Increase of sub-Antarctic fur seals at the Tristan da Cunha Islands
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Sub-Antarctic fur seal, Arctocephalus tropicalis, pups were counted on some of the beaches on all four Tristan da Cunha (TdC) islands, in January 2017, to determine the status of the population, in the face of climate change that is magnified in polar regions. Compared to counts done 40 years earlier on Gough, the breeding population increased markedly on some beaches, although negligibly on the largely open boulder beaches on the leeward northeastern sector of the island. Similarly, on the northern group of the TdC islands, the breeding population had increased markedly (including the very first pup counts at Inaccessible and Nightingale), despite fur seal females currently selecting only certain beaches for pupping (at Inaccessible and Tristan). At Tristan da Cunha, only one small breeding colony occurs which is remote from the human settlement, probably the result of anthropogenic disturbance.
KeywordsSub-Antarctic fur seals Pup counts Tristan da Cunha islands Population increase
Andy Schofield from the RSPB arranged for our (MRI, UP) participation in the NGPS expedition to the TdC islands; the NGPS project expedition leader (Paul Rose) and chief scientist (Jennifer Caselle) factored in our research needs; the TdC Conservation and Fisheries departments provided additional logistical support; and the logistical support of the Captain, officers, and crew of the SVS Grenville is acknowledged. The authors thank Dan Meyer (NatGeo) and Jonathan Hall (RSPB) for assistance in the field, and Peter Ryan for sharing his unpublished results from Inaccessible Island.
Compliance with ethical standards
The University of Pretoria Animal Ethics Committee (Project Number EC077-15) cleared the procedures of this project, executed under an Environmental Research Permit, including the Wildlife and Protected Areas Research Permit, of the Tristan da Cunha Government.
- Bester MN (1982a) Distribution, habitat selection and colony types of the Amsterdam Island fur seal Arctocephalus tropicalis at Gough Island. J Zool Lond 196:17–231Google Scholar
- Bester MN (1982b) The effect of the Subantarctic environment on aspects of the terrestrial phase of fur seal populations. Com Nat fr Rech Antarct 51:469–478Google Scholar
- Bester MN (1984) Status of the populations of the fur seals Arctocephalus tropicalis and Arctocephalus gazella north of the Antarctic Convergence. S Afr J Sci 80:27–28Google Scholar
- Bester MN (1987) Subantarctic Fur Seal, Arctocephalus tropicalis, at Gough Island (Tristan da Cunha Group). In: Croxall JP, Gentry RL (eds) Status, biology, and ecology of fur seals: proceedings of an international symposium and workshop, Cambridge, England, 23–27 April 1984, NOAA Technical Report NMFS 51, Seattle, Washington, pp 57–60Google Scholar
- Bester MN (1990) Population trends of Subantarctic fur seals and southern elephant seals at Gough Island. S Afr J Antarct Res 20:9–12Google Scholar
- Bester MN, Ryan PG (2007) Mammals. In: Ryan P (ed) Field guide to the animals and plants of Tristan da Cunha and Gough Island. Pisces Publications, Newbury, pp 99–108Google Scholar
- Bester MN, Wilson JW, Burle M-H, Hofmeyr GJG (2006) Population trends in Subantarctic fur seals at Gough Island. S Afr J Wildl Res 36:191–194Google Scholar
- Condy PR (1978) Distribution, abundance and annual cycle of fur seals (Arctocephalus spp.) on the Prince Edward Islands. S Afr J Wildl Res 8:159–168Google Scholar
- Cooper J, Headland RK (1991) A history of South African involvement in Antarctica and at the Prince Edward Islands. S Afr J Antarct Res 21:77–91Google Scholar
- Hofmeyr GJG, Bester MN, Makhado AB, Pistorius PA (2006) Population changes in Subantarctic and Antarctic fur seals at Marion Island. S Afr J Wildl Res 36:55–68Google Scholar
- Wace NM, Holdgate MW (1976) Man and nature in the Tristan da Cunha Islands. IUCN Monogr 6:1–114Google Scholar
- Wilkinson IS, Bester MN (1990) Continued population increase in fur seals, Arctocephalus tropicalis and A. gazella, at the Prince Edward Islands. S Afr J Antarct Res 20:58–63Google Scholar