9 fish species on verge of extinction

On May 7, a fisherman in Sylhet caught a 180kg Baghair from the Kushiyara river and brought it to Lalbazar, a famous fish market in the city.

Having learned that the fish would be put on display, hundreds of curious locals flocked in for a glimpse. Too big for a single customer, the fish was later cut into pieces and sold among locals within hours.

Such "celebrations" of big catch and its public display has long been a tradition in rural Bangladesh, but experts are concerned at the rate some sweetwater fish species, including Baghair, are vanishing.

This particular fish species is listed as "critically endangered" by the IUCN Red List of Threatened Species and declared 'protected' under the Wildlife (Conservation and Security) Act 2012.

Despite that, at least 25 Baghair fish, each weighing at least 30kgs, have been netted from Kushiyara, Padma, Jamuna, Brahmaputra and other major rivers since January 2019, according to media reports.

THREATENED AND PROTECTED SPECIES

The International Union for Conservation of Nature (IUCN) published its first Red List of Threatened Animals of Bangladesh in 2000. Of the 266 freshwater and brackish fish species it assessed, 54 were listed as "threatened" at the time.

Among them, 12 were termed critically endangered, 28 endangered, and 14 vulnerable.

In 2015, the IUCN updated the Red List by assessing 253 freshwater fish species and, by this time, the number of "threatened" species rose to 64. Of them, nine were declared critically endangered, 30 endangered and 25 vulnerable. Another 27 were categorised as "near threatened".

Overall, 25.3 percent local fish species are threatened while nine others are at the verge of extinction, it found. 

Majority of the threatened fish groups (53 percent) belong to carps, barbs and loaches.

The critically endangered fish species are Bhangon Bata, Nandi, Mohashol, Khorka or Khorika, Goalpara Puia, Pipla Shol or Tila Shol, Kala Pabda, Baghair and Chenua.

The 21 freshwater fish species declared protected under the Wildlife Act 2012 are: Tila Shol, two species of Mohashol, Bhangon Bata, Nandi, Ghora Muikha, Baghair, Chenua, Kotha Kumirer Khil, Telotaki, Tara Baim, Napit Koi, Neftani, Kuicha, Rita, Bhool, Joya Hiralu, Rani, Bishtara, Gang Magur and Shilong.

Among them, Tila Shol, one variety of Mohashol, Bhangon Bata, Nandi, Baghair and Chenua are critically endangered, while another type of Mohashol, Ghora Muikha, Rita, Bhool, Joya and Rani are endangered.

"Local fish species are depleting fast. But it's not visible like other animals as fish live underwater," said Prof Dr Mostafa Ali Reza Hossain, of Fisheries Biology and Genetics department of Bangladesh Agriculture University (BAU).

While preparing the 2015 IUCN Red List, experts assessed that many fish species were already extinct, he said, adding, "But we are waiting to make that announcement as existing protocols require a 25-year timeframe before declaring any species extinct."

WHAT'S CAUSING THE DEPLETION ?

Data from Department of Fisheries (DoF) yearbooks show how some fish species are making up the major share of overall fish production while other local varieties deplete.

According to the 2019 Yearbook, major carps (Rui, Katla and Mrigal) account for 19.97pc of the total production while Hilsa 12.15pc, exotic carp (Silver Carp, Grass Carp, etc) 10.87pc, Pangas 10.45pc and Tilapia 8.91pc.

One key reason behind this is increased production of cultured fish in inland close waters, which is 67.42pc of the total fish production. The catch from inland open waters stands at 32.57pc.

Data also show that Hilsa accounts for 74.30pc of the total fish captured from rivers while Rui, Katla and Mrigal together account for 30.86pc of the catch from Beels. The rest belong to other species.

"Overexploitation of fish resources, use of illegal gear, water pollution, increasing flash flood and siltation, unplanned construction on riverbanks, deforestation, fishing by complete dewatering, destruction of swamp forests are among the key reasons behind this," said Prof Dr Mrityunjoy Kunda of Aquatic Resource Management at Sylhet Agriculture University.

Jalmohal (waterbody) management and leasing system is also responsible for the loss of fish biodiversity, he added.

HOW TO REVERSE IT?

Experts suggested a number of measures, including building permanent sanctuaries at every river and beel and other water bodies, preventing river pollution and taking up waterbody dredging projects to reverse the current trend.

Building permanent sanctuaries at every river and beel will help fish species breed safely, said Dr Md Khalilur Rahman, director (research and planning) of Bangladesh Fisheries Research Institute (BFRI).

"All rivers must be protected from pollution and mother fish must be protected at any cost," he noted.

On the other hand, large-scale dredging is vital to regain navigability of rivers, beels and canals. Besides, controlled breeding of all declining species all across the country is crucial, said Prof Dr Mostafa Ali, director of Fish Museum and Biodiversity Centre at BAU.

"Where there is a sanctuary, the production of declining varieties has increased. So there must be sanctuaries at every possible fish breeding area by targeting specific fish species of the area," he said.

While the fish species are declining fast, relevant government authorities are working to reverse the trend.

Last year, BFRI started purchasing brood Mohashol fish from fishermen around Someswari river in Netrokona, the only known waterbody for this critically endangered fish, for controlled breeding.

"For years, we've been breeding declining fish species in hatcheries and releasing them into open waters. But our efforts will go in vain if the waterbodies are not properly protected," said Dr Khalilur of BFRI.

Hasan Ahmmed Chowdhury, former principal scientific officer (fish research and survey) of the DoF, said they had already taken a number of projects while some other schemes are at the planning stage to save the endangered fish populations.

He also suggested that the government revise relevant laws and rules for the department to work more effectively and efficiently. "If the laws can be implemented for all fish species like in the case of Hilsa, it would be the best way of conservation."