Ecological significance of the coastal plain in west bengal

The coast and its adjacent areas on and off shore are an important part of a local ecosystem: the mixture of fresh water and salt water in estuaries provides many nutrients for marine life. Salt marshes and beaches also support a diversity of plants, animals and insects crucial to the food chain. The high level of biodiversity creates a high level of biological activity, which has attracted human activity for thousands of years. More and more of the world's people live in coastal regions. Many major cities are on or near good harbors and have port facilities. Some landlocked places have achieved port status by building canals. Coasts, especially those with beaches and warm water, attract tourists. In many island nations such as those of the Mediterranean, South Pacific and Caribbean, tourism is central to the economy. Coasts offer recreational activities such as swimming, fishing, surfing, boating, and sunbathing. Growth management can be a challenge for coastal local authorities who often struggle to provide the infrastructure required by new residents.

The coastal zone of West Bengal, i.e., the lower 'Bengal Basin' comprises the districts of North and South 24 Parganas and Medinipur. The zone covers 6 rural Blocks of the North 24 Parganas district, 14 rural Blocks of South 24 Parganas district and 21 rural Blocks of Medinipur The areas under CRZ-I, CRZ-II and CRZ-III have been discussed in Chapter-I of this Report. Total length of the West Bengal coast line from west to east is about 220 km, extending from the eastern part of the river Subarnarekha or New Digha coast to the river Harinbhanga or Herobhanga, which delineates the India — Bangladesh border .The entire coastal stretch is intersected by the rivers Haldi and Rasulpur in the Medinipur district with the mouth of the Hugli river separating the districts Medinipur and South 24 Parganas. On the other hand, six major estuarine rivers, viz., Baratala Saptamukhi, Thakuran or Jamira, Matla, Goasaba, Herobhanga or Harinbhanga flow from north to south and meet the Bay of Bengal. Most of these estuarine rivers were once connected with the river Hugli or with the river Padma of Bangladesh, directly or indirectly. Due to the neo-tectonic movement of the lower Ganga plateau, since the12th Century and inclination of river Ganga towards east, most of these river systems in the Indian part of the Sundarbans have been silted up. The upstreams in the Indian part of the Sundarbans have silted up and the upstream connections with the river Ganga have also been choked. Besides these, large scale human interactions. and deforestation, vis- a-vis, reclamation and renovation of the mangrove forest lands of Sundarbans, the silt deposition and land accretion and on these estuarine river beds have accelerated and land accretion of the coastal phases took place. In coastal West Bengal, which is predominantly influenced by the river Hugli, the tidal impact in these• river system traverse upstreams about 290 km while the down stretches, i.e., the coastal zones including the estuarine mouths, sustain the important multiple commercial fisheries and fishing. Furthermore, good number of broad to narrow rivers, rivulets, viz., the river Bidya, Raimangal, Kalindi, Kartal, Hogol, Jamuna, Ichhamati, Gomor, Ajmalmari and a number of tidal canals and creeks intersect all these major estuarine rivers, which ultimately helped in forming several large and small islands. All these form a closely network system with the anastomosing tidal rivers, canals and creeks. During high tide and sea surges, most of these coastal areas/islands and deltaic lands in this coastal phase in general and the Sundarbans mangals in particular are inundated with saline sea water. In these saline zones, the mangroves and the halophytic herbs, shrubs and climbers grow naturally and if transplanted or migrated during the early period, they also get naturalised. A variety of nets and gears are used for capture fishing from these estuarine rivers, canals, off-shores and in-shores of the Sundarbans. With the existence of the dense mangrove forests and ideal mangal habitat in this lower Ganga delta, the estuaries have become distinct and very much potential for estuarine fisheries. The mangrove habitats are identified as important components in this intertidal coastal zone of West Bengal and the mangrove ecosystem is also identified as Nature's own aquaculture system. In Indian part of the Sundarbans, the mangrove forest area covers about 2300 sq km(55% of the total Sundarbans mangals) and the water spread area is estimated at about 1960 sq. km. (about 45% of the total Sundarbans mangals). Majority of the rivers of the Indian Sundarbans are considered as treasure troves of aquatic marine resources having enormous quantity and quality of estuarine and in-shore fish prawn, shrimp and crabs. These fish, prawn, shrimp and crabs are the cheapest sources of animal protein and are the important food items throughout West Bengal in general and coastal West Bengal in particular. As such, fishing and fisheries in these coastal water bodies, viz., in-shore, off-shore, estuarine mouths, rivers, canals, creeks, brackishwater ponds etc, are the age old practices in these lower Ganga deltaic region. Here, fishing practices are largely of multi species involving use of multi gears. The Sundarbans mangals are very rich with diverse mangroves and mangrove associated flora and fauna, which are of unique and diverse types. Since the beginning of human settlement in these coastal areas, fishing, fisheries and aquaculture were the common practices of the local and migratory rural fishermen communities. During recent years however, due to massive population growth and less opportunities available for other means of livelihood, most of the rural people are engaged in fishing or aquaculture besides their agricultural and other vocational activities. All these estuarine rivers of this zone meet the Bay of Bengal and form ideal fishery zones with great resource potentiality. The river Ganga and the river Brahmaputra unitedly form this extensive and world's largest estuarine system in its southernmost part at the coastal stretches of Bangladesh and West Bengal in India. Within the Indian portion, it extends upto the southern part of West Bengal, i.e., the South 24 Parganas and part of the Medinipur district. It comprises the Hugli-Matla estuarine system, which also include the distributaries of the river Hugli, viz., Baratala, Saptamukhi, Thakuran or Jamira, Matla, Goasaba and Herobhanga. These are divergences from the mother river Ganga-Bhagirathi-Hugli. The river Rupnarayan also meets with the Hugli river. The river Hugli is the positive estuary in the myxohaline zone and this estuarine system supports commercial fishing. Furthermore, on these commercial fishing and brackishwater shrimp and fish culture, the local economy is substantially dependent.

The coastal area of West Bengal, which is largely influenced by the Hugli — Matla estuarine system along with the interactions of the Rupnarayan, Damodar, Haldi and Rasulpur rivers, form one of the largest estuarine systems in the world, which is also very rich with diverse and bountiful floral and faunal assemblage. Both shell-fish and fin-fish species are abundant in these estuarine ecosystems and coastal stretches and these natural aquatic resources form the mainstay of capture fisheries of West Bengal. Fish, estuarine fisheries and fishing activities in the coastal zone provide a source of livelihood to lakhs of poor fishermen, fish farmers and also fish traders, who in turn support the flourishing trade in this lower Ganga deltaic region. The fish in this Hugli Matla estuarine system is mainly of two types, viz, the residents and the transients or migrants. The marine fish species migrating upstream for spawning in freshwater rivers, are the Sillaginopsis, Tenualosa ilisha, Polynemus paradiseus, Sillago sihama, Macrobrachium rosenburgii breed in saline water. The local economy of the West Bengal coast is largely dependent on fishing and fisheries from the coastal water and inland water bodies like estuaries, rivers, canals and other small and large water bodies. Agriculture in these zones are mostly dependent on monsoon precipitation as irrigation facilities have not been much developed in these coastal areas as required. Industrialisation in the coastal zone is almost absent, except in the Haldia region, which has received a great boost after the implementation of the petrochemicals project. The region has scattered small scale industrial (SSI) units; which are inadequate to spur economic upliftment of the rural poor of the coastal region through employment generation. As such, fishing and fisheries in the coastal zone are the chief and the most important life — sustaining transactions.

In the coastal West Bengal , the problem of freshwater is fairly acute because of extensive abstraction from a depth of 700- 1000 mtr .The shallow salt water table often renders stored water in ditches and ponds brackish and the surface soil saline. The wind velocity [7-12 km/hr] offers scope for its utilization for energy generation. Tourism facilities in the Sunderbans are to be developed in view of an influx of 23000 visitors annually. The Sunderbans and the beaches of Digha and Bhakkali are considered as fragile coastal areas recently by a study report published.

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