A field study combining biotelemetry and biologging to determine how long the behaviour of fish is impacted by catch-and-release angling

Assessing the behaviour of fish in the wild is challenging given the lack of relevant “controls” to assess recovery following capture. Our aim was to assess how long it takes largemouth bass (Micropterus nigricans) and northern pike (Esox lucius) equipped with pop-off biologgers to resume normal behaviour (i.e., return to baseline movement and exploration activity) once released. Both species were equipped with acoustic transmitters in a whole-lake positioning system to model their movement patterns and behaviour. We recaptured those same individuals at a minimum of 37d later and affixed pop-off biologgers that recorded acceleration and depth allowing us to combine data from two technologies to assess the post-release behaviour of the fish. In 20–28.5C water temperatures, it took largemouth bass equipped with biologgers 129h (95% CI: 106-149h) to resume normal movement and 154h (103-195h) for exploration activity. Northern pike equipped with pop-off biologgers took 145h (110-174h) to resume normal movement activity. Exploratory behaviour of northern pike was not influenced. These results reveal that catch-and-release angling can yield post-release behavioural consequences for up to 7d.