Ecological impacts on the distribution of Ganges River dolphin (Platanista gangetica) in the lower Gangetic plains and its conservation challenges
Abstract
Despite threatened status, the Ganges River dolphin (Platanista gangetica) received insufficient attention in many habitats including the lower Ganges. In this study, through standardised monitoring programmes, we recorded the population and distribution of the species from a 100-km long stretch of the lower Ganges between January and December 2023. Important ecological parameters (e.g. fish abundance and water quality parameters) were also monitored to understand their effects on dolphin population in the river. Number of Ganges River dolphin varied over time (ANOVA: F11,88 = 10.9, p < 0.001) and space (F8,88 = 24.1, p < 0.001). Maximum number of dolphin was sighted in the month of August; whereas, the minimum was in February. Population of Ganges River dolphin was affected positively by fish abundance (LMM: F = 19.7, p < 0.001) and water transparency (F = 4.4, p = 0.042) and negatively by total dissolved solids (TDS; LMM: F = 13.5, p = 0.001). A range of challenges related to fishermen’s knowledge and attitude towards the Ganges River dolphin were identified. These include lack of awareness, high market demand and price for the species and negative attitude towards the species. Illegally harvested Vulnerable dolphins were sold only to produce dolphin oil to catch another Endangered fish species Clupisoma garua. The results of this study have conservation management applications and implications.
References
Alam SMI, Hossain MM, Baki MA, Bhouiyan NA (2015) Status of Ganges dolphin, Platanista gangetica gangetica (Roxburgh, 1801) in the river Buriganga, Dhaka. Bangladesh Journal of Zoology 43(1): 109–120.
Alam SMI, Sarker NJ (2012) Status and distribution of the Gangetic dolphin, Platanista gangetica gangetica (Roxburgh, 1801) in river Buriganga during 2003-2004 and its conservation. Bangladesh Journal of Zoology 40(1): 21–31.
Arthington AH, Dulvy NK, Gladstone W, Winfield IJ (2016) Fish conservation in freshwater and marine realms: status, threats and management. Aquatic Conservations: Marine and Freshwater Ecosystems 26: 838–857.
Aziz MA, Khan MMH, Ahsan MM, Chowdhury MRK, Faisal AM (2023) Identification of key habitats and conservation threats of the Ganges river dolphin (Platanista gangetica) of Bangladesh. Bangladesh Journal of Zoology 51(3): 253–266.
Baki MA, Bhouiyan NA, Islam MS, Alam SMI, Shil S, Hossain MM (2017) Present status of Ganges River dolphins Platanista gangetica gangetica (Roxburgh, 1801) in the Turag River, Dhaka, Bangladesh. International Journal of Zoology 2017: 1–7.
Bates D, Mächler M, Bolker B, Walker S (2015) Fitting Linear Mixed-Effects Models using lme4. Journal of Statistical Software 67(1): 1–48.
Choudhury NB, Mazumder MK, Chakravarty H, Choudhury AS, Boro F, Choudhury IB (2019) The endangered Ganges river dolphin heads towards local extinction in the Barak river system of Assam, India: a plea for conservation. Mammalian Biology 95: 102–111.
Dudgeon D, Arthington AH, Gessner MO, Kawabata Z-II, Knowler DJ, ... Sullivan CA (2006) Freshwater biodiversity: importance, threats, status and conservation challenges. Biological Reviews 81: 163.
Galib SM, Lucas MC, Chaki N, Fahad FH, Mohsin ABM (2018) Is current floodplain management a cause for concern for fish and bird conservation in Bangladesh’s largest wetland? Aquatic Conservation: Marine and Freshwater Ecosystems 28(1): 98–114.
Galib SM, Naher S, Arnob SS, Khatun MT, Reza MS, ... Lucas MC (2023) Stakeholders' knowledge of threatened freshwater fishes and their involvement in fishery value chains in order to assist conservation in developing countries. Frontiers in Freshwater Science 1: 1239605.
Hammond PS (2009) Mark-recapture (pp. 705–709). In: Perrin WF, Wursig B, Thewissen JGM (Eds) Encyclopedia of marine mammals, 2nd edition. Academic Press, San Diego, CA.
IUCN Bangladesh (2015) Red list of Bangladesh: a brief on assessment result 2015. International Union for Conservation of Nature, Bangladesh Country Office, Dhaka, Bangladesh, Bangladesh.
Kelkar N, Dey S (2024) A new method to detect illegal oil use and estimate mortality rates of endangered Ganges river dolphins based on Clupisoma fish catches. Journal of Cetacean Research and Management 25: 49–69.
Kelkar N, Krishnaswamy J, Choudhary S, Sutaria D (2010) Coexistence of fisheries with river dolphin conservation. Conservation Biology 24: 1130–1140.
Kelkar N, Smith BD, Alom MZ, Dey S, Paudel S, Braulik GT (2022) Platanista gangetica. The IUCN Red List of Threatened Species 2022: e.T41756A50383346.
Khan MAG, Galib SM, Hasnath M, Mia MR, Kibria R (2022) Exotic fish and decreasing habitats vis-à-vis conservation of freshwater fish biodiversity of Bangladesh. Journal of Fisheries 10(1): 101301.
Kibria MM, Siam MAH, Owaresat JK, Khan AR, Asek AA, Nahian SMA (2023) Current status of Ganges river dolphin (Platanista gangetica) in Halda River, Chittagong, Bangladesh. Asian Journal of Conservation Biology 12(1): 27–34.
Kuznetsova A, Brockhoff PB, Christensen RHB (2016) lmerTest: tests in Linear Mixed Effects Models. R Package version 2.0-33. URL https://cran.r520project.org/package=lmerTest
McDonald JH (2014) Handbook of biological statistics, 3rd edition. Sparky House Publishing, Maryland.
Parvez MT, Lucas MC, Hossain MI, Chaki N, Mohsin ABM, ... Galib SM (2023b) Invasive vermiculated sailfin catfish (Pterygoplichthys disjunctivus) has an impact on highly valued native fish species. Biological Invasions 25: 1795–1809.
Parvez MT, Mohsin ABM, Arnob SS, Lucas MC, Chaki N, ... Galib SM (2023a) Fish diversity decline in the lower Gangetic plains: a victim of multiple stressors. Biodiversity and Conservation 32: 341–362.
Paudel S, Koprowski JL (2020) Factors affecting the persistence of endangered Ganges River dolphins (Platanista gangetica gangetica). Ecology and Evolution 10: 3138–3148.
Paudel S, Pal P, Cove M, Jnawali S, Abel G, ... Ranabhat R (2015) The Endangered Ganges River dolphin Platanista gangetica gangetica in Nepal: abundance, habitat and conservation threats. Endangered Species Research 29: 59–68.
R Core Team (2022) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL https://www.r-project.org/
Rahman MS, Sarker SU, Jaman MF (2012) Ecological status of the herpeto-mammalian fauna of the Padma River and its adjacent areas, Rajshahi and their conservation issues. Bangladesh Journal of Zoology 40(1): 135–145.
Rashid SMA, Akonda AW, Ahmed B (2015) Ganges river dolphin (Platanista gangetica gangetica) in the Padma, Jamuna and Hurasagar-Baral rivers of Pabna district, Bangladesh. International Journal of Current Science 14: 107–124.
Reeves RR, Leatherwood S (1994) Dolphins, porpoises, and whales: 1994–1998. Action plan for the conservation of cetaceans. IUCN Species Survival Commission. IUCN, Gland, Switzerland. 92 pp.
Sarkar UK, Bakshi S, Lianthuamluaia L, Mishal P, Das Ghosh B, Saha S, Karnatak G (2020) Understanding enviro-climatological impact on fish biodiversity of the tropical floodplain wetlands for their sustainable management. Sustainable Water Resources Management 6: 96.
Shostell JM, Ruiz-García MR (2010) An introduction to river dolphin species (pp. 1 − 28). In: Ruiz-García M, Shostell JM (Eds) Biology, evolution and conservation of river dolphins within South America and Asia. NOVA Science Publishers Inc., New York.
Singh S, Singh A, Dutta S, Srivastava S (2023) Rescuing Ganges river dolphins (Platanista gangetica) from irrigation canals in Uttar Pradesh, North India, 2013-2020. Journal of Cetacean Research and Management 24: 175–188.
Sinha RK, Kannan K (2014) Ganges River dolphin: an overview of biology, ecology, and conservation status in India. AMBIO 43: 1029–1046
Sinha RK, Verma SK, Singh L (2010) Population status and conservation of the Ganges River dolphin (Platanista gangetica gangetica) in the Indian subcontinent (pp. 419 – 444). In: Ruiz-García M, Shostell JM (Eds) Biology, evolution and conservation of river dolphins within South America and Asia. Nova Science Publishers Inc., New York.
Smith BD, Ahmed B, Ali ME, Braulik G (2001) Status of the Ganges river dolphin or shushuk Platanista gangetica in Kaptai Lake and the southern rivers of Bangladesh. Oryx 35(1): 61–72.
Smith BD, Haque AKMA, Hossain MS, Khan A (1998) River dolphins in Bangladesh conservation and the effects of water development. Environmental Management 22(3): 323–335.
Smith BD, Reeves RR (2000) Report of the second meeting of the Asian River Dolphin Committee, Rajendrapur, Bangladesh, 22–24 February 1997 (pp. 1–14). In: Reeves RR, Smith BD, Kasuya T (Eds) Biology and conservation of freshwater cetaceans in Asia. Occasional Paper of the IUCN Species Survival Commission, Volume 23. IUCN, Gland, Switzerland.
Sonkar GK, Gaurav K (2020) Assessing the impact of large barrages on habitat of the Ganga River dolphin. River Research and Applications 36(9): 1916–1931.
Strayer DL, Dudgeon D (2010) Freshwater biodiversity conservation: Recent progress and future challenges. Journal of the North American Benthological Society 29(1): 344–358.
Suski CD, Cooke SJ (2007) Conservation of aquatic resources through the use of freshwater protected areas: opportunities and challenges. Biodiversity and Conservation 16(7): 2015–2029.
Vörösmarty CJ, McIntyre PB, Gessner MO, Dudgeon D, Prusevich A, ... Davies PM (2010) Global threats to human water security and river biodiversity. Nature 467: 555–561.
Weber-Scannell PK, Duffy LK (2007) Effects of total dissolved solids on aquatic organisms: a review of literature and recommendation for salmonid species. American Journal of Environmental Sciences 3(1): 1–6.
![](https://journal.bdfish.org/public/journals/1/article_718_cover_en_US.jpg)
Copyright (c) 2024 The Author(s)
![Creative Commons License](http://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png)
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.