Bangladesh is poised to lose most of its marine fish populations as a result of climate change, dealing a big blow to thousands of people dependent on fishing in the sea, according to experts. "Bangladesh has a long coastal belt of 710 kilometers with abundant marine resources. We've so far found some 475 species of marine fishes, 400 of mollusc and 200 species of sea-woods. Unfortunately, some of them have disappeared and many more are on the verge of extinction," Prof Nani Gopal Das of Chittagong University's Marine Biology Department told UNB.The scientific names of some of the marine fishes of various countries, including Bangladesh, which have been included in the Red List of the International Union for Conservation of Nature (IUCN) are Johnius coitor, Nematalosa galatheae, Pseudapocryptes elongates, Thunnus albacares, Thunnus obesus and Xiphias gladius. Prof Nani Gopal said monsoon variations, frequent droughts and severe storms will also kill the fish in inland freshwater bodies and affect their breeding patterns. "When there will be a significant effect on the ecosystems, this would also endanger a vital food source in some coastal areas."He added: "Several fishes as we mentioned will be eliminated from these areas if they cannot quickly adapt to the changing salinity levels. Fishes are very sensitive to temperature too and some species those that can't swim very far - may go locally extinct." Nani Gopal pointed out a number of rea sons behind the ecological degradation of the Bay of Bengal. These include increase in sea temperature due to global warming; increase in salinity due to environmental pollution, habitat conversion of the marine fishes; massive resource consumption by the growing population; introduction of exotic species; and commercial exploitation or over-hunting. According to an international study conducted by WorldFish with support from the UK's Department for International Development (DFID), both coastal and landlocked countries in Africa, including Malawi, Guinea, Senegal and Uganda, four Asian tropical countries - Bangladesh, Cambodia, Pakistan and Yemen - and two countries in South America, Peru and Colombia, are the most economically vulnerable to the effects of global warming on fisheries. Overall, of the 33 countries that were considered highly vulnerable, 19 are already classified by the United Nations as "least developed" due to their particularly poor socioeconomic conditions. According to the United Nation's Food and Agriculture Organisation (FAO), fishes provide more than 2.6 billion people worldwide with at least 20 percent of their average annual per capita protein intake. The "highly vulnerable" countries identified in the WorldFish study produce 20 percent of the world's fish exports (by value). The researchers note that these countries should be on a priority list for adaptation efforts that will allow them to endure the effects of climate change and maintain or enhance the contributions that fisheries can make to poverty reduction.Worried at the rapid climate change, Prof Nani Gopal said the impact of climate change on fisheries and aquaculture is already being felt. In marine waters, extreme weather events will increase in frequency and intensity - the most well known of these is the El Niño phenomenon in the South Pacific.AFM Shahidur Rahman, an environmentalist, said the ongoing warming of the world's oceans is likely to continue, but with geographical differences and some decadal variability. Warming is more intense in surface waters but is not exclusive to these with the Atlantic showing particularly clear signs of deep warming.He said changes in fish distributions in response to climate variations have already been observed, generally involving pole ward expansions of warmer-water species and pole ward contractions of colder-water species.Prof Nani Gopal said shifts in ocean salinity are occurring, with near-surface waters in the more evaporative regions of most of the world's oceans increasing in salinity, while marine areas in high latitudes are showing decreasing salinity due to greater precipitation, higher runoff, melting ice and other atmospheric processes. And the oceans are becoming more acidic, with probable negative consequences to many coral reef and calcium-bearing organisms.He put forward three recommendations - developing a proper management policy, conservation of biodiversity through pollution control and maintenance of the breeding ground - to protect the endangered marine fish populations. "The 200 species of sea-woods growing around the St Martin's Island are the main food of the marine fishes," he said underscoring the need for protection of these planktons as these creature play a vital role in maintaining the ecological balance of the sea.
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