The relevance and application of measures of thermal tolerance to fish ecology, conservation and aquaculture

Over the past 20 years, the fish research community has invested considerable effort into measuring the thermal tolerance limits of many freshwater and marine species. We have learned a lot regarding mechanisms that determine tolerance limits, and how climate-related warming of aquatic environments may affect fish biology, ecology and distribution. However, in our opinion, some research has used methods that are likely to provide inaccurate estimates of thermal tolerance with respect to wild and cultured fish populations. Given the rate of global warming, the increase in the frequency and severity of heat waves, and that these challenges are often combined with other climate change-related stressors (e.g. hypoxia, increased pathogen prevalence), we need to ensure that future efforts are more effectual for species' conservation and management. Herein, we provide a comprehensive and critical review of the methods currently used to measure the sub-lethal and lethal thermal limits of fishes, and discuss the relevance of these methods to fishes in the wild or in culture. In part, our aim is to educate fisheries managers and conservationists about what information is relevant to efforts to preserve species and biodiversity in the face of climate change. Finally, we provide explicit recommendations for researchers designing future thermal tolerance experiments.