Coastal Aquaculture and Mariculture (2+1)

Unit 6 - Culture of Crustaceans

6.1. Shrimp Culture

Shrimps had formed a subsidiary species in most types of fish culture in coastal ponds in Asia; and in countries like India, rice fields have been used for a form of extensive culture of shrimps for centuries. Intensive culture and semi-intensive cultures of these crustaceans are of recent origin. Interest in their culture, particularly shrimps was triggered by the increase in export demand and the inadequacy of capture fisheries to meet the demand. As the expanding markets were in economically advanced countries like Japan and USA, the prospects of an export market and opportunities for earning foreign exchange attracted support from the governments of developing countries and led investment by private entrepreneurs. Shrimps and prawns became high value commodities in many developing countries because of their market potential. In India shrimps are the mainstay of coastal aquaculture.

Major cultivated species of shrimps

Attention so far has been directed to the culture of tropical and sub-tropical species of shrimps. In Asia important species are Penaeus monodon, P. merguiensis, P. semisulcatus and P. chinensis. P. penicillatus is a species cultured in Taiwan. Metapenaeus monoceros, M. brevicornis and M. ensis form subsidiary species in shrimp farms in several Asian countries.

The most important species in Central and South America are P. vannamei and P. stylirostris. P. japonicus is the major species in temperate countries like Japan and Taiwan and in a less intensive way in France, Italy and Brazil. P. orientalis = P. chinensis is the major species grown in China and Korea. P. setiferus is the species of interest in temperate USA.

The tiger shrimp Penaeus monodon is the fastest growing species among shrimps. This is the main species cultured in Asia including, India. It is highly euryhaline tolerating salinities from freshwater to full-strength seawater, even though 15-25ppt has been considered optimum. The optimum temperature is around 26-30^oC. It cannot tolerate temperatures below 21^oC and above 37.5^oC.

P. indicus and P .merguiensis are the other species cultured to a lesser extent in Asia. Both have similar habits in many respects, but the former exhibits a preference for sandy bottom and the later muddy ones. Both species require salinities higher than P. monodon for good growth, both cannot tolerate salinities outside the range of 5-40ppt.

Among the species cultured in south and Central America, P. vannamei is highly euryhaline and can withstand salinities from 0-50ppt. and temperatures ranging from 22-32^oC. It has higher survival rates than other species and hence its preference for pond farming.