Coastal Aquaculture
Coastal Aquaculture raising fish, molluscs or crustaceans under controlled conditions in polders, tanks, ghers (ponds), or specially constructed polders in the coastal regions. Coastal aquaculture is an old traditional practice in Bangladesh, but from early seventies when demand and price of shrimp in the world market became very high, much emphasis has been given on culture of bagda shrimp Penaeus monodon rather than fin fishes, and shrimp culture expanded rapidly in the mangrove and polder areas. The culture operation in 51,812 ha (in 1983-84) was expanded to about 1,42,110 ha (in 1993-94) of which bagda shrimp culture (in about 1,33,670 ha) dominates over the culture of golda shrimp, Macrobrachium rosenbergii (in 8,439 ha).
Coastal aquaculture farms are mostly located in Bagerhat (29%), Satkhira (19%), Khulna (19%), and Cox';s Bazar (33%). In addition, there are about 422 ha in Keshabpur (Jessore), 43 ha in Kalapara (Patuakhali), and 87 ha in Anwara and Banskhali (Chittagong).
Shrimp farming being a profitable business, most of the coastal polders constructed during 1950s and 60s by the water development board to protect agricultural land from inundation of salt water have now been turned into large shrimp culture ghers (ponds). The priority has now been reversed and salt water is willingly being allowed in the ghers of the polder areas to raise shrimps. Unplanned and rapid expansion of shrimp farming in Bangladesh has generated many environmental, ecological, social, and economic problems; most notable of them being destruction of mangroves and planktonic resources during collection of shrimp fry, and environmental pollution.
Recently, clustering of intensive shrimp farms around Cox';s Bazar and Moheshkhali has led to serious environmental degradation. Disease outbreak and mass mortality has also led to bankruptcy of many of the farms, and thus sustainability of this type of coastal aquaculture is now under serious question. Some local and foreign experts have recently reviewed coastal aquaculture practices and environmental management, and have made certain useful recommendations. These are as follows: unplanned expansion of shrimp farming should be strictly restricted; no more mangrove areas should be converted into shrimp farms; the study of mangroves (mangrovology) be introduced in the national curricula from the graduate level; changes in the biodiversity of degraded and undegraded mangroves should be monitored; shrimp hatcheries should be established on a priority basis in order to gradually eliminate dependence on wild fry of Penaeus monodon for coastal aquaculture; feed should be of low cost, and in no case should contain ingredients which could be used directly for human consumption; and that economically and environmentally sustainable aquaculture should be practised with a programme planned to meet the country';s need. [Nuruddin Mahmood]
See also prawn. [Mahmood, Nuruddin Professor, Institute of Marine Sciences and Fisheries, Chittagong University]
