Studies on fish recovery

by Matthew Robbins | May 15, 2020
fish recovery fisheye

The “murky water” surrounding angler-caught fish recovery and survival is becoming clearer thanks to recent efforts at two Canadian Universities.

Researchers from Carlton University’s Fish Ecology and Conservation Physiology Laboratory explored the fate of pike that break line and escape with an angler’s lure. For this experiment, lures equipped with radio transmitters were lodged into the mouths of 51 pike before they were released back into Lake Opinicon, Ontario. 

While three of these fish died after release, only one of the remaining 48 was unable to dislodge its lure within the study’s two-week span. Fish with lures that had barbed hooks were slower at shedding their lures than those without. Though hook locations also influence behaviour, feeding, and distribution in the waterbody of these pike, the study authored by Christopher Pullen, Robert Arlinghaus, Robert J. Lennox, and Steven J. Cooke says “…anglers can be reasonably confident that long-term damage to individuals is limited…” 

Fish recovery from photographs

Another study, conducted this past summer by researchers from the University of Manitoba, assessed the effect that continued fish handling for photographs has on their survival. The study took place in the remote waters of Alberta’s Willmore Wilderness Park, where researchers used fly and spinning gear to catch a total of 50 mature bull trout over two days. Twenty were immediately released into a holding pen, while the remaining thirty were handled, photographed and measured. 

The result was a more than twofold increase in the number of dead bull trout among the photo- released group, with a mortality of 33%. 

Food for thought

Both studies provide food for thought. “Anglers are often required by regulation to release their fish, and others simply enjoy practicing catch and release,” said Ontario Federation of Anglers and Hunters Fisheries Biologist Adam Weir. “Regardless of whether you have to or want to, anglers should always follow proper care and handling techniques to minimize harm to fish and ensure successful releases.”

Study results reflect “average” fish-handling practices and not, as the authors point out, the abilities of an experienced and knowledgeable angler. For this reason, it may be hard to say what implications they hold for the practice of catch and release fishing as a whole.

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