Known to many as Mississauga’s ecological gem, Rattray Marsh has seen a steady invasion of non-native carp over the decades, destroying the native ecosystem. Throughout the spring, CVC blocked and removed hundreds of carp from the marsh. To commemorate the project, our resident artist and Manager of Natural Heritage, Bob Morris, created unique prints of some of the carp that were removed.
Each unique print is entitled The Ghost Carp of Rattray Marsh. Carp have haunted the marsh for years. The ones that were removed no longer harm the marsh’s delicate ecological balance. The only thing they leave behind is their ghostly imprint.
Carp are native to the rivers and lakes of Europe and Asia and were introduced to North America in the 1830s. They escaped from flooded fish ponds into the Holland River in 1896 and from there invaded the Great Lakes. They impact Rattray Marsh in three ways. Carp compete with native fish like catfish and suckers for food. They uproot underwater plants that predatory fish such as pike and bass use to hide and ambush their prey. Carp kick up a lot of sediment, making the water murky, reducing the amount of sunlight and limiting the growth of new underwater plants required by fish, amphibians and birds. An adult carp living up to twenty years old and weighing over twenty pounds can lay up to two million eggs. Many will outgrow native predators very quickly.
For all their destructive influence, the carp’s long and storied journey from the old world to the new is an important part of the history of Rattray Marsh and the Great Lakes watershed.
Over the decades, upstream development around Sheridan Creek has changed the marsh by contributing excess sediment, burying the native marsh ecosystem. This has resulted in poor water quality and loss of water depth, making it difficult for native fish to survive. Carp thrive in these conditions. Visitors to the marsh will notice the surrounding habitats appear quite healthy. The real ecological problems lay just below the water’s surface.
In 2011, the Ministry of Natural Resources approved an Environmental Assessment and Restoration Plan for this “Provincially Significant Wetland and Area of Natural and Scientific Interest”. In addition to carp control, over a metre of sediment will be removed to expose the original peat and native seed bank now completely covered. The restoration project is financially supported by the Region of Peel and the Province of Ontario. The restoration is consistent with CVC’s climate change strategy to restore and build resilience into the natural environment. It also achieves restoration objectives laid out in CVC’s Lake Ontario Integrated Shoreline Strategy.
Community-based stewards like the Rattray Marsh Protection Association, Mississauga Bass Masters as well as other volunteers and sponsors are helping to foster a rebirth of Rattray Marsh.