Almost all fish raised in aquaculture facilities are carnivorous or omnivorous. In order to provide them with cheap protein, farm-raised fish are fed a diet consisting mostly of forage and small ocean fish such as anchovies and sardines, which have been processed into pellets as fish oil and fishmeal. These forage fish are consequently overharvested in order to supply feed for aquaculture facilities, thereby removing a critical component of the ocean food web and putting other marine animals at risk. Predatory finish such as salmon, tuna, and grouper are just a few of the fish that suffer from this practice.
Feeding fish in this manner is not only unsustainable—it is inefficient. Depending on the species, it takes between two and six pounds of wild fish to produce just one pound of farmed fish. This feed inefficiency further indicates current aquacultural practices as poorly planned—and harmful—pursuits.