Heard Island, Kerguelen and Surrounding Waters IMMA

Size in Square Kilometres

1,767,353 km2

Qualifying Species and Criteria

Southern elephant seals – Mirounga leonina

Criterion C (1; 2)

Antarctic fur seals – Arctocephalus gazella

Criterion C (1; 2)

Kerguelen Commerson’s dolphin – Cephalorhynchus commersonii kerguelenensis

Criterion A; B (1)

Marine Mammal Diversity 

Arctocephalus tropicalis, Physeter macrocephalus, Orcinus orca, Globicephala melas edwardii, Eubalaena australis, Balaenoptera acutorostrata, Balaenoptera bonaerensis, Megaptera novaeangliae, Hyperoodon planifrons, Ziphius cavirostris, Mesoplodon layardii, Lagenorhynchus cruciger, Phocoena dioptrica, Hydrurga leptonyx, Balaenoptera musculus brevicauda


The Heard and Kerguelen Islands are located in the middle of the Indian Ocean sector of the Southern Ocean. The islands themselves provide terrestrial breeding and moulting sites for Antarctic fur seals (Arctocephalus gazella), and southern elephant seals (Mirounga leonina). The IMMA encompasses the Kerguelen Plateau surrounding these islands, an area associated with high seasonal productivity. Satellite tracking studies indicate that both species feed in the waters over the plateau, as well as its shelf edge and a particularly rich offshore feeding ground to the east.

These productive waters also serve as a foraging ground for pygmy blue whales (Balaenoptera musculus brevicauda), and host resident populations of killer whales (Orcinus orca) and a unique, endemic subspecies of Kerguelen Islands Commerson’s dolphins (Cephalorhynchus commersonii kerguelenensis).

Description of Qualifying Criteria

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations 

A small population of Commerson’s dolphin, widely separated from the South American main population, inhabits the coastal waters of the Kerguelen Islands (Crespo et al. 2017). Robineau et al. (2007) classify this population as a sub-species of Cephalorhynchus commersonii (C. commersonii kerguelenensis) based on several characteristics including geographic isolation, and morphological and genetic differences. The candidate area includes the entire known range of this subspecies, and are currently red-listed as Least Concern. However, the state of knowledge on some populations are data deficient so that it is difficult to assess the population status. This is particularly the case for cetaceans, and especially for the subspecies Commerson’s dolphin of Kerguelen. The global species assessment from the IUCN Red List states “The Kerguelen subspecies is restricted in range and is therefore probably very small in number and relatively vulnerable to any anthropogenic threats” (Crespo et al., 2017)

Criterion C: Key Life Cycle Activities

Sub-criterion C1: Reproductive Areas

The islands themselves provide terrestrial breeding and moulting sites for Antarctic fur seals (Arctocephalus gazella), and southern elephant seals (Mirounga leonina), with a glacier preventing easy access to the western part of the island. Some islands around Kerguelen have restricted access, such as Iles Leygues, Iles nuageuses or Iles Clugny. Several zones on the main island are open to scientific investigations (non exhaustively, the islands of Baie du Morbihan, some part of the Peninsula Rallier du Baty, etc.). Annual counts of Pinnipeds are conducted on the Courbet Peninsula by the scientists of the polar program 109 (CNRS CEBC UMR7372, France), logistically supported by the French Polar Institute and the Natural Reserve.

Sub-criterion C2: Feeding Areas

The at-sea movements of pinniped species have been studied using tracking devices of various types since the 1990s. Elephant seal and Antarctic fur seal data were collated by the Retrospective Analysis of Antarctic Tracking Data project (Ropert-Coudert et al. in press). Please also refer to the at-sea sighting data compiled in the Biogeographic Atlas of the Southern Ocean (Ropert-Coudert et al. 2014). Southern elephant seals exhibit two foraging strategies. Males mostly feed on the plateau, an important foraging ground for a community of top predators (Hindell et al. 2011), while females adopt a pelagic strategy (Bailleul et al. 2007). The latter are located in the “vicinity” of Kerguelen during their post-breeding trips (October – December) in an area corresponding to the spring bloom plume located on the Plateau and extending eastward. They perform longer trips during the extended post-moulting period (January-August), but still favour the region east of the Kerguelen Plateau (Fig S1) where they use long-lived mesoscale eddies and cold water filaments that aggregate their fish prey (Cotte et al 2015, Della Penna et al. 2017). Juvenile male elephant seals are benthic foragers that feed on the Kerguelen Plateau and along the shelf edge (O’Toole et al. 2014). This species is capable of diving up to 1500 m (McIntyre et al 2010), but regularly dive between 300 – 500 m in benthic and pelagic environments (Guinet et al 2014).

Antarctic fur seals perform relatively short trips during their breeding season (Jan-Feb). Animals from Kerguelen forage on the Kerguelen Plateau, as well as to the east of the Kerguelen Plateau along the shelf edge, while seals from Heard are distributed along the shelf edge, east of the Kerguelen Plateau or in the Fawn Trough (Fig S1). Fur seals from Kerguelen and Heard Island perform most foraging dives around dawn and dusk (Lea et al 2002, Goldsworthy et al 2010), diving up to 150 m to access their fish prey (Lea and Dubroca 2003). The IMMA encompasses the plateau and the recirculation gyre east of the Plateau, which covers an important part of the feeding activity of both seal species, and extends east to include the broader area where elephant seals forage during winter.

Supporting Information

Bailleul F, Charrassin J-B, Monestiez P, Roquet F, Biuw M, Guinet C. 2007. Successful foraging zones of southern elephant seals from the Kerguelen Islands in relation to oceanographic conditions. Philosophical Transactions of the Royal Society B: Biological Sciences, 362:2169-2181.

Bailleul F, Cotté C, Guinet C, 2010. Mesoscale eddies as foraging area of a deep-diving predator, the southern elephant seal. Marine Ecology Progress Series, 408:251-264.

Bost, C. A., C. Cotté, F. Bailleul, Y. Cherel, J. B. Charrassin, C. Guinet, D. G. Ainley, and H. Weimerskirch, 2009. The importance of oceanographic fronts to marine birds and mammals of the southern oceans. Journal of Marine Systems, 78:363–376.

Branch TA, Allison A, Mikhalev YA, Tormosov DD, and R. L. Brownell Jr., 2008. “Historical catch series for Antarctic and pygmy blue whales,” Paper Presented to the Scientific Committee of the IWC SC/60/SH09, 2008.

Cotté C, d’Ovidio F, Dragon AC, Guinet C, Lévy M. 2015. Flexible preference of southern elephant seals for distinct mesoscale features within the Antarctic Circumpolar Current. Prog Oceanogr 131:46–58

Crespo, E., Olavarria, C., Dellabianca, N., Iñíguez, M., Ridoux, V. & Reeves, R. 2017. Cephalorhynchus commersonii (errata version published in 2018). The IUCN Red List of Threatened Species 2017: e.T4159A128963283.

d’Ovidio F, Penna A Della, Trull TW, Nencioli F, Pujol MI, Rio MH, Park YH, Cotté C, Zhou M, Blain S. 2015. The biogeochemical structuring role of horizontal stirring: Lagrangian perspectives on iron delivery downstream of the Kerguelen Plateau. Biogeosciences 12:5567–5581

Della Penna A, Monte S De, Kestenare E, Guinet C, d’Ovidio F. 2015. Quasi-planktonic behavior of foraging top marine predators. Sci Rep 5:18063

Delord K, Barbraud C, Bost C-A, Cherel Y, Guinet C, et al. 2014. Atlas of top predators from French Southern Territories in the Southern Indian Ocean. [Research Report] CNRS. 2014, http://www.cebc.cnrs.fr/ecomm/Fr_ecomm/ecomm_ecor_OI1.html.

Fontaine M., Carravieri A., Simon-Bouhet B., Bustamante P., Gasco N., Bailleul F., Guinet C., and Cherel Y. 2015. Ecological tracers and at-sea observations document the foraging ecology of southern long-finned pilot whales (Globicephala melas edwardii) in Kerguelen waters. Marine Biology 162:207–219.

Goldsworthy, S. D., B. Page, A. Welling, M. Chambellant, and C. J. A. Bradshaw. 2010. Selection of diving strategy by Antarctic fur seals depends on where and when foraging takes place. MARINE ECOLOGY PROGRESS SERIES 409:255-U273.

Guinet, C., J. Vacquié-Garcia, B. Picard, G. Bessigneul, Y. Lebras, A. C. Dragon, M. Viviant, J. P. Y. Arnould, and F. Bailleul. 2014. Southern elephant seal foraging success in relation to temperature and light conditions: Insight into prey distribution. Marine Ecology Progress Series 499:285–301.

Guinet, C. et al. 2001. Spatial distribution of foraging in female Antarctic fur seals Arctocephalus gazella in relation to oceanographic variables: a scale-dependent approach using geographic information systems. Marine Ecology Progress Series 219, 251–264 (2001).

Hindell, M.A., Lea, M., Bost, C., Charrassin, J., Gales, N.J., Goldsworthy, S.D., Page, B., Robertson, G.C., Wienecke, B., O’Toole, M.D., & Guinet, C. 2011. Foraging habitats of top predators, and Areas of Ecological Significance, on the Kerguelen Plateau. In: The Kerguelen Plateau: marine ecosystem and fisheries, (Duhamel G. & Welsford D. Eds). Société d’Ichtyologie. 2011, 203-215

Koubbi P, Guinet C, Alloncle N, Ameziane N, Azam CS, Baudena A, Bost CA, Causse R, Chazeau C, Coste G, Cotté C, D’Ovidio F, Delord K, Duhamel G, Forget A, Gasco N, Hautecoeur M, Lehodey P, Monaco C Lo, Marteau C, Martin A, Mignard C, Pruvost P, Saucède T, Sinegre R, Thellier T, Verdier AG, Weimerskirch H. 2016. Ecoregionalisation of the Kerguelen and Crozet islands oceanic zone. Part I: Introduction and Kerguelen oceanic zone. CCAMLR Document WG-EMM-16/43.

Labadie G., Tixier P., Barbraud C., Fay R., Gasco N., Duhamel G., Guinetoole C. 2018. First demographic insights on historically harvested and poorly known male sperm whale populations off the Crozet and Kerguelen Islands (Southern Ocean). Marine Mammal Science. 2018, 34, (3), 595-615

Lea MA, Cherel Y, Guinet C, Nichols PD. 2002. Antarctic fur seals foraging in the Polar Frontal Zone: Inter-annual shifts in diet as shown from fecal and fatty acid analyses. Mar Ecol Prog Ser 245:281–297

Lea, M. A., M. Hindell, C. Guinet, and S. D. Goldsworthy. 2002. Variability in the diving activity of Antarctic fur seals, Arctocephalus gazella, at Iles Kerguelen. Polar Biology 25:269–279.

Lea, M.-A., and L. Dubroca. 2003. Fine-scale linkages between the diving behaviour of Antarctic fur seals and oceanographic features in the southern Indian Ocean. ICES Journal of Marine Science 60:990–1002.

Leroy EC, Samaran F, Stafford KM, Bonnel J, Royer JY, 2018. Broad-scale study of the seasonal and geographic occurrence of blue and fin whales in the Southern Indian Ocean. Endang Species Res 37:289-300

McIntyre, T., P. J. N. de Bruyn, I. J. Ansorge, M. N. Bester, H. Bornemann, J. Plötz, and C. A. Tosh. 2010. A lifetime at depth: Vertical distribution of southern elephant seals in the water column. Polar Biology 33:1037–1048.

Minton, G., Reeves, R. & Braulik, G. 2018. Globicephala melas. The IUCN Red List of Threatened Species2018: e.T9250A50356171.

O’Toole M., Hindell M. A., Charrassin J.-B., Guinet C. 2014. Foraging behaviour of southern elephant seals over the Kerguelen Plateau. Marine Ecology Progress Series. 2014, 502, 281-294

O’Toole M, Guinet C, Lea MA, Hindell MA. 2017. Marine predators and phytoplankton: how elephant seals use the recurrent Kerguelen plume. Mar Ecol Prog Ser 581:215-227

Page, B., A. Welling, M. Chambellant, S. D. Goldsworthy, T. Dorr, and R. van Veen. 2003. Population status and breeding season chronology of Heard Island fur seals. Polar Biology 26:219–224.

Robineau, D., Goodall, R. Natalie Prosser, Pichler, F., & Baker, C. S. 2007. Description of a new subspecies of Commerson’s dolphin, Cephalorhynchus commersonii (Lacépède, 1804), inhabiting the coastal waters of the Kerguelen Islands. Mammalia, 71(4), 172-180.

Robineau, D. & Duhamel, G. 2007. New data on cetaceans of the Kerguelen Islands. Mammalia, 70: 28-39.

Roche C, Guinet C, Gasco N, Duhamel G. 2007. Marine mammals and demersal longlines fishery interactions in Crozet and Kerguelen exclusive economic zones: an assessment of the depredation level. CCAMLR Sci 14:67–82

Ropert-Coudert Y, Hindell MA, Phillips R, Charrassin JB, Trudelle L, Raymond B. 2014. Chapter 8. Biogeographic patterns of birds and mammals. In: De Broyer C, Koubbi P, Griffiths HJ, Raymond B, d’Udekem d’Acoz C, Van de Putte AP, Danis B, David B, Grant S, Gutt J, Held C, Hosie G, Huettmann F, Post A, Ropert-Coudert Y (eds.) Biogeographic Atlas of the Southern Ocean. Scientific Committee on Antarctic Research, Cambridge, pp. 364-387

Ropert-Coudert, Y., Van de Putte, A.P., Reisinger, R.R. et al. 2020. The retrospective analysis of Antarctic tracking data project. Sci Data 7, 94 (2020). https://doi.org/10.1038/s41597-020-0406-x

Samaran F, Stafford KM, Branch TA, Gedamke J, Royer J-Y, Dziak RP, et al. 2013. Seasonal and Geographic Variation of Southern Blue Whale Subspecies in the Indian Ocean. PLoS ONE 8(8): e71561

Slip, D.J., Moore, G.J. and Green, K. 1995. Stomach contents of a southern bottlenose whale, Hyperoodon planifrons, stranded at Heard island. Marine Mammal Science 11(4): 575-584.


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