Affects on Fish and Wildlife

Affects on fish

We’ve conducted more than 12 years of research on fish in Mayo Lake. Detailed studies have shown that lake trout and lake whitefish populations are healthy and continue to do well despite low water levels during the past few years.

Lake trout are an important fish species in Mayo Lake. They support a considerable fishery and are at the top of the food chain in the lake, making them sensitive to changes. Lake whitefish are also important because they are a key food fish for other species including lake trout, pike and burbot.

what we have done

  • Studies have been done to understand where and how deep lake trout spawn. We discovered that they can be attracted to spawn in deeper areas which are "safer" during low water levels.
  • We located lake whitefish spawning areas in larger tributaries to the lake and identified important areas for spring rearing (feeding and growing).
  • Detailed studies have shown that lake trout and lake whitefish continue to do well despite low water levels during the past few years.

lake trout and lake white fish

Both species spawn during the fall and their eggs incubate over the winter months. This overlaps with the time of year when water is used to generate power and therefore their egg survival may be affected by the project. Most lake whitefish spawn in streams that flow into the lake. They rely on the shallow areas at the ends of Roop and Nelson arms to feed and grow during the spring.

beach seining and spawning

Since 2008, detailed studies have been carried out to understand lake trout and lake whitefish in Mayo Lake. These have included annual beach seining since 2009 to track the numbers of juvenile lake trout as well as studies to understand where (and how deep) the lake trout spawn. We are currently completing a study using lake trout eggs from Mayo Lake in an aquarium to understand how the eggs develop and when they hatch. Studies on lake whitefish have focused on learning where important spawning and rearing (feeding) areas are located.