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Does aquaculture use more wild fish than it produces?

There is no single answer for all aquaculture. The relationship between wild-fish inputs and farmed-fish production varies by species, life stage, feed formulation, feed efficiency and the method used to make the calculation.

Fishmeal and fish oil are important sources of nutrients in many aquaculture feeds. They may be produced from whole fish or from by-products generated when seafood is processed for human consumption. Their use differs between species and feeds and can also change during the production cycle.

Pelagic fish

How is wild-fish use measured?

Forage fish dependency ratios compare the wild fish used to supply fishmeal or fish oil with the quantity of farmed fish produced. Fishmeal and fish oil are calculated separately because they are produced and used in different proportions.

Results depend on the data and assumptions used, including:

  • whether the calculation covers fishmeal, fish oil or both;
  • the proportion produced from whole fish and from processing by-products;
  • the yield of fishmeal and fish oil from the source material;
  • the feed conversion achieved; and
  • the species and production period assessed.

For this reason, one ratio should not be presented as representative of all aquaculture.

Using marine resources responsibly

Skretting works to use marine ingredients effectively while broadening the range of suitable ingredients available for aquaculture feed. Feed formulation considers the nutrients required by the species and life stage, the quality and source of the ingredients, and the intended use of the product.

Reducing the percentage of fishmeal or fish oil in a feed does not by itself demonstrate lower wild-fish use or better environmental performance. Feed efficiency, ingredient origins and the calculation method must also be considered.

Our marine-ingredient requirements consider available information on species, fishery and origin, the use of whole fish and by-products, traceability, certification and fishery improvement programmes. We report our use of marine ingredients and responsible-sourcing progress in the latest Impact Report.