Sundarbans provide livelihood to many people who work as fishermen, wood-cutters, and gather honey. Approximately 2.5 million people live in the surrounding villages. Dire poverty urges the people of Sundarbans to frequent the forest in search of livelihood. Some of them take the risk of cyclone for fishing and other enters the forest to collect honey and fuel wood. The vulnerable mangrove eco-system is under stress due to such interference. Among the principle threats, which have so far been identified, some are reached into menacing proportion and are all related to the lack of any alternative, rewarding and at the same time ecofriendly livelihood. Ecological crop loss due to wild harvest of prawn seeds, irregular and over fishing, cutting of mangrove trees for timber and fire wood, shell lime generation from ruthlessly procured molluscs, are all causing severe biodiversity loss and if not checked or utterly stopped may not only ring the death bell of this unique ecosystem but also cause severe damage to the economy of this area vis. the West Bengal state and the whole country in general.
Wild Harvest of prawn seeds:
Thousands of men, women and children regularly collect post larvae of the highly demanded tiger prawn (Penaeus monodon) from tidal creeks and rivers due to absence of hatcheries in the state. The catchers operate in anchored boats in the middle of the rivers with fry filter nets, or they may drag the nets (fry seine) at banks in waist deep waters or they may simply put the nets (fry lure) near the banks of the estuary.During such operation, a large variety of finfish and shellfish juveniles are also caught in the nets. As these juveniles are non remunerative to the fry catchers, they are simply thrown away and wasted. An investigation done on this problem revealed that about 50 species of finfish juvenile and 28 species of shellfish juveniles are wasted per net per day (Anon, 2002). Thus this operation may pose negative stress to the coastal fishery of the state in near future by simply destroying the food chain. Apart from that random trampling by the fry catchers cause uprooting of mangrove seedlings and destroy the benthic fauna along the banks of the estuary.
Huge numbers of people of Sundarbans are engaged in fishing. In absence of any proper and centralized monitoring and due to lack of other suitable employment opportunities much of this fishing is extremely irregular and unscientific. There is no restriction on mesh size of nets, nor there any restriction on catching of gravid fish or fishing in breeding/egg laying period. As a result extensive catching of Hilsa, shrimps and crabs may cause heavy depletion of the stock. Hilsa is steadily becoming rare in each year while the shrimp catching boats use extremely fine nets and causing severe damage to the benthic fauna of the estuaries. The wild harvest of crabs to meet the export demand is also alarming. Thousands of boats regularly patrol the mangrove forests in the monsoon, which is egg-laying time of the crabs, totally unregulated and carry home boatloads of crabs of various sizes. Considerable portions of these catches are gravid females as the price of the later is the hightest in the market. Presently there are 5550 registered boats that fish with in the forest area of Sundarbans (Annual Report of Forest Directorate, West Bengal, 1990-1991). In the absence of any accurate data on fish landing, proper maintenance of log books on fishing vessels and trawlers and proper monitoring of foreign vessels, no correct data on exploitation is being recorded, which is a major threat to fishery stock of the coastal zone of West Bengal (Anon, 2002). Endangered species like horseshoe crab, marine turtles and dolphins are also the worst sufferers of these unregulated fishing activities as they get entangled in the gill nets and die. Killing of marine turtles and cetaceans by strangulation after being entangled in net can largely be avoided by the proper use of Turtle Excluder Device (TED). But so far not a single trawler operator is convinced to use the TED resulting in to large scale damage of precious wildlife.
Ministry of Environment and Forests has placed nine species of sharks, rays and skates (Elasmobranchs) on Schedule I of the Wildlife (Protection) Act (amended act, 2002), making their killing illegal. Among this list at least five are found in the Sundarbans, i.e. Ganges shark (Glyphis gangeticus), Glyphis glyphis, Small toothed saw fish (Pristis microdon), Pointed saw fish (Anoxypristis cuspidatus), White spotted shovelnosed guitar fish (Rhinocobatus djeddensis). In absence of any regulation, shark killing is rampantly going on in our coast. Truckloads of dead sharks are sent to the Kolkatas processing plants from the various fishing harbours in and around Sundarbans. Sharks are viviparous (give live birth) and extremely slow breeders. Such ruthless exploitation has already depleted the standing stock of these amazing animals from our coast.
Cutting of Mangrove Trees:
Although mangroves have been cleared in many pockets of coastal West Bengal for construction of shrimp culture farms, saltpans, etc but cutting of mangrove trees for timber and firewood causes maximum damage to mangroves. Mangrove trees like Dhudul (Xylocarpus sp.), Keora (Sonneratia sp.), Garan (Ceriops sp.), Garjan (Rhizophora sp.), Sundari (Heritiera fomes) are extensively used and still being used as timber materials for making village hutments, furniture and boats. Both Garia (Kandelia candel) and Sundari (Heritiera sp.) have become endangered from Indian Sundarbans due to alteration of salinity but both were extensively exploited as source of timber. Demand of fire wood (for cooking, cremation etc) is also severe threat to mangrove as the impoverished population may seldom have a better and cheaper source of fuel. Illegal collection of timber and fuel wood from the fringe areas of Reserved Forests of Tiger Project and 24- Parganas Division is common and the produce mostly finds its way to far off towns and even Kolkata.
Generation of Shell Lime from Molluscs:
Huge amount of gastropods and bivalves are regularly killed to obtain the shells as these are very good source of lime (CaCO3). Molluscan species like Telescopium telescopium. Saccostrea cucullata, Crassostrea gryphoides, Anadara granosa are sacrificed to obtain shell from which lime is manufactured (Mitra and Pal, 2001). Over exploitation is taking a heavy toll on the molluscan species and already several species including Anadara granosa have become extremely rare. It also prevents Calcium recycling in to the system and affects ecological balance.
Though every year a few cases of tiger poaching is detected and /or tiger skins recovered, yet the extent of actual poaching is not fully known. One conservative estimate says that between 1990 and 2000, 15 tigers death have been recorded and 21 tiger skins have been recovered between 1994 and 2001. Killing of tigers, straying in to villages, is also not uncommon.
Killing of chital deer for meat is also well known and selling and buying of the deer meat continue undercover in various islands, especially in the weekly markets. The common technique of poaching of tiger and spotted deer is the use of nylon-rope traps laid in the forest.
Straying of Tiger:
Straying of tiger in to villages along the western boundary of Sundarban Tiger reserve and north- western fringes of 24- Parganas (South) Forest Division is the cause behind acute man-animal conflict, which poses direct threat to conservation efforts.
The increased pressure on land for expansion of activities like aquaculture, prawn farming, drying of sea-fish etc are posing direct threat to the existing mangrove forests, especially in northern and north- western and south- western peripheries of Sundarbans, which are areas of forest lands out side project Tiger.
Reduced Flow of Sweet water:
Due to shift in the fresh water flow towards eastern side, the headwater sources of the rivers like Matla, Bidyadhari got cut off and are now mostly tidal rivers. As a result, fresh water flushing of mangroves has reduced considerably and salinity level in the waters of greater part of Indian Sundarbans has increased considerably. This has resulted into considerable changes in vegetation pattern with the fresh water loving species like Sundari (Hertiera fomes) almost become extinct from some parts and formation of saline blanks inside the islands. Construction of barrages in the upper stretch of Hooghly river (Farakka barrage) has manifold the problem considerably.
Construction of Embankments:
Since the initial days of reclamation embankments have been constructed to protect human settlements. The total area of embankment now extends over to more than 3500 km. It affects the drainage problem and cuts off the sweet water flow in to adjoining areas, resulting into increased salinity. Also, due to embankments, the silt deposition along the inner banks and river beds have raised the levels of river beds higher than the level of human settlements.
Vehicular and Industrial Pollution:
Large numbers of mechanized boats, launches, trawlers regularly ply through the Sundarbans. These impart petroleum hydrocarbon, heavy metals like lead and remnants of anti fouling paints in the form of zinc, copper, tar etc in the water. The tourist vessels, which move regularly in side the STR, also cause all these kind of damages to the mangrove ecosystem. Any future expansion plan of tourism in Sundarbans must remember this point and improvement of fuel and environment friendly engines with the help of automobiles and marine engineers are urgently required. In this respect the recent influx of large numbers of condemned Bangladeshi cargo vessels through the western part of Indian Sundarbans are a matter of great concern for the security of environment and the country in general.These cargo vessels generally anchor in the small riverside port of Namkhana in south 24 parganas, in the western Sundarbans. The present routes of these vessels need to be diverted from moving in side the Sundarbans. Instead they should be allowed to move inside India by the mouth of Hooghly only and from there straight to Haldia or Kolkata port.
The industrial sewage from Haldia and Kolkata ultimately drain through the waters of Sundarbans and falls to the sea. This sewage contains heavy metals, hydrocarbons and all kinds of pollution, which contaminate the mangrove ecosystem.
Long International Border:
The long international and national borders along the eastern boundary of Indian Sundarbans is a matter of great concern and difficult to man. The poachers of the international and national level take advantage of the same.
Dredging of Riverbeds:
Occasional dredging to improve the navigability for the large vessels affects the benthic fauna, primary production and fishery stock of the rivers enormously.
Oil Drilling and Oil Terminal:
Oil and Natural gas Commission of India (ONGC) have found oil in the offshore of Sundarbans. Though it is great news for country but such exploration, if taken up in future, will surely cause some serious disturbances in the fragile mangrove ecosystem of India.
Calcutta Port Trust has already set up an oil transfer jetty in the southwestern part of Sagar island. They have a definite plan to build a major terminal there for unloading and transfer of oil through pipeline. The possibility of oil spill and damage and destruction of marine life is unavoidable in case of any further development.
Socio- political Condition:
The region is most inaccessible even today. Thus administrative control, power of governance, and developmental activities are very poor. Adding to this is the petty local politics of the area. All these factors combined to propagate criminals and poachers in some of the poverty stricken islands.
Like the rest part of the country the Forest department of Sundarbans are depleted with staffs, patrolling vessels, enough communicating tools, firearms, medical and other benefits etc. All these pose serious limitation towards effective management.
Some Important Recommendations:
As a concluding remark the following important recommendations are being made
- Mass collection of prawn seeds should slowly but steadily be stopped permanently. For the time being, after banning the random catching in all the islands, self help group or cooperatives can be formed with the help of gram panchayats, which shall operate a selective numbers of nets in a particular territory (e.g. by taking one member from each of the family presently involved in the trade) and seeds collected will be sold by the cooperative and profit will be shared by all members. The practice of wasting of the seeds of other finfish and shellfish by throwing them in the shore should be made punishable by passing strict rule. Some wide mouthed and rectangular plastic containers can be made available to the seed catchers in which they can keep the haul during segregation with ample amount of ambient water and after the segregation is over the other finfish and shellfish juveniles should be released in water. Awareness campaign will take a greater role here, as per head income will initially drop in this method and people will not be convinced easily. But with other eco-development projects coming and with a greater assurance of security people will surely be convinced. Gradually the people should be encouraged to take up the other economically and ecologically viable profession with Govt. and NGO support. A time frame should ideally be chalked out for doing this phasing out operation in different islands.
- Mass exploitation of crabs should be stopped with selective permission of mud crab fishery in the villages. The process needs detail investigations as any monoculture practice may cause fouling and disease out break. A ban should be in place restricting catching of juveniles, larger males and gravid females. Only catching of young adults would be allowed which is going to be fattened to attend marketable size.
- Mesh size of net should be controlled. Use of mosquito net should be banned.
- Hilsa fishing should be stopped during the initial days of migration months (at least two months in the early monsoon months and catching season should starts from mid August with only riverine catching of Hilsa should be allowed) and catching of gravid females and young ones should be stopped permanently. This banning should strictly be implemented in the coastal zones where maximum and intensive catching takes place by placing nets horizontally to the flow of river water. Apart from that trawlers also catch excessively in the coastal areas giving these fishes no chance whatsoever for migration. The ban, as proposed should immediately be implemented as a delay in this may seriously deplete the Hilsa stock, making it extinct from our waters.
- Instead of giving individual supports creation of more and more village self help groups or cooperatives are needed to be developed to provide the benefit of eco-development to the greater masses.