Satun-Langkawi Archipelago IMMA
Size in Square Kilometres
5 493 km2
Qualifying Species and Criteria
Indo-Pacific finless porpoise – Neophocaena phocaenoides
Criterion A; B (2); C (1, 2)
Indo-Pacific humpback dolphin – Sousa chinensis
Criterion A; B (2); C (1, 2)
Irrawaddy dolphin – Orcaella brevirostris
Criterion A; B (2); C (1, 2)
Marine Mammal Diversity
Dugong dugon, Stenella longirostris, Tursiops aduncus, Balaenoptera edeni
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The Satun-Langkawi Archipelago is an area at the shared Thailand-Malaysia border located in the Straits of Malacca-Andaman Sea interface region. These two separate but adjacent areas are recognized as UNESCO Global Geoparks, having been granted this status in 2018 and 2006 respectively. Both areas boast a diverse range of topography and landscape of significant geological uniqueness and importance dating back to the Palaeozoic Era more than 500 million years ago. The shallow tropical waters of this area are considered important for aggregations of Indo-Pacific finless porpoises, Indo-Pacific humpback dolphins and Irrawaddy dolphins. Boat-based surveys have documented the occurrence of some of the largest known groups of Indo-Pacific humpback dolphins across its global range, with group sizes of more than 200 individuals. Research has also found that the area especially around the Langkawi Archipelago hosts one of the most significant areas of occurrence of Indo-Pacific finless porpoises in the Southeast Asian region.
Description of Qualifying Criteria
Criterion A – Species or Population Vulnerability
Indo-Pacific humpback dolphins (Sousa chinensis) and Indo-Pacific finless porpoises (Neophocaena phocaenoides) are listed as VU on the IUCN Red List of Threatened Species (Jefferson et al. 2017; Wang and Reeves, 2017), while Irrawaddy dolphins (Orcaella brevirostris) are listed as EN (Minton et al. 2017). However, in Malaysia all three species are listed as Marine Endangered Species and protected under the Fisheries Act 1985 and Fisheries (Control of Endangered Species) Regulation (Amendment) 2008. In Thailand, the three species are all protected under the Wild Animal Reservation and Protection Act, B.E. 2535, and are listed as Endangered on the Thailand Red Data 2017. Research by Ponnampalam et al. (2019) showed that finless porpoises around Langkawi are at highest risk of bycatch from trawl nets and gillnets.
Criterion B: Distribution and Abundance
Sub-criterion B2: Aggregations
Indo-Pacific finless porpoises and Indo-Pacific humpback dolphins have overlapping habitat around the Langkawi archipelago however the latter
species’ distribution is primarily along the eastern part of the Langkawi Archipelago and across to the adjacent Perlis-Kedah mainland coast. Both cetacean species have some of the largest recorded groups known for these species – up to 30 and 204 individuals respectively (Ponnampalam and Jamal Hisne, 2011; Ponnampalam et al. 2014; MareCet, unpublished data). In Satun, Thailand, there appears to be two aggregations of coastal cetaceans segregated to the north and south of Satun respectively. The northern aggregation is mainly comprised of Indo-Pacific humpback dolphins that have a wider distribution as compared to Irrawaddy dolphins that are more confined within a limited area closer to the river mouths. The southern aggregation is mainly comprised of a mix of Irrawaddy dolphins, humpback dolphins and Indo-Pacific finless porpoises (Kittiwattanawong, 2015, 2016, 2017). Estimates of humpback dolphins in Satun are reported to be 29-52 individuals (Cherdsukjai and Kittiwattanawong, 2013). Data available from interview surveys and boat-based surveys indicate that the coastal cetaceans occur year-round in Satun, Thailand.
Criterion C: Key Life Cycle Activities
Sub-criterion C1: Reproductive Areas
Systematic research by the Marecet Research Organisation amounting 187 survey days across 22 surveys between 2010 – 2018 (11682 km and 895 h of search effort), in the Langkawi Archipelago and adjacent coastal waters, recorded numerous observations of cetacean sightings with calves and a few observations of sexual behaviour (Ponnampalam and Jamal Hisne, 2011; Ponnampalam et al. 2014; MareCet, unpublished data). A total of 34.6% (n = 120) of finless porpoise sightings (N = 347) in Langkawi were of groups containing calves, while 71.2% (n = 99) of humpback dolphin sightings (N = 139) included calves. Irrawaddy dolphin sightings that contained calves made up 55.6% (n = 10) of the species’ total sightings (N = 18) recorded from the mainland coast of Kuala Perlis-Kuala Kedah (MareCet, unpublished data). These suggest the area to be important for the cetaceans’ calving and nursing. In June 2016, a local Langkawi netizen had encountered a dead pregnant finless porpoise whose near-term foetus was found protruding halfway out of the adult animal’s genital opening. A stranded finless porpoise neonate bearing foetal folds was also observed in the area in May 2018 (MareCet, unpublished data). These records imply the occurrence of calving and mating within this IMMA. Groups of humpback dolphins containing neonates made up 7.1% (n = 10) of the species’ total sightings in Langkawi (N = 139). Additionally, humpback dolphins mating or engaging in sexual behaviour were observed in the area and comprised 9.3% (n = 13) of the species’ total sightings (N = 139) (MareCet, unpublished data).
Sub-criterion C2: Feeding Areas
Research by the MareCet Research Organisation amounting to 187 survey days across 22 surveys between 2010 – 2018 (11682 km and 895 h of search effort) in the Langkawi archipelago and adjacent coastal waters recorded numerous observations of cetaceans preying on various types of prey such as marine catfish, garfish and octopus. Finless porpoises recorded as feeding or engaging in probable feeding behaviour constituted 28.8% (n = 100) of the total species’ sightings in Langkawi and adjacent waters (N = 347). This species has been observed feeding on cephalopods, as evidenced by the presence of squid ink during sightings and cephalopod beaks found in the stomach contents of dead stranded animals (MareCet, unpublished data). Humpback dolphins observed feeding or engaging in probable feeding behaviour constituted 56.8% (n = 79) of the total species’ sightings (N = 139), while 50.0% (n = 9) of the total Irrawaddy dolphin sightings (N = 18) were of feeding or probable feeding groups (Ponnampalam and Jamal Hisne, 2011; Ponnampalam et al. 2014; MareCet, unpublished data).
Bono, S., Kimura, S.S., Teoh, Z., Ng, J.E., Ichikawa, K. and Ponnampalam, L.S. 2022. Whistle variation in Indo-Pacific humpback dolphins (Sousa chinensis) in relation to behavioural and environmental parameters in northwestern Peninsular Malaysia. Acoustics Australia. Available at:
Cherdsukjai, P. and Kittiwattanawong, K. 2013. The population sizes of Indo-Pacific humpback dolphins (Sousa chinensis) around Sukon and Sarai Islands, Thailand estimated using photo-identification technique. Proceedings of the Design Symposium on Conservation of Ecosystem (2013) (The 12th SEASTAR 2000 workshop) (2013): 51-54. Available at: ttps://repository.kulib.kyotou.ac.jp/dspace/bitstream/2433/176190/ 1/12thseastar_051.pdf
Hoffman, J.M., Ponnampalam, L.S., Araújo, C.C., Wang, J.Y., Kuit, S.H. and Hung, S.K. 2015. Comparison of Indo-Pacific humpback dolphin (Sousa chinensis) whistles from two areas of western Peninsular Malaysia. Journal of the Acoustical Society of America 138(5): 2829-2835. DOI: dx.doi.org/10.1121/1.4934254
Jefferson, T. A. and Rosenbaum, H. C. 2014. Taxonomic revision of the humpback dolphins (Sousa spp.), and description of a new species from Australia. Marine Mammal Science, 30(4), 1494–1541. http://doi.org/10.1111/mms.12152
Jefferson, T.A., Smith, B.D., Braulik, G.T. and Perrin, W. 2017. Sousa chinensis. The IUCN Red List of Threatened Species 2017: e.T82031425A50372332. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T82031425A 50372332.en. Downloaded on 14 March 2018.
Kimura, S.S., Sagara, T., Yoda, K. and Ponnampalam, L.S. 2022. Habitat preference of two sympatric coastal cetaceans in Langkawi, Malaysia, as determined by passive acoustic monitoring. Endangered Species Research 48: 199–209. Available at: https://doi.org/10.3354/esr01194
Kittiwattanawong, K. 2015. Annual report on status and change of marine endangered species in Thailand. Department of Marine and Coastal Resources (in Thai). Available online: www.marinegiscenter.dmcr.go.th
Kittiwattanawong, K. 2016. Annual report on status and change of marine endangered species in Thailand. Department of Marine and Coastal Resources (in Thai). Available online: www.marinegiscenter.dmcr.go.th
Kittiwattanawong, K. 2017. Annual report on status and change of marine endangered species in Thailand. Department of Marine and Coastal Resources (in Thai). Available online: www.marinegiscenter.dmcr.go.th
Langkawi Development Authority (LADA). 2017. Tourist Arrival Statistics. https://www.lada.gov.my/en/information/statistics/tourist-arrival-statistics. Downloaded on 23 October 2018.
Minton, G., Smith, B.D., Braulik, G.T., Kreb, D., Sutaria, D. and Reeves, R. 2017. Orcaella brevirostris. The IUCN Red List of Threatened Species 2017: e.T15419A50367860. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T15419A50367860.en. Downloaded on 14 March 2018.
Ponnampalam, L. S. and Jamal Hisne, F. I. 2011. Distribution, ecology, and conservation of cetaceans around the Langkawi Archipelago, with special reference to Indo-Pacific humpback dolphins, Sousa chinensis. Final report submitted to the Ocean Park Conservation Foundation Hong Kong, August 2011. 41 pp.
Ponnampalam, L.S., Kimura, S. and Fairul Izmal, J. H. 2014. The abundance and conservation management of cetaceans in Langkawi, Malaysia, with special references to the Indo-Pacific finless porpoise (Neophocaena phocaenoides) and Indo-Pacific humpback dolphin (Sousa chinensis). Final report of Project No. IPCF 12/2 submitted to the Australian Marine Mammal Centre Grants Program, April 2014. 30 pp.
Ponnampalam, L. S., Verutes, G., Kuit, S. H., Ng, J. E., Teoh, Z. Y. and Fairul Izmal, J. H. 2019. Shining the spotlight on a highly overlooked porpoise within an IUCN Important Marine Mammal Area (IMMA) – Indo-Pacific Finless Porpoises (Neophocaena phocaenoides) in the Langkawi Archipelago, Malaysia, Deserve Conservation Attention. Poster presentation at the World Marine Mammal Conference, Barcelona, Spain. December, 2019.
Teoh, Z. Y. 2018. Humpback dolphin social ecology under anthropogenic threats in Langkawi, Malaysia. Final report (Project No. 03286416) submitted to the Conservation Leadership Program, September 2018. 46 pp. Available at: https://www.conservationleadershipprogramme.org/media/2016/04/CLP-Final-Report_ProjectID-03286416.pdf
Wang, J.Y. and Reeves, R. 2017. Neophocaena phocaenoides. The IUCN Red List of Threatened Species 2017: e.T198920A50386795.http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T198920A50386795.en. Downloaded on 14 March 2018.