The welfare cost of wild fish used to produce fishmeal and fish oil for aquaculture feeds is a hidden but significant aspect of the farmed fish welfare equation.
The welfare implications of fishmeal production are rarely discussed despite involving enormous numbers of animals. Wild-caught pelagic fish used for reduction fisheries undergo all the welfare harms of any commercial fishing — crowding in nets, barotrauma from pressure changes, crushing, and suffocation. These fish are killed without welfare consideration as they are destined for meal production not direct consumption. The scale is vast — many billions of individual fish annually. Progress is being made through replacement of fishmeal in aquaculture feeds with insect protein, single-cell protein, and plant-based ingredients, which has dual benefits of reducing both fishmeal demand and the welfare cost of reduction fisheries.