|Avian Demography Unit
Department of Statistical Sciences
University of Cape Town
Seabird Islands of the Southern Ocean
The Prince Edward Islands
Samantha Petersen, Avian Demography Unit
The Prince Edward Islands are situated in the heart of the roaring forties, some 1 770 km south east of Port Elizabeth. This remote group of islands lie in the vast and largely inhospitable Southern Ocean. Here they are frequently at the mercy of tempestuous winds that blow from the west in these latitudes. With ever changing strength, they buffet the island, often reaching gusts of 160-200 km per hour. These circumpolar winds are constantly interrupted by cyclones producing rain, snow or graupel, which is "shotgun pellet-like ice-rain". Precipitation averages 2500 mm/year and the temperature averages 5.7 C. Observed temperatures are frequently somewhat lower as a result of wind chill. One might experience temperatures of minus 10 or 20 depending on wind speed, this is compounded by the rain resulting in dangerously low temperatures. There is also a low incidence of sunshine - only 3.6 hours per day on average. This group of islands is made up of Marion Island, the larger of the two islands and Prince Edward Island only 19km to the north. Marion Island is approximately 290 km2 with 72 km of mostly cliff-faced coastline.
This breathtakingly beautiful archipelago is home to 29 species of bird.
Penguins: Four species of penguin breed on the Prince Edward Islands, namely the King, Macaroni, Eastern Rockhopper and the Gentoo Penguin. There are over 200 000 King Penguins Aptenodytes patagonicus. These penguins are unusual in that they have no fixed breeding site, making population counts difficult. However, new breeding colonies have been established suggesting that the population is increasing. Rockhopper Penguins Eudyptes chrysocome, on the other hand are in not looking so good as their numbers have plummeted in recent years. This is the smallest of the four species and breed in relatively small groups all along the coastline of both islands. They moult shortly after breeding in summer and leave the island from May to October. Macaroni Penguins Eudyptes chrysolophus breed in larger colonies and boast a population in excess of 400 000. Their breeding season is similar to that of the Rockhopper although Macaroni Penguin returns to the island slightly earlier. Gentoo Penguins Pygoscelis papua the rarest penguin species of only 800 pairs are winter breeders and are resident on the island. Breeding is asynchronous and foraging is largely inshore.
Albatrosses: Four species of slbatross breed at the Islands, but the Yellow-nosed Albatross, an annual breeder, breeds only at Prince Edward Island. The Grey-headed Albatross, Wandering Albatross and the two Sooty Albatross species are biennial breeders on both islands.
Scavenging species: Both the southern (3300 pairs) and the more rare, Northern Giant Petrel (450 pairs) breed in summer on the Prince Edward Islands. The Sub-Antarctic Skua (1000 pairs) breeds territorially on the coastal plains. Most of these birds leave the island for the winter. The numbers of skuas have decreased in recent years. The Lesser Sheathbill (1400 pairs) is the only terrestrial species resident on the Prince Edward Islands. The Kelp Gull is a summer-breeding species and feeds terrestrially on earthworms and scavenged material, as well as limpets and bivalves in inshore waters.
Mammals: Two species of fur seal, namely the Antarctic Fur Seal and the sub-Antarctic Fur Seal as well as the Elephant Seal breed and moult on the Prince Edward Islands. Vagrant species include the Leopard Seal, Weddel Seal and South African Fur Seal. Pods of Killer Whales frequent both islands in summer.
The Prince Edwards Islands were first discovered in March of 1663 when the Maerseveen under the command of Barent Barentszoon Ham passed them en route to Java. The names then given to the islands were Dina and Maerseveen. More than a century passed before a French naval officer, MM Marion du Fresne was to rediscover the group of islands on his way south in search of the Antarctic continent. Due the fact that no land mass had been charted in the area he mistakenly thought he had reached the continent and renamed the islands terre d'Esperance or Ilse of Hope and the smaller island he named Ile de la Caverne, after a large cave he found on the north-east side of the island. After five days of attempting to land on the island he gave up and discovered that this was not a promontory of the continent, but in fact an island and changed the name to Ile des Froides or The Frigid Islands and sailed on eastwards to later discover the Crozet Islands. Only five years later the islands were renamed again, this time by Captain James Cook. Since his chart did not reveal the names bestowed by du Fresne, Captain Cook called them both the Prince Edward Islands after the fourth son of King George III. He too made no landing. Captain Cook subsequently heard of du Fresne's voyage and named the larger of the two islands in his honour, but it was not until the mid 19th century that this island was in fact referred to as Marion Island by sealers.
Sealers came from all over the world to exploit the animal resources on the islands from 1803. It took a mere seven years for the fur seal population to decline to a point were this activity alone was no longer viable and so in 1810 exploitation shifted its attention to the Elephant Seal. Blubber from these animals represented retrievable oil. By 1860 their numbers too had plummeted making this activity no longer economically viable. Richard Harris, a sealer recorded observations and collected sea birds during a visit in 1830. This was the first scientific endeavour ashore. A handful of scientific endeavours were attempted, but it was not until its annexation by South Africa in 1948 that the first scheduled research visits were officially undertaken in 1965.
Initially a meteorological station was set up. This station plays an important role in weather forecasts for South Africa and are crucial for the understanding of global climate patterns. Following close on the weather station was the initiation of a biological research program. The information gained from 36 years of continuous research is almost unparalleled in our understanding of the animals, plants and ecosystems on these islands.
Today teams of approximately 12 people occupy the island. Amongst these are a radio technician to ensure communication with the outside world, a medic (vital, as it is a five day voyage in the case of an emergency) and a diesel mechanic to ensure power, water etc. The remainder of the team is made of three people to manage and run the weather office and on average six scientist or field assistants. A relief voyage is undertaken annually by the SA Agulhas to replenish the island's food supplies and to replace the expedition members. Living on Marion is an experience hard to measure in worldly terms. Samantha Petersen was fortunate in that she spent a year living on Marion Island and working on Marine and Coastal Management's Seabird program. This project forms part of the South African National Antarctic program (SANAP) run by the Department of Environment and Tourism and is in part fulfilment of South Africa's obligation as a signatory to the Convention for the Conservation for Marine Living Resources (CCAMLR)