Economic Importance of Fishes
Fish unsuitable for human consumption is often discarded during processing. These and such species which have little market value from important raw material for a fishery by-product industry. Fish is a highly perishable food material because of its moisture and nutrient contents, and spoilable begins as soon as fish dies, it is the result of a series of complicated chemical reactions taking place in a dead fish, mainly by enzymes and bacteria. These are either thrown back into the sea immediately after their catch or utilized wholly or partly as manure.
Fishes are largely consumed as a source of food material all over the world because of its nutritional value. Fishes in India are mostly consumed fresh and some are preserved or dried for further use as food. The major source of fishes is oceans which fulfill the need of food for the growing population. Most of the time waste fishes are thrown back into the sea just immediately after a catch or used wholly or partly as manure. Fishes are highly perishable food material because of the presence of moisture and nutrients, fishes get spoil soon after death. These are unutilized for the preparation of many byproducts of human and industrial use. It would enhance the economy of the country by selling them.
Some of the important fish byproducts are as follows
1. Fish protein concentrate
2. Fish flour
3. Fish glue
4. Fish skin
5. Fish liver oil
6. Body oil
7. Fish meal
8. Gelatin
9. Insulin
10.Fish fins
11. Isinglass
12. Fish guano
13. Fish manure
1. Fish protein concentrate – It is a stable protein concentrate prepared from whole fish. It is a colorless and odorless powder with high nutritional value for human use. It contains protein and minerals. It is also known as fish flour or edible fish meal.
2. Fish flour - Fish flour is the superior quality of the fish meal, which is used for human intake. It can be mixed with another foodstuff such as wheat flour for enriching nutritive value of bread, biscuits, cakes, etc.
3. Fish glue or adhesive - fish glue is prepared from skin, fins, and bones of fishes. which are washed, crushed and cooked in large vessels for 6-10 hours with acetic acid. The liquid is separated and concentrated to form fish glue which is used as an adhesive for fixing wood, paper and leather. bookbinding, labels, paper boxes etc.
4. Fish skin- the skin of a shark is used for the preparation of polish paper which is called as shagrin used in furniture polishing.
5. Fish liver oil – it has huge content of vitamin A and D used to prevent deficiency or cure rickets, xeropthlamia, , impaired vision and eye defects, abnor¬malities of skin, mucous membranes and vertebrae in the body.
6. Body oil – It is used in the manufacture of cosmetics, lubricants, candles and cutting oils, printing inks, water-proof preparations, cheaper grade toilet soap. Body oil is used for coating the surface of boats for longer preservation. Body oil is used for coating the surface of boats for longer preservation.
7. Fish meal- It is excellent poultry and animal feed as the highly nutritive product contains all the essential amino acids. Fish meal is good for all classes of livestock. It increases milk and egg production. As it is rich in calcium, phosphorus, iodine and rich variety of vitamins promotes building of tissue and bones used for the healthy growth of growing cattle. Waste fish meal mixed with rice bran and vitamins, forms an excellent feed in aqua- culture.
8. Geletin – gelatin is extracted from bones and skin of fishes. Gelatin is a rich source of lysine and methionine. It is used in the food industry as a gelling, stabilizing, emulsifying, dispersing or thickening agent.
9. Insulin : Insulin is a hormone used for correcting the condition called diabetes mellitus in humans. Fish insulin is more stable as it is not subjected to decomposition by protein splitting enzymes of the pancreas.
10. Fish fins –The dried fins of sharks are exported to China where they have great demand for the preparation of soups.
11. Isinglass: The air bladder of some fishes such as catfish, eels, carps, seabass etc. are used for the preparation of isinglass. Isinglass reduces the suspended solids in beer and increases filtration. It can also be used as an adhesive base and in the sweet product, it is used for the preparation of ink and also used as an effective adhesive for glass, pottery, and leather.
12. Guano: is the byproduct form body oil extraction industries. It is nothing but the dried waste left after the extraction of body oil. fish guano is more effective as it contains a large quantity of nitrogen and phosphoric acid. Fish guano is also used as fish manure.
13. Fish Manure: Fish manure and guano are the lower quality of fish meal. It is not fit for animal consumption. Fish ma¬nure is a by-product of the curing yards, fish glue industries, and oil extraction plants, where waste or spoilt fishes have been used. The fishes which are spoilt and unhealthy for use as food is used for the preparation of fish manure. The fish manure contains nitrogen and phosphates which are useful for agricultural use.
