Drought-driven low river flows cause fish kills, oxygen depletion, and thermal stress in wild fish populations, with welfare implications that are largely invisible to the public.
Fish kills during river droughts cause welfare harm at enormous scale: thousands of fish dying from oxygen deprivation, thermal stress, or concentrated toxins over days or weeks. The suffering involved — gasping at the surface, disoriented swimming, eventual loss of consciousness — is real and significant for species we now know to be pain-sensitive. The welfare response requires both emergency management (oxygen addition, emergency fish rescue into cooler water) and structural reform: reducing abstraction licences that drain rivers in summer, tightening pollution discharge controls that worsen low-flow conditions, and addressing the climate change that is making summer droughts more frequent and severe.