Experts observed this on the eve of the 'fish fortnight' that will be observed from today.

Indiscriminate fishing in open water bodies and water pollution are responsible for the vulnerability and dwindling of the local fish population, the experts noted. Over the years, 14 foreign fish species have filled up the vacuum.

Prof. Shahadat Ali of the zoology department of Dhaka University said the natural breeding places of local fish are being disturbed due to snapping of linkage between the open water bodies and rivers. "Fish species from abroad including African catfish are now taking over the local market," noted Prof. Shahadat.

As many as 54 local species of fish are now endangered out of 267 sweet water species. The International Union for Conservation of Nature (IUCN) has observed in a report that at least 11 species of local fish are critically endangered and facing near extinction.

The critically endangered species are Boga Labeo (Bhangon Bata), Nandi Labeo, Pangusia Labeo (Ghora Muikkha), Olive Barb (Sor Puti), Tor Mahseer (Moha shol), Ritha, Garua Bacha, Batchawa Bacha, Pangas, Gangetic Goonch (Bagair), Sisor catfish and Barca snake head (Tila shol). But the report does not say how many species have disappeared already.

According to the officials of the department of fisheries, there are 40.47 lakh hectres of open water bodies in the country like haors, canals, beels and other marshy land, while lakes and ponds cover an area of 2.42 lakh hectres.

The open water bodies are 17 times bigger than the stagnant water bodies. In 2001-2002, a total of 18.90 lakh metric tons of fish was produced. Out of which 6.88 lakh metric tons was procured from the open water bodies, 7.86 lakh metric tons from stagnant water bodies and 4.15 lakh metric tons from the deep sea.

Most of the fish produced from stagnant water are foreign species. Over the last 50 years, no fewer than 14 foreign species have become popular among the fish farmers.

In 1953, gold fish was introduced for farming as aquarium fish and then grass carp was introduced as food fish in 1966. The other notable alien species now being cultivated as food fish are scale carp, mirror carp, silver carp, big head carp, black carp, silver barb, putitor masheer, catfish (African), big cat fish, Mozambique cichild (Telapia) etc..