Sammendrag
Average global air temperature has increased in recent decades resulting in accompanying changes in river temperatures. Poikilotherms, like Atlantic Salmon (Salmo salar L.), are vulnerable to temperature fluctuations. At the same time, many Atlantic Salmon populations are subject to catch and release angling. Catch and release mortality is influenced by angler practices and water temperature. Because Atlantic Salmon are commonly caught by anglers during the warmest months, angled fish can be exposed to physiologically stressful and potentially lethal water temperatures. Here we test interactions between river warming and mortality in recreational Atlantic Salmon fisheries. We first quantify the range of mortality rates observed at a given water temperature for caught and released Atlantic Salmon by compiling and analyzing published and unpublished data on catch and release mortality. We then focus on the region of Newfoundland and Labrador, Canada, and provide mortality estimates for caught and released Atlantic Salmon on an individual river basis by combining estimates for number of caught and released salmon from angler survey data with river temperature data. Lastly we update and compare regional and temporal trends (~1978 to 2018) for river temperatures and river closures due to high water temperatures and/or low water levels. Catch and release mortality for Atlantic Salmon was variable across studies with the majority of published data (~75%) having mortalities of
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