| Ecologically
Important Areas of West Bengal Coast |  |
| | ||
|
Environmental
Status | ||
|
Home |
Environmental Status: Sundarbans houses a national park and tiger reserve. Some 2584 sq.km of the Indian Sunderban, including almost all of the mangrove forest, were declared a Tiger Reserve in 1974 under Project Tiger. The core are (1330 sq.km) was declared a National Park in 1982. This region adjoins the Sunderban Wildlife Sanctuary of Bangladesh. The park and the tiger reserve are situated among the estuarine mangrove forests which is most suited to the tiger. It is also one of the most important Project Tiger areas and ahs the largest number of tigers in India. Conservation of the ridley sea turtles has also been undertaken by Project Tiger. The main wildlife include tiger, saltwater crocodile, estuarine and marine turtle, different species of birds and gangetic dolphin. The Lothian Islands cover an area of 38 sq.km and was established as a wildlife sanctuary in the year 1976. the forest area of the Sundarbans has an expanse of 4,264 sq.km as the core area. The vast eastern portions of the Sundarbans (now with Bangladesh) are served with perennial freshwater by the distributaries of the Ganga Brahmaputra system such as Baleswar, Passar, Sipsa, Kobadok, etc. - the "rivers" of the western Sundarbans (within India) have practically no connection with Ganga - (mainly due to change in the course of Ganga further eastward over the past centuries and associated tectonic rise). They merely serve to drain the local areas and on the lower reaches as neritic straits or inlet of the Bay of Bengal. Thus, one encounters more saline conditions on the western side than on the eastern. In the Indian Sundarbans the difference during spring tide, between high and low water varies form 3.60 m to 4.80 m. In the Sundarbans of Bangladesh it varies form 1.50 m to 2.10m. The Sundarbans lie at the apex of the funnel shaped Bay of Bengal and receive the full force of cyclonic storms (4-8 nos./yr) between August and November. Strom surges with waves of 5-8 m. in height present a considerable marine invasion, creating tidal amplitudes for in excess of the 4.16m average for spring tides. Under normal conditions, the tidal amplitude in the Hooghly estuary ranges from 1.6 m to 4.3 m and the tidal influence extends almost 290 km inland. Between 40% and 60% of Sunderban soil is composed of silt; the amount of coarse sand does not exceed 2%, and the amount of organic matter remains constant at between 1% and 1.5%. The pH ranges from 5.5 to 8. Salinities ranged from 3.6 ppt to 23.5 ppt; at the beginning of the dry season the salinity is already high, but by the end of the dry season it is so excessive as to be inimical to the development or regeneration of all but the most halophilous plant species . The mangrove forests of the Indian Sunderban are now almost confined to a number of islands to the east of the Matlah River. Five principal formations have been distinguished in the Sunderban: (a) mangrove scrub or back-mangals; (b) saltwater mangrove forest; (c) a Phoenix paludosa belt; (d) moderately saline, mixed forest with Heritiera fomes and (e) brackishwater, mixed forest dominated by Heritiera fomes. However, only the first three of these formations are widespread in the Indian portion of the Sunderban. The back-mangals form the inland edge of the mangrove forests and were once widespread in the northern part of the delta. However, land reclamation has been very acute in this zone and, as a result; back-mangals are now found only in small isolated patches. The saltwater mangrove forest is the most widespread formation in the Indian Sunderban. These forests cover a large number of islands and islets, 3-5 m above sea level. The plant cover is very dense, averaging 12 trees (10-18 m in height), 440 shrubs (4-8 m high), and 2200 understorey shrubs (less than 4 m high) per hectare. Sunderbans: The Bengal Tiger and the Wild Life Sanctuary 
. The Sunderban supports a major inshore and estuarine fishery; the fishing season lasts 4 or 5 months, and at least 10,000 fishermen are engaged in the fishing operations. There are many brackishwater aquaculture farms (bheris) particularly in the northern part of the delta. These are impoundments of naturally inundated areas, often of several hundred hectares in extent. The mangroves are selectively felled for timber, the felling cycle varying with the dominant species; the rotation is 20 years for Heritiera fomes, 30 years for Excoecaria agallocha, and 40 years for Ceriops spp. Wood cutting continues under license from the forest department. Large numbers of people enter the forests in April and May to gather wild honey. A small number of tourists visit the tiger reserve each year usually by boat. The principal landuse in adjacent areas is the cultivation of rice. . The fishery is also threatened by the increasing capture of postlarval and early juvenile prawns, together with the growing trade in seed prawn. About 900 fishing permits are issued each year, admitting over 1 lakh people into the buffer zone. For every kg. of the desired species caught, 10kgs of fish fry and prawn seed of other species are discarded with great mortality. The construction of the Farakka barrage on the Ganga and flushing of the Hooghly with bypassed freshwater from the Ganga has significantly reduced not only the salinity of the estuary, but also its turbidity. The one time gradient zone in respect of salinity is now virtually a freshwater zone. The continuing reduction in freshwater inflow poses a serious long term treat to the whole region. The head of the Bay of Bengal is most important for fishery in the subcontinent; fishes and prawns caught in this region are sold in the markets of Calcutta and throughout northern India. The mangrove forests and mudflats of Sunderban provide vital breeding and nursery grounds for a large proportion of finfish, crustaceans and molluscs that make up the fishery. Prawns are the most rewarding in economic terms, and major efforts are being made to develop the prawn fishery of the area. About 20% of the Bengal lprawn catch is of species that are dependent upon the Sunderban for some period of their life. Approximately 33% of the annual catch of Hilsa ilisha in West Bengal and Orissa comes from the Hooghly and Matlah estuaries. However, only a tiny fraction of taxed revenue from fishing is reinvested in the region. | |
|
Home | Introduction | Objectives | Methodology | EI Areas | Info in Detail | ||
