Fish meal, or fishmeal, is a commercial product made from fish and the bones and offal from processed fish. It is a brown powder or cake obtained by drying the fish or fish trimmings, often after cooking, and then grinding it. If it is a fatty fish it is also pressed to extract most of the fish oil.
Fishmeal is a nutrient-rich and high protein supplement feed ingredient that stores well, and is used primarily in diets for domestic animals and sometimes as a high-quality organic fertilizer.
Fish by-products 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 fourteenth 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 utilization 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.
Raw materials used
Fishmeal can be made from almost any type of seafood but is generally manufactured from wild-caught, small marine fish that contain a high percentage of bones and oil, and is usually deemed not suitable for direct human consumption. The fish caught for fishmeal purposes solely are termed "industrial". Other sources of fishmeal are from bycatch of other fisheries and by-products of trimmings made during processing (fish waste or offal) of various seafood products destined for direct human consumption. Virtually any fish or shellfish in the sea can be used to make fishmeal, although there may be a few rare unexploited species which would produce a poisonous meal.
1. The species must be in large concentrations to give a high catching rate; this is essential because the value of industrial fish is less than that of fish for direct human consumption. 2. The fishery should preferably be based on more than one species in order to reduce the effect of fluctuations in supply of any one species. 3. The total abundance of long-lived species varies less from year to year, and 4. Species with a high fat content are more profitable, because the fat in fish is held at the expense of water and not at the expense of protein.
Fish meal is manufactured primarily from anchovies in Peru; menhaden in the United States; pout in Norway; capelin, sand eel and mackerel in other parts of northern Europe; and sauries, mackerels and sardines in Japan.
Fishmeal is made by either cooking, pressing, drying and grinding of fish or fish waste to which no other matter has been added. It is a solid product from which most of the water is removed and some or all of the oil is removed. Four or five tonnes of fish are needed to manufacture one tonne of dry fishmeal.
There are several ways of making fishmeal from raw fish; the simplest way is to let the fish dry out in the sun. This method is still used in some parts of the world where processing plants are not available, nevertheless the end product is poor in comparison with ones made by modern methods. Nowadays all industrial fish meal is made by the following processes:
Cooking: A commercial cooker is a long steam jacketed cylinder through which the fish are moved by a screw conveyor. This is a critical stage in preparing the fishmeal, as incomplete cooking means that the liquor 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: A perforated tube with increasing pressure is used for this process. This stage involves removing some of the oil and water from the material and the solid is known as press cake. The water content in pressing is reduced from 70% to about 50% and oil is reduced to 4%.
Drying: It is important to get this stage of the process right. If the meal is under-dried, moulds or bacteria may grow. If it is over-dried, scorching may occur and this reduces the nutritional value of the meal.
Two main types of dryer: Direct and Indirect
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. This is the quicker method, but heat damage is much more likely if the process is not carefully controlled.
Indirect: Cylinder containing steam heated discs which also tumble the meal.
Grinding: This is the last step in processing which involves the breakdown of any lumps or particles of bone.
Any complete diet must contain some protein, but the nutritional value of the protein relates directly to its amino acid composition and digestibility. The amino acid profile of fishmeal is what makes this feed ingredient so attractive as a protein supplement. High-quality fishmeal normally contains between 60% and 72% crude protein by weight. Typical diets for fish may contain from 32% to 45% total protein by weight. Fishmeal is sought after as an ingredient in aquaculture diets because it contains compounds that make the feed more palatable. This allows the feed to be ingested rapidly, and will reduce nutrient leaching. It is thought the non-essential amino acid glutamic acid is one of the compounds that imparts palatability to fishmeal.
Fish lipids are also highly digestible by all species of animals and are excellent sources of the essential polyunsaturated fatty acids (PUFA) in both the omega-3 and omega-6 families of fatty acids. The predominant omega-3 fatty acids in fishmeal and fish oil are linolenic acid, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). Essential fatty acids are necessary for normal larval development, fish growth, and reproduction. They are important in normal development of the skin, nervous system, brain, and visual acuity. PUFAs appear to assist the immune system in defense of disease agents and reduce the stress response. Fishmeal also contains valuable phospholipids, fat-soluble vitamins, and steroid hormones.
Such high digestibility of fish lipids means they can provide lots of usable energy. If a diet does not provide enough energy, the fish or shrimp will have to break down valuable protein for energy, which is expensive and can increase production of toxic ammonia. Fishmeal is considered to be a moderately rich source of vitamins of the B-complex especially cobalamine (B12), niacin, choline, pantothenic acid, and riboflavin.
Fishmeal in diets increase feed efficiency and growth through better food palatability and enhances nutrient uptake, digestion and absorption. The balanced amino acid composition of fishmeal complements and provides synergistic effects with other animal and vegetable proteins in the diet to promote fast growth and reduce feeding costs.[original research?]
High quality fishmeal provides a balanced amount of all essential amino aids, phospholipids and fatty acids required for optimum development, growth and reproduction especially of larvae and broodstock. The nutrients in fishmeal also aid in disease resistance by boosting and helping to maintain a healthy functional immune system. It also allows for formulation of nutrient-dense diets, which promote optimal growth. 
Incorporation of fishmeal into diets of aquatic animals helps to reduce pollution from the waste water effluent by providing greater nutrient digestibility. The incorporation of high-quality fishmeal into feed imparts a 'natural or wholesome' characteristic to the final product, such as that provided by wild fish.[original research?]
Aquaculture's heavy reliance on wild caught seed and broodstock is of increasing concern. Fishmeal and its source of raw materials and costs are highly debated by scientists and conservationists. Since fishmeal uses wild fish stock to feed farmed fish, this places direct pressure on fisheries resources. Indirect effects are also apparent such as diminishing wild fisheries, habitat modification and food web interactions. There is also the possibility of trace contaminants in the feed which will cause diseases and fish mortality.
About 23.13 million tonnes of compound aquafeeds were produced in 2005 of which approximately 42 percent was consumed by aquaculture. The aquaculture sector consumed approximately 3.06 million tonnes or 56 percent of world fishmeal production and 0.78 million tonnes or 87 percent of total fish oil production in 2006 with over 50 percent of fish oil going into salmonid diets. Increasing prices of fishmeal, fish oil, grains and other feed ingredients, and also fuel and energy will certainly affect the cost of aquaculture production.  Sustainability remains a concern, however, even more so when the demand for aquaculture products is outstripping the supply, and prices soar so that even inefficient farms might make money.[original research?]
Unmodified fish meal can spontaneously combust. In the past ships have sunk because of such fires. These days the danger is eliminated by adding antioxidants, namely, Ethoxyquin, a poison. 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 (FDA) 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 there are 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. Ethoxyquin is not permitted for use in Australian foods, nor is it approved for use within in the European Union, though it is an accepted additive in the U.S.A (most likely due to the FDA approving this pesticide safe for U.S citizens). Besides the USA, it is also widely used in other third world countries which have very poor food controls in place. This is in contrast to all other first world countries that have banned the use of this poison [pesticide] in their citizens food due to possible and serious health concerns. Even though it has been approved for use in foods in the US, and as a spray insecticide for fruits, Ethoxyquin has surprisingly not been thoroughly tested for its carcinogenic potential. It has long been suggested that Ethoxyquin is a possible carcinogen, a very closely related chemical 1,2-dihydro-2,2,4-trimethylquinoline has been shown to cause carcinogenic activity in rats, as well as a Manson et al (1987) study suggested Ethoxyquins potential for carcinogenic effect to fishmeal prior to storage or transportation.
According to FAO's[clarification needed] statistics (FAO 2002) and their future predictions, wild capture will decrease slightly in the years to come. In 2030 the Stratospheric Observatory for Infrared Astronomy predicts that aquaculture production will rise to a level of more than 80 million tonnes, while the wild catch still will be approximately 90 million tonnes. Sustainability is a major issue and further research and study is needed in this area to make effective decisions.
Despite the adverse effects, organisations like the Fishmeal Information Network (FIN) which is one source of contact for fishmeal and gives information on its supply chain and its role in the nutrition of farm livestock. FIN aims to present fact-based information, independent evidence and respected expert opinion on fishmeal and its use. It recognises the imperatives of safety in the food chain, healthy diets, animal welfare and protection of the environment.
The FIN monitors two key areas: A. Legislation which governs fishmeal use in animal feed, and B. Contaminant issues and regulations that are, or are likely to impact on fishmeal, fish oil, wild finfish and farmed fish. Such regulations and precautions will help companies better their products and will benefit the consumers greatly. More research into this area is needed to make effective decisions and to obtain optimal results.
Main fishmeal producing countries
- Chile: anchovy, horse mackerel
- China: various species
- Denmark: pout, sandeel, sprat
- European Union: various species
- Iceland and Norway: capelin, herrings, bluewhiting
- Japan: sardine, pilchard
- Peru: anchovy
- South Africa: pilchard
- Thailand: various species
- United States: menhaden, pollock
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- The fish site
- Miles RD and Chapman FA (2006) "The Benefits of Fish Meal in Aquaculture Diets" University of Florida. Document FA122, p.6.
- "Manufacture, Storage, Composition And Use Of Fish Meal".
- Johnston, I. A., S. Manthri, et al. (2002). "Effects of dietary protein level on muscle cellularity and flesh quality in Atlantic salmon with particular reference to gaping." Aquaculture 210(1-4): 259-283.
- Regost, C., J. Arzel, et al. (2001). "Fat deposition and flesh quality in seawater reared, triploid brown trout (Salmo trutta) as affected by dietary fat levels and starvation." Aquaculture 193(3-4): 325-345.
- Lie, Ø. (2001). "Flesh quality – the role of nutrition." Aquaculture Research 32: 341-348.
- "Higher fishmeal prices result in good business".
- Olafsen, T (2006). Exploitation of Marine Living Resources – Global Opportunities for Norwegian Expertise. The Royal Norwegian Society of Sciences and Letters (DKNVS)