Improvements in Food Resources

FISH PRODUCTION: THE ART OF FISH FARMING

• Fish are a very high source of proteins and have great nutritional value.
• They are used by humans for their meat and products such as their oil and glue, sauces and other food products and are also the ingredients of traditional Chinese medicines, some pigments, fertilizers and numerous other products. Fish production refers to obtaining all these products and fish themselves.

MODES OF OBTAINING FISHES

• Fishes can be obtained from following two ways:
  • Capture Fishery or wild fishery
  • Culture Fishery or fish farming or pisciculture
• Capture Fishery or wild fishery: In this type of fishery, the fish is caught from natural resources i.e. from natural waters, both marine and inland. Modern technology is used to capture and store the fish before marketing. Electronic equipments are used to locate fish in the sea. Mechanised fishing boats and deep sea trawlers are often employed in capture fishery.
• Culture Fishery or fish farming or pisciculture: In this type of fishery, cultivating, rearing and harvesting of fish is carried out in a controlled form. The growing of various types of aquatic organisms in water bodies is called aquaculture. Pisciculture is a form of aquaculture.

WATER SOURCES OF FISH PRODUCTION

Base on the water sources of fish production, three types of fisheries can be recognized:

• Marine Fisheries
• Fresh Water Fisheries
• Inland water Fisheries

MARINE FISHERIES

• Marine fisheries deal with fishes found in oceans and seas.
• These fishes are either caught using traditional methods or using modern methods.
• Traditional methods:  This includes catching fish using nets or fishing vessels
• Fishing trawler: A vessel that drags a net behind it is called fishing trawler. Such fishing trawlers are fitted with electronic fish locating device and are put into service for boosting the deep-sea fishing
• Modern methods using modern technologies like echo sounders and satellites to locate fish shoals.
• Following are themarine fishes of India that are most preferred sea fishes or table fishes, i.e, popularly consumed fishes :
  • Pomphrets,
  • Mackerels,
  • Tuna,
  • Sardines,
  • Bombay duck,
  • Eel,
  • Hilsa,
  • Salmon
  • Ribbon Fish,
  • Flat fish or sole,
  • Seer,
  • Flying Fish.

Inland Fisheries

• Inland fisheries deal with fresh water and brackish water resources such as lakes, ponds, rivers, and tanks.
• The method incorporated here is generally pisciculture, as the yield of capture fishery is not very high.
• 5-6 species are reared in one water body.
• This selection of species is such that they have different food habits yet there is no competition for food.
• Common varieties reared are Rohu, Catla, Grass Carp, Common Carp, etc.They are further classified as:
  • Riverine fishery;
  • Reservoir fishery;
  • Lake or lacustrine fishery
  • Pond fishery and
  • Estuarine fishery.
• Reservoirs where freshwater bodies and seawater bodies join also form inland fisheries.
• Cage culture: Fish is cultured in large cages, made of bamboo or steel, which are lowered into the river. Generally, carnivorous species are cultured in cages.
• Integrated fish culture: Fish culture is practiced along with some agricultural crops such as paddy, banana and coconut to give higher yield.

AQUACULTURE

Aquaculture pertains to production of useful (ie, of high economic value) aquatic plants and animals such as fishes, prawns, crayfish, lobsters, crabs, shrimps, mussels, oysters and seaweeds by proper utilization of available waters in the country.

COMPOSITE FISH CULTURE (POLYCULTURE OF FISH)

• The yield obtained by inland fishery is not that high. And so, it is sometimes combined with rice crop farming. This process of fish farming alongside agriculture is known as composite fish culture system.
• The food habits of these six species are as follows
  • Fish production by culturing a single species in a pond (called monoculture). The silver carp (Hypophthalmichthys molitrix) is a surface feeder which feeds on phytoplankton.
  • The catla (Catla catla) is also surface feeder which feeds on zooplankton.
  • The rohu (Labeo rohita) feeds in middle zone of the pond, i.e. column feeder which feeds on decaying plants and detritus.
  • The grass carp (Ctenopharyngodon idella) feeds on all macro-vegetation and consumes the aquatic plants/ weeds not used by other species in this group.
  • The mrigal (Cirrhinus mrigala) is a bottom feeder using decaying plants and detritus.
  • The common carp (Cyprinus carpio) is an omnivorous bottom feeder.

These six species possess complementary feeding habits and do not harm each other, and constitute a good combination of polyculture.

FACTORS TO BE TAKEN INTO CONSIDERATION FOR FISH CULTURE

Important factors to be taken into consideration for fish culture include:

• Topography or location of pond;
• Water resources and quality;
• Soil quality.