Research into the cognitive abilities of freshwater fish is transforming understanding of their capacity for learning, problem-solving, and suffering in both wild and managed river environments.
The welfare of wild freshwater fish is affected by a wide range of anthropogenic stressors including pollution, temperature increases, deoxygenation, physical barriers to migration, and recreational angling. As evidence of fish cognition and pain processing has grown, the ethical weight of these impacts has increased. River management decisions that affect fish populations now increasingly incorporate welfare considerations alongside ecological and hydrological factors. The welfare of individually caught fish during angling has also received growing attention, with research demonstrating that catch-and-release fish suffer physiologically even when they survive the immediate encounter.