Fish meal

Commercial product made from fish to feed farm animals
Fish meal, sometimes spelt fishmeal, is a commercial product made from whole wild caught fish, bycatch, and fish by products to feed farm animals, e. g., pigs, poultry, and farmed fish. Because it is calorically dense and cheap to produce, fishmeal has played a critical role in the growth of factory farms and the number of farm animals it is possible to breed and feed. Fishmeal takes the form of powder or cake. This form is obtained by drying the fish or fish trimmings, and then grinding it. If the fish used is a fatty fish it is first pressed to extract most of the fish oil. The production and large scale use of fishmeal are controversial. The lucrative market for fishmeal as a feed encourages corporate fisheries not to limit their yields of by catch (from which fish meal is made), and thus leads to depletion of ecosystems, environmental damage, and the collapse of local fisheries. Its role in facilitating the breeding and over feeding of millions of pigs and chickens on factory farms has also been criticized by animal rights and animal welfare groups. Manufacturers of fishmeal counter that fishmeal's role in the feeding and breeding of millions of farm animals leads to the production of more food and the feeding of millions of people around the world.

Fish byproducts have been used historically to feed poultry, pigs, and other farmed fish. A primitive form of fishmeal is mentioned in The Travels of Marco Polo at the beginning of the 14th century: "they accustom their cattle, cows, sheep, camels, and horses to feed upon dried fish, which being regularly served to them, they eat without any sign of dislike." The use of herring as an industrial raw material started as early as about 800 AD in Norway; a very primitive process of pressing the oil out of herring by means of wooden boards and stones was employed.

Fishmeal is made by cooking, pressing, drying, and grinding of fish or fish waste into a solid. Most of the water and some or all of the oil is removed. Four or five tonnes of fish are needed to manufacture one tonne of dry fishmeal.

Unmodified fish meal can spontaneously combust from heat generated by oxidation of the polyunsaturated fatty acids in the meal. In the past, factory ships have sunk because of such fires. That danger has been eliminated by adding antioxidants to the meal. A recent study showed that a wide range of plastics content was found, ranging from 0 to 526.7 n/kg in samples from 26 different fishmeal products, from 11 countries on four continents and Antarctica.