The purpose of this review is to explore the likely effects of climate change on the world´s freshwater fisheries. Global warming affect fish populations through direct temperature effects on physiology. All freswater fish are cold-blooded, and their physiological mechanisms are directly or indirectly temperature-dependent. The optimal physical and byological ranges of a fish species are determined by temperatures that are required for efficient metabolism, reproductive success, and disease resistance. Any changes in those temperatures, inclusing those predicted to result from global climate change, will result in range shifts and local species extirpations...