Ontario SWAT Team members using a backpack electrofisher to find Brook Trout.
By Mike McKenzie Strategic Watershed Action Team Member
When the Ontario Strategic Watershed Action Team hasn’t been busy building in-stream structures, they have been implementing Brook Trout Monitoring programs around the province. Population monitoring is critical as it allows Trout Unlimited Canada to assess previous restoration efforts and determine which areas to focus on next.
After years of tireless work, two dams were removed on Armstrong creek in Markdale. Both previous mill dams had been preventing resident Brook Trout from moving between the upper reaches of Armstrong and the large river just downstream it flows into, the Rocky Saugeen. With the dams now removed the Brook Trout would be able to move between the systems to better take advantage of cooler water temperatures and food resources. To determine if this was true the SWAT crew and a group of volunteers electrofished three separate reaches of the stream; below both barriers, above both barriers, and in between them. The surveys managed to find Brook trout in all three reaches, suggesting the fish can once more move throughout the watershed!
As mentioned, this work was carried out using the team’s backpack electrofisher. If you haven’t heard of an electrofisher before, it is a fish collection tool that functions by emitting electric pulses into the water that momentarily stuns nearby fish. Stunned fish are quickly scooped out of the water and moved to a live well (a box with holes that are placed in the creek so freshwater can pass through it) where they can comfortably recover. Each fish is then identified, measured, and counted before being returned to its peaceful lives in the stream.
It was not only the progress of TUC’s restoration work that needed to be assessed. Our friends at Outdoor Adventures from Owen Sound have spent the past few years rehabilitating sections of the Upper Sydenham River that had been degraded through agriculture. Though Brook Trout can be found just downstream, this portion of the river hasn’t had a sustainable population in many years. In hopes of enticing the fish to return, OA has already stream-side trees for shade, placed cover structures in the stream, build undercut banks, and even restored a side tributary to act as spawning grounds. Alongside their volunteers, the SWAT crew electrofished the entire 270m stream section, catching an assortment of Sculpins, White Suckers, and Brown Trout. Though no Brook Trout were found this year, the team was able to identify which stream features the Brown Trout liked to under, letting Outdoor Adventures know which of their structures are most likely to help the Brook Trout re-establish themselves.
Each fish is then identified, measured, and counted before being returned to its peaceful lives in the stream.
Finally, the recent formation of the Millbrook chapter necessitated the cataloging of a number of stream reaches to uncover which of the area’s many waterways contain Brook Trout. By determining where the fish live, their population size, and how many each stream can sustain the chapter can go on to make better decisions as to where to direct their restoration efforts in the coming years. Together with local, chapter volunteers, the SWAT crew sampled eleven sites on four creeks, finding Brook Trout throughout the area. Additionally, by observing the body size of certain individuals it was possible to determine that while a few individuals were likely stocked in local ponds and escaped, many others appeared to be the products of natural reproduction in the stream. A great sign for the area’s Brook Trout and a great start to the Millbrook Chapter!
While we may not have Brook Trout at every site we visited, each excursion provided new bits of information that can be used moving forward to help preserve and bring back our native salmonids. Be it where the fish were found, what habitat they were using, or how many fish were living in a stream, this summer’s monitoring projects have set Trout Unlimited Canada, and their stream restoration allies, up for a productive 2022!
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