Shrimp Farming production cycle, methods, feeds and diseases ; To meet the growing demand for shrimps internationally shrimp aquaculture was introduced in the 70s. However Bangladesh adopted the firming method some twenty years later mainly because of encouragements from World Bank. There are two ways shrimp can be conditioned and grown: the first method involves collecting shrimp fry from hatcheries and keeping them in nursery ponds before transferring them to grow-out ponds a few weeks later, while the second one involves transferring fish fry from hatcheries straight to grow-out areas.
Shrimps nurtured in the hatchery or captured from natural sources can spawn between 50,000 and 1,000,000 eggs each. There are three larval stages for a shrimp: nauplii, zoeae and myses. The post-larval shrimps are technically known as PL, PL-1 meaning the first day of adulthood, PL-2 the second day and so on.
Feeding starts with zoeae and generally algae, naupili and formulated diets are given. A lot of manufactured feeds contain a high level of protein to ensure the growth of healthy shrimps. In impoundments feeds can include organic or chemical fertilizer.
In coastal areas in the tropics low stocking density shrimp farming also known as extensive shrimp farming takes place with a maximum of 25000 adult marine shrimps per hectare. In the case of intensive farming there is heavy concentration of shrimp in small areas like ponds and tanks. In this method while the yield is high production costs are low.
Shrimps can be affected by bacteria borne diseases. A virus called Taura destroyed almost all the shrimps of the species Penaeus vannamei at a farm in Hawaii in 1994. Taiwan, China, Indonesia, India and Panama are among the countries to have sustained considerable damage from viral attack on their shrimp farms.
Shrimp farming may involve huge environmental and social costs. Intensive aquaculture is known to be responsible for destroying mangroves. Mangroves help control flooding, maintain water quality, and protect shorelines from storms and erosion. Chemicals and antibiotics used as shrimp feeds also affect the environment seriously. With saltwater pumped into shrimp ponds, salinity spreads to the nearby areas, causing loss of fertility to the soil and, as a consequence, eventual loss of livelihood for agricultural farmers.
0 comments:
Post a Comment