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III. Selection of species for aquaculture

1. Desirable characteristics of aquaculture organisms

Fast growth, short food chain, efficient conversion of food, ready acceptance of compounded feeds, good table quality, disease resistance, ease of breeding in captivity, early maturation, high fecundity, tolerance to a wide range of environmental parameters, no adverse environmental impact, etc.

2. Commonly cultured organisms

Fishes, crustaceans and molluscs; other cultured organisms - seaweeds, frogs, crocodiles and turtles.

3. Biological features of commonly cultured fishes, crustaceans and molluscs

Tolerance limits of salinity, temperature and oxygen tension; growth rates and yields in different types of culture; breeding habits; feeding habits and geographic distribution.

4. Criteria for selection of species for culture

Objectives of culture; geographic and climatic considerations; culture qualities of the organisms; consumer acceptance and marketability; cost of production; domestic consumption versus export.

5. Indigenous versus exotic species

Conditions for introduction of exotic species or strains; procedures for deciding on introductions and transplantations; precautions to prevent adverse effects on local fauna and flora and the spread of infections.

6. Selection of strains of cultivated species for favourable characters

Growth, food conversion, shape and body conformation, resistance to diseases, tolerance of wide fluctuations in environmental factors, meat quality, etc.; use of hybridization techniques for obtaining superior strains and monosex progeny.

Practicals

Identification of cultivated organisms of Asia and their various stages; study of food habits, maturity stages and fecundity of important cultivated organisms.


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