Fall Salmon Spawning Run in Durham Region Creeks

Each fall in Central Lake Ontario Conservation’s (CLOCA’s) watershed, through our Integrated Watershed Monitoring Program, we collect data on the movement of spawning adult Chinook and Coho Pacific Salmon from Lake Ontario. The fish are searching for a suitable location to lay their eggs, and we call this a ‘spawning run’. The success of the run depends on access to suitable spawning habitat. Low water levels, typical in our creeks during late summer and early fall, often make natural and human-made barriers impassable obstructions for the salmon. An example of a natural barrier is a log jam or beaver dam. A human-made barrier can be a dam to address flooding or a culvert constructed under a road.


Whether natural or human-made, the barriers create a ‘wall’ during low water conditions, forcing the fish to jump this ‘barrier’ to move further upstream, to their preferred spawning habitat. If conditions are not suitable to navigate past a barrier, fish will eventually drop back into lower reaches of the creek and spawn there.






The Circle of Life

What is also interesting about these two salmon species, is that they actually die after spawning, completing their lifecycle in the creek. As the fish’s body decomposes, the nutrients provide an important source of food for aquatic organisms and sometimes terrestrial species like crows and ravens. The Department of Fisheries and Oceans Canada has more information about the lifecycle of salmon.


Roles and Responsibilities

Under the Fisheries Act, the Ontario Ministry of Natural Resources and Forestry (OMNRF) is responsible for fisheries management in the Province. Central Lake Ontario Conservation, like other Conservation Authorities, plays an important role in fish management, providing more detailed data at the local level to better inform the OMNRF.


Fish monitoring in creeks

We have developed integrated watershed plans for each of the creeks in our watershed jurisdiction, examining and assessing the relationships and interactions between the natural ecosystem and human activities. The Integrated Watershed Monitoring Program provides extensive data to assess existing conditions of our land and water resources, and inform recommendations for action in our watershed plans.



Fish monitoring

Action Plan # 17, The Instream Barriers Action Plan

The ultimate goal of the watershed plans is to provide us with tools to implement projects that address specific watershed-related issues. Central Lake Ontario Conservation’s Action Plan # 17, Instream Barrier Action Plan targets instream barriers, which act as obstructions for the spawning runs taking place in our watershed’s creeks. The Instream Barrier Action Plan investigates and evaluates known barriers, confirming their ecological impacts, and establishes a ranking system to justify and prioritize their removal. Removing a barrier is a very complex process, involving extensive study, many stakeholders, a willing landowner, significant financial commitments and technical expertise. At Central Lake Ontario Conservation, we have worked with Valleys 2000 to create the Bowmanville Fishway, a community project which addressed a significant instream barrier. For more information on what CLOCA does for fish in our watershed, check out the Central Lake Ontario Fisheries Management Plan.




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Healthy watersheds for today and tomorrow.
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Central Lake Ontario Conservation is a

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© 2019 by Central Lake Ontario Conservation

100 Whiting Avenue, Oshawa, ON L1H 3T3

Email: mail@cloca.com, Phone: 905-579-0411