Aquaculture affects surrounding ecosystems in ways that have direct implications for wild animal welfare. Understanding these impacts enables more responsible production choices.
The welfare of wild animals in the vicinity of aquaculture operations is affected through multiple pathways. Eutrophication events cause hypoxic conditions that cause fish kills — acute mass mortality events involving suffering at scale. Sea lice from salmon farms spread to wild salmon populations, causing the same skin damage and osmoregulatory problems documented in farmed fish. Escaped farmed fish that hybridize with wild populations may reduce the fitness of offspring. Seabird bycatch in fishmeal fisheries represents a significant welfare cost often invisible to aquaculture consumers. Ecosystem welfare accounting that includes these downstream effects produces a more complete picture of the welfare costs of different aquaculture products.