Guidelines for Handling and Sampling Adult Salmon during Periods of Elevated Water Temperatures in Alaska Rivers.pdf

Water temperature is an important hydrological parameter that influences spawning success in Pacific salmon Oncorhynchus spp. Suboptimal water temperatures can elicit behavioral and (or) physiological stress responses that have the potential to impact the fitness of spawning stocks. The Environmental Protection Agency (EPA) has identified critical temperature thresholds known to have sublethal and lethal effects on adult Pacific salmon returning to spawn. Water temperatures near or exceeding these sublethal thresholds have recently been recorded within the Yukon River and its tributaries. The duration and intensity of exposure to stressful environments, such as elevated water temperatures, influences individual survival. There is increasing concern among managers and researchers that sampling adult salmon during periods of elevated water temperatures may negatively affect the survival of salmon preparing to spawn. This document provides guidelines for handling adult salmon when sampling during periods of elevated water temperatures. The goal of these guidelines is to minimize the cumulative impacts of handling and heat stress on adult salmon preparing to spawn.