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New project tracks walleye in the Hamilton Harbour to assess success of restoration efforts

The aquatic ecosystem in the Hamilton Harbour area of Lake Ontario has been degraded over the last 120 years as a result of industrialization and land use change. Sewage, fertilizers and industrial pollutants flowing into the relatively small system combined with extensive physical habitat alteration has resulted in Hamilton Harbour being deemed as an Area of Concern (AOC).

The past 25 years has seen collaboration between government, NGOs, and members of the public in restoring the harbour to the pre-1920s conditions. These efforts have included stricter sewage treatment policies, the protection and creation of critical fish habitat, the planting of native marsh plants, the installation of the Great Lake’s first two-way fish barrier, and the reintroduction of native fish species, including walleye (Sander vitreus). The final stages of the Harbour’s Remedial Action Plan (RAP) are to monitor the progress of these restoration efforts to facilitate refinements necessary to meet delisting criteria.

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This August and September, Cooke Lab MSc student Jill Brooks and summer Research Assistant, Will Twardek, are working with the team at DFO to install a Vemco acoustic array around the harbor and will attempt to capture and internally tag 25 walleye. Year-round acoustic tracking of this reintroduced population of walleye will allow us to assess if these ‘remedies’ are working. The walleye are quickly reaching sexual maturity so this is a critical time to follow their movements. Are the fish using these protected and rejuvenated fish habitats? Are there other habitats that they are using over winter that could be restored? Will they spawn in the harbour or will they leave through the canal into Lake Ontario? Will they return to the harbour post-spawning? The answers to these questions could inform future management decisions in Hamilton Harbour and other areas experiencing similar habitat degradation issues, and will provide information that can be used to define targets and contribute to the delisting of the Hamilton Harbour Area of Concern. This telemetry project is a collaborative effort between Carleton University, Fisheries and Oceans Canada, Ontario Ministry of Natural Resources and Forestry, Environment Canada, and Hamilton Port Authority, and funded by the Great Lakes Sustainability Fund.