Rediscovering Brook Trout in Hanlon Creek-In mid-June, the TUC staff in collaboration with the Speed Valley TUC Chapter, teamed up to conduct a fish survey in Hanlon Creek in the City of Guelph. The crew was using a backpack electrofishing unit to determine the presence of Brook Trout in this urban stream that had not been assessed since 1993.
If you have ever seen a team of people electrofishing in a stream, it might look like a scene from the movie Ghostbusters. One person might have been wearing a backpack unit and holding a long rod, passing back and forth through the water. Instead of searching for ghouls, the electrofishing team is most likely conducting a fish survey.
Electrofishing is a common scientific method used to sample fish populations in streams. The Crew Lead operates the electrofishing unit by sending an electric pulse into the water to stun nearby fish. Once temporarily immobilized, the other crew members can then scoop up the fish and transfer them to a bucket of fresh water. Electrofishing is less stressful for the fish than other survey methods because of the reduced amount of handling and they are released shortly after their measurements are taken.
During this year’s electrofishing survey, TUC staff were joined by five volunteers from the Speed Valley Chapter and the Ontario Ministry of Natural Resources and Forestry. Together they surveyed seven sites that had been previously surveyed 25 years ago during the Hanlon Creek Watershed Plan. Brook Trout were captured in five of the seven sites, including at a location where they were not found historically! In addition to Brookies, the electrofishing crew also collected species that were typical of the area, including:
Eastern Blacknose Dace
Sculpin
White sucker
Pumpkinseed
Overall, the survey was a success and provides an updated snapshot of the state of the Brook Trout population within an increasingly urbanized coldwater system. It is our hope to continue electrofishing surveys on a regular basis moving forward in part to monitor the success of future stream rehabilitation features that will be installed later this summer and in future years by TUC staff and chapter members.
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