Fish meal (sometimes spelled fishmeal) is a commercial product made from whole wild-caught

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...

, and fish

by-products A by-product or byproduct is a secondary product derived from a production process, manufacturing process or chemical reaction; it is not the primary product or service being produced. A by-product can be useful and marketable or it can be cons ...

to feed farm animals, such as pigs, poultry, and farmed fish.R. D. Miles and F. A. Chapman.
FA122: The Benefits of Fish Meal in Aquaculture Diets
Fisheries and Aquatic Sciences Department, UF/IFAS Extension. Original publication date November 2005. Reviewed January 2015. Because it is calorically dense and cheap to produce, fish meal has played a critical role in the growth of factory farms and the number of farm animals it is possible to breed and feed. Fish meal 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 Fish oil is oil derived from the tissues of oily fish. Fish oils contain the omega−3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), precursors of certain eicosanoids that are known to reduce inflammation in the bod ...

.M. L. Windsor for the UK Department of Trade and Industry, Torry Research Station
Fish meal. Torry Advisory Note No. 49
Published by FAO in partnership with Support unit for International Fisheries and Aquatic Research, SIFAR, 2001) Bibliographical information fro

The production and large-scale use of fish meal are controversial. The lucrative market for fish meal as a feed encourages corporate fisheries not to limit their yields of

(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 overfeeding of millions of pigs and chickens on factory farms has also been criticized by animal rights and animal welfare groups. Manufacturers of fish meal counter that fish meal'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.

History

Fish by-products such as

fish fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

s, fish heads and

fish scale A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as w ...

s 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 ''Book of the Marvels of the World'' ( Italian: , lit. 'The Million', possibly derived from Polo's nickname "Emilione"), in English commonly called ''The Travels of Marco Polo'', is a 13th-century travelogue written down by Rustichello da Pis ...

'' at the beginning of the 14th century: "they accustom their cattle, cows, sheep, camels, and horses to feed upon

dried fish Fresh fish rapidly deteriorates unless some way can be found to preserve it. Drying (food), Drying is a method of food preservation that works by removing water from the food, which inhibits the growth of microorganisms. Open air drying using sun ...

, which being regularly served to them, they eat without any sign of dislike." The use of

herring Herring are various species of forage fish, belonging to the Order (biology), order Clupeiformes. Herring often move in large Shoaling and schooling, schools around fishing banks and near the coast, found particularly in shallow, temperate wate ...

as an industrial raw material started as early as about 800 AD in Norway; a very primitive process of pressing the

oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) and lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturate ...

out of herring by means of wooden boards and stones was employed.

Use

Prior to 1910, fish meal was primarily used as fertilizer, at least in the UK. Fish meal is now primarily used as a protein supplement in

compound feed Animal feed is food given to domestic animals, especially livestock, in the course of animal husbandry. There are two basic types: fodder and forage. Used alone, the word ''feed'' more often refers to fodder. Animal feed is an important input t ...

. As of 2010, about 56% of fish meal was used to feed

farmed fish Fish farming or pisciculture involves commercial animal husbandry, breeding of fish, most often for food, in fish tanks or artificial pen (enclosure), enclosures such as fish ponds. It is a particular type of aquaculture, which is the controlled ...

, about 20% was used in pig feed, about 12% in

poultry feed Poultry feed is food for farm poultry, including chickens, ducks, geese and other domestic birds. Before the twentieth century, poultry were mostly kept on general farms, and foraged for much of their feed, eating insects, grain spilled by cattl ...

, and about 12% in other uses, which included fertilizer. Fishmeal and fish oil are the principal sources of omega-3 long-chain polyunsaturated fatty acids (eicosapentaenoic acid PAand docosahexaenoic acid HA in animal diets. The cost of 65% protein fishmeal has varied between around $385 to $554 per ton since 2000, which is about two to three times the price of

soybean meal Soybean meal is used in food and animal feeds, principally as a protein supplement, but also as a source of metabolizable energy. Typically 1 bushel (i.e. 60 lbs. or 27.2 kg) of soybeans yields 48 lbs. (21.8 kg) of soybean meal. Mos ...

. The rising demand for fish, as people in the developed world turn away from red meat and toward other sources of meat protein, has increased demand for farmed fish, with farmed fish accounting for half the fish consumed worldwide as of 2016. Demand for fish meal has increased accordingly, but harvests are regulated and supply cannot expand. This has led to a trend towards use of other ingredients such as soybean meal,

cottonseed Cottonseed is the seed of the cotton plant. Composition The mature seeds are brown ovoids weighing about a tenth of a gram. By weight, they are 60% cotyledon, 32% coat and 8% embryonic root and shoot. These are 20% protein, 20% oil and 3.5% sta ...

meal, leftovers from processing from corn and wheat,

legumes Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consu ...

, and

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

, and an increase in research to find alternatives to fish meal and alternate strategic uses (for instance, in the growth phase, after newborn fish are established).Fry JP, et al. Environmental health impacts of feeding crops to farmed fish. Environ Int. 2016 May;91:201-14. Review.
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Fish used

Fish meal can be made from almost any type of

seafood Seafood is any form of Marine life, sea life regarded as food by humans, prominently including Fish as food, fish and shellfish. Shellfish include various species of Mollusca, molluscs (e.g., bivalve molluscs such as clams, oysters, and mussel ...

, but is generally manufactured from wild-caught, small

marine fish Saltwater fish, also called marine fish or sea fish, are fish that live in seawater. Saltwater fish can swim and live alone or in a large group called a school. Saltwater fish are very commonly kept in aquariums for entertainment. Many saltwater ...

that contain a high percentage of bones and oil. Previously, these fish have been considered unsuitable for direct human consumption, but more recent research indicates the vast majority of fishmeal made from whole wild-caught fish is made from fish suitable for direct human consumption. Other sources of fishmeal are from

and byproducts of trimmings made during processing (fish waste or offal) of various

seafood products Seafood is any form of Marine life, sea life regarded as food by humans, prominently including Fish as food, fish and shellfish. Shellfish include various species of Mollusca, molluscs (e.g., bivalve molluscs such as clams, oysters, and mussel ...

destined for direct human consumption. The main fish sources by country are:Tim Cashion from ''Sea Around Us''
The end use of marine fisheries landings
Fisheries Centre Research Reports, 2016 * Chile:

anchovy An anchovy is a small, common forage fish of the Family (biology), family Engraulidae. Most species are found in marine waters, but several will enter brackish water, and some in South America are restricted to fresh water. More than 140 speci ...

, horse mackerel * China: various species * Denmark: pout,

sand eel Sand eel or sandeel is the common name used for a considerable number of species of fish. While they are not true eels, they are eel-like in their appearance and can grow up to in length. Many species are found off the western coasts of Europe ...

sprat Sprat is the common name applied to a group of forage fish belonging to the genus ''Sprattus'' in the Family (biology), family Clupeidae. The term also is applied to a number of other small sprat-like forage fish (''Clupeoides'', ''Clupeonella ...

* European Union: pout,

capelin The capelin or caplin (''Mallotus villosus'') is a small forage fish of the smelt family found in the North Atlantic, North Pacific and Arctic oceans. In summer, it grazes on dense swarms of plankton at the edge of the ice shelf. Larger capel ...

mackerel Mackerel is a common name applied to a number of different species of pelagic fish, mostly from the family Scombridae. They are found in both temperate and tropical seas, mostly living along the coast or offshore in the oceanic environment. ...

* Iceland and Norway:

blue whiting The blue whiting (''Micromesistius poutassou'') one of the two species in the genus '' Micromesistius'' in the order of Gadiformes, which also contains cod, haddock, whiting, and pollock. It is common in the northeast Atlantic Ocean from Morocco ...

* Japan:

sardine Sardine and pilchard are common names for various species of small, oily forage fish in the herring suborder Clupeoidei. The term "sardine" was first used in English during the early 15th century; a somewhat dubious etymology says it com ...

pilchard Sardine and pilchard are common names for various species of small, oily forage fish in the herring suborder Clupeoidei. The term "sardine" was first used in English during the early 15th century; a somewhat dubious etymology says it comes ...

saury The saury (''Cololabis adocetus'') is a species of fish that is a member of the family Scomberesocidae, or the saury family. It is widespread in the Eastern Pacific in the surface waters, typically remaining in the top 50 centimeters of the water ...

, mackerel * Peru:

* South Africa: pilchard * Thailand: various species * United States:

menhaden Menhaden, also known as mossbunker, bunker, and "the most important fish in the sea", are forage fish of the genera ''Brevoortia'' and ''Ethmidium'', two genera of marine fish in the order Clupeiformes. ''Menhaden'' is a blend of ''poghaden'' ...

pollock Pollock or pollack (pronounced ) is the common name used for either of the two species of North Atlantic ocean, marine fish in the genus ''Pollachius''. ''Pollachius pollachius'' is referred to as "pollock" in North America, Ireland and the Unit ...

It takes four to five tons of fish to produce one ton of fish meal; about six million tons of fish are harvested each year solely to make fish meal.

Environmental impact

Fish meal production is a significant contributor of over-fishing, and risks pushing fisheries beyond their replacement rate. Some areas of the world, such as Western Africa, have seen a large increase in fish meal production which in turn is hurting local fisheries and driving fisheries into collapse.

Processing

Fish meal 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. Of the several ways of making fish meal from raw fish, the simplest is to let the fish dry out in the sun before grinding and pressing. This method is still used in some parts of the world where processing plants are not available, but the end product is poor quality in comparison with ones made by modern methods. Today, all industrial fish meal is made by the following processes: Cooking: The fish are moved through a commercial cooker – a long, steam-jacketed cylinder – by a

screw conveyor A screw conveyor or auger conveyor is a mechanism that uses a rotating helical screw (simple machine), screw blade, called a "''flighting''", usually within a tube, to move liquid or granular materials. They are used in many bulk handling in ...

. This is a critical stage in preparing the fish meal, as incomplete cooking means the liquid from the fish cannot be pressed out satisfactorily and overcooking makes the material too soft for pressing. No drying occurs in the cooking stage. Pressing: The cooked fish is compressed inside a perforated tube, expelling some of its liquids, leaving "press cake". Water content is reduced from 70% to about 50% and oil down to 4%. Drying: The press cake is dried by tumbling inside a heated drum. Under-drying may result in the growth of molds or bacteria; over-drying can cause scorching and reduction in the meal's nutritional value. Two alternative methods of drying are used: * Direct: Very hot air at a temperature of 500 °C (932 °F) is passed over the material as it is tumbled rapidly in a cylindrical drum. While quicker, heat damage is much more likely if the process is not carefully controlled. * Indirect: The meal is tumbled inside a cylinder containing steam-heated discs. Grinding: The dried meal is ground to remove any lumps or bone particles.

Nutrient composition

Any complete diet must contain some

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

, but the nutritional value of the protein relates directly to its amino acid composition and digestibility. High-quality fish meal normally contains between 60% and 72% crude protein by weight. Typical diets for fish may contain from 32% to 45% total protein by weight.

Risks

Unmodified fish meal can spontaneously combust from heat generated by

oxidation Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

of the

polyunsaturated fatty acids In biochemistry and nutrition, a polyunsaturated fat is a fat that contains a polyunsaturated fatty acid (abbreviated PUFA), which is a subclass of fatty acid characterized by a backbone with two or more carbon–carbon double bonds. Some polyunsa ...

in the meal. In the past,

factory ship A factory ship, also known as a fish processing vessel, is a large ocean-going vessel with extensive on-board facilities for processing and freezing caught fish or whales. Modern factory ships are automated and enlarged versions of the earlier ...

s have sunk because of such fires. That danger has been eliminated by adding

antioxidants Antioxidants are Chemical compound, compounds that inhibit Redox, oxidation, a chemical reaction that can produce Radical (chemistry), free radicals. Autoxidation leads to degradation of organic compounds, including living matter. Antioxidants ...

to the meal. As of 2001, ethoxyquin was the most commonly used antioxidant, usually in the range of 200–1000 mg/kg. There has been some speculation that ethoxyquin in pet foods might be responsible for multiple health problems. To date, the

U.S. Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

has only found a verifiable connection between ethoxyquin and buildup of protoporphyrin IX in the liver, as well as elevations in liver-related enzymes in some animals, but with no known health consequences from these effects. In 1997, the Center for Veterinary Medicine asked pet food manufacturers to voluntarily limit ethoxyquin levels to 75 ppm until further evidence is reported. However, most pet foods that contain ethoxyquin have never exceeded this amount. Ethoxyquin has been shown to be slightly toxic to fish. Though it has been approved for use in foods in the US, and as a spray insecticide for fruits, ethoxyquin has not been thoroughly tested for its carcinogenic potential. Ethoxyquin has long been suggested to be a possible carcinogen, and a very closely related chemical, 1,2-dihydro-2,2,4-trimethylquinoline, has been shown to have carcinogenic activity in rats, and a potential for carcinogenic effect to fish meal prior to storage or transportation. Globally, most of the fish meal products are characterised by possessing a certain level of plastics pollution. 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 fish meal products, from 11 countries on four continents and Antarctica.

Sources

References

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