Thunderstorms have species and gear-specific indirect effects on the catchability of Mongolian salmonids

Climate change is predicted to cause increasingly frequent and intense storms. Northern Mongolia is already warming at a rate twice the global average, and thunderstorms, defined as intense, short, patchy rains associated with thunder, lightning and high precipitation rates, are becoming more frequent. Because Mongolia's fish populations are lightly exploited, Mongolia provides a model system in which to study the effects of storms on fish behaviour and fishing vulnerability. The impacts of thunderstorm-related hydrological changes on fishes’ vulnerability to two fishing gears were evaluated. Two thunderstorm-related factors, turbidity and river stage, reduced catch rates of the salmonids lenok Brachymystax lenok (Pallas) and Baikal grayling Thymallus baicalensis Dybowski. Fly-fishing gear was more effective than spinning gear in this fishery and retained higher catch rates in extreme conditions. These gear-specific effects suggest that turbidity and rising river stage affect fishing vulnerability by influencing feeding behaviour.