Toliara, St. Augustine Canyon and Anakao IMMA

Size in Square Kilometres

6 069 km2

Qualifying Species and Criteria

Humpback whale – Megaptera novaeangliae

Criterion C (1)

Indian Ocean humpback dolphin – Sousa plumbea

Criterion A; B (1)

Spinner dolphin – Stenella longirostris

Criterion B (2)

Risso’s dolphin – Grampus griseus

Criterion B (2)

Short-finned pilot whale – Globicephala macrorhynchus

Criterion B (2)

Marine Mammal Diversity 

Criterion D (2)

Balaenoptera bonaerensis, Balaenoptera musculus brevicauda, Balaenoptera musculus intermedia, Balaenoptera physalus, Eubalaena australis, Kogia sima, Lagenodelphis hosei, Peponocephala electra, Physeter macrocephalus, Pseudorca crassidens, Stenella attenuata, Steno bredanensis, Tursiops aduncus, Tursiops truncatus



This region in the Southwest of Madagascar is dominated by  the third largest reef system in the world, the  Grand Recif de Toliara, which is made up of barrier and fringing reefs and extensive shallow lagoons.  The IMMA also includes coastal mangroves, submarine canyons, a relatively narrow shelf, and a steep continental slope. These diverse habitats support high cetacean biodiversity, with a minimum of 18 documented species, including five baleen whales, two highly coastal dolphin species, and 11 species of oceanic dolphins and toothed whales. The Toliara and Anakao area is a well-documented breeding area for humpback whales (Megaptera novaeangliae), and a migratory area for Antarctic and pygmy blue whales (Balaenoptera musculus intermedia and B. m. brevicauda), fin whales (Balaenoptera physalus) and Antarctic minke whales (Balaenoptera bonaerensis). The Endangered Indian Ocean humpback dolphins (Sousa plumbea) and Near Threatened Indo-Pacific bottlenose dolphins (Tursiops aduncus) that are found in the IMMA’s inshore waters were the target of active directed hunts, and are still at risk of bycatch in artisanal fisheries in the region.

Description of Qualifying Criteria

Criterion A – Species or Population Vulnerability

Indian Ocean humpback dolphin (Sousa plumbea), IUCN Red List Endangered: A population resides in the near coastal habitat of this region, as documented by several studies (Andrianarivelo 2001, Razafindrakoto et al 2004, Van Canneyt et al. 2010, Cerchio et al. 2015). There is a history of extensive artisanal hunting and bycatch in local fisheries that has resulted in a documented decline in group size and encounter rate of groups and individuals (Andrianarivelo 2001, Razafindrakoto et al 2004, Cerchio et al. 2009, 2015). However, conservation efforts working with local villages to develop community-based protection mechanisms, outreach and education, and alternative-livelihoods to replace hunting, has resulted in the apparent cessation of hunting among the three main “Communes” (groups of villages) of the Anakao region (Cerchio et al. 2014, Andrianarivelo, personal communication). These conservation efforts are currently sustained by the presence of a community-based Association for the Protection of Whales and Dolphins (or in Malagasy, Fikambanana Miaro ny Trozona sy Fesotra, FMTF), consisting entirely of traditional Vezo fishers from the three participating Communes (Cerchio et al. 2014).

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations 

Indian Ocean humpback dolphin, Sousa plumbea: The impacted small population, as described above, is likely resident in the area, although the extent of individual movements is unknown. Photographic identification data collected within the IMMA between 2004 and 2009, indicate relatively few individuals (almost certainly <50) with several re-sighted between years; at least one individual was sighted in four of the five years in which photographic data were collected (Cerchio et al. 2015, Cerchio and Andrianarivelo, unpublished data). Group size was relatively small compared to other areas with a mean of 3.6 individuals, and exhibited a declining trend from 2004 to 2013 (Cerchio et al. 2015).  Other regions in the southwest Indian Ocean have documented partially resident to highly resident populations, including Maputo Bay, Mozambique (Guissamulo & Cockcoft 2004), Richards Bay/KwaZulu-Natal coast, South Africa (Keith et al. 2002), and Zanzibar, Tanzania (Stensland et al. 2006).

Sub-criterion B2: Aggregations

The St. Augustine submarine canyon supports notable aggregations of several deep water delphinids, including: Short-finned pilot whales, Globicephala macrorhynchus – on several occasions, large groups have been documented in the Anakao and St. Augustine Canyon area, composed of 2 or 3 subgroups of 20-40 individuals; Risso’s dolphins; Grampus griseus – the most commonly sighted oceanic delphinid during small boat-based surveys, found along the steep continental slope and canyon; Spinner dolphins, Stenella longirostris – regularly sighted along the shelf break and at times in large groups in excess of 500 individuals, in association with spotted dolphins along the edges of the canyon; and pantropical spotted dolphins, Stenella attenuata – often sighted in large groups in excess of 500 individuals, in association with spotted dolphins along the edges of the canyon.

Criterion C: Key Life Cycle Activities

Sub-criterion C1: Reproductive Areas

Humpback whale, Megaptera novaeangliae: The area is an active breeding area for humpback whales during July to October, with sightings continuing into December (Cerchio et al. 2009, Cerchio unpublished data, Cerchio et al. 2016, Trudelle et al. 2016). Breeding behaviour was regularly observed and satellite tracks of 11 whales tagged off Anakao indicated extensive movement through the boundaries of the IMMA and along the southern coast of Madagascar to Tôlanaro (Fort Dauphin), in the adjacent areas of Southern Madagascar.

Criterion D: Special Attributes

Sub-criterion D2: Diversity

High diversity with minimum 18 species documented: In addition to the species listed above, the following notable species are part of the diversity of the area: Southern right whale, Eubalaena australis – although this species is rarely sighted in the waters of Madagascar, there have been two documented sightings during boat surveys in the area, one of which was a mother-calf. In general right whales are sighted infrequently but regularly around Madagascar, with anecdotal sightings on both the west and east coasts (Rosenbaum et al. 2001, Cetamada unpublished data, Cerchio unpublished data). It is unclear whether these individuals represent range expansion from the South Africa population, or potentially represent remnants of an historical and near-extirpated population from Mozambique / Madagascar (Banks et al. 2011, Findlay personal communication), that was heavily hunted off the Crozet Islands (Townsend 1935); Common bottlenose dolphins, Tursiops truncatus – large offshore forms of bottlenose dolphins have been sighted on several occasions during boat surveys and aerial surveys (at times in association with pilot whales), and likely utilize the steep slope and canyon habitat; False killer whale, Pseudorca crassidens – sighted on several occasions during boat surveys and aerial surveys, and likely utilize the steep slope and canyon habitat; Sperm whale, Physeter macrocephalus – sighted on several occasions during aerial surveys and detected acoustically using dipping hydrophones during boat surveys and documented extensively during passive acoustic monitoring, and likely utilize the steep slope and canyon habitat.

Supporting Information

Andrianarivelo, N., 2001. Essai d’évaluation de l’importance de la pêche aux dauphins dans la région d’Anakao (sud-ouest de Madagascar). Unpublished DEA thesis. Institut Halieutique et des Sciences Marines, Université de Toliara, Madagascar.

Banks, A, Best, P, Gullan, A, Guissamulo, A, Cockcroft, V, Findlay, K. 2011. Recent sightings of southern right whales in Mozambique.  International Whaling Commission document SC/S11/RW17, 21 pp.

Braulik GT, Findlay K, Cerchio S, Baldwin R, Perrin W. 2017. Sousa plumbea. The IUCN Red List of Threatened Species 2017: e.T82031633A82031644.

Braulik G. T., Findlay K., Cerchio S. and Baldwin, R. 2015. Assessment of the Conservation Status of the Indian Ocean Humpback Dolphin (Sousa plumbea) Using the IUCN Red List Criteria. In: Jefferson T, and Curry B, editors. Humpback Dolphins (Sousa spp.): Their Current Status and Conservation. Advances in Marine Biology, Vol. 72. Oxford: Academic Press. Pp. 119-141.

Cerchio S, Trudelle L, Zerbini AN, Charrassin JB, Geyer Y, Mayer FX, Andrianarivelo N, Jung JL, Adam O, Rosenbaum HC. 2016. Satellite telemetry of humpback whales off Madagascar reveals long range movements of individuals in the Southwest Indian Ocean during the breeding season. Marine Ecology Progress Series 562, 193-209.  DOI:10.3354/meps11951.

Cerchio S, Andrianarivelo N, Andrianantenaina B, Cordi V. 2014. Ecology, status, fisheries interactions and conservation of coastal Indian Ocean humpback dolphins and Indo-Pacific bottlenose dolphins on the west coast of Madagascar. Paper SC/65B/SM21 presented to the IWC Scientific Committee.

Cerchio S, Andrianarivelo N, and Andrianantenaina B. 2015. Ecology and conservation status of Indian Ocean humpback dolphins (Sousa plumbea) in Madagascar. In: Jefferson T, and Curry B, editors. Humpback Dolphins (Sousa spp.): Their Current Status and Conservation. Advances in Marine Biology Series, Vol. 72. Oxford: Academic Press. Pp. 163-199.

Cerchio S, Gruden P, Andrianarivelo N, Strindberg S. 2012. Assessment of cetacean diversity, distribution and population status on the west coast of Madagascar and Mozambique Channel. Report to the International Union for Conservation of Nature, Species Survival Commission. 31pp.

Cerchio S, Andrianarivelo N, Razafindrakoto Y, Mendez M, and Rosenbaum H. 2009. Coastal dolphins hunting in the southwest of Madagascar: status of populations, human impacts and conservation actions. Paper SC/61/SM15 presented to the IWC Scientific Committee.

Dulau V, Pinet P, Geyer Y, Fayan J, Mongin P, Cottarel G, Zerbini A, Cerchio S. 2017. Movement behavior of humpback whales during the breeding season: on the road again! Movement Ecology 5:11. DOI 10.1186/s40462-017-0101-5.

Guissamulo, A. and Cockcroft, V. G. 2004. Ecology and population estimates of Indo-Pacific humpback dolphins (Sousa chinensis) in Maputo Bay, Mozambique. Aquatic Mammals 30(1): 94-102.

Keith, M., Peddemors, V. M., Bester, M. N. and Ferguson, J. W. H. 2002. Population characteristics of Indo-Pacific humpback dolphins at Richards Bay, South Africa: implications for incidental capture in shark nets. South African Journal of Wildlife Research 32: 153-162.

Laran, S., Van Canneyt, O., Dorémus, G., Mannocci, L., Ridoux, V. & Watremez, P. 2012. Distribution et abondance de la mégafaune marine dans le sud-ouest de l’océan Indien tropical. REMMOA-Océan Indien. Rapport final pour l’Agence des Aires Marines Protégées. 168p

Laran, S., Authier, M., Van Canneyt, O., Doremus, G., Watremez, P., Ridoux, V. (2017a). A Comprehensive Survey of Pelagic Megafauna: Their Distribution, Densities, and Taxonomic Richness in the Tropical Southwest Indian Ocean. Front. Mar. Sci. 4:139. doi: 10.3389/fmars.2017.00139

Razafindrakoto, Y., Andrianarivelo, N., Rosenbaum, H.C., 2004. Sightings, catches, and other records of Indo-Pacific humpback dolphins in the coastal waters of Madagascar. Aquat. Mamm. 30, 103–110.

Rosenbaum, H. C., Razafindrakoto, Y., Vahoavy, J. & Pomilla, C. (2001) A note on recent sightings of southern right whales (Eubalaena australis) along the east coast of Madagascar. Journal of Cetacean Research and Management, (special issue) 2, 177-180.

Stensland, E., Carlén, I., Särnblad, A., Bignert, A., Berggren, P., 2006. Population size, distribution, and behavior of indo-pacific bottlenose (Tursiops aduncus) and humpback (Sousa chinensis) dolphins off the south coast of Zanzibar. Mar. Mamm. Sci. 22, 667–682.

Trudelle L, Cerchio S, Zerbini AN, Geyer Y, Mayer FX, Jung JL, Hervé MR, Pous S, Sallée JB, Rosenbaum HC, Adam O, Charrassin JB. 2016. Influence of environmental parameters on movements and habitat utilization of humpback whales (Megaptera novaeangliae) in the Madagascar breeding ground. Royal Society Open Science 3: 160616. DOI:10.1098/rsos.160616.

Van Canneyt, O., Dorémus, G., Laran, S., Ridoux V., Watremez, P. 2010. Distribution et abondance de la mégafaune marine dans le sud sud-ouest de l’océan Indien tropical. Campagne REMMOA – Océan Indien – Rapport préliminaire. Université La Rochelle.


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