Considerations for Water Temperature-Related Fishery Closures in Recreational Atlantic Salmon (Salmo salar) Catch and Release Fisheries: A Case Study from Eastern Canada

Abstract Accumulating evidence has demonstrated a decrease in post-release survival of angled Atlantic salmon (Salmo salar) during periods of warm water temperatures. Consequently, the application of water temperature-related fishery closures by resource managers is gaining interest. Here, the role of water temperature-related fishery closures in recreational Atlantic salmon fisheries is reviewed by (1) presenting a synopsis of factors that could influence the effectiveness of these fishery closures, (2) using novel fisheries and water temperature data from Eastern Canada, to illustrate how various closures can affect management outcomes, and (3) discussing alternative options for managers to implement such fishery closures. Results suggest there are a number of considerations when implementing a water temperature-related fishery closure. For populations meeting conservation requirements, results show that additional angling opportunities can occur at minimal conservation cost by applying morning-angling-only protocols in rivers during periods of reduced catch and release and moderately warm water temperatures. The impact on salmon populations, however, will be higher in situations where high catch and release rates overlap with warm water periods (e.g. when day-night water temperatures remain in excess of 20 °C or remain high during the summer) or occur over prolonged periods of extreme warm water temperatures. In situations where resource managers have few resources and need to implement water temperature-related fishery closures on a large spatial scale, it is recommended that strategically chosen index rivers to inform water temperature-related fishery closures are used. In rivers with healthy salmon populations, angling opportunities during periods of warm water could be considered if supported by enhanced monitoring (e.g., monitoring salmon abundance, spatially-structured water temperature data, and mandatory catch reporting (catch and effort)) that optimize tradeoffs between socio-economic benefits and conservation.