Scott Islands and Iselin Bank IMMA

Size in Square Kilometres

765,120 km2

Qualifying Species and Criteria

Humpback whale – Megaptera novaeangliae

Criterion C (2)

Antarctic Blue whale – Balaenoptera musculus intermedia

Criterion A; C (2)

Fin whale – Balaenoptera physalus

Criterion A

Antarctic minke whale – Balaenoptera bonaerensis

Criterion C (2)

Marine Mammal Diversity 

Criterion D (2)

Lobodon carcinophaga, Globicephala melas edwardii, Hydrurga leptonyx,
Mirounga leonina, Orcinus orca, Balaenoptera acutorostrata

Download fact sheet


The Scott Islands IMMA includes Scott Island, Balleny Island and the Iselin Bank. Situated at the northern end of the Ross Sea, they are far enough from the Antarctic mainland to be directly in the path of circumpolar ocean currents. Consequently, they create an upwelling of nutrient-rich deep water to the surface, which then generates high levels of biological productivity. This rich marine ecosystem serves as an important feeding area for humpback whales (Megaptera novaeangliae) and a hot spot for Critically Endangered Antarctic blue whales (Balaenoptera musculus intermedia) and Antarctic minke whales (Balaenoptera bonaerensis). The IMMA is used by many other species of marine mammals such as killer whales (Orcinus orca – both Type C and Type B1); Vulnerable fin whales (Balaenoptera physalus); southern long-finned pilot whales (Globicephala melas edwardii), southern elephant seals (Mirounga leonina), crabeater seals (Lobodon carcinophaga) and leopard seals (Hydrurga leptonyx).

Description of Qualifying Criteria

Criterion A – Species or Population Vulnerability

Blue whales, Balaenoptera musculus, were hunted for over a century and whaling brought them to the brink of extinction before the species became protected by international agreement in 1966. The subspecies is red-listed as Critically Endangered (Cooke, J.G. 2018) and is of global interest as one of the most at risk baleen whale species in the Southern Ocean. The Antarctic form B. m. intermedia, which used to be the most abundant form of blue whale, occurs in the Antarctic in summer, from the Antarctic Polar Front up to and into the ice (Branch et al. 2006), including (in the past) the South Georgia area. Its winter distribution is poorly known, but the presumption has been that animals migrate in winter to lower latitudes, largely because blue whales were caught off Namibia, South Africa, in winter (Best 1998, Mackintosh 1965). Commercially exploited to critical population levels, the fin whale, Balaenoptera physalus, is currently a vulnerable species in the Southern Ocean (Reilly et al. 2013). Fin whales have a nearly circumpolar distribution in the Southern Ocean (De Broyer et al. 2014) with numerous records around the Balleny Islands (Naganobu et al. 2005).

Criterion C: Key Life Cycle Activities

Sub-criterion C2: Feeding Areas

This area has been identified as an important feeding area for humpback whales (Andrews Goff et al. 2018). Found in oceans and seas around the world, humpback whales typically migrate up to 25,000 km each year. Most populations feed in high-latitude waters, and migrate to tropical or subtropical waters to breed and give birth, fasting and living off their fat reserves. Their diet consists mostly of krill and small fish and their foraging habitat in the Scott Islands region is associated with the marginal ice zone (Andrews Goff et al.2018). This area has also been identified as an important feeding area, using passive acoustics, for Antarctic blue whales (Double et al. 2015, Miller et al., 2015). In addition, Antarctic minke whales are known to occur from around 7ºS to the ice edge (and into the ice fields) during the austral summer in the region where they feed mainly on krill (Ballard et al., 2012).

Criterion D: Special Attributes

Sub-criterion D2: Diversity

There is good tracking data to show that humpback whales use the area for feeding (Andrews Goff et al. 2018). This is also the case for some southern elephant seals (Hindell et al. 2017). Transect survey data show that this productive area is used by many species of marine mammals, including: Antarctic blue whales (Tangaroa Census of Antarctic Marine Life); minke whales (probably mainly B. bonaerensis but possibly also B. acutorostrata) (Tangaroa Census of Antarctic Marine Life); killer whales, Orcinus orca, (Tangaroa Census of Antarctic Marine Life); fin whales,  Balaenoptera physalus, (Tangaroa Census of Antarctic Marine Life); southern long-finned pilot whales, Globicephala melas edwardii, and leopard seals, Hydrurga leptonyx. Satellite studies conducted in both McMurdo Sound and Terra Nova Bay show areas along the western Ross Sea coastline where Type-C killer whales engage in feeding activities and long-distance travel beyond the coast, outside the polar front (Eisert et al., 2015). The Type-B1 killer whale whales, which mammal-feed on mammals and birds that commonly occurs along the ice shelf in this region during the austral summer, taking advantage of both the seal and Adelie penguin colonies in the area (Andrews et al., 2008; Lauriano et al., 2007a,b). Antarctic minke whales are known to occur from around 7ºS to the ice edge (and into the ice fields) during the austral summer in the region. They feed mainly on krill and, in turn, are important prey for killer whales. High densities of Antarctic minke whales are recorded in the entire Ross Sea area (Ballard et al., 2012). The distribution of crabeater seals is tied to seasonal fluctuations of the pack ice. They can be found right up to the coast and ice shelves of Antarctica, as far south as the Bay of Whales, during late summer ice break-up. They occur in greatest numbers in the seasonally shifting pack ice surrounding the Antarctic continent (Hückstädt, L. 2015). Van Dam & Kooyman (2004) reported several sightings during a late autumn transect through the Ross Sea. Southern long-finned pilot whales are found circumpolar throughout the Southern Ocean in cold currents (Goodall and Galeazzi, 1985). The Australian ‘Southern Ocean Cetacean Ecosystem Program’ (SOCEP) surveys, whales were found near ice as south as 64° South (Waerebeek et al. 2004) and Brownell (1974) reported sightings near Scott Island (67°S, 179°W).

Supporting Information

Andrews R, Pitman R, and Ballance L. 2008. Satellite tracking reveals distinct movement patterns for Type B and Type C killer whales in the southern Ross Sea, Antarctica. Polar Biology, 31 (12).

Andrews-Goff, V., Bestley, S., Gales, N.J., Laverick, S.M., Paton, D., Polanowski, A.M., Schmitt, N.T., Double, M.C. 2018. Humpback whale migrations to Antarctic summer foraging grounds through the southwest Pacific Ocean. Scientific Reports, 8 (1).

Ballard, G, Jongsomjit, D, Veloz, S and Ainley, D. 2012. Coexistence of mesopredators in an intact polar ocean ecosystem: The basis for defining a Ross Sea marine protected area. Biological Conservation, 156, 72-82.

Best, P. B. 1998. Blue whales off Namibia – a possible wintering ground for the Antarctic population. Reports of the International Whaling Commission.

Branch, T. A., Palacios, D. M., Stafford, K. M., Allison, C., Bannister, J. L., Burton, C. L. K., Gill, P. C., Jenner, K. C. S., Jenner, M.-N. M., Maughan, B., Miyashita, T., Morrice, M. G., Sturrock, V. J., Anderson, R. C., Baker, A. N., Best, P. B., Borsa, P., Childerhouse, S., Findlay, K. P., Ilangakoon, A. D., Jörgensen, M., Kahn, B., Mikhalev, Y. A., Oman Whale and Dolphin Research Group, Thiele, D., Tormosov, D., Van Waerebeek, K. and Warneke, R. M. 2006. Past and present distribution, densities and movements of blue whales in the Southern Hemisphere and adjacent waters. Paper SC/58/SH16 presented to the IWC Scientific Committee, June 2006.

Brownell, R.L. jr. 1974. Small odontocetes of the Antarctic. pp. 13-19. In: V.C. Bushnell (ed.) Antarctic Map Folio Series. Folio 18. American Geographic Society, New York.

Cassandra M. Brooks 2013. Competing values on the Antarctic high seas: CCAMLR and the challenge of marine-protected areas, The Polar Journal, 3:2, 277-300

Castellini, M. A., R. W. Davis, and G. L. Kooyman. 1992. Annual cycles of diving behavior and ecology of the Weddell seal. Bull. Scripps. Inst.Oceanogr. 28:1–54

Cooke, J.G. 2018. Balaenoptera musculus ssp. intermedia. The IUCN Red List of Threatened Species 2018: e. T4171 3A 50 22 696

Cooke, J.G., Zerbini, A.N. & Taylor, B.L. 2018. Balaenoptera bonaerensis. The IUCN Red List of Threatened Species 2018: e.T2480A50350661.

Constantine et al. 2014. Remote Antarctic feeding ground important for east Australian humpback whales. Marine Biology 161: 1087-1093 doi 10.1007/s00227-014-2401-2

Double, M.C., Miller, B.S., Leaper, R., Olson, P., Cox, M.J., Miller, E., Calderan, S., Collins, K., Donnelly, D., Ensor, P., Goetz, K., Schmitt, N., Andrews-Goff, V., Bell, E., O’Driscoll, R. 2015. Cruise report of the 2015 Antarctic blue whale voyage of the Southern Ocean Research Partnership. Reports to the Scientific Committee of the International Whaling Commission SC/66a/SH7

Double et al. 2013. Cruise report of the 2013 Antarctic blue whale voyage of the Southern Ocean Research Partnership. Reports to the Scientific Committee of the International Whaling Commission SC/65a/SH21

Eisert R, Ovsyanikova E, Visser I, Ensor P, Currey R and Sharp B. 2015. Seasonal site fidelity and movement of type-C killer whales between Antarctica and New Zealand. Reports to the Scientific Committee of the International Whaling Commission SC/66a/SM/9

Franklin, W, Franklin T, Brooks, L, Gibbs, N, Childerhouse, S, Smith, F, Burns, D, Paton, D, Garrigue, C, Constantine, R, Poole, M, Hauser, N, Donogue, M, Russel, K, Mattila, D, Robbins, J, Oosterman, A, Leaper, R, Harrison, P, Baker, S, and Clapham, P. 2012. Antarctic waters (Area V) near the Balleny Islands are a summer feeding area for some eastern Australian Breeding Stock E(i) Humpback Whales (Megaptera Novaeangliae). J. Cetacean Res. Manage. 12(3): 321–327.

Goodall, R. N. P and Galeazzi, A. R. 1985. Sightings of pilot whales off southern South America. Rep. Int. Whal. Commn. 37, Resumé Section., p. 400.

Hindell, M. A., Sumner, M., Bestley, S., Wotherspoon, S., Harcourt, R. G., Lea, M.-A., McMahon, C. R. 2017. Decadal changes in habitat characteristics influence population trajectories of southern elephant seals. Global Change Biology, 23(12), 5136–5150.

De Broyer C., Koubbi P., Griffiths H.J., Raymond B., Udekem d’Acoz C. d’, Van de Putte A.P., Danis B., David B., Grant S., Gutt J., Held C., Hosie G., Huettmann F., Post A., Ropert-Coudert Y. (eds.), 2014. Biogeographic Atlas of the Southern Ocean. Scientific Committee on Antarctic Research, Cambridge, XII + 498 pp

Hückstädt, L. 2015. Lobodon carcinophaga. The IUCN Red List of Threatened Species 2015

Lauriano G., Fortuna C.M., Vacchi M. 2007a. Observation of killer whale (Orcinus orca) possibly eating penguins in Terra Nova Bay, Antarctica. Antarctic Science, 19(1): 95-96.

Lauriano G., Vacchi M., Ainley D., Ballard G. 2007b. Observations of top predators foraging on fish in the pack ice of the southern Ross Sea. Antarctic Science, 19(4): 439-440.

Laws, R. M. 1979. Southern elephant seal. Pp. 106-109 in Mammals in the seas. FAO fisheries Series No. 5, Volume II.
Mackintosh, N. A. 1965. The stocks of whales. Fishing News Ltd., London, UK.

Miller, B, Barlow, J, Calderan, S, Collin, sK, Leaper, R, Olson, P, Ensor, P, Peel, D, Donnelly, D, Andrews-Goff, V, Olavarria, C, Owen, K, Rekdahl, M, Schmitt, N, Wadley, V, Gedamke, J, Gales, N and Double, M . 2015. Validating the reliability of passive acoustic localisation: a novel method for encountering rare and remote Antarctic blue whales. Endangered Species Research, 26: 257-269.

Naganobu, M. Nishiwaki, H. Yasuma, R. Matsukura, Y. Takao, K. Taki, T. Hayashi, Y. Watanabe, T. Yabuki, Y. Yoda, Y. Noiri, M. Kuga, K. Yoshikawa, N. Kokubun, H. Murase, K. Matsuoka, and K. Ito. 2005. Interactions between oceanography, krill and baleen whales in the Ross Sea and Adjacent Waters: An overview of Kaiyo Maru-JARPA joint survey in 2004/05

Reilly, S.B., Bannister, J.L., Best, P.B., Brown, M., Brownell Jr., R.L., Butterworth, D.S., Clapham, P.J., Cooke, J., Donovan, G.P., Urbán, J. & Zerbini, A.N. 2008. Balaenoptera musculus. The IUCN Red List of Threatened Species

Reilly, S.B., Bannister, J.L., Best, P.B., Brown, M., Brownell, Jr. R.L., Butter-worth, D.S., Clapham, P.J., Cooke, J., Donovan, G.P., Urbán J, Zerbini AN, 2013. Balaenoptera physalus. In: IUCN 2013. IUCN red list of threatened species. Version 2013.1

Van Damm R and Kooyman G, 2004. Latitudinal distribution of penguins, seals and whales observed during a late autumn transect through the Ross Sea. Antarctic Science, 16 (3), 313-318.

Waerebeek, K. V., Russell, L., Baker, A. N., Papastravou, V., and Thiele, D. 2004.Odontocetes from the Southern Ocean Sanctuary. Reports to the Scientific Committee of the International Whaling Commission SC/56/SOS1


Download the full account of the Scott Islands and Iselin Bank IMMA using the Fact Sheet button below:

To make a request to download the GIS Layer (shapefile) for the Scott Islands and Iselin Bank IMMA please complete the following Contact Form:

    * Required fields

    Please read the User Licence Agreement and IMMA Layer Metadata Description