Background: Most marine fish consumed in the U.S. eat other marine animals (e.g., fish, squid, crustaceans, etc.) and many feeds prepared to grow marine fish have relied on fishmeal as the primary protein source. Fishmeal is produced from “forage” or “baitfish” such as sardines, anchovies, herring and menhaden.
Some argue that as marine fish farming grows, increasing amounts of forage fish will need to be used in feeds, and stocks will be depleted, limiting their ability to recover. Significant progress has been made to ensure that this will not be the case.
- Cultured fish are more efficient than land-based livestock at converting feed into body mass because they do not have to maintain body temperature or fight gravity.
- A recent report from Conservation International and World Fish states that “aquaculture is by far the most ecologically efficient way to culture animal protein for human consumption.”
- Global production of fishmeal has remained stable for the last 15 years while global aquaculture production has increased almost threefold. This is the result of increasing efficiencies and changing composition of aquaculture feeds.
- Scientists and fishery managers generally believe that fishmeal fisheries are some of the best managed and sustainable fisheries.
- The cost of feed is the single greatest proportion of a fish farm’s operating budget, sometimes approaching 50%, and fishmeal is the most expensive ingredient in any commercially available, fishmeal based diet. Accordingly, researchers and feed companies have made substantial progress in substituting other ingredients (for example, vegetable proteins and vegetable oil) in aquaculture feeds, a trend that will continue because it provides greater price stability.
- There is also been significant research dedicated to the use of fish trimmings (what is left after a fish is cleaned for market) as a protein source, thereby reducing the need for fish meal from forage fish.
- Wild fish are less efficient at converting protein into body mass than farmed fish. A comparison between wild-caught cod and farmed salmon showed that salmon were five times more efficient in converting baitfish into edible protein.
- Attempts to incorporate bait fish directly into human diets have mostly failed. Canned sardines are an exception, but in general humans find these small, bony, “fishy tasting” species unpalatable.
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