Red List of South African Species

Alternatively, Explore species
| National Red List categories | Partners |
Least Concern (LC)
Assessors: Nico de Bruyn Marthan Bester Chris Oosthuizen Greg Hofmeyr Pierre Pistorius
Contributors: Steven Kirkman Herman Oosthuizen Mike Meyer Mdu Seakamela Lloyd Lowry Cheryl Tosh Samantha Page-Nicholson Mia Wege Matthew Child
Reviewers: Nico de Bruyn Marthan Bester Chris Oosthuizen Greg Hofmeyr Pierre Pistorius

Rationale

No serious threats have been affecting the land breeding colonies at Prince Edward Islands in the last 30 years (three generations time). The population on Marion Island, as estimated through annual pup production, declined by 83% between 1951 and 1994, which prompted the Endangered A2b listing in 2004. At its nadir in 1997 annual pup production at Marion Island was 421, but this has gradually increased to around 552 pups in 2015, representing a mature population of 1,740. If females not breeding in that year and neighbouring Prince Edward Island’s population are included, it probably equates to about 3,000 individuals in total for the Prince Edward Island population. Thus, although the population declined by 37% between 1986 and 1994, over the past three generations (1986–2015), the population only declined (from 690 pups in 1986 to 552 pups in 2015) by about 20% and in fact pup production has increased by 33% between 1997 and 2015, providing hope for a sustained positive population trajectory.

A 20% reduction over the last three generations is close to the threshold for applying the Near Threatened listing for the A criterion (20–25% reduction; IUCN Standards and petitions Subcommittee 2014). Thus, with no major current threats that could cause rapid population decline, and currently increasing pup production, we list the national population of Southern Elephant seals as Near Threatened A2b, with a prediction that this species can be further downlisted to Least Concern in the next revision. It is also worth noting that we do not fully understand the cause/s of the past decline, albeit attributed to food limitation. The causes of changes in food availability remains poorly understood. In all likelihood climate related impacts and oceanographic changes have influenced prey availability and distribution as well as spatial distribution of southern elephant seal foraging efforts.

Regional population effects: The global range is continuous and connected by movement of individuals between islands, with potential for augmentation or rescue of locally declining or extinct subpopulations. There is connectivity with the Îles Crozet but also with distant Îles Kerguelen (see Oosthuizen et al. 2011).

Distribution

Southern Elephant Seals have a circumpolar distribution in the Southern Hemisphere. Although they reach the Antarctic continent and even very high latitude locations such as Ross Island, they are most common north of the seasonally shifting pack ice, especially in Subantarctic waters where most rookeries and haul-outs are located. The northern-most breeding locality for the species is Gough Island, southern Atlantic, although the population is tiny (pup production c. 18 / year; Bester et al. 2001).

Some pups are also born on the Antarctic continent. Southern Elephant Seals prefer sandy and cobble beaches, but will haul-out on sea ice, snow and rocky terraces and regularly rest (but especially moult) above the beach in tussock grass, other vegetation, and mud wallows. At sea, females and males tend to disperse to different feeding grounds, although there is large individual variation in foraging site fidelity, and some overlap between the sexes and ages.

Within the assessment region, this species breeds on Prince Edward Island and Marion Island. Movement at sea is considerable and, even though breeding colonies are disjunct or fragmented, there is movement of individuals between colonies to ensure gene flow, and in one instance, Marion Island to Gough Island, which likely represents gene flow between provinces (Kerguelen and South Georgia provinces – see Reisinger & Bester 2010).

Wandering and vagrant Southern Elephant Seals reach southern Africa (with 1–3 sightings per year off South African coastlines).

Population trend

Trend

The worldwide population of Southern Elephant Seals was estimated to be 650,000 in the mid-1990s. No recent integrated estimate is available throughout the entire distribution.

Traditionally, three distinct provinces/populations have been distinguished: South Georgia, Macquarie and Îles Kerguelen. However, Elephant Seals breeding at Península Valdes on the mainland of South America and at the Falkland (Malvinas) Islands are now thought to be a distinct province/population from those at South Georgia. Similarly, the elephant seal populations at the Prince Edward Islands and Îles Crozet are also considered to be distinct from those at Îles Kerguelen and Heard Island, and the small subpopulation at Gough Island may also be distinct. Additionally, some colonies have unknown affiliations (e.g. Bouvet). Thus, there may be at least five and perhaps more, distinct breeding populations, although their foraging areas overlap quite extensively at sea (Reijnders et al. 1993; Bailleul et al. 2007; Biuw et al. 2007) and we suspect there is gene flow between the subpopulations (Reisinger & Bester 2010).

Due to the strict conservation status of Prince Edward Island access is sporadic and difficult. Population monitoring of Southern Elephant Seals is therefore based on annual censuses conducted on Marion Island which hosts the bulk of the Prince Edward Islands population. Adult females haul out synchronously to reach a peak on 15 October during which island-wide counts of females and pups are conducted. Based on life table analyses it has been estimated that the entire population can be estimated through multiplying pup numbers by a conversion factor of 3.15 (Pistorius et al. 1999). However, this is based on the assumption that all females (past primiparity) breed annually, which is not the case (de Bruyn et al. 2011). In fact about half seem to breed annually, so the correction factor based on 552 pups (2015) would give us around 1,740 animals from all sex-age categories annually, but because of skipping we would actually have a higher number in the mature population.

Within the assessment region, two periods of population decline are recorded: hunting pressure during the 1900s significantly reduced population size, which then recovered until the 1950s, but then saw a sharp decline of 83% between 1951 and c. 1994/1997 (Pistorius et al. 1999; McMahon et al. 2009), for largely unknown reasons although the “food limitation hypothesis” (suspected loss of prey availability, the drivers of which remain speculative) has received most support (Pistorius et al. 1999). Between 1986 and 1994 the population declined by 37% (2,120 [690 pups born] to 1,330 [437 pups born] individuals, Pistorius et al. 1999). Over the last three generations (1984/1986 – 2015), the population decline decelerated to 20% (from 690 pups to 552 pups) and in fact pup production (based on direct counts) has increased by 33% between 1997 and 2015 (from 421 to 552 pups), providing hope for a sustained positive population trajectory.

The population remained stable between 1993 and 1999 (Pistorius et al. 2004, but see McMahon et al. 2009) and has since shown a general increase; numbering about 1,740 individuals (552 pups born) in 2015 at Marion Island alone (Pistorius et al. 2011). By utilizing total peak breeding season counts at Marion Island and including conversion factors from pup numbers, the mature archipelago population, including the smaller Prince Edward Island population, numbers between 2,500 and 3,200 individuals (Mammal Research Institute, unpubl. data).

Threats

There are few threats and conflicts today, as Southern Elephant Seals live far from human population centres and have minimal interactions with commercial fisheries, but are affected to various degrees by entanglement in fishing gear (Hofmeyr et al. 2002; Campagna et al. 2007). Intensive fishing could potentially deplete important prey stocks. However, relatively little is known about their feeding habits. There is no evidence that recent declines for animals breeding in the Indian and Pacific Oceans are related to fisheries in the Southern Ocean. However, development of new fisheries at high latitudes in the future could have a significant impact on Elephant Seal populations.

Southern Elephant Seals that haul out at mainland sites could come in contact with feral dogs and other terrestrial carnivores and be exposed to a variety of diseases including morbilliviruses (Bester 2014).

The possible effects of global climate and associated oceanographic change on Southern Elephant Seals are not well understood. Learmonth et al. (2006) suggest that while the effects of global climate change are uncertain, the species is likely to decline as a result of habitat and ecosystem changes. For example, predicted reduction in sea ice habitats due to continued climate warming will impact the distribution of food and breeding habitat for the species. Predictions are not clear yet regarding how these effects will impact the size of the populations.

Small population sizes facilitate minor threats such as predation and genetic drift, which may threaten local breeding colonies. Reisinger et al. (2011) refuted the claim that predation from Killer Whales is a current threat at the Prince Edward islands, although such predation undoubtedly plays some regulatory role on this population. Furthermore, there is immigration into the Prince Edward Islands population from elsewhere (particularly the French Islands to the east). Changes in Elephant Seal numbers at these islands could impact on local population growth.

Uses and trade

Southern Elephant Seals were historically commercially harvested, starting in the early 19th century and not ending completely until 1964 at South Georgia. They were prized for their large quantity of blubber that could be rendered to fine, valuable oil. This hunting caused precipitous declines. However, this species is no longer commercially harvested.

Conservation

Any future exploitation within the Antarctic Treaty area (south of 60ºS) would be regulated by the Convention for the Conservation of Antarctic Seals. Listed on CITES Appendix II.

Seals on the Prince Edward Islands are protected by virtue of these islands’ status as a special nature reserve and also by the South African Seabirds and Seals Protection Act (PEIMP 2010), and thus the breeding grounds within the assessment region are secure.

Recommendations for land managers and practitioners:
  • Continuation of monitoring and research programme conducted to date (over the past 3 decades) by the Marion Island Marine Mammal Programme under the auspices of the Mammal Research Institute, University of Pretoria.
Research priorities:
  • Understanding cause of decline since the 1950s, and reasons for current increase.
  • Understanding the causes and consequences of skipping behaviour in breeding female southern elephant seals
  • Understanding individual temporal and spatial variation in foraging behaviour
  • The effect of global climate change on the foraging and breeding behaviour of this species.
  • The incredible physiological feats shown by the species, for example deep diving, breath holding and fasting abilities, provide challenging questions to enhance our broader understanding of ecophysiology, environmental adaptation and evolution in mammals more generally.
Encouraged citizen actions:
  • Foraging ecology research is progressing but impeded by the financial investment that is required for satellite telemetry. Aid in funding this aspect can be securely provided through: http://www.givengain.com/cause/4655/

References 

[@article{2058,
 author = {Learmonth, J.A., Macleod, C.D., Santos, M.B., Pierce, G.J., Crick, H.Q.P. and Robinson, R.A.},
 journal = {Oceanography and Marine Biology: An Annual Review},
 pages = {431--464},
 title = {Potential effects of climate change on marine mammals},
 volume = {44},
 year = {2006}
}
,@article{2058,
 author = {Hofmeyr, G. J. G., De Maine, M., Bester, M. N., Kirkman, S. P., Pistorius, P. A. and Makhado, A. B.},
 journal = {Australian Mammalogy},
 pages = {141--146},
 title = {Entanglement of pinnipeds at Marion Island, Southern Ocean, 1991-2001},
 volume = {24},
 year = {2002}
}
,@book{2060,
 author = {Reijnders, P., Brasseur, S., van der Toorn, J., van der Wolf, P., Boyd, I., Harwood, J., Lavigne, D. and Lowry, L.},
 publisher = {IUCN Seal Specialist Group},
 title = {Seals, fur seals, sea lions, and walrus. Status survey and conservation action plan},
 year = {1993}
}
,@article{2062,
 author = {Reisinger, R.R., de Bruyn, P.J.N. and Bester, M.N.},
 journal = {Journal of Zoology, London},
 pages = {1--10},
 title = {Predatory impact of killer whales on pinniped and penguin populations at the Subantarctic Prince Edward Islands: fact and fiction},
 volume = {285},
 year = {2011}
}
,@article{2062,
 author = {Smith VR},
 journal = {Polar Record },
 pages = {211–226},
 title = {Energy flow and nutrient cycling in the Marion Island terrestrial ecosystem: 30 years on},
 volume = {44},
 year = {2008}
}
,@article{13583,
 author = {Jones, E.},
 journal = {Australian Wildlife Reseach},
 pages = {327--334},
 title = {Age in relation to breeding status of the male southern elephant seal, <i>Mirounga leonina</i> (L.), at Macquarie Island},
 volume = {8},
 year = {1981}
}
,@article{13583,
 author = {Pistorius, P. A., Bester, M. N., Lewis, M., Taylor, F. E., Campagna, C. and Kirkman, S. P.},
 journal = {Journal of Zoology (London)},
 number = {2},
 pages = {107--119},
 title = {Adult female survival, population trend, and the implication of early primiparity in a capital breeder, the southern elephant seal (<i>Mirounga leonina</I>)},
 volume = {263},
 year = {2004}
}
,@article{13583,
 author = {Bailleul, F., Charrassin, J. B., Monestiez, P., Roquet, F., Biuw, M. and Guinet, C.},
 journal = {Philosophical Transactions of the Royal Society B, Biological Sciences},
 pages = {2169--2181},
 title = {Successful foraging zones of southern elephant seals from the Kerguelen Islands in relation to oceanographic conditions},
 volume = {362},
 year = {2007}
}
,@article{13583,
 author = {Biuw, M., Boehme, L., Guinet, C., Hindell, M., Costa, D., Charrassin, J. B., Roquet, F., Bailleul, F., Meredith, M., Thorpe, S., Tremblay, Y., McDonald, B., Park, Y. H., Rintouul, S. R., Bindoff, N., Boebel, M., Crocker, D., Lovell, P., Nicholson, J., Monks, F. and Fedak, M. A.},
 journal = {Proceedings of the National Academy of Sciences of the United States of America},
 pages = {13705--13710},
 title = {Variations in behavior and condition of a Southern Ocean top predator in relation to <i>in situ</i> oceanographic conditions},
 volume = {104},
 year = {2007}
}
,@article{13583,
 author = {Campagna, C., Falabella, V. and Lewis, M.},
 journal = {Marine Mammal Science},
 number = {2},
 pages = {414--418},
 title = {Entanglement of southern elephant seals in squid fishing gear},
 volume = {23},
 year = {2007}
}
,@article{13583,
 author = {McCann, T. S.},
 journal = {Biological Journal of the Linnean Society},
 pages = {133--150},
 title = {Population structure and social organization of southern elephant seals <i>Mirounga leonina</i> (L)},
 volume = {14},
 year = {1980}
}
,@article{13583,
 author = {McIntyre, T., deBruyn, P.J.N., Ansorge, I.J., Bester, M.N., Bornemann, H., Plötz, J. and Tosh, C.A.},
 journal = {Polar Biology},
 pages = {1037--1048},
 title = {A lifetime at depth: vertical distribution of southern elephant seals in the water column},
 volume = {33},
 year = {2010}
}
,@article{13583,
 author = {McMahon, C.R., Bester, M.N., Hindell, M.A., Brook, B.W. and Bradshaw, C.J.A.},
 journal = {Oecologia},
 pages = {69--82},
 title = {Shifting trends: detecting environmentally mediated regulation in long-lived marine vertebrates using time-series data},
 volume = {159},
 year = {2009}
}
,@article{13583,
 author = {Pistorius, P.A., de Bruyn, P.J.N. and Bester, M.N.},
 journal = {African Journal of Marine Science},
 pages = {523--534},
 title = {Population dynamics of southern elephant seals: a synthesis of three decades of demographic research at Marion Island},
 volume = {33},
 year = {2011}
}
,@article{13583,
 author = {Reisinger, R.R. and Bester, M.N.},
 journal = {Polar Biology},
 pages = {1289--1291},
 title = {Long distance breeding dispersal of a southern elephant seal},
 volume = {33},
 year = {2010}
}
,@inbook{13583,
 address = {Dordrecht, Netherlands.},
 author = {Freedman },
 booktitle = {Marine Mammals – Natural and Anthropogenic Influences},
 editor = {Bester M.},
 pages = {167–174},
 publisher = {Springer},
 title = {Global Environmental Change},
 year = {2014}
}
,@article{13583,
 author = {Bester MN, Möller H, Wium J, Enslin B.},
 journal = {South African Journal of Wildlife Research},
 pages = {68–71},
 title = {An update on the status of southern elephant seals at Gough Island},
 volume = {31},
 year = {2001}
}
,@article{13583,
 author = {De Bruyn PJN, Tosh CA, Bester MN, Cameron EZ, McIntyre T, Wilkinson IS.},
 journal = {Animal Behaviour},
 pages = {445–451},
 title = {Sex at sea: alternative mating system in an extremely polygynous mammal.},
 volume = {82},
 year = {2011}
}
,@article{13583,
 author = {McIntyre T, Ansorge IJ, Bornemann AH, Plötz J, Tosh CA, Bester MN.},
 journal = {Marine Ecology Progress Series},
 pages = {257–272},
 title = {Elephant seal dive behaviour is influenced by ocean temperature: implications for climate change impacts on an ocean predator.},
 volume = {441},
 year = {2011}
}
,@article{13583,
 author = {Oosthuizen WC, Bester MN, Tosh CA, Guinet C, Besson D, de Bruyn PJN.},
 journal = {Antarctic Science},
 pages = {567–577},
 title = {Dispersal and dispersion of southern elephant seals in the Kerguelen Province Southern Ocean},
 volume = {23},
 year = {2011}
}
,@article{13583,
 author = {Pistorius PA, Bester MN, Kirkman SP.},
 journal = {Oecologia},
 pages = {201–211},
 title = {Survivorship of a declining population of southern elephant seals, Mirounga leonina, in relation to age, sex and cohort.},
 volume = {121},
 year = {1999}
}
,@article{13583,
 author = {Tosh CA, de Bruyn PN, Steyn J, Bornemann H, van den Hoff J, Stewart BS, Plötz J, Bester MN.},
 journal = {Marine Biology},
 pages = {2131–2140},
 title = {The importance of seasonal sea surface height anomalies for foraging juvenile southern elephant seals.},
 volume = {162},
 year = {2015}
}
,]
Send feedback about this assessment to SANBI

Lead agencies, Partners and Funders

See the partners page