Wetlands are the most essential component of any aquatic ecosystem. They influence water quality with their ability to absorb excess nutrients and pollutants including toxins like lead and oils. Wetlands provide essential fish spawning and nursery habitat. Large fish like musky and pike can lay their eggs among the submerged plants and once hatched the young fish find protection among the floating and emergent plants where it is too dense for larger predator fish to move in. Wetlands are also protected habitat for many amphibians – frogs, turtles and snakes such as the Threatened Eastern Foxsnake and Endangered Massassauga Rattlesnake.
According the Dr. Pat Chow-Fraser, Georgian Bay contains the highest quality, most diverse wetlands found anywhere in the Great Lakes. These wetlands are on the Canadian Shield in protected bays where there is glacial deposit left from the retreat of the last ice age. But that makes these wetlands very vulnerable to both low and high extremes of water level. Where the adjacent submerged shorelines are exposed granite bedrock, the wetland plants are unable to migrate out during exremely low water levels. If fish cannot find suitable spawning habitat they simply do not spawn. During extremely high water levels, such as those of 2019, wetland plants essential for spawning and habitat appear not to be flourishing.
We have been working with and supporting aquatic biologist Dr. Pat Chow- Fraser of McMaster University since 2003. Some of her published reports are available on our website. Her team of researchers continue to document and learn more every year about the benefits of finding a healthy range of water levels that supports wetlands. During the unprecedented 14 years of low water levels from 2000 to 2014, Dr. Chow-Fraser found there was a 25% submerged wetland habitat lost. (Normally a wetland habitat loss of anything more than 5% is considered significant.) Their team works with Ontario Ministry of Natural Resources and Forestry’s Lake Huron Management Unit and, utilizing tracking devices surgically inserted into large pike and musky, they found these fish swimming many kilometres beyond their normal range trying to find wetlands they could get into to spawn.
The good news is that with the higher water levels of 2015 and 2016 our McMaster research team have seen increases in fish populations and the fish are staying within their normal ranges. But it will take several more years for the wetlands plants to re-establish. In some locations 6 foot tall pine and willow trees were growing where once there were wetlands. The trees are slowly dying but it will take time for them to decompose enough to allow fish movement.
In 2019, the McMaster team is investigating the apparent loss of suitable wetland submergent vegetation for fish spawning and habitat during the current excessively high water.
We continue to work with and support Dr. Pat Chow-Fraser and her lab of researchers. Each year we find host cottages for the researchers to stay in for a week. One of the most interesting volunteer experiences happens when the volunteers get to see the team at work and can ask questions and discuss their preliminary observations. If you would like to help buy hosting the McMaster team please get in touch with us email@example.com