Gulf of Mannar and Palk Bay IMMA

Size in Square Kilometres

20 663 km2

Qualifying Species and Criteria

Dugong – Dugong dugon

Criterion A; B (1); C (2)

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The Gulf of Mannar and Palk Bay form a transboundary area within the waters off India and Sri Lanka. A remnant but still breeding population of dugongs (Dugong dugon) is found in this area, and large seagrass meadows occur within the IMMA. Historically the region harbored a much larger population of dugongs but popuation size is now very small and it is likely to be vulnerable to declines. Fishery entanglements and historical hunting pressure for consumption have greatly diminished this population and it may be facing local extirpation. Interview surveys, seagrass bed surveys and boat-based surveys have been used to monitor this population. Both India and Sri Lanka have taken up dugong species recovery programs in their respective areas, and the highest level of legal protection is offered to dugongs in the waters of both countries.

Description of Qualifying Criteria

Criterion A – Species or Population Vulnerability

The dugong is listed as Vulnerable in the IUCN Red List and its conservation status in South Asia is critical with no more than 300 individuals left. As a result the population in the Gulf of Mannar and Palk Bay is very important for the long-term survival of dugongs in South Asia (Marsh et al. 2002; Pandey et al. 2010; Sivakumar and Nair, 2013; Balaji, 2017). Although both the Government of India and the Government of Sri Lanka have legally protected dugongs, they still face multiple threats throughout this region and the IMMA.

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations

The Gulf of Mannar and Palk Bay region holds a very small, resident and isolated population of dugongs, the population brought down to its present size mainly from hunting pressure in both countries. Population size is unknown but sightings are very rare. It is the only population along the east coast of India, and the only population throughout Sri Lanka’s waters. The loss of this population could make the species extinct from the east coast of India and from Sri Lanka.The dugong population here is likely to be resident year-round, solitary individuals make up  60% of the observations reported,  and pregnant females have also been reported. A total of 409 interviews were carried out in the Gulf of Mannar and Palk Bay (Sivakumar and Nair, 2013), of which 70% of respondents sighted dugongs in the Gulf of Mannar and 57% of respondents in Palk Bay. A total of 262 (158 in Gulf of Mannar and 104 in Palk Bay) encounters were reported. Of these 29% and 16% were of mother-calf pairs in the Gulf of Mannar and Palk Bay respectively (Sivakumar and Nair, 2013), and dugong calves have been reported as stranded in this region (

Criterion C: Key Life Cycle Activities

Sub-criterion C2: Feeding Areas

The Gulf of Mannar and Palk Bay support dense seagrass meadows, mainly along nearshore coastal waters (Balaji, 2017). Around the islands in the Gulf of Mannar the seagrass beds extend approximately 2-3 km from the coastline towards the open sea. Dugong grazing trails have been observed in Palk Bay with seagrass patches extending to a depth of 18 m (Balaji, 2017).

Supporting Information

Alling, A. 1986. Records of odontocetes in the northern Indian Ocean (1981–1982) and off the coast of Sri Lanka (1982–1984). Journal of Bombay Natural History Society 83(2): 376–94.

Balaji, V. 2017. Acoustic survey of seagrass beds in northern Palk Bay, India
Indian Journal of Geo Marine Sciences. 47 (08), 1607-1615

Choudhury, B.C. & K. Sivakumar, 2009. Management Plan of Gulf of Mannar Marine National Park (2008-2016). Tamil Nadu Forest Department and Wildlife Institute of India, Dehradun, India.

Dayaratne, P. and Joseph, L. 1993. A study of dolphin catches in Sri Lanka. Bay of Bengal Programme, Madras BOBP/REP/56: 47pp

D’Souza, N., Edward, J.K.P., Ishwar, N.M. 2013. Study and assessment of seagrass beds in the Gulf of Mannar and Palk Bay to support strategy to conserve and manage seagrass habitats. SDMRI report. Tuticorin, Tamil Nadu, India. 1-29pp.

Ilangakoon, A. 1997. Species composition seasonal variation, sex ratio andbody length of small cetaceans caught off west, south-west and southcoast of Sri Lanka. J. Bombay Nat. Hist. Soc. 94: 298–306.

Ilangakoon, A. D. 2006a. Cetacean occurrence and distribution around the Bar Reef Marine Sanctuary, North-west Sri Lanka, Journal of the National Science Foundation of Sri Lanka, 34(3): 149-154.

Ilangakoon, A. D. 2006b. Preliminary analysis of large whale strandings in Sri Lanka 1889-2004, Pakistan Journal of Oceanography, 2(2): 61-68.

Ilangakoon, A. 2007. A developing country perspective of cetacean bycatch monitoring and mitigation. pp.80–83. In: Kizka, J. and Muier, C.(eds). Incidental Catch of Non-Targeted Marine Species in the Western Indian Ocean: problems and Mitigation Measures. Workshop Proceedings, 13–15 November 2006, Mayotte. 111pp.

Ilangakoon, A. D. 2008. Cetacean species richness and relative abundance around the Bar Reef Marine Sanctuary, Sri Lanka. Journal of the Bombay Natural History Society, 105(3):274-278

Ilangakoon, A.D., Sutaria, D., Hines, E. and Raghavan, R. 2008. Community interviews on the status of the dugong (Dugong dugon) in the Gulf of Mannar (India and Sri Lanka). Marine Mammal Science, 24(3):704–710

Ilangakoon, A. D. 2011. Survival prospects and conservation needs of the dugong in Sri Lanka. In Arai, N. (Ed) Proceedings of the 6th International Symposium on SEASTAR2000 and Asian Biologging Science, 23-25 February 2010, Phuket, Thailand. 51pp.

James, P.S.B.R. and Mohan, R.S.L. 1987. The marine mammals of India. Marine Fisheries Information Services, Technical and Extension Series, CMFRI 71:1–13

Leatherwood, S. and Reeves, R.R. 1989. Marine mammal research and conservation in Sri Lanka 1985–1986. UNEP Marine Mammal Technical Report. 1: [vi],1–138.

Marsh, H. 1989. The status of the dugong in Palk Bay Gulf of Mannar Region: recommendations for management, education and research. Report to the Bombay Natural History Society, May 1989. 30pp.

Marsh, H., Penrose, H., Eros, C. and Hugues, J. 2002. Dugong Status Report and Action Plan for Countries and Territories. UNEP/DEWA/RS.02-1

Norris, C. E. 1960. The dugong. Loris, 8(5): 296-300.

Phillips, W. W. A. 1927). Guide to the Mammals of Ceylon, part VII. Sirenia (the dugong). Spolia Zeylanica 14(1): 51-55.

Pandey, C.N., Tatu,  K.S. and Anand. Y.A. 2010. Status of dugong (Dugong dugon) in India. Gujarat Ecological Education and Research (GEER) Foundation, Gandhinagar. 146 pp.

Sathasivam, K. 2000. A catalogue of Indian marine mammal records. Blackbuck 16(2 and 3): 23–74.

Sathasivam, K. 2004. Marine Mammals of India. Universities Press, Hyderabad, India.

Silas, E.G, Fernando, A.B. 1985. Dugong in India: Is it going the way of the dodo? In: Proceedings of the Symposium on Endangered Marine Animals and Marine Parks pp. 167-176.

Sivakumar, K. and Nair, A. 2013. Dugong Distribution, Habitat and Risks Due to Fisheries and Other Anthropogenic Activities in India. Wildlife Institute of India – Technical Report. 74 pp.

Sivakumar, K., 2013. Status and conservation of Dugong dugong in India: Strategies for species recovery. In Venkataraman, K. Sivaperuman, C. and Raghunathan, C. (ed.) Ecology and conservation of tropical marine faunal communities. Springer, pp.553, Kolkota.

Sutaria, D., Panicker, D., Jog, K., Sule, M., Muralidharan, R. and Bopardikar, I. 2015. Humpback Dolphins (Genus Sousa) in India: An Overview of Status and Conservation Issues. In ‘Conservation status of Humpback Dolphins (Sousa spp.). T.A.Jefferson and B.E.Curry (Ed.) Advances in Marine Biology Series. Vol. 72. Elsevier/Academic Press.

Sutaria, D., Sule, M., Jog, I., Bopardikar, I., Jamalabad, A., and Panicker, D. 2017. Baleen whale records from India. Primary paper SC/67A/CMP/03. International Whaling Commission, Slovenia

Thangaradjou, T. and Kannan, L., 2007. Nutrient characteristics and sediment texture of the seagrass beds of the Gulf of Mannar. Journal of Environmental Biology 28(1), 29-33.

Whitehead, H. 1985. Humpback whale songs from the North Indian Ocean. Invest. Cetacea 17: 157–62


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