Size in Square Kilometres
19,470
Qualifying Species and Criteria
Irrawaddy dolphin – Orcaella brevirostris
Criterion A; B (1); C (1)
Sperm whale – Physeter macrocephalus
Criterion A; C (2)
Indo-Pacific humpback dolphin – Sousa chinensis
Criterion A; C (1, 2)
Criterion D (2) – Marine Mammal Diversity
Balaenoptera omurai, Balaenoptera physalus, Delphinus delphis, Dugong dugon, Feresa attenuata, Globicephala macrorhynchus, Grampus griseus, Kogia sima, Kogia breviceps, Lagenodelphis hosei, Megaptera novaeangliae, Neophocaena phocaenoides,Orcaella brevirostris, Orcinus orca, Peponocephala electra, Physeter macrocephalus, Pseudorca crassidens, Sousa chinensis, Stenella attenuata, Stenella coeruleoalba, Stenella longirostris, Steno bredanensis, Tursiops aduncus, Tursiops truncatus, Ziphius cavirostris
Other Marine Mammal Species Documented
Summary
The area has a high importance for at least 25 identified cetacean species (70% of all cetacean species present in Indonesia) and one Sirenian species. The area covers two districts, i.e. Berau and East Kutai of which the first is a Protected Marine Park. The areas encompass both estuaries and bay areas that provide habitat to two species including the Irrawaddy dolphin (Orcaella brevirostris) and the Indo-Pacific humpback dolphin (Sousa chinensis). Irrawaddy dolphins are known to be present year-round in the IMMA. Surveys conducted between 2003, 2007-2008 and 2013-2017 showed that most species are sighted near islands and reefs. Sperm whales (Physeter macrocephalus) have been observed feeding at different locations throughout the IMMA range during all survey periods (March-August, October, except for December). Omura’s (Balaenoptera omurai) and fin whales (Balaenoptera physalus) were observed feeding in nearshore narrow shelf habitat with steep slope in months March-June, the former species over different years.
Description of Qualifying Criteria
Criterion A – Species or Population Vulnerability
Irrawaddy dolphins (Orcaella brevirostris) are listed as Endangered on the IUCN Red List (Minton et al. 2017). Sperm whales (Physeter macrocephalus), fin whales (Balaenoptera physalus) and Indo-Pacific humpback dolphins (Sousa chinensis) are both listed as Vulnerable on the IUCN Red List (Jefferson et al. 2017; Cooke, 2018; Whitehead et al. 2025).
Criterion B – Distribution and Abundance
Sub-criterion B1 – Small and Resident Populations
Irrawaddy dolphin populations that locally occur in the region are small and occupy small areas in relation to the species’ global population. They occupy specific niche habitats within the IMMA such as estuaries and bays where they are observed throughout the years of study. They have never been observed in coastal habitat outside of these estuarine or bay habitats and therefore it is suspected that these form discrete populations. The two areas where they have been observed in the IMMA is in the Berau Delta and Sangkulirang Bay. These locations are separated by the Tanjung Mangkalihat Peninsula, which has a very narrow shelf with a steep bathymetric drop off to 1km, and Irrawaddy dolphins here but also in other parts of Kalimantan and Indonesia have never been observed in waters deeper than 100m.
Sub-criterion B2 – Aggregations
Criterion C: Key Life Cycle Activities
Sub-criterion C1 – Reproductive Areas
Criterion C1 applies as the locally occurring Irrawaddy population only occupies the bays and estuaries within the IMMA, where they occur year-round with young calves having been observed within groups (as well as mating behaviour) (Kreb, 2008). Calves of Indo-Pacific humpback dolphins, Sousa chinensis, have been observed in the month of April with total best-estimated group sizes between 11 to 15 individuals (Kreb, 2008).
Sub-criterion C2: Feeding Areas
Sperm whales have been recorded to undertake repeated long-dives and respiration behaviour has been observed for sperm whales during 5 out of 8 sightings at more or less similar locations. These observations indicate the likely feeding activities. A maximum of 6 sperm whales have been observed, with observations in the months of May, June, August, and October. Sousa chinensis was also observed in April 2008 to be mud feeding in the Berau estuary, and were observed several times to perform head stands with their tailstock vertical out of the water while shaking their body.
Sub-criterion C3: Migration Routes
Criterion D – Special Attributes
Sub-criterion D1 – Distinctiveness
Sub-criterion D2 – Diversity
25 species of cetaceans and one sirenian species have been observed in this IMMA (Kreb et al. 2015). These include Omura’s whales (Balaenoptera omurai), Fin whales, Common dolphins (Delphinus delphis), Long-beaked common dolphins (D.d. tropicalis), Dugongs, Pygmy killer whales (Feresa attenuata), Short-finned pilot whales (Globicephala macrorhynchus) , Risso’s dolphins (Grampus griseus), Dwarf sperm whales (Kogia sima), Pygmy sperm whales (K. breviceps), Fraser’s dolphins (Lagenodelphis hosei) , Humpback whales (Megaptera novaeangliae), Indo-Pacific finless porpoises (Neophocaena phocaenoides), Irrawaddy dolphins, Killer whales (Orcinus orca), Melon-headed whales (Peponocephala electra), Sperm whales, False killer whales (Pseudorca crassidens), Indo-Pacific humpback dolphins, Gray’s spinner dolphins (Stenella longirostris longirostris), Dwarf spinner dolphin (S.l. roseiventris), Pantropical spotted dolphin (Stenella attenuata), Striped dolphin (Stenella coeruleoalba), Indo-Pacific bottlenose dolphin (Tursiops aduncus), Rough-toothed dolphin (Steno bredanensis), Common bottlenose dolphin (Tursiops truncatus), and Cuvier’s beaked whale (Ziphius cavirostris).
Supporting Information
Jefferson, T.A., Smith, B.D., Braulik, G.T. & Perrin, W. 2017. Sousa chinensis (errata version published in 2018). The IUCN Red List of Threatened Species 2017: e.T82031425A123794774. https://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T82031425A50372332.en. Accessed on 15 November 2025.
Kreb, D. and Budiono, I. 2004. ‘Biodiversity assessment of cetaceans and mantas near the Berau Islands, East Kalimantan, Indonesia’. Provisional Final Report for the Indonesian Institute of Sciences (LIPI).
Kreb, D. and Budiono, I. 2005. ‘Cetacean Diversity and Habitat Preferences in Tropical Waters of East Kalimantan, Indonesia’. The Raffles Bulletin of Zoology 53 (1), 149-155.
Kreb, D., Budiono, I. and Pitman, R.L. 2008. ‘Sulawesi Sea Cetacean Project 2007-2008. Conservation and diversity of marine cetaceans in the Berau Archipelago, East Kalimantan, Indonesia’. Final technical report.
Kreb, D., Budiono, I. and Syachraini. 2012. ‘East Kalimantan Cetacean Conservation Project 2009-2012. Conservation and diversity of cetaceans within a new potential MPA in East Kalimantan, Indonesia’. Final technical report.
Kreb, D. and Budiono, I. 2015. ‘Berau Cetacean Conservation Project 2013-2014. Cetacean species identification, distribution and relative abundance in the northern part of Derawan Islands Marine Park’. Final technical report.
Whitehead, H., Barlow, J., Dawson, S.M., Eguiguren, A., Miller, B. & Shabangu, F. 2025. Physeter macrocephalus. The IUCN Red List of Threatened Species 2025: e.T41755A50382216. https://dx.doi.org/10.2305/IUCN.UK.2025-2.RLTS.T41755A50382216.en. Accessed on 15 November 2025.
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