Aquaculture Feed Sustainability and Fish Welfare

What farmed fish eat has profound implications for both sustainability and welfare. The shift away from wild-caught fishmeal toward alternative proteins raises both environmental questions and welfare considerations for the fish being fed.

Key Facts

Atlantic salmon farming traditionally relied on fishmeal from wild-caught anchovies, herring, and other small fish; typically 5-10 kg of wild fish were needed to produce 1 kg of farmed salmon
The industry has substantially reduced fishmeal inclusion rates through partial replacement with soy, insect meal (black soldier fly larvae), single-cell proteins, and other alternatives
Nutritional completeness of alternative feeds is critical for fish health and welfare; deficiencies in omega-3 fatty acids, amino acids, or micronutrients cause specific welfare problems
Soy-based feeds have been associated with enteritis (intestinal inflammation) in Atlantic salmon at high inclusion rates — a welfare concern requiring management
Insect meal from black soldier fly larvae is increasingly used and provides a nutritionally appropriate, sustainable protein source with potentially lower welfare footprint
Fish welfare depends on diet matching species-specific nutritional requirements; generic alternative feeds that reduce costs but compromise nutrition impose welfare costs

Welfare Considerations

Aquaculture feed is a welfare issue as well as a sustainability issue. The nutritional plane on which farmed fish are maintained directly determines their immune competence, growth rate, susceptibility to disease, and response to stress. Inadequate omega-3 provision — a common consequence of high soy inclusion in salmon diets — impairs inflammatory regulation and neurological function. Soy-induced enteritis causes intestinal inflammation that reduces nutrient absorption and causes chronic gastrointestinal discomfort. The welfare case for feed reform aligns with the sustainability case: reducing reliance on wild-caught fishmeal reduces both the welfare cost to the wild fish harvested for feed and the nutritional risks associated with cheaper, less appropriate alternative proteins. Insect-based and single-cell protein alternatives that provide appropriate nutritional profiles represent a convergence of welfare, sustainability, and economic interests.

What You Can Do

Support aquaculture operations investing in nutritionally appropriate sustainable feed alternatives
Advocate for feed welfare standards to be included in aquaculture certification schemes
Support research into alternative aquaculture feeds that maintain fish welfare while reducing environmental footprint
Choose farmed fish from operations with transparent feed sourcing and nutritional management documentation
Support the development of black soldier fly and other insect protein industries as welfare-positive feed alternatives