Acidification increases sensitivity to hypoxia in important forage fishes
Hypoxia and acidification are important stressors in marine and estuarine ecosystems and are likely to increase in severity through climate change. Miller and colleagues investigated how these stressors could influence fish behavior and survival alone and in combination. Fish exposed to both hypoxia and acidification in the laboratory performed aquatic surface respiration (a behavioral response to hypoxia) and died at higher dissolved oxygen concentrations than fish exposed to only hypoxia. Additionally, fish exposed to both stressors together beat their opercula slower than fish exposed only to hypoxia. Taken together, these experiments show that acidification can make fish more sensitive to the effects of hypoxia, potentially increasing fish mortality both directly and through increased predation by birds.