Q.What is hypophysation?

Besides being used directly as food, fish yield several commercially important by-products used in feed, medicine, industry and agriculture.

Pisciculture (fish farming) is economically important not only for fish as food but also for the useful by-products obtained from fish processing:

1. Fish meal - dried, ground fish used as a protein-rich supplement in poultry and animal feed.
2. Fish oil - extracted from fish liver (e.g. cod-liver oil, shark-liver oil) and body fat, rich in vitamins A and D and used as a dietary supplement. …

Pisciculture (fish farming) yields several economically valuable by-products besides the fish itself.

Beyond fish flesh as food, several useful by-products are obtained from fish processing:

1. Fish oil (e.g. cod liver oil, shark liver oil) — used as a dietary supplement, rich in vitamins A and D and omega-3 fatty acids.
2. Fish meal — a protein-rich powder made from processed fish waste/whole fish, used as high-quality animal and poultry feed.
3. Fish manure — fish waste used as an organic fertiliser in agriculture. …

Besides fish flesh used directly as food, several commercially useful by-products are obtained from fish.

Apart from fish being used directly as a food source, fisheries yield a number of valuable by-products:

1. Fish oil — extracted mainly from the liver (e.g., cod liver oil, shark liver oil) and body of oily fish; rich in vitamins A and D and omega-3 fatty acids, used in nutritional supplements, in the manufacture of paints, varnishes and soaps.
2. Fish meal — the dried, ground residue left after oil extraction; a protein-rich product used as poultry and livestock feed, and as an organic fertiliser.
3. Fish manure/guano — waste parts of fish (bones, offal) processed and used as an organic fertiliser rich in nitrogen and phosphorus. …

Besides being an important food source, fish yield several valuable commercial by-products.

Fisheries do not just provide fish as food; several economically valuable products are derived as by-products from fish processing:

1. Fish oil - Extracted from the liver (e.g., cod liver oil) and body of fatty fish; rich in vitamins A and D and used in the pharmaceutical, cosmetic and food industries.
2. Fish meal - Made by drying and grinding fish waste/whole fish; a protein-rich supplement used in poultry feed, cattle feed and aquaculture feed.
3. Fish manure - The residue left after oil and meal extraction is used as an organic fertiliser in agriculture. …

Indian major carps (Catla, Rohu, Mrigal) are native species, while exotic carps (Common, Silver, Grass carp) were introduced from abroad — both are important in composite fish culture.

In pisciculture/aquaculture, carps cultured in India are grouped as:

Indian (major) carps — native species:

1. Catla (Catla catla) — surface feeder
2. Rohu (Labeo rohita) — column feeder (also Mrigal — Cirrhinus mrigala — bottom feeder)

Exotic carps — introduced from other countries:

1. Common carp (Cyprinus carpio) — introduced from Europe/China
2. Silver carp (Hypophthalmichthys molitrix) — introduced from China …