Half Moon Island / Yankee Harbour, Greenwich Island - Thursday, January 6, 2005
Long: 62° 35,46 S
Lat: 59° 54,39 W
Temp: 1 C°
Water Temp: 0,5 C°
Wind: 5 Knts
Wind Direction: Variable
Photo ci contre : Antarctic Fur Seal at Half Moon Island (by Colin Baird)
In February 1819, British merchant William Smith was rounding Cape Horn in his brig Williams when he was blown south by a storm and first sighted the islands. Smith was promptly made the pilot of his own ship as the British authorities in Valparaiso placed aboard naval Captain Edward Bransfield. Together Bransfield and Smith surveyed the islands naming them for their similarity in latitude to Scotland's Shetland Islands. They then crossed Bransfield's eponymous strait and sighted the Antarctic Peninsula. This was considered for many years to be the first known sighting of Antarctica. However, an ethnic German from Estonia working for the Russian Navy named Thaddeus Thaddevich von Bellingshausen had unknowingly beaten them by three days. Being a Russian ship captain, Bellingshausen was working off the ten month Julian calendar and it wasn't until the 1940's when his work was translated into the twelve month Gregorian calendar that his prior claim was discovered. Smith's discovery precipitated a massive invasion of the islands by sealers and within a few years the fur seal population was almost entirely decimated. Since the sealers were largely secretive about their findings, we can never be truly sure of who discovered what and when.
The South Shetlands are the "banana belt" of Antarctica with the highest concentration of scientific bases and diversity of species. Adélie, gentoo, chinstrap, and macaroni penguins all breed here, the fur seal population has recovered from its earlier devastation, elephant seal wallows abound and Weddell seals often haul out on shore. One can also see orca, humpback, fin, Minke, and Sei whales in the water around the islands and many pintado petrels, kelp gulls, south polar skuas, Antarctic terns, and snowy sheathbills in the air. The shores flourish with moss beds, lichen covered rocks, and Antarctica's two species of vascular plant; the hair grass Deschampsia antarctica and the pearlwort Colobanthis quitensis. Remains from the sealing and whaling eras are plentiful including beaches littered with whalebones and skeletons. Due to the treacherous nature of the nine main and 150 or so tiny islands, shipwrecks were a common occurrence in the early years and have added to the rich history of the islands. It is thought that shipwrecked sailors on King George Island were the first people to winter over in the Antarctic.
Photo ci contre : Whale bones at Half Moon Island (by Colin Baird)
A tiny two-kilometre long crescent-shaped island in the shadow of the picturesque mountains and glaciers of nearby Livingston Island, Half Moon is a favoured expedition stop for its large chinstrap penguin rookery. There are over 6,000 chinstraps nesting on the jagged, scree-covered slopes and a lone, obviously errant macaroni penguin was spotted on the far end of the island. This area featured an impressive array of coloured lichens clinging to the rocks. The serrated and crevassed cliffs are also home to Antarctic terns, kelp gulls, snowy sheathbills, and Wilson's storm petrels. Our landing was made on an easily accessible, wide beach where an abandoned dory lies decaying. Once up the hill, there were magnificent views of Livingston. Down towards the western end of the beach is Teniente Camara station with its huge Argentine flags emblazoned on the orange buildings. The station has been sporadically staffed in recent years due to the Argentine economy and was not available for visitation. Like all penguins, chinstraps are counter-shaded white on the front and black on the back. They can be distinguished by the white face and black cap with a distinctive black stripe from ear to ear running under the chin. This gives them the appearance of wearing a small black bicycling helmet. Typical size is 70-75 centimetres tall and 3.5-5 kilograms. Chinstraps are quite quarrelsome and noisy and the rookery was bustling with activity. They are the second most abundant species behind the macaroni penguin and the world population is estimated at 7.5 million. Unlike other species that lay two eggs, chinstraps treat both chicks equally. The 18th century Macaroni Club consisted of British haute couture enthusiasts who were noted for their elaborate hairstyles. The macaroni penguin's name derives from them and not the pasta as they have flamboyant yellow-orange tassels that meet in the centre of their heads. Typically seventy centimetres tall and 4-5.5 kilograms, macaronis are among the largest of the Eudyptes or crested penguins. The female lays two eggs but rarely are both reared. A single fur seal was also seen in the opposite direction from the macaroni. The Antarctic fur seal is found on the rocky coastlines of ice-free islands and beaches south of or close to the Antarctic Convergence including the South Shetland Islands and the South Orkney Islands with 95% of the population breeding on the island of South Georgia. The species was hunted to near extinction in the 19th and 20th centuries. It is thought that their resurgence is due to the ensuing slaughter of whales, removing them as a competition for food. Sexual dimorphism is noticeable with the males growing to an average of 188 kilograms and the females an average of only 37 kilograms. Total infant gestation is just short of a year and females mate within a week of giving birth to a single pup. Mating takes place in the Antarctic spring and summer from October to January with most of the births in November and December. Male fur seals are viciously territorial and absolutely unapproachable at this time. Antarctic fur seals dive up to fifty metres and feed chiefly on krill but fish, squid, and some birds may be taken. In rare occurrences, they will take a penguin.
Photo ci contre : Elephant Seal (by Colin Baird)
A natural haven created by a 1 kilometre-long curved spit; Yankee Harbour is so well situated as to appear man-made. Named for the American sealers that frequented here in the 1820's, remnants of the era linger and a sealer's 'trypot' could be seen on the beach. Elephant and Weddell seals were seen on the beach and the main attraction was a terraced gentoo colony numbering around 4 000 pairs. Elephant seals are characterized by their large size and the enormous proboscis of the adult males, from which the species gets its name. The trunk-like noses are inflated, partly by blood pressure, in the mating season and may help in resonating the deep roars they make to announce their territory. In breeding season of September to November, larger males known as "beachmasters" can have harems of up to fifty females that they protect vigilantly. Sexually mature at four years, a male may have to wait until he is eight or nine before he is big enough to claim his own piece of beach. Battles for territory are fierce and pups can be crushed in the melee. By far the largest of the pinnipeds, adult males have been recorded as much as six metres long and
as heavy as a whopping 4,000 kilograms. The females are smaller averaging 2.7 metres long and 500 kilograms. Elephant seals have the richest milk of any mammal and pups can grow as much as nine kilograms per day. They are also noted for the deep dives they make for fish and squid that have been recorded to depths of 900 metres and lengths of 48 minutes. Their population has been decreasing rapidly in recent years and the reasons for this are not understood. While the South Georgia population remains stable, some islands like Macquarie and the Kerguelens have seen an 80-90% drop in numbers in the last forty years and the Argentine colony is the only one increasing.
The nearby glacier offered a dramatic backdrop and it was heard to grumble and crack. As it was a clear day, we could see across to Livingston and Half Moon Islands. A Zodiac ride back to the sip included a close-up of the glacier and a leopard seal. This is the Bad Boy of the Antarctic; the lean mean penguin-eating machine. Although the sight of a leopard seal thrashing a dead penguin against the water to separate flesh from feather is an exemplary Antarctic image, penguins represent as little as 10% of their diet. Leopards eat krill in abundance as well as young seals, fish, and squid. An exception to the usual phocidae rule, leopards have large front flippers that account for much of their propulsion and are extremely graceful in the water. Leopard seals have been seen to leap entirely out of the water in order to catch their prey. Despite their fierce reputation, there is only one recorded case of a leopard seal killing a human and this is largely considered an unfortunate fluke accident. As predatory as they are, leopards are not the top of the food chain and often fall prey to orca.
Our Little Red Ship then hauled up its anchor and set course for the Drake Passage and South America. As much as the penguins and seals still beckon, it was time to head home with our computer discs full of photos and our heads full of memories.
Programme de la Journée - planning of the day