Water temperature at the time of the catch-and-release event is a better predictor of survival in Atlantic salmon (Salmo salar) than acute water temperature changes before and after.

Despite studies on the effect of catch-and-release on the survival of Atlantic salmon (Salmo salar) being widespread in the literature, studies to date have failed to evaluate the potential role of thermal history. Herein, we show that despite cooler conditions post-release, 4/18 (22%) salmon died when caught-and-released at water temperatures ≥20°C, whereas 1/13 (8%) salmon caught-and-released at water temperatures ≤20°C, but who encountered mean water temperatures ≥20°C post-release, died. We conclude water temperature at time of the catch-and-release event remains the most suitable predictor of post-release survival.