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For the last few years, the Margaree Salmon Association in northern Cape Breton has been using electrofishing to monitor fish populations in the Margaree River.
The technique uses an electric current to briefly stun fish so crews can safely net, measure and identify them before releasing them back into the water.
Michael Fabiano, conservation co-ordinator with the association, says crews electrofish from May through late September. The process has a two per cent mortality rate across the thousands of fish processed each season.
“We put fish safety as our No. 1 priority,” Fabiano says. “We don’t shock if water temperatures are too high.”
Crews set current levels so electricity causes fish to roll over for only a few seconds. To prevent injury from working with electricity in water, crew members wear heavy rubber gloves and chest waders. No members have received a serious shock during Fabiano’s 18 months with the group.
Crews survey locations along the 120-kilometre river to identify its most productive streams and assess overall fish health. About 95 per cent of the catch consists of trout and Atlantic salmon, alongside occasional eels and lampreys.
So far this season, the association has caught and released about 1,800 fish across nine streams — down from last year.
“That could be in large part due to the difficult year we had last year,” Fabiano says. “Water levels were low and really warm for a lot of the summer. It was a horrible drought that really affected the Margaree.”
Paul MacNeil, president of the association, says the group stepped up its scientific research because Fisheries and Oceans Canada has scaled back data collection on the river over the past five years. Founded in 1982, the group wanted reliable data to track river health as climate conditions shift.
To fill the gap, the association partnered with the Chéticamp River Salmon Association to buy electrofishing gear. While members also swim the river to count fish, MacNeil says electrofishing provides much more accurate juvenile population data.
“When we do electrofishing, we have a good potential of capturing all of the juvenile fish in that one territory,” MacNeil says.
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