Fish products. Clockwise from upper left are: a sheet of gelatin; skins from Alaska pollack fish (Theragra chalcogramma); shrimp feed pellets; and salmon hydrolysate powder. The gelatin was made from Alaska pollack fish skins, and the shrimp feed pellets were made from the salmon hydrolysate powder. Salmon hydrolysate is a concentrated form of salmon protein and oils, formed by hydrolysis from salmon residues. An alternative use of this product is to produce salmon oil for use as a biofuel. Gelatin is formed from the connective tissue collagen, found in animal skins. It is used in various industries, including the food, drugs and cosmetics industries.