Dhaka:DNA sequences of five fish species and two shrimp species newly documented in the Sundarbans are set to be submitted to the international GenBank database, marking a significant milestone in biodiversity research and conservation of the world's largest mangrove forest.
According to Bangladesh Sangbad Sangstha, the inclusion of the genetic data in the US-based database will help establish the species' genetic identities in the international scientific community and facilitate further research into the aquatic biodiversity of the Sundarbans.
The findings of a 16-month study titled "Assessment of Aquatic Resources of the Sundarbans" will be handed over to the Forest Department at a final project workshop in Dhaka next month, in the presence of the Minister for Forest and Environment. The sequences will subsequently be submitted to GenBank through the department.
The study was jointly conducted by the Centre for Natural Resource Studies (CNRS) and the Arannayk Foundation under the Bangladesh government's Sundarbans Protection Project. Its draft findings were presented at a recent event in Khulna.
The research team surveyed 65 rivers and canals across the four ranges of the forest between March 2024 and June 2025. It also conducted boat surveys covering 424 kilometers inside the forest and collected data from fish landing centers in Shyamnagar, Koyra, Mongla, and Sharankhola.
Dr. M Enamul Haque, head of the research team and former director of the Bangladesh Fisheries Research Institute, stated that the team prepared DNA sequences of the seven species for submission to GenBank.
"As the matter falls under the jurisdiction of the Forest Department, the research findings will be handed over to the department at the project's final workshop in Dhaka in November. The sequences will then be submitted to the international database through the government," he said.
Haque noted that DNA sequences of 141 fish species from the Sundarbans had previously been included in GenBank through research conducted by Sher-e-Bangla Agricultural University in collaboration with South Korean researchers and the Forest Department.
As part of the latest study, researchers developed DNA barcodes for 30 fish species and 11 crustacean species. DNA analysis of 83 fish samples identified five fish species and two shrimp species whose sequences had not previously been recorded in international genetic databases.
The five fish species are large-scale mullet (Planiliza macrolepis), keeled mullet (Crenimugil seheli), Burmese halfbeak (Dermogenys burmanica), flathead goby (Butis humeralis), and green-spotted goby (Acentrogobius viridipunctatus). The two shrimp species are spider shrimp (Cloridos scorpio) and spotted shrimp (Nematopalaemon tenuipes).
The study assessed aquatic resources, breeding seasons, and the impacts of climate change across the Sharankhola, Satkhira, Khulna, and Chandpai ranges of the Sundarbans. Among these, Sharankhola recorded the highest species diversity, with 164 species.
The latest survey confirmed the presence of 251 fish species and 51 crustacean species in the surveyed areas. Combined with findings from previous studies, the total number of documented species in the Sundarbans stands at 382 fish species and 88 species of other aquatic animals, including shrimp, crabs, snails, oysters, octopuses, and squid.
Using a combination of morphological identification and molecular analysis based on mitochondrial gene sequencing, researchers examined 83 fish samples and 28 crustacean samples. They developed DNA barcode sequences for 30 fish species and 11 crustacean species, bringing the total to 41 species. The sequences showed between 98.19 percent and 100 percent similarity with reference sequences in international genetic databases.
Researchers warned that excessive fishing and illegal activities, including the use of poison in rivers and canals, were threatening natural fish stocks in several parts of the forest. They also found that unregulated fishing, the capture of juvenile fish, and the use of toxic substances were contributing to alarming declines in commercially important large fish species, including barramundi, croakers, and pangasius.
The report recommends introducing catch limits for selected species and reviewing existing fishing restrictions. It also calls for a complete ban on poisoning waterways and using harmful fishing nets. Researchers have proposed declaring ecologically suitable canals as protected to safeguard breeding grounds and support the replenishment of fish stocks.
The report also emphasizes the need to create alternative livelihood opportunities for communities dependent on forest resources. Haque mentioned that the Sundarbans' aquatic resources could increase substantially if appropriate environmental conditions were maintained and effective conservation measures implemented.
Imran Ahmed, director of the Sundarbans Protection Project and conservator of forests in the Khulna region, stated that the achievement would further highlight the international importance of the Sundarbans. He said immediate, short-term, and long-term plans were being formulated to protect the forest's aquatic resources in line with the study's recommendations.