Spawning habitat

Lake Superior National Marine Conservation Area

There are several important spawning areas identified within the NMCA, and maintaining these sites is critical to the persistence of healthy fish populations. Work is underway to review the existing data on spawning habitats, update information where available, and work with other organizations such as the Ontario Ministry of Natural Resources and Forestry to understand what work is being done and what gaps remain.

Nipigon River, Gapen’s Pool erosion

The part of Nipigon River known as Gapen’s Pool is one of the most important spawning habitat for the largest remnant population of the famous “coaster” brook trout of Lake Superior. Coasters typically spend part of their life in the big lake, then migrate back to tributary streams, estuaries, or near-shore locations in the late summer and early fall to spawn.

Gapen’s Pool is a special site because it is sheltered, well-oxygenated, has cooler waters, and spawning habitat of loose, silt-free gravel and coarse sand over an area of percolating groundwater. It is one of only three known spawning areas on the lower Nipigon River.

Red Rock Indian Band has expressed concern about fluctuation of water levels, erosion of the headland point above Gapen’s Pool, and potential impacts on the conditions of the site and its use by fish. Lake Superior NMCA staff began qualitative monitoring, using photography to view changes in erosion / deposition over time by comparing (and superimposing) photos taken from consistent, standard positions. The potential for monitoring using UAV photography is also being investigated.

Additional monitoring of erosion at Gapen’s Pool is being undertaken by Ontario Power Generation and the Ontario Ministry of Natural Resources and Forestry.

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