Threatened Fish Genetic Resources and Biological Diversity of the Tanguar Haor Wetland in Bangladesh

M. Gulam Hussain

Overall editing and formatting by Kristen Dechert

Photos by M. Gulam Hussain

Tanguar Haor is a unique wetland ecosystem in Bangladesh with national and international importance due to its rich aquatic and terrestrial resources. Haors are floodplain wetland areas typified by many shallow, bowl-shaped habitats. The Tanguar Haor lies in the Tahirpur and Dharmapasha Upazilas of Sunamganj District, Sylhet, Bangladesh. Within the haor, there are 200 beels or ponds of various sizes and 46 villages. The total area of the haor is about 114 km2 of which 2802.36 ha is wetland. Unlike other natural resources, the haor wetland is rich in fisheries resources, with approximately 141 freshwater fish species. Due to gradual alteration of the haor ecosystem habitat and over-exploitation of natural resources, the Government of Bangladesh (GOB) declared Tanguar Haor as an Ecologically Critical Area in 1999. In 2000, the hoar basin was declared a Ramsar Site­—a wetland of international importance (Figure 1). The GOB is committed to preserving these natural resources.          

Fig. 1. A partial view of Tanguar Hoar Wetland
Figure 1. A partial view of the Tanguar Haor wetland in Bangladesh.

 

After the declaration of Tanguar Haor as an Ecologically Critical Area and a Ramsar Site by the GOB, a well--designed co-management system that will conserve ecosystem values and services and provide a basis for the improvement of livelihoods for rural communities was formulated. This long-term project was funded by the Swiss Agency for Development and Cooperation (SDC) as the Community Based Sustainable Management of Tanguar Haor Project (CBSMTHP). The GOB successfully implemented the co-management goals during the functional CBSMTHP project period (2009-2015). After the completion of the CBSMTHP project in 2016, the co-management system was run under the direction of the deputy commissioner, Sunamganj District, with GOB support.

There were no follow-up reports about the effectiveness of the designed co-management practices undertaken by the CBSMTHP project for protecting ecosystem services and values. Therefore, a fisheries survey team was assigned under a GOB-funded project in the Department of Bangladesh Haor and Wetland Development, Ministry of Water Resources, GOB for protecting the haor and other wetland resources. This project was implemented by the Institute of Water Modelling in Bangladesh to provide an overview of the present Tanguar Haor management system and assess the overall fisheries resources and fish biological diversity issues of the haor ecosystem through public consultation and interviews with targeted stakeholders.

Assessment of Fish Genetic Resources and Biological Diversity of the Wetland

The Tanguar Haor is located in the northeastern part of Bangladesh, between 25o12’10.572” and 25o5’47.969” north latitude and 90o58’49.426” and 91o10’0.018” east longitude. The total area of the haor is approximately 114 km2 (Figure 2).         

Figure 2. Map of Tanguar Haor in dry and wet seasons (IWM, 2020).
Figure 2. Map of Tanguar Haor in dry and wet seasons (IWM, 2020).

 

During the summer season, from August 31 through September 6, 2019, the survey and study were conducted at Tahirpur and Dharmapasha Upazilas at the Tanguar Haor wetland. The adjacent villages and fish-landing centers, including Indropur, Benagl Vita, Lama Gaon, Lalabazar, Tahirpur Sadar and Soliamanpur Landing Center at Tahirpur and Rupnagar, Amtorpur and Rongchi villages at Dharmapasha, were visited by the survey team, who consulted with all the targeted groups and stakeholders. Data were collected through focus group discussions (FGDs); direct questionnaire interviews of stakeholders via key informant interviews (KIIs) with Upazila Fishery Officers; personal interviews (PIs) with fishers, people settled around the wetland, and fish traders at landing centers and local markets; and household surveys (HSs) of housewives. During consultation and group interviews for all FGD groups, major topics of discussion were

  • Assessment and quantification of the existing fish resources presently available/not available at harvesting during the summer season and determining the status of fish biological diversity
  • Determination of present fishing practices and types of crafts and gear used during the season
  • Identification of the major reasons of declining catch, fish biodiversity, and degradation of aquatic habitat
  • Assessment of the impact of declining catch and biodiversity on fish traders and consumers
  • Suggested mitigating measures for improvement of catch and fish availability at the landing centers and local markets
  • Suggested mitigating measures for conservation of fish biodiversity, natural breeding grounds, and habitat

During the summer season survey, the major intention was to address all stakeholders involved in all FGDs, PIs, KIIs, household surveys, and fish landing center/local market visits at the Tanguar Haor. The present scenario and status of fish biological diversity and fish genetic resources were assessed through stakeholder consultations and discussions. It was determined that there were only 67 species captured by local fishermen during the summer season; among those numbers, 11 fish (16%) were Commonly Available Species (CAS), 14 fish (21%) were Moderately Available Species (MAS), 22 fish (33%) were Less Available Species (LAS) and 20 fish (30%) were Rarely Available Species (RAS). Both LAS and RAS can be categorized as vulnerable species: those at risk of becoming endangered within a few years. The report of the fisher groups revealed that a total of eight other fish species have not recently been found in catches. A similar opinion was given by all other stakeholders interviewed. Among this list, one or two species have already become extinct, and other species were either endangered or critically endangered. From the data collected from the summer season study on fisheries resources and fish biodiversity, it was estimated that during that season only 47.5% of fish (67 species) are available among the 141 species known to have inhabited Tanguar Haor, indicating 52.5% loss of species.

A comparative availability of fish species during the summer season at the Tangaur Haor wetland is shown in Figure 3.                    

Figure 3. Comparative fish species availability during the summer season at the Tanguar Haor wetland.
Figure 3. Comparative fish species availability during the summer season at the Tanguar Haor wetland.

 

The Tanguar Haor is one of the largest wetland ecosystems in the country, and it was once very rich in fisheries resources and fish biodiversity. The overall fisheries of the Haor wetland have significant importance to support natural fish production, the national economy, and livelihoods of surrounding people. In terms of fish species diversity, the Haor wetland has been described as one of six principal “Mother Stocks” in Bangladesh, facilitating nursery grounds for fish species and supporting surrounding fish populations (Alam et al., 2015). According to Doz (1997), Nuruzzaman (1997), and Khan (1997), Tanguar Haor supports approximately 141 fish species, representing nearly half of the 260 freshwater fish species of Bangladesh. Tanguar Haor also contains a large number of nationally threatened and endemic fish species. Among 55 threatened fish taxa, 23 of which are endangered fish species, 17 were found only in Tanguar Haor (Alam et al., 2015). Presently, fisheries resources and species diversity have become depleted due to degradation of wetland habitat, degradation of natural fish breeding grounds, and illegal harvest of fish by unsustainable fishing practices using various banned gears. These factors have contributed to the reduction of fish populations, leading to loss of genetic diversity or genetic erosion and threatening the continued survival of indigenous fish species (GOB, 2004).

Based on the summer season survey, it was revealed that although harvest of gravid fish during breeding season and undersized young wild fish catch has been banned, a large number of fishers continue to use illegal fishing harvest gears in the Tanguar Haor wetland across seasons. Banned gears include seine nets, monofilament gill nets (Figure 4), hook and line fishing, and some configurations of bamboo fishing traps and gears (Figure 5), all of which are extremely harmful for gravid indigenous species (Figure 6 and Figure 7) available at the Haor waterbodies.

Figure 4. Banned monofilament gill nets were being used to harvest gravid indigenous fish species throughout the Tanguar Haor wetland.
Figure 4. Banned monofilament gill nets were being used to harvest gravid indigenous fish species throughout the Tanguar Haor wetland.

      

Figure 5. Harmful bamboo made traps were being used to harvest large numbers of small prawns and indigenous small and medium sized fish species at the Tanguar Haor wetland.
Figure 5. Harmful bamboo made traps were being used to harvest large numbers of small prawns and indigenous small and medium sized fish species at the Tanguar Haor wetland.

  

Figure 6. Banned hook and line fishing were being used to harvest the gravid indigenous small and medium sized fish species including needlefish species from the Tanguar haor wetland.
Figure 6. Banned hook and line fishing were being used to harvest the gravid indigenous small and medium sized fish species including needlefish species from the Tanguar haor wetland.

 

Figure 7. Banned hook and line fishing as well as monofilament nets were being used to harvest the gravid indigenous small and medium fish species, including leaf fish species from the Tanguar Haor wetland.
Figure 7. Banned hook and line fishing as well as monofilament nets were being used to harvest the gravid indigenous small and medium fish species, including leaf fish species from the Tanguar Haor wetland.

 

Mitigation Measures for Fish Genetic Resources and Biological Diversity Conservation

From the present study, in assessing all the stakeholder’s consultations and discussions, it was clear that Best Wetland Management Practices (BWMPs) and an improved Management Framework should be formulated and implemented earlier at Tanguar Haor wetland by the GOB. After completion of donor-funded project periods, there were some lapses and gaps observed. Afterwards, although the overall co-management efforts were guided and supervised by local administration in that region, in many cases, there was a severe lack of implementation. Government fishing rules and regulations were not enforced, resulting in continued use of illegal and banned fishing nets and leading to depletion of indigenous fish populations. Therefore, it is strongly recommended by all the interviewed stakeholders that the integrated BWMPs should be continued, enhanced, and re-adopted by the GOB and concerned departments and ministries through a coordinated effort to restore the threatened natural ecosystem habitat and conserve fish biological diversity in the wetland. From this study, it is revealed that BWMPs are the only solution to protecting the wetland ecosystem from measurable destruction and declining of biological diversity related to valuable fisheries and other aquatic resources at Tanguar Haor wetland.

References

Alam, A.B.M.S., Badhon, M.K. and Sarker, M.W. (2015). Biodiversity of Tanguar Haor: A Ramsar Site of Bangladesh. Volume III: Fish. IUCN, International Union for Conservation of Nature, Bangladesh Country Office, Dhaka, Bangladesh. 216 p.

DOZ (1997). Survey of Fauna. Draft Final Report, Vol. 1 (Narikal Jinjira and Tanguar Haor), Department of Zoology, University of Dhaka, Ministry of Environment and Forests, GOB, National Conservation Strategy Implementation Project-1. Dhaka pp: 85 – 95.

GoB (2004). Ministry of Environment and Forests. Tanguar Haor Wetland Biodiversity Conservation Project.

IWM (2020). Study on Interaction between Haor and River Ecosystem including Development of Wetland Inventory and Sustainable Wetland Management Framework. Draft Final Report: Volume III, Appendix-F.

Khan, A. (1997). Consultancy Report on Land Tenure and Land Management of Tanguar Haor. Draft Final Report. Ministry of Environment and Forests, GOB, National Conservation Strategy Implementation Project-1, Dhaka, December 1997. Part one. 82 p; Part two. 80 p.

Nuruzzaman, A.K.M. (1997). The Sustainable Management of Fisheries Resources at Tanguar Haor (Draft Final Report). Towards Sustainable Development: National Conservation Strategy of Bangladesh. National Conservation Strategy Project – 1. Ministry of Environment and Forests, Dhaka, Bangladesh.

M. Gulam Hussain is the Asia Regional Coordinator at the Feed the Innovation Lab for Fish and the former Director General at Bangladesh Fisheries Research Institute (BFRI).

 

Acknowledgements

This study was conducted under the GOB-funded project entitled “Study on Interaction between Haor and River Ecosystem including Development of Wetland Inventory and Sustainable Wetland Management Framework” of the Department of Bangladesh Haor and Wetland Development, Ministry of Water Resources, which was implemented by the Institute of Water Modelling (IWM) during 2018-2020. The authors would like to express their gratitude and thanks to all the authorities concerned in those departments and institutes. The author also acknowledges the assistance of Peter Allen, productivity frontier specialist at the Fish Innovation Lab, for critically reviewing the manuscript of this blog article.