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 (www.marinemammals.in).
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).
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