Our coast and threats to it

Specialities
Bangladesh has the largest mangrove forest, the Sundarbans (one of the RAMSAR site and also declared as the World Heritage according to the provision given in World Cultural and Natural Heritage Convention) on the delta of the Ganges, Brahmaputra and Meghna rivers on the Bay of Bengal. The whole forest is intersected by a complex network of tidal waterways, mudflats and small islands of salt-tolerant mangrove forests, and presents an excellent example of ongoing ecological processes. The area is known for its wide range of fauna, including 260 bird species, the Royal Bengal Tiger and other threatened species such as the estuarine crocodile and the Indian python.

The Cox's Bazar is the longest uninterrupted sandy sea beach (120 km) where tourism has a great potential. Presently the beach is attracting nearly 50,000 tourists every year.

Bangladesh has second largest shipbreaking industry in the world and is dependent on it for its domestic steel requirement. Chittagong shipbreaking yard is in the coastal belt at Sitakunda. The economic, occupational, health, environmental consequences are the main issues deriving from the industry.

Bangladesh has one of the largest networks of inland waterways. The rivers flowing from the highest mountain of the world -- the Himalayas -- carry down to the Bay a huge discharge of silt. Its effects, together with a heavy monsoon rainfall, cyclonic storms and tidal surges, have contributed to a continuous process of erosion and shoaling both inland and at the mouth of the mighty rivers. The shoaling bed of the Bay is believed to the rich in resources. Rivers drain a total area of 54900 sq km and bring in or carry away over 2.4 billion tons of sediment load annually.

There are some other activities in the coastal zone of Bangladesh namely salt and shrimp culture, fishing and fish drying, forestation etc. The coast is fragile and concave with plenty of indentation. Erosion is quite a common phenomenon occurring almost throughout the year and mainly in monsoon.

Threats
Over exploitation: Overfishing and excessive oil and gas exploration are the most obvious threat to the coastal ecosystem. In 1995, FAO estimated that some 70 percent of major fish stocks they assessed were overexploited or in danger of being so, particularly the high value fisheries. Attempts to control overfishing have been largely unsuccessful even in developed countries. Moreover some fishing methods, including dredging, trawling, dynamite fishing, have been very destructive to marine habitats. Excessive bycatches of non-target species have decimated population of marine mammals. Unwanted catches of several marine species and destroying them while catching child-shrimps in the coastal belt of Bangladesh should be of great concern along with the issues of overfishing.

Pollution: At early stage, most legal agreement dealing with marine pollution focused on sea-based sources, particularly the deliberate dumping of oil and other wastes and spills from marine accidents and offshore oil driling. However, it became clear that most pollution of the marine and coastal environment originated on land, in the form of municipal, industrial and agricultural wastes and run-off. These sources account for as much as 80 percent of all marine pollution. Sewage and wastewater, persistent organic pollutants (including pesticides), heavy metals, oils, nutrients and sediments -- whether brought by rivers or discharged directly into coastal water -- ultimately take a severe toll on human health and well-being as well as on coastal ecosystem.

Physical alteration and destruction of marine habitat: The other threat is degradation of marine environment by alteration of physical habitats stemming from a variety of human motives and activities. Coastal development and offshore exploration often entail dredging up of bottom sediments. Sand mining, construction of jetties, beach "improvement" etc alter wave action and destabilize shoreline. Aquaculture development can mean, sometimes, wholesale cutting of mangrove forests. It can even cause conversion of natural habitat and subsequent loss of important fisheries. Two major effects of these activities are erosion and sedimentation. Shoreline alterations interfere with normal sediment movement, leading to severe erosion of beaches. Excessive sedimentation can destroy entire benthic habitats such as seagrass beds, and kill corals and other marine invertebrates.

Rising sea level: Most scientists agree that greenhouse warming of the planet will lead to a general increase in regional temperature and sea-level rise, changes in precipitation pattern and regional circulation. These will in turn affect surface and groundwater flow, surface and groundwater availability, incidence of floods and sedimentation, movement of marine water masses (wave, tide and current), intensity and tracks of tropical cyclones, natural ecosystems. They will also affect human activities, especially in the coastal zone, including changes to agriculture, fishing industry, tourism and the quality of life. In the opinion of many scientists, the global mean sea level has already risen by 10-15 cm during the past century. Global warming may also cause a further rise of 50 cm by the year 2100. Most at risk are the unprotected, densely populated coastal regions, such as Bangladesh.

Conclusion
Now, it requires a genuinely interdisciplinary approach to combat the above threats nationally, regionally and internationally. Considering the peculiarities of the coast and importance of sea-use activities, for Bangladesh, it is now necessary to establish a new managerial method with close cooperation between science, industry and government departments, and with an integrated but flexible and decentralised, dynamic management concept. Since function and structure evolve together, there should be sufficient motivation and justification for a timely study of the institutional implications.

Md Zahid Hossain is Inspector, Department of Shipping.