Lake Simcoe's Changing Fish Community

Unfortunately, Lake Simcoe's coldwater fish, including species such as lake trout, lake whitefish and lake herring (cisco), have been severely impacted by excess phosphorus loading over the last several decades.

Large scale MNR stocking programs for lake trout and whitefish maintain these populations while infrastructure improvement and restoration efforts are undertaken in the watershed to improve water quality.  It is hoped that a self-sustaining coldwater fish community can be achieved. These populations however, continue to be affected by changes to the ecology of the lake, including the arrival of invasive species such as zebra mussels and round goby, and the prolific growth of aquatic plants in some near-shore areas.

Positive signs of potential recovery in the coldwater fish community have been seen in the last few years coinciding with recent water quality improvements. There has been evidence of naturally reproduced lake trout every year since 2001, something that has not been seen in the lake in over 20 years. Other members of the coldwater fish community, such as lake herring (cisco) and lake whitefish, have also seen increased levels of natural reproduction. Get more information on MNR’s Lake Simcoe stocking program and review recent changes to MNR’s lake trout stocking program.

The warmwater fish community in the SDW has not been impacted to the same extent as the coldwater fish community and remains healthy. Some of the more common warmwater fishes include: yellow perch, largemouth and smallmouth bass, northern pike, pumpkinseed and bluegill sunfish, crappie and rock bass.