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Site description (2015 baseline):
Site location and context
Cormorant Island is a small, ice-free island located in Bismarck Strait, ~1 km south of Anvers Island and ~5 km from Arthur Harbour and Palmer Station (USA). The island is named for the large number of Imperial Shags (
Phalacrocorax [
atriceps]
bransfieldensis) observed on the island.
Cormorant Island and the nearshore marine area up to 50 m surrounding the island is now designated a Restricted Zone under the Management Plan for Antarctic Specially Managed Area No. 7: Southwest Anvers Island and Palmer Basin. The IBA qualifies on the basis of the Imperial Shag colony present and is defined by the boundary of the Restricted Zone.
Anvers Island and surrounding islands are dominated by granitic and volcanic rocks. Vegetation comprises a wide range of mosses, lichens and algae and includes the two native flowering plants Antarctic Hairgrass (
Deschampsia antarctica) and Antarctic Pearlwort (
Colobanthus quitensis) (ASMA No.7 Management Plan, 2009).
Climate data are not available specifically for Cormorant Island, although good records exist for nearby Palmer Station, where the average annual air temperature for the period 1989-2009 was –1.7°C. The minimum and maximum temperatures recorded at Palmer Station over the same period were –26.0°C and 11.6°C respectively. January is typically the warmest month and August the coldest (CLIMDB/HYDRODB, accessed 16/08/2010). Average annual precipitation has been 655 mm since 1989. Storms in the region are relatively frequent, whilst prevailing winds are generally light to moderate and from the northeast (ASMA No.7 Management Plan, 2009).
The nearest permanent scientific station is Palmer (USA), situated ~5 km to the northwest in Arthur Harbour. Palmer Station operates year-round, with summer occupancy of ~43 people (COMNAP, Antarctic Facilities, accessed 16/08/2010).
Cormorant Island is one of the largest colonies of Imperial Shag in the Antarctic Peninsula region, with 729 breeding pairs recorded in 1985 (unpublished data S. Poncet pers. comm. 2005). Adélie Penguins (
Pygoscelis adeliae) also breed on Cormorant Island, with 872 pairs recorded in the last published count (Parmelee & Parmelee 1987). Southern Giant Petrels (
Macronectes giganteus) breed on the island, numbering around 13 breeding pairs (W. Fraser, pers. comm. 2006).
Non-bird biodiversity: Fin Whale (
Balaenoptera physalus) and Sei Whale (
Balaenoptera borealis) have previously been observed near southern Anvers Island (ASMA No.7 Management Plan, 2009). Other species observed in the area include Minke Whale (
Balaenoptera bonaerensis), Killer Whale (
Orcinus orca), Humpback Whale (
Megaptera novaeangliae), Southern Right Whale (
Eubalaena australis) and Hourglass Dolphin (
Lagenorhynchus cruciger).
Seal species common to the Anvers Island area include the Weddell Seal (
Leptonychotes weddellii), Southern Elephant Seal (
Mirounga leonina), Crabeater Seal
(Lobodon carcinophagus), Leopard Seal (
Hydrurga leptonyx) and Antarctic Fur Seal (
Arctocephalus gazella). However, there are no records of seals breeding in the area (ASMA No. 7 Management Plan, 2009).
Pressure/threats to key biodiversity
One of the largest marine oil spills in Antarctica occurred ~5 km from Cormorant Island with the sinking of the ship Bahia Paraiso in 1989 in Arthur Habour. The spill of ~600 000 litres of diesel oil affected bird breeding performance and the nearshore marine environment for several years. It has been estimated that ~16 % of Adélie Penguins exposed to the spill may have been killed (Penhale et al. 1997). Populations have now recovered, and the impacts are not considered to have been as long-term as initially feared. The event, however, raised significant conservation and marine planning concerns. With large colonies of breeding wildlife in the local area, and a substantial programme of science being carried out, ASMA No. 7 Southwest Anvers Island and Palmer Basin was designated in 2007 to coordinate national program activities and protect the outstanding environment of the region and science being conducted in the area.
Restricted Zones such as Cormorant Island have been designated under ASMA No. 7 because of their ecological and scientific value and their sensitivity to disturbance. Access to Cormorant Island between 1 October and 15 April is not permitted except by those conducting ‘essential scientific research, monitoring or maintenance' (ASMA No. 7 Management Plan, 2009). Specific guidelines aim to minimise disturbance to birds during the breeding season.
Arthur Harbour and Palmer Station are popular destinations for tourist cruise ships and yachts. However, under the ASMA No. 7 Management Plan tour visits are directed to Palmer Station itself and to the Torgersen Island Visitor Zone, and all visits are strictly controlled. Thus, whilst the annual number of tourists visiting the vicinity are relatively high (e.g. 8637 at Palmer Station in the 2009/10 summer), the Restricted Zone ensures that human activity and disturbance at Cormorant Island is kept to a minimum.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Cormorant Island (Antarctica). Downloaded from
https://datazone.birdlife.org/site/factsheet/cormorant-island-iba-antarctica on 23/12/2024.
