so they may end up spawning over open sand, gravel, or coarse particulate organic matter and spawning in areas without vegetation. For objective two, the best-performing MaxEnt model included shoreline development index, presence of nearby shallow areas, distance from outflowing streams, effective fetch, maximum depth, Carlson's trophic status index, and an indicator of east- or west-facing shoreline as significant factors predicting spawning locations in inland lakes. Overall, 64% of all observed spawning fell within locations predicted by a model, including the most suitable 40% of available habitat for all lakes. For objective 3, we compared habitat selection of Great Lakes-strain Muskellunge with the inland strain. MaxEnt models of habitat for Great Lakes Muskellunge included some similar factors like shallow depth and low slope, butalso included river habitat factors like presence of moderate vegetative cover and woody debris. To conclude, we propose a conceptual model of Muskellunge spawning and nursery habitat where survival from egg to larva is limited by water quality, predation on eggs, and abundant food resources.