A CATCH &RELEASE By: Luc LaRochelle, PhD Student, Carleton University & Dr. Steven J. Cooke, Professor, Carleton University
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any anglers release some of their catch. During the open water period, you can often see fish swim away when they are released, but have you ever thought about what happens to fish during the ice fishing season when you release them down the hole? That same question has troubled researchers for years. Logistically it is much easier to track released fish during the open water season and therefore there is lots of information about fish injury, stress, and survival during the open water season, yet we know virtually nothing about what happens to released fish in the winter. Fortunately, in the last few years there have been some creative efforts that have allowed researchers to study catch-and-release in the winter. Here we provide an overview of what we have learned and what it means for anglers. We conclude with some key best fish handling practices catch-and-release during the winter. It goes without saying that wintertime brings challenges for fish, anglers, and researchers. Fishing in the winter requires some specialized tools to access the fish whether that be an auger, a spot to escape the cold (i.e., hut) or method of transportation to get out to fishing spots.
Harsh winter day on frozen lake with high winds and cold temperatures. Essential tissue of fish would freeze in a matter of seconds in these conditions.
Lake Trout caught ice fishing on the same day as the other picture by one of the authors (Luc LaRochelle). Fish inside a hut to block the wind and extreme cold weather to avoid freezing the essential tissues of the fish. Notice how the fish is dripping with water?
The sub-freezing temperatures during the ice fishing season are demanding on the fish, human body, fishing equipment, and research equipment. From a research point of view, it not easy to monitor and track released fish below the ice. Specialized equipment is needed to monitor fish released in the winter such as underwater drones to visually observe the fish and electronic tags that are attached to fish with sensors that measure swimming activity, depth, and temperature selection.
Catching fish from cold water can be advantageous for catch-and-release. There is generally less mortality for fish caught and released in colder water temperatures compared to warmer water temperatures present during the open water season. Fish are ectotherms meaning that their body temperatures are regulated by the surrounding environment. In the winter, the body temperatures of fish are reduced, leading to the reduction of their metabolic rate and demand for oxygen compared to the warm open-water season.
Although water temperatures are less problematic for fish in the winter, it is the air exposure period during hook removal, measurement or if you pause to take a picture of your prize catch when things can go poorly for fish in the winter. It is challenging to avoid air exposure when ice fishing – even to release fish down the hole properly (headfirst)! (Continued on page 26.)
Just Fishing . 24
Winter 2024
