Aquaculture initiatives by the Bangladesh Fisheries Research Institute (BFRI) in Mymensingh have helped preserve 16 endangered local fish varieties in Bangladesh in the last decade.
There are some 260 native freshwater varieties in Bangladesh, 64 of which have become extinct over the years, according to scientists at the government research institution.
Some of the reasons behind the wipe out include drying up of open water bodies, environmental perturbations and destruction of natural breeding and nursery grounds, said Dr Mohammad Nurullah, chief scientific officer of BFRI Mymensingh.
Even two decades ago, 80 percent demand for freshwater fish was met through the rivers, which has now dropped to about 30 percent, said the scientist.
Farmers now rear a particular variety of fish in ponds and get good responses in the local market and are also able to export, given that size requirements are met.
This preference of farmers also has a negative impact on the ecosystem, he added. For example, the boyal fish eat up other varieties of fish and so, is a threat to fish farms.
The International Union for Conservation of Nature documented about 56 freshwater fish species as critically endangered in 1998 in the country, he added.
Many fish farmers ready their ponds by draining out all the water in the dry season and adding lime to the base, so as to kill bacteria and other fish varieties, said research officials. This also stops the natural growth of many varieties, they added.
Another key reason for endangering varieties is fishing before reaching maturity, they said.
BFRI has developed breeding and culture technologies to help conserve 16 endangered species, said Md Moshiur Rahman, a scientific officer for indigenous varieties at the institute.
The varieties are -- pabda, gulsa, tengra, local koi, shingi, magur, foli, ayir, bata, gania, puti, chital, beda, mohashol, shorputi, titputi.
“We are currently working on the kholisa and shalbaim varities; research is a continuous process,” said Rahman.
Apart from research, the institute that was established in 1984 also focuses on farmers' training programmes and supply of juvenile fish for rearing.
Dr Subhash Chnadra Chakraborty, a professor at the Fisheries Technology Department at Bangladesh Agricultural University, said natural breeding spots are destroyed by the indiscriminate use of chemical fertilisers and insecticides on agricultural lands near the river banks.
These are washed out by rainwater into the rivers, killing many fish, he added.
The native fish varieties are nutritionally dense and more flavoursome, said Dr Yahia Mahmud, the institute's director general.
“The budgetary allocation in recent years will ensure extensive research through artificial breeding.”
Farmers' training programmes to breed these fish varieties are also ongoing, added the scientist.
Over 1,000 farmers from Mymensingh, Comilla, Moulavibazar, Narayanganj, Sirajganj, Gaibanda, Sunamganj, Narsingdi and other districts are involved in fish rearing, officials of BFRI said.
Shafiqul Islam, owner of Satota Hatchery in Tarakanda upazila in Mymensingh, said he saved up a bit of money in the last couple of years by breeding native fish varieties.
“I collect juvenile fish from the institute and then breed the variety in my own pond.”
The institute has so far developed 57 aquaculture and management technologies and most of them have already been transferred to the field level that helped overall fish production to rise.
Fish farmers Qudrat-e-Elahi of Trishal upazila and Shahina Parvin and Liton Khan of Muktagacha uapzila said they have seen a marked rise in fish production after adopting these modern techniques from the institute.
The government developed the 'Hilsa Management Action Plan' based on the research findings of BFRI scientists, increasing hilsa production by eight to ten percent every year.
The institute has also successfully researched Thai pangas, GIFT tilapia, native and exotic carp and non-carp species, and mud eel (kuchia) for commercial production, said a BFRI official.