Negative effects of parasite exposure and variable thermal stress on brown trout (Salmo trutta) under future climatic and hydropower production scenarios

Future water temperature changes may have a profound impact on fish-parasite interactions. However, while the effect of fish, and particularly salmonids, is well-understood, its combined effects with parasitic exposure are not. Here, we use multi-stage experimental approach to explore increased temperatures consistent persistent climate change-induced warming extreme thermal fluctuations from hydropower (thermopeaking) brown trout alevins fry before during Saprolegnia parasitica. Parasite had strongest most significant survival both host life stages. The combination parasite exposure, pre-conditioning ongoing regime weak but influence alevin mortality. Both parasite-exposed experienced mortality when constant increase in was intermittent increases. outcomes this provide basis for future studies scaling up potential impacts that key fish species face wild. They also highlight anthropogenic populations, as pressures aquatic organisms likely intensify scenarios development thermopeaking, presence pathogens.