Antongil Bay, Northeast Madagascar

Location / Description / Jurisdiction / Features of Potential Outstanding Universal Values / Threats / Management status / Key References

Antongil Bay is on the upper NE coast of Madagascar, some 300 km south of the sites mentioned in the N Madagascar site page.
© Wildlife Conservation Society

Location - Antongil Bay is in the NE of Madagascar (16°00’S, 49°55’E).

Description - Antongil Bay is the largest bay in Madagascar, covering 2800 km², of which half is less than 50 m deep and 270 km of coastline. It is situated where the South Equatorial Current (SEC) hits the east coast of Madagascar and splits north and south, and is sheltered from the southeast swell and winds by the Masoala Peninsula. Situated in a high rainfall area, the bay is surrounded by lush tropical forests, with 9 rivers flowing into it. The bay is among the most productive in the Indian Ocean, with a very high biomass of small pelagic fish (27,000 tonnes), also serving as a mating and nursery ground for many marine species. .

The forests surrounding the bay host an estimated 50% of Madagascar’s floral and faunal diversity, and are designated under three protected areas – the Masoala National Park, which is a natural World Heritage Site, the Mananara National Park, which is a UNESCO Biosphere Reserve, and the Makira Protected Area.

Jurisdiction – Madagascar

Features of Potential Outstanding Universal Values

Criterion viii - Geology and oceanography
Oceanography: the bay is situated where the SEC hits the east coast of Madagascar and splits north and south, so is among the first settling sites for larvae transported across the ocean. It may play a key source role for downstream regions, such as in the Mozambique Channel.

Criterion ix – Ecology, species and evolution
The bay contains more than 140 species of fish, of which 19 are sharks. Three turtle species frequent the bay: green turtles (Chelonia mydas), hawksbills (Eretmochelys imbricata) and leatherback (Dermochelys coriacea). At least 13 marine mammal species are reported in the bay and adjacent offshore region: the dugong (Dugong dugon), one pinniped (Arctocephalus tropicalis), and 11 species of cetaceans (humpback whales Megaptera novaeangliae, southern right whales Eubaleana australis, sperm whales Physeter macrocephalus, beaked whales Ziphius cavirostris and Mesoplodon sp., bottlenose dolphins Tursiops sp, spinner dolphins Stenella longirostris, pantropical spotted dolphins Stenella attenuata, Fraser’s dolphins Lagenodelphis hosei, false killer whales Pseudorca crassidens, and melon-headed whales Peponocephala electra).

Criterion x - Habitats & conservation
The bay contains many marine habitats: estuaries, mangroves, rocky shores, coral reefs, and seagrass beds.  Coral reefs on the east coast of Madagascar have shown potential resilience to coral bleaching due to climate change.
The bay is globally important for its role as a mating ground for humpback whales, and is one of the largest and best-studied wintering sites in the Indian Ocean. Research in Antongil Bay from 2000 to 2006 suggests that the population of humpback whales utilizing the Bay is composed of approximately 7000 individuals and is continuing to recover from depletion by commercial whaling that occurred in the 19th and early 20th centuries.

Threats - Antongil Bay faces similar exploitation threats to other parts of the region, particularly from high fishing pressure and illegal fishing, depletion of mangrove forests, sedimentation from terrestrial runoff, and petroleum industry exploration and production.

Management status - The bay has had a variety of regulations and management zones decreed. In 2010, the entire bay and its outer reaches, an area of about 4400 km² were put under temporary full protection by an interministerial decree (n°52005/2010), to enable measures to be put in place to assure long term sustainable resource use. Prior to this, within the Masoala National Park, 3 marine protected areas covering 100 km² were established in 1997, and the Marine Park of Nosy Antafana, created in 1989, has an area of 10 km². Since 2009, 7 community protected areas were established, covering a total of 2000 ha.  In 2006 the first regulation of its kind in Madagascar was imposed, banning the use of destructive gears such as beach seines, and fine-mesh (mosquito net) nets. In 2011 this was extended as a ban on the manufacture, sale and use of beach seines in the Région Analanjirofo, in which the bay is found.

Key References – Doukakis et al. (2007); Doukakis et al. (2011); Grove et al. (2010); Jonahson (2003); McClanahan (2007); McClanahan et al. (2009); Rabarison 1983; Razafindrakoto et al. (2010). --> References