Aquaculture operations discharge nutrients, chemicals, and pathogens into surrounding waterways. The welfare impacts on wild fish and invertebrates downstream are increasingly recognised as significant.
The welfare impacts of aquaculture extend beyond the farmed animals to the wild fish, invertebrates, and ecosystems downstream. Eutrophication from nutrient discharge reduces dissolved oxygen and causes slow, distressing suffocation in wild fish. Sea lice from salmon farms parasitise and kill migrating wild salmon. Antibiotic resistance driven by aquaculture effluent affects entire aquatic communities. Mitigating these impacts requires transitions to land-based RAS systems, stricter siting regulations for sea cage operations, and mandatory effluent treatment. Consumers can support better outcomes by choosing aquaculture products from systems with lower environmental footprints and by reducing overall aquatic animal consumption.