Bintuni Bay, West Papua IMMA

Size in Square Kilometres

5 558 km2

Qualifying Species and Criteria

Australian Humpback Dolphin – Sousa sahulensis

Criterion A; C (2)

Marine Mammal Diversity 

Stenella longirostris, Tursiops aduncus, Tursiops truncatus, Balaenoptera edeni

Summary

Bintuni Bay is located in south-western West Papua, Indonesia. The bay has extensive river and mangrove habitats and is one of the largest contiguous mangrove forests in the world (~450,000 ha). The species of high conservation significance within the Bay is the ‘Vulnerable’ Australian humpback dolphin, Sousa sahulensis.  Bintuni Bay represents one of only three known locations in West Papua where Australian humpback dolphins have been confirmed; the other two locations being Mayalibit Bay and the Kaimana Region. Australian humpback dolphins have not been recorded from any other area within the North East Indian Ocean and South East Asian Seas region. At least four other marine mammals have been confirmed to occur in Bintuni Bay, with more species (i.e. Australian snubfin dolphin, Orcaella heinsohni) likely to be recorded with future dedicated survey effort

Description of Qualifying Criteria

Criterion A – Species or Population Vulnerability

The Australian humpback dolphin is listed as ‘Vulnerable’ by the IUCN and considered to be potentially declining throughout much of its range (Parra et al. 2017). The major threats are considered to be habitat loss and degradation, by-catch in fisheries, water pollution, underwater noise, floods and cumulative threats (Parra et al. 2017). West Papua represents the northwest extent of the species known distribution, with Australian humpback dolphins confirmed to occur in three locations in West Papua: Mayalibit Bay, Bintuni Bay and Kaimana Region. These regions comprise extensive mangrove, estuarine and coastal habitat particularly important for their survival. Bintuni Bay is notably important, as it represents one of the largest contiguous mangrove forests in the world. These habitats are subsequently important for the survival of Australian humpback dolphins in the region.

There are no known population or residency estimates for Australian humpback dolphins in Bintuni Bay. However, based on other known populations in northern Australia and southern Papua New Guinea, it is likely that the Australian humpback dolphin population in Bintuni Bay is relatively small and resident (Parra et al. 2018, Beasley et al. 2013, 2015). Bintuni Bay is one of only three regions in West Papua where humpback dolphins have been sighted, with no other Australian humpback dolphin sightings known for the region. As a result of the habitat characteristics of Bintuni Bay, it is proposed that aggregations of Australian humpback dolphins occur in the Bay, representing an important concentration for this species.

Criterion C: Key Life Cycle Activities

Sub-criterion C2: Feeding Areas

Bintuni Bay is a notably important feeding area, as it represents one of the largest contiguous mangrove forests in the world. As a result of this rich biodiversity and productivity, the region provides an important nutritional base on which many terrestrial and marine fauna species depend, particularly Australian humpback dolphins and other coastal dolphin species.

The known habitat preferences of Australian humpback dolphins are shallow and protected coastal habitats such as inlets, estuaries, shallow bays, inshore reefs and coastal archipelagos rather than in open stretches of coastline. In Queensland and Northern Territory, Australian humpback dolphins are mainly found in water less than 20 km from the nearest river mouth and in water less than 15-20 m deep (Parra et al. 2004, 2017). Few animals have been observed in waters up to 30-50 m deep but remained in close proximity (within 5 km) to the coast (Parra et al. 2004, 2017). In both Queensland and Northern Territory, Australian humpback dolphins have been also recorded as far as 20-50 km upstream in large rivers such as the East Alligator River, Northern Territory, and in the Fitzroy and Brisbane rivers in Queensland (Cagnazzi, 2010, Palmer et al. 2014, Parra et al. 2004). In Southern Papua New Guinea, Australian humpback dolphins were only found adjacent to delta/coastal mangroves, and no further than 2km from the coast (Beasley et al. 2013, 2015). Bintuni Bay therefore represents ideal habitat to support biological productivity and concentration of prey aggregations for marine mammals.

Supporting Information

Beasley, I. Golding, M. and Anamiato, J. 2013. Looking for Pidu (Dolphins and Dugongs) in the Kikori Delta of Papua New Guinea – 2013 Surveys. Unpublished report submitted to James Cook University.

Beasley, I. Golding, M. and Anamiato, J. 2015. Looking for Pidu (Dolphins and Dugongs) in the Kikori Delta of Papua New Guinea – 2015 Surveys. Unpublished report to James Cook University.

Beasley, I., Jedensj, M., Wijaya, G.M., Anamiato, J. Kahn, B. and Kreb, D. Observations on Australian Humpback Dolphins (Sousa sahulensis) in Waters of the Pacific Islands and New Guinea. In: Thomas A. Jefferson and Barbara E. Curry, editors, Advances in Marine Biology, Vol. 73, Oxford: Academic Press, 2016, pp. 219-271.

Cagnazzi, D. 2010. Conservation Status of Australian snubfin dolphin, Orcaella heinsohni, and Indo-Pacific humpback dolphin, Sousa chinensis, in the Capricorn Coast, Central Queensland, Australia. PhD Thesis, Southern Cross University.

Kahn, B. 2006. Bintuni-Berau Bay rapid ecological assessment (REA): Marine mammals and marine reptiles. Unpublished technical report APEX Environment

Palmer, C., Parra, G.J., Rogers, T. and Woinarski, J. 2014b. Collation and review of sightings and distribution of three coastal dolphin species in waters of the Northern Territory, Australia. Pacific Conservation Biology 20: 116-125.

Parra, G., Cagnazzi, D., Perrin, W. and Braulik, G.T. 2017. Sousa sahulensis. The IUCN Red List of Threatened Species 2017: e.T82031667A82031671. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T82031667A82031671.en. Downloaded on 01 November 2018.

Parra, G.J., Cagnazzi, D., Jedensjö, M., Ackermann, C., Frere, C., Seddon, J., Nikolic, N. and Krützen, M., 2018. Low genetic diversity, limited gene flow and widespread genetic bottleneck effects in a threatened dolphin species, the Australian humpback dolphin. Biological Conservation, 220, pp.192-200.

Parra, G.J., Corkeron, P.J. and Marsh, H. 2004. The Indo-pacific humpback dolphin, Sousa chinensis (Osbeck 1765) in Australian waters: a summary of current knowledge. Aquatic Mammals 30(1)

Rudolph, P., Smeenk, C and Leatherwood, S. Preliminary checklist of Cetacea in the Indonesian Archipelago and adjacent waters. Zool. Verh. Leiden 312, 30.xii.1997: 1-48.

Ruitenbeek, J. 1995. Evaluating Bintuni Bay: Some practical lessons in applied resource valuation. Economy and Environment Program for Southeast Asia Special Paper.

Sahri, A., Putra, M.I.H., Mustika, P.L.K., Kreb, D. and Murk, T. In Submission. Cetacean habitat suitability modelling in Indonesia: An effort to provide their more detailed distributions for conservation.

Sihite, J., Lense, O.N., Suratri, R., Gustiar, C. and Kosamah, E. 2005. Bintuni Bay nature reserve management plan, Irian Jaya Barat Province, 2006 – 2030. The Nature Conservancy Coral Triangle Centre. 252pp.

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