Prince Edward Islands and Western Oceanic Waters IMMA

Size in Square Kilometres

2,861,819 km2

Qualifying Species and Criteria

Southern elephant seal – Mirounga leonina

Criterion C (i; ii)

Antarctic fur seal – Arctocephalus gazella

Criterion C (i; ii)

Subantarctic fur seal – Arctocephalus tropicalis

Criterion C (i; ii)

Killer whale – Orcinus orca

Criterion C (ii)

Marine Mammal Diversity 

Hydrurga leptonyx, Globicephala melas edwardii, Physeter macrocephalus, Lagenorhynchus cruciger, Lagenorhynchus obscurus, Balaenoptera physalus, Balaenoptera borealis, Eubalaena australis, Mesoplodon layardii, Lissodelphis peronii, Megaptera novaeangliae, Balaenoptera musculus intermedia, Balaenoptera musculus brevicauda

Summary

The Prince Edward Islands are situated in the south-west Indian Ocean and extends longitudinally from approximately 16° E – 43° E, and latitudinally from approximately 43° S – 55° S. The islands themselves provide terrestrial breeding and moulting sites for Antarctic fur seals (Arctocephalus gazella), Subantarctic fur seals (A. tropicalis) and southern elephant seals (Mirounga leonina). The area further encompasses the core at-sea distributions of these seal populations as well as that of killer whales (Orcinus orca) (defined using tracking data). The IMMA includes bathymetric features (e.g., South West Indian Ridge, Africana II Bank, Gallieni Bank and various seamounts) and oceanographic features (Subantarctic front, Polar Front) that create important foraging grounds for pinnipeds and killer whales, and likely for other marine mammal species as well that have been recorded in the cIMMA. The cIMMA is defined by tracking data for seals and killer whales tracked from the Prince Edward Islands.

The Prince Edward Islands archipelago is South African territory comprising two islands: Marion Island and Prince Edward Island. A Marine Protected Area was declared in the South African EEZ around the Prince Edward Islands in 2013 (Lombard et al., 2007; UNEP-WCMC & IUCN, 2018). The area hosts breeding populations of four marine mammal species: Antarctic fur seals, Subantarctic fur seals, southern elephant seals and killer whales. At least 12 other marine mammal species have been recorded in the area (Ryan & Bester, 2008) (Section 15). At the Prince Edward Islands, marine mammal populations are monitored by the Marion Island Marine Mammal Programme (Mammal Research Institute, University of Pretoria, South Africa) (Bester et al., 2011). The at-sea movements of the three pinniped species and killer whales have been studied using telemetry tags since 1990 (Bester & Pansegrouw, 1992). These tracking data were collated and synthesized in Reisinger et al. (2018). Additional Antarctic fur seal tracking data are reported in (Arthur et al., 2018, 2017, 2016), further collated by the Retrospective Analysis of Antarctic Tracking Data project (Ropert-Coudert et al., 2020).

Description of Qualifying Criteria

Criterion C: Key Life Cycle Activities

Sub-criterion Ci: Reproductive Areas

On Marion Island, 1,553 Antarctic fur seal pups were counted in summer 2013 (Wege et al., 2016a). There were approximately 8,312 Subantarctic fur seal pups in the same season (Wege et al., 2016a). The total population size of fur seals on Marion Island was estimated to be approximately 5,800 Antarctic fur seals and 80,000 Subantarctic fur seals in 2004 (Hofmeyr et al., 2006). On Prince Edward Island, there were approximately 810 Antarctic fur seal pups and approximately 14,130 Subantarctic fur seal pups in summer 2008 (Bester et al., 2009). These represent total populations of approximately 5,280 Antarctic fur seals and approximately 67,824 Subantarctic fur seals (Bester et al., 2009). Together, the Prince Edward Islands account for approximately 25% of the worldwide pup production of Subantarctic fur seals (Hofmeyr et al., 2016b). The global Antarctic fur seal population numbers around 600,000 adult females (Hofmeyr et al., 2016a). Pup production at Prince Edward (~810) plus Marion (~1,553) therefore indicates that the Prince Edward Islands host about ~3.9% of the global population (assuming one adult female per pup counted). The Prince Edward Islands therefore harbour the largest sympatric population of Antarctic – and Subantarctic fur seals in the world; only two other locations have sympatric populations, namely the Crozet Islands and Macquarie Island.

At Marion Island, 589 elephant seal pups were born in summer 2017 (Mammal Research Institute, University of Pretoria, unpublished data). At Prince Edward Island the estimated number of births was 130 in 2004 (Bester & Hofmeyr, 2005). There has been no count since, but the number is likely higher currently, assuming the same increasing trend as that documented at neighbouring Marion Island (Pistorius et al., 2011). Using these counts and a conversion factor, the elephant seal population at the Prince Edward Islands numbers around 2,500 – 3,200 individuals (De Bruyn et al., 2016). The global population has been estimated ~749,385 (Hindell et al., 2016), and the Prince Edward Islands population thus represents less than 1% of the global population.

Sub-criterion Cii: Feeding Areas

Female Antarctic fur seals tracked from Marion Island frequently used areas east and northeast of the island, including the Del Cano rise and areas west of the island at 20-30˚ E (upstream of the Island relatively to the eastward Antarctic circumpolar current) of the Southwest Indian Ridge (Arthur et al., 2017). Seals also favour areas south of the island, at about 55˚S, and areas near Bouvet Island and west of Iles Kerguelen (Arthur et al., 2017). A pilot study of Subantarctic fur seal movements showed that adult females used the region between the Subtropical Front to the north of the islands, and the Polar Front to the south (De Bruyn et al., 2009). Females move to the Del Cano rise to the northeast of the Prince Edward Islands and to fracture zones on the Southwest Indian Ridge (Andrew Bain Fracture Zone and Prince Edward Fracture Zone) to the west of the islands (De Bruyn et al., 2009). A second study of female Subantarctic fur seals at Marion Island (Wege et al., 2016b) confirmed the use of the Gallieni Bank to the east of the islands during summer and the Del Cano rise and Southwest Indian Ridge during winter (Wege, et al. 2016b). Subantarctic fur seals tracked from Prince Edward Island use similar areas at sea (Kirkman et al., 2016).

Adult female elephant seals target the strong eddy field southwest of the Prince Edward Islands, in the lee (east) of the Southwest Indian Ridge for foraging (Massie et al., 2016). Adult and subadult males use areas west of the Prince Edward Islands, including areas north of the Subantarctic front to areas south of the Antarctic Polar Front. They use areas around the Southwest Indian Ridge, but also zones north of the Ridge (McIntyre et al., 2010). Juvenile southern elephant seals show restricted behaviour to the west and southwest of the Prince Edward Islands, around the Southwest Indian ridge, but area restricted search locations are also strongly associated with the Subantarctic Front and Polar Front (Tosh et al., 2012). Tracked killer whales spend most of their time in the inshore waters of Marion and Prince Edward Islands. Some individuals also use seamounts to the north and northeast of the islands. Here, they sometimes interact with longline fishing vessels catching Patagonian toothfish (Reisinger et al. unpublished data) but their dive behaviour (Reisinger et al., 2015) and stable isotope analysis (Reisinger et al., 2016) suggests that these seamounts could be places where they naturally prey on Patagonian toothfish or cephalopods (Reisinger et al., 2015; Reisinger et al., 2016). Some individuals make rapid, long-distance migrations north of the islands (Reisinger et al., 2015). Killer whales patrol the inshore waters of Marion and Prince Edward Islands, where they feed on seals and penguins (Reisinger et al., 2011).

Supporting Information

Arthur, B., Hindell, M., Bester, M., De Bruyn, P. J. N., Goebel, M. E., Trathan, P., & Lea, M.-A. 2018. Managing for change: Using vertebrate at sea habitat use to direct management efforts. Ecological Indicators, 91, 338–349. doi: 10.1016/j.ecolind.2018.04.019

Arthur, B., Hindell, M., Bester, M., De Bruyn, P. J. N., Trathan, P., Goebel, M., & Lea, M.-A. 2017. Winter habitat predictions of a key Southern Ocean predator, the Antarctic fur seal (Arctocephalus gazella). Deep Sea Research Part II: Topical Studies in Oceanography, 140, 171–181. doi: 10.1016/j.dsr2.2016.10.009

Arthur, B., Hindell, M., Bester, M. N., Oosthuizen, W. C., Wege, M., & Lea, M.-A. 2016. South for the winter? Within-dive foraging effort reveals the trade-offs between divergent foraging strategies in a free-ranging predator. Functional Ecology, 30(10), 1623–1637. doi: 10.1111/1365-2435.12636

Bester, M., de Bruyn, P., Oosthuizen, W., Tosh, C., McIntyre, T., Reisinger, R., … Wege, M. 2011. The Marine Mammal Programme at the Prince Edward Islands: 38 years of research. African Journal of Marine Science, 33(3), 511–521. doi: 10.2989/1814232X.2011.637356

Bester, M. N., Hofmeyr, G. J. G., Kirkman, S. P., Chauke, L. F., De Bruyn, P. J. N., Ferreira, S. M., … Wilkinson, I. S. 2006. The leopard seal at Marion Island, vagrant or seasonal transient? South African Journal of Wildlife Research, 36(2), 195–198.

Bester, M. N., Pansegrouw, H. M. 1992. Ranging behaviour of southern elephant seal cows from Marion Island. South African Journal of Science, 88, 574–575.

Bester, M N, Ryan, P. G., & Visagie, J. 2009. Summer survey of fur seals at Prince Edward Island, southern Indian Ocean. African Journal of Marine Science, 31, 451–455.

Bester, Marthán N, & Hofmeyr, G. J. 2005. Numbers of elephant seals at Prince Edward Island, Southern Ocean. South African Journal of Wildlife Research, 35, 85–88

De Bruyn, P. J. N., Bester, M. N., Oosthuizen, W. C., Hofmeyr, G. J. G., Pistorius, P. A. 2016. A conservation assessment of Mirounga leonina. In Child MF, Roxburgh L, Do Linh San E, Raimondo D, Davies-Mostert HT, editors. The Red List of Mammals of South Africa, Swaziland and Lesotho. South African National Biodiversity Institute and Endangered Wildlife Trust, South Africa.

De Bruyn, P. J. N., Tosh, C. A., Oosthuizen, W. C., Bester, M. N., & Arnould, J. P. Y. 2009. Bathymetry and frontal system interactions influence seasonal foraging movements of lactating subantarctic fur seals from Marion Island. Marine Ecology Progress Series, 394, 263–276.

Hindell, M. A., McMahon, C. R., Bester, M. N., Boehme, L., Costa, D., Fedak, M. A., … Charrassin, J.-B. 2016. Circumpolar habitat use in the southern elephant seal: implications for foraging success and population trajectories. Ecosphere, 7(5), e01213. doi: 10.1002/ecs2.1213

Hofmeyr, G. J. G., Bester, M. N., Makhado, A. B., & Pistorius, P. A. 2006. Population changes in Subantarctic and Antarctic fur seals at Marion Island. South African Journal of Wildlife Research, 36(1), 55–68.

Hofmeyr GJG, de Bruyn PJN, Bester MN, Wege M. 2016a. A conservation assessment of Arctocephalus gazella. In Child MF, Roxburgh L, Do Linh San E, Raimondo D, Davies-Mostert HT, editors. The Red List of Mammals of South Africa, Swaziland and Lesotho. South African National Biodiversity Institute and Endangered Wildlife Trust, South Africa.

Hofmeyr GJG, de Bruyn PJN, Wege M, Bester MN. 2016b. A conservation assessment of
Arctocephalus tropicalis. In Child MF, Roxburgh L, Do Linh San E, Raimondo D, Davies-Mostert HT, editors. The Red List of Mammals of South Africa, Swaziland and Lesotho. South African National Biodiversity Institute and Endangered Wildlife Trust, South Africa.

Kirkman, S. P., Yemane, D. G., Lamont, T., Meÿer, M. A., & Pistorius, P. A. 2016. Foraging behavior of subantarctic fur seals supports efficiency of a marine reserve’s design. PLoS ONE, 11(5), 1–19. doi: 10.1371/journal.pone.0152370

Lombard, A. T., Reyers, B., Schonegevel, L. Y., Cooper, J., Smith-Adao, L. B., Nel, D. C., … Chown, S. L. 2007. Conserving pattern and process in the Southern Ocean: designing a Marine Protected Area for the Prince Edward Islands. Antarctic Science, 19(01), 39–54. doi: 10.1017/S0954102007000077

Massie, P. P., McIntyre, T., Ryan, P. G., Bester, M. N., Bornemann, H., & Ansorge, I. J. 2016. The role of eddies in the diving behaviour of female southern elephant seals. Polar Biology, 39(2), 297–307. doi: 10.1007/s00300-015-1782-0

McIntyre, T., de Bruyn, P. J. N., Ansorge, I. J., Bester, M. N., Bornemann, H., Plötz, J., & Tosh, C. A. 2010. A lifetime at depth: vertical distribution of southern elephant seals in the water column. Polar Biology, 33(8), 1037–1048. doi: 10.1007/s00300-010-0782-3

Pistorius, P., De Bruyn, P., & Bester, M. 2011. Population dynamics of southern elephant seals: a synthesis of three decades of demographic research at Marion Island. African Journal of Marine Science, 33(3), 523–534. doi: 10.2989/1814232X.2011.637613

Postma, M., Wege, M., Bester, M. N., van der Merwe, D. S., & De Bruyn, P. J. N. 2011. Inshore occurrence of southern right whales (Eubalaena australis) at Subantarctic Marion Island. African Zoology, 46(1), 188–193.

Reisinger, R. R., de Bruyn P. J. N. 2014. Marion Island killer whales: 2006-2013. Mammal Research Institute, University of Pretoria. DOI: https://doi.org/10.6084/m9.figshare.971317

Reisinger, R. R., Keith, M., Andrews, R. D., & de Bruyn, P. J. N. 2015. Movement and diving of killer whales (Orcinus orca) at a Southern Ocean archipelago. Journal of Experimental Marine Biology and Ecology, 473, 90–102. doi: 10.1016/j.jembe.2015.08.008

Reisinger, R. R., Raymond, B., Hindell, M. A., Bester, M. N., Crawford, R. J. M., Davies, D., … Pistorius, P. A. 2018. Habitat modelling of tracking data from multiple marine predators identifies important areas in the Southern Indian Ocean. Diversity and Distributions, 24(4), 535–550. doi: 10.1111/ddi.12702

Reisinger, R. R, de Bruyn, P., Tosh, C., Oosthuizen, W., Mufanadzo, N., & Bester, M. 2011. Prey and seasonal abundance of killer whales at sub-Antarctic Marion Island. African Journal of Marine Science, 33(1), 99–105. doi: 10.2989/1814232X.2011.572356

Reisinger, R. R., Gröcke, D., Lübcker, N., McClymont, E., Hoelzel, A., & de Bruyn, P. 2016. Variation in the diet of killer whales Orcinus orca at Marion Island, Southern Ocean. Marine Ecology Progress Series, 549, 263–274. doi: 10.3354/meps11676

Ropert-Coudert, Y., Van de Putte, A., Reisinger, R., Bornemann, H., Charrassin, J.-B., Costa, D., … Hindell, M. 2020. The retrospective analysis of Antarctic tracking data project. Sci Data 7, 94. https://doi.org/10.1038/s41597-020-0406-x

Ryan, P. G., & Bester, M. N. 2008. Pelagic predators. In S. L. Chown & P. W. Froneman (Eds.), The Prince Edward Islands. Land-sea interactions in a changing ecosystem (pp. 121–164). doi: 10.18820/9781928314219/06

Tosh, C., Steyn, J., Bornemann, H., van den Hoff, J., Stewart, B., Plötz, J., & Bester, M. 2012. Marine habitats of juvenile southern elephant seals from Marion Island. Aquatic Biology, 17(1), 71–79. doi: 10.3354/ab00463

UNEP-WCMC and IUCN. 2018. Protected Planet: The World Database on Protected Areas (WDPA)/The Global Database on Protected Areas Management Effectiveness (GD-PAME)]. Cambridge, UK: UNEP-WCMC and IUCN. Available at: www.protectedplanet.net.

Wege, M., Tosh, C. A., De Bruyn, P. J. N., & Bester, M. N. 2016b. Cross-seasonal foraging site fidelity of subantarctic fur seals: Implications for marine conservation areas. Marine Ecology Progress Series, 554, 225–239. doi: 10.3354/meps11798

Wege, Mia, Etienne, M. P., Chris Oosthuizen, W., Reisinger, R. R., Bester, M. N., & de Bruyn, P. J. N. 2016a. Trend changes in sympatric Subantarctic and Antarctic fur seal pup populations at Marion Island, Southern Ocean. Marine Mammal Science, 32(July), 960–982. doi: 10.1111/mms.12306

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