Aquaculture

Aquaculture is defined is as cultivation of fish and other aquatic organisms of economic importance like crustaceans (e.g. prawn, lobsters, crabs, etc.), mollusks and algae plants and anything else grown in water. Aquaculture uses methods in which the density of the cultured aquatic organisms is significantly higher than in nature. These organisms grow to a marketable size in a controlled environment such as ponds, channels, net pens, and enclosures.

According to Hansan (1974), “Aquaculture is the cultivation of aquatic and semi aquatic plants or animals to serve human purposes by deliberate modification of their natural environment and by selective breeding of stock to improve cultured Species”.

Aquaculture is generally used to denote-

1. The type of culture techniques or systems, e.g., pond culture, raceway culture, cage culture, pen culture, rafts culture, etc.
2. The type of organisms cultured, e.g., fish, oyster, mussel, shrimp or sea weed.
3. The environment in which the culture is done, e.g., fresh water, brackish water, saltwater or marine culture or mericulture.
4. A specific character of the environment used for culture, e.g., cold water or warm water aquaculture, upland, low land, inland, coastal and estuarine environment.

Example: Fish culture is a form of aquaculture.

References:

Gupta, S. K., and Gupta, P. C., (2006), General and applied ichthyology (fish and fisheries).

Santhanam, R., et al., (1990), Coastal Aquaculture in India.

Aims of Aquaculture

The main aims to be achieved through aquaculture are as follows:

1.                  To improving the quality of the product.

2.                  To contributes to the production of proteins which can provide a serious addition to food.

3.                  To boost national economy by way of increasing per capita production for per capita consumption and per capita income.

4.                  To create employment opportunities.

5.                  To properly utilize the available natural water resources.

6.                  To uplift the socio-economic status of the people.

7.                  To fulfill sport and game purposes by culturing fishes.

8.                  To earn foreign exchange.

9.                  To culture fishes of ornamental value for aquarists.

10.              To culture larvicidal fishes with a view to control mosquito larvae.

References:

Gupta, S. K., and Gupta, P. C., (2006), General and applied ichthyology (fish and fisheries).

Importance of Aquaculture

Aquaculture can have an important role as for example in:

1.                  Fish and other aquaculture products serve as the main source of cheap protein to combat malnutrition and under nutrition, fish having ten essential amino acids.

2.                  In addition to supplying cheap protein for human consumption, aquaculture provides excellent opportunities for employment and income generation, particularly in the more economically depressed rural areas.

3.                  Supplementing or replacing capture fishery production of over exploited fish and shell fish stock.

4.                  Earning foreign exchange through export of high value species like shrimps, oysters, and seaweeds or saving foreign exchange through import substitution.

5.                  The intensive cultivation of brood stock as suppliers of eggs or juveniles for restocking programmers, where native stocks are extinct or unviable.

6.                  Using waste lands productively and using organic wastes for food production and environmental management.

7.                  Creating and maintaining leisure-time activities including sport fishing and home and public aquaria.

8.                  Promoting agro-industrial development, which could include processing and marketing of fishery products, feeds and equipment for aquaculture, and seaweed culture for the production of marine colloids, pearl oyster culture etc.

9.                  Overall development of rural areas through integrated projects, including aquaculture.    

References: Pillay, T. V. R., (1991), Aquaculture principles and practices.

Negative impact of Aquaculture

Aquaculture may also have negative impacts on environment particularly on fisheries resources. These negative impacts are as follows:

1.                  Misuse of chemicals in diseases treatment and these chemicals may affect the health of other aquatic organisms.

2.                  Contamination of the aquatic environment with the discharge of aquaculture farm effluent (for example, from integrated fish cum duck / Chicken farming) containing high concentrations of organic substances.

3.                  Reduction of biodiversity due to introduction of exotic species.

4.                  Use of toxicant to kill the predators.

5.                  Loss of natural habitats, such as the mangroves and other wetland ecosystems. The conversion of mangrove land into prawn ponds has also transformed a common properly and multiuse resource.

6.                  Some of the post larvae for stocking grow-out ponds are still collected from the wild, which may adversely affect the recruitment of fry in their natural fisheries.

7.                  The spread of diseases through introduced species is a serious concern. Disease agents introduced with exotic species may be more pathogenic in their new environment.

8.                  Due to flood, escape of exotic species may breed with local species and produce hybrids that may be sterile or in viable.    

References: Kenneth Black, D., Environmental impacts of aquaculture.