Amsterdam Island, Saint Paul and Associated Waters IMMA

Size in Square Kilometres

1,431,225 km2

Qualifying Species and Criteria

Subantarctic fur seals – Arctocephalus tropicalis

Criterion C (i, ii)

Marine Mammal Diversity 

Orcinus orca, Physeter macrocephalus, Balaenoptera musculus brevicauda, Mirounga leonina


The Amsterdam and St Paul Islands are the northernmost of the French Subantarctic territories in the eastern part of the Indian Ocean Basin. Since 2006, the islands and part of the EEZ waters are listed as a French Natural Reserve (Biological Integral Reserve) and administered by the French Ministry of the Terres Australes and Antarctique Francaises. The waters around the islands are part of the French EEZ and as such benefit from the protected status of the reserve. Amsterdam Island is 58 km2 while St Paul is 8 km2. They are separated by ca. 100 km. Amsterdam and St Paul are located just north of the subtropical front, which is accepted as one of the definitions of the northern limit of the Southern Ocean. They are volcanic small islands on the southeast Indian ridge that present a very narrow shelf. Apart from La Roche Quille there is no restricted zones on Amsterdam island. Several zones on the main island are open to scientific investigations including the Plateau des tourbières and the Falaises de la Pointe d’Entrecasteaux where the scientists of the polar program 109 (Centre d’Etudes Biologiques de Chize CNRS UMR7372, France) have long-term monitoring programs. Ile St Paul is also monitored annually by the Reserve agents. The area hosts populations of Subantarctic fur seals (Arctocephalus tropicalis). There have been opportunistic sightings of other marine mammals at and around the islands, including Killer whales (Orcinus orca) that are present year-round in the vicinity of Amsterdam and St Paul Islands, southern elephant seals (Mirounga leonina) that are regular visitors, although no breeding has been reported at Amsterdam Island for this species. Additionally, sperm whales (Physeter macrocephalus) and pygmy blue whales (Balaenoptera musculus brevicauda) have been documented in the region (Branch et al. 2007, Samaran et al. 2010).

Description of Qualifying Criteria

Criterion C: Key Life Cycle Activities

Sub-criterion Ci: Reproductive Areas

The population of subantarctic fur seals on Amsterdam Island is especially interesting in the sense that it was almost completely depleted during the whaling era with less than 100 individuals being left in 1956 (Paulian 1964). This population increased to 30 500 adults by 1982 (Roux 1978). A good marker of the health of the population can be found in the annual pup production that was 6334 pups in 1982, 6414 pups in 1993 (Guinet et al. 1994) and the latest count in 2018 gives a figure of 4748 Subantarctic fur seal pups. The population increased throughout the 1990’s and is now thought to be stable or decreasing slightly. It has been suggested that this population has reached its carrying capacity and is now impacted by density-dependent effects (Chambellant et al. 2003). Pups are counted annually by the scientists of the Polar Program 109 (CNRS CEBC UMR7372, France), logistically supported by the French Polar Institute (IPEV) and the Natural Reserve.

Sub-criterion Cii: Feeding Areas

Subantarctic fur seals adjust their foraging behaviour according to both seasonal and annual changes in oceanographic conditions, and thus probably, food availability (Georges et al. 1997, Beauplet et al. 2004). The fur seals exploit the Subtropical Front, but also exhibit large differences in their seasonal distributions, ranging from short trips in restricted foraging areas during summer to widely distributed foraging grounds during the winter, possibly reflecting a decrease in food availability close to the islands. The proposed cIMMA thus encompasses the largest foraging range measured (Fig. S1, Beauplet et al. 2004), so as to ensure that food resources would not be a limitation to this population. Acoustic studies suggest that the pygmy blue whales, one of the subspecies of blue whales in the Southern Ocean, also use the proposed cIMMA as a foraging area (Samaran et al., 2010).

Supporting Information

Beauplet, G., Dubrocal, L., Guinet, C., Cherel, Y., Dabin, W., Gagne, C., Hindell, M. 2004. Foraging ecology of subantarctic fur seals Arctocephalus tropicalis breeding on Amsterdam Island: seasonal changes in relation to maternal characteristics and pup growth. Marine Ecology Progress Series. 2004, 273, 211-225

Branch, T.A., Stafford, K.M., Palacios, D.M., Allison, C., Bannister, J.L., Burton, C.L.K., Cabrera, E., Carlson, C.A., Galletti Vernazzani, B., Gill, P.C. and Hucke-Gaete, R. Past and present distribution, densities and movements of blue whales Balaenoptera musculus in the Southern Hemisphere and northern Indian Ocean. Mammal Review, 2007, 37(2), pp.116-175

Chambellant M., Beauplet G., Guinet C., Georges J.Y. 2003. Long-term evaluation of pup growth and preweaning survival rates in subantarctic fur seals, Arctocephalus tropicalis, on Amsterdam Island. Canadian Journal of Zoology. 2003, 81, 1229-1239 

Georges J.Y., Bonadonna F., Guinet C. 2000. Foraging habitat and diving activity of lactating Subantarctic fur seals in relation to sea-surface temperatures on Amsterdam Island. Marine Ecology Progress Series. 2000, 196, 291-304

Guinet C., Jouventin P., Georges J.Y. 1994. Long term population changes of fur seals Arctocephalus gazella and A. tropicalis on subantarctic (Crozet) and subtropical (Saint Paul and Amsterdam) islands and their possible relationship to El Niño Southern Oscillation. Antarctic Science. 1994, 6, 473-478

Paulian, P. 1964. Contribution a l’etude de l’otarie de l’Ile d’Amsterdam. Mammalia 1964, 28, 1-146.

Roux, J.P. 1987. Subantarctic fur seal, Arctocephalus tropicalis, in French Subantarctic territories. In Status, Biology, and Ecology of Fur Seals. Croxall, J. P. and R. L. Gentry (Eds). NOAA tech. Rep. NMFS 51: 79–81 (Proceedings of an International Symposium and Workshop, Cambridge, England, April 1984)

Samaran, F., Adam, O., Guinet, C. 2010. Discovery of a mid-latitude sympatric area for two Southern Hemisphere blue whale subspecies. ESR 12:157-165 (2010) DOI:

Tixier P., Guinet C. 2013. Catalogue de Photo-Identification 2013: Orques des îles Amsterdam et St Paul.  Réserve Naturelle des Terres Australes Terres Australes et Antarctiques Françaises & Centre d’Etudes Biologiques de Chizé – CNRS.


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