- Tanguar Haor, Bangladesh’s second largest Ramsar site and one of the country’s most important habitats of breeding fish, has been losing its fish diversity.
- A recent study found that the number of available fish species is now below 100 while, just two decades ago, the figure was recorded to be 141.
- Experts blame anthropogenic factors, including overfishing and habitat destruction, as the causes of declining diversity.
- However, authorities are ignoring the rising urgency for conservation and are instead celebrating the “increased fish production in the wetland.”
Born and raised in the locality of one of Bangladesh’s Ramsar site Tanguar Haor, 58-year-old farmer Bazlur Rahman says he feels proud to belong to the scenic swamp. A wetland that the country’s fisheries department says is a crucial hub of breeding fishes. At the same time, he says he feels frustrated witnessing the decline in Tanguar Haor’s fish diversity year by year.
In response to which fish are found in the haor, or wetland, Bazlur lists over 50 names, but occasionally adds in between that many of them have disappeared.
He could speak specifically about unavailable fish species including chital (Chitala chitala), pabo catfish (Ompok pabo), bacha (Eutropiichthys vacha), jhilang (Silonia silondia), nanid (Labeo nandina), mohashol (Tor tor), baghair (Bagarius bagarius), pangash (Pangasius pangasius), darkina (Rasbora rasbora) and tila (Channa barca).
“I’m worried. Some of the fish that were available even a decade ago have become rarely available now,” Bazlur, who is also the president of Tanguar Haor’s Central Co-Management Committee (CCC), tells Mongabay.
A 2015 report by IUCN cites the National Conservation Strategy (NCS)-Fisheries Report 2001 saying Tanguar Haor supports “nearly 141” fish species. However, IUCN found 134 fish species during the survey.
However, a recently published study by Gulam Hussain, Feed the Future Innovation Lab for Fish’s (FFILF) Asia regional coordinator, assesses only 58 available fish species in the haor.
From a survey with the local fishers, Hussain identified that among the 58, 16 fish species are “commonly available,” 18 are “moderately available,” 12 are “less available,” and 12 are “rarely available.”
Hussain categorizes both the “less” and “rarely available” fishes as vulnerable species, saying that “these are on the line to be endangered within a few years.”
Hussain’s list of vulnerable species includes kani pabda (Ompok bimaculatus), chaka (Chaca chaca), gharua (Clupisoma garua), napid koi (Badis badis), kajuli (Ailia coila), batashi (Pseudeutropius atherinoides), ekthuta (Hyporhamphus limbatus), bou rani (Botia dario), cheng (Channa orientalis), lal khalisha (Trichogaster lalius), lachu (Cirrhinus reba), dhela (Osteobrama cotio) and mola (Amblypharyngodon mola).
“Habitat destruction, illegal netting, overfishing, pollution and absence of conservation efforts in the five fish sanctuaries are the main factors accelerating the decline in fish diversity of Tanguar Haor,” Hussain says.
A unique waterbody
The Tanguar Haor area is an expansive back-water swamp comprising many shallow and saucer-shaped depressions, called beels in Bangla, between ridges or banks of river systems at the foothill of the Jaintia Hills of India’s Meghalaya state.
Located in the Tahirpur and Dharmapasha sub-districts of Sunamganj in north-eastern Bangladesh, this hoar faces challenges from ecosystem degradation and overuse of its natural resources. In 1999, the Bangladesh government designated it an Ecologically Critical Area (ECA) to conserve the unique wetland.
Tanguar Haor was also recognized as a Ramsar site the following year, granting it international importance as a wetland.
Referring to some research works, a study published in Nov. 2022 says Tanguar Haor supports a higher number of fish species compared to several other Ramsar sites, including East Kolkata Wetlands of West Bengal and Kolleru Lake of Andhra Pradesh in India, the Rapids of Mboungou Badouma and Doume in Gabon, Sultan Sazligi in Turkey, and Tasek Bera in Peninsular Malaysia.
Government inaction
To support conservation efforts, five sanctuaries were established in 2011 within the haor’s deeper portions: Rupaboi, Rowa, Tekunna, Ballardubi and Alamer Duar. These sanctuaries provide crucial breed grounds in the beels, which are perennial waterbodies as they retain monsoon runoff even during the dry season, allowing juveniles and breeding female fish to gather and thrive.
To protect the sanctuaries, IUCN developed the Tanguar Haor Management Plan and Guidelines, which prohibit the catching of rare species and ban nighttime fishing within these areas.
“But most of the fishermen don’t cooperate with implementing the guidelines. They catch whatever gets trapped in their nets,” Bazlur says. He blames the authorities’ inaction for the non-compliant fishing.
When inquired, the chief of the department of the haor and wetlands development, Akhtaruzzaman, advocates for increased fish production instead of conservation.
He says, “Bangladesh, with a population of more than 170 million people, sees a growing demand for fish. It is quite usual for the fishermen to try to catch more fish.” He also glorifies that fish production from the haor area has increased manifold.
Mongabay recently spoke with the Sunamganj district fisheries officer Shamshul Karim, who shared that the district’s 94 beels, including those inside Tanguar Haor, spanning over 60,000 hectares (148,000 acres) totally, produced around 36 thousand tons of fish in 2023-24 — an increase of 22% since 2018-19.
Overfishing an urgent issue
Mrityunjoy Kunda, a professor at Sylhet Agricultural University and an expert in aquatic resource management, points out that fishers commonly rely on harmful and illegal fishing gear to overfish and meet the growing demand for fish.
A recent study identifies the use of synthetic monofilament gill nets (locally known as current jal), fine-meshed seine nets (ber jal) and other illegal fishing devices as the major anthropogenic causes behind the decrease of fish species in the haor.
Kunda continues, “In an aggressive effort, fishers pump out the last drops of water from the deep part of the swamp during the summer to collect the few remaining fish. By [doing] this, they often kill the [breeding] fish.”
According to Kunda, water pollution due to the frequent movement of minerals-laden vessels and tourism-based houseboats through the sanctuaries, especially during the breeding season, which is April to July, also contributes to the decline in Tanguar Haor’s fish diversity.
He says the government needs to enforce stricter overfishing regulations and protect the vital sanctuaries.
Bazlur says that the livelihoods of the local fishing communities may eventually be at risk if they don’t find diverse fish stocks.
“We have requested the relevant authorities to create alternative livelihood options for the 80,000 local fisherfolk to discourage them from overfishing. But we are still waiting for a positive response,” Bazlur concludes.
Banner image: Water pollution due to the frequent movement of minerals-laden vessels and tourism-based houseboats through the sanctuaries contributes to the decline in Tanguar Haor’s fish diversity. Image by Sadiqur Rahman.
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Citations:
Hussain, M. G., Biological Diversity Status of Fish Genetic Resources at Tanguar Haor Wetland in Bangladesh, BMJ Vol 5 Issue 1 ISSN 2519-5972. Retrieved from: https://bsmrmu.edu.bd/public/files/econtents/6056ecd80147e12-Biological%20Diversity%20Status%20of%20Fish%20Genetic%20Resources%20at.pdf
Sultana, M. A., Pandit, D., Barman, S. K., Fagun, I. A., … Kunda, M. (2022). A review of fish diversity, decline drivers, and management of the Tanguar Haor ecosystem: A globally recognized Ramsar site in Bangladesh, Heliyon, Vol. 8(11), e11875. doi:10.1016/j.heliyon.2022.e11875