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Africa News afrol News
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Africa News afrol News
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afrol.com, 29 June - In terms criteria of The World Conservation Union (IUCN), both the African Penguin and Bank Cormorant, the two seabirds most at risk at Robben Island following sinking of Treasure, are classified as "Vulnerable", meaning that they have a high risk of extinction in the medium term. Their populations number about 0.18 million adults and 5000 breeding pairs respectively. The breeding population of African Penguins is about 56000 pairs because not all birds that have moulted to adult plumage are of breeding age. In 2000, Robben Island was home to the third largest colony of African Penguins. A count undertaken from 17 May-14 June showed that the island was used by 5700 pairs of breeding penguins, the third largest colony for the species. This indicates that the island is used by a minimum of 11400 adults. As most colonies also include non-breeders, it is expected that 12-14 thousand penguins will have been based at Robben Island at the time that Treasure sank on 23 June 2000. From 22-27 April 2000, Dassen Island, to the north of the spot where Treasure sank, supported 15600 breeding pairs of penguins. It was the largest breeding colony for the species in 2000, and Dassen and Robben islands supported at least 38% of the overall population of the species. On 25 June 2000, oil washed ashore at Robben Island on the entire stretch of coastline from the northern point to Murray’s Bay Harbour, i.e. along that stretch of the coastline used by almost all penguins at the island to access their nest sites. All birds entering the sea from the island were becoming immediately oiled. Staff of Marine and Coastal Management at the island confirmed that on the evening of 25 June 2000 all birds leaving the sea for the island were oiled. Therefore, it is apparent that, unless oil is speedily cleared from the coastline used by penguins at Robben Island, the entire adult population there will soon be oiled. On 26 June 2000, Mr A. Moldan advised that penguins putting to sea at Robben Island in the next 4-5 days will be at high risk of oiling. Ms E. van der Merwe, centre manager of SANCCOB (Southern African National Foundation for the Conservation of Coastal Birds), estimates that it takes an experienced penguin feeder 20 minutes per day to feed an adult penguin. Therefore, should 14000 penguins be oiled and rescued, the feeding time per day would amount to 280000 minutes or 4667 hours. This would mean that 583 persons would have to feed penguins for eight hours each daily. The number of experienced feeders is probably less than 50. In addition to feeding penguins, it is necessary to medicate oiled birds. Ingested oil can cause ulceration in the mouth, oesophagus and stomach, and in severe cases can lead to substantial blood loss. Oil absorbed into the system can cause red blood cells to rupture, leading to anaemia. Further, an immuno-suppressent effect makes birds more susceptible to diseases such as pneumonia and aspergillosis. If a bird gets oil in its eye, it can lead to ulceration of the cornea, which can lead to blindness if left untreated. It is necessary to medicate each oiled penguin, and this too is a time-consuming process. Similarly, each oiled penguin must be cleaned, again a time-consuming process. Oil destroys a bird’s waterproofing by causing its feathers to clump together. This leads to hypothermia in cold seawater. An oiled bird will not hunt, but mobilise its fat reserves and eventually dehydrate and die. Clearly, the fewer birds that SANCCOB has to deal with, the better it will be able to cope with those it has and the greater will be the success of rehabilitating oiled penguins. Therefore, it is essential to keep as many un-oiled birds at Robben Island form becoming oiled as possible. Two possibilities exist for these birds. Either they can be held and fed in a captive situation similar to that at SANCCOB, or they can be transported away from the oil spill and released to the wild. The latter alternative has the enormous advantages of decreasing the number of birds that need to be fed, as they will find their own food in the wild, and decreasing the risk of the clean birds contracting disease in a crowded situation. Hence, this is the preferred option. This is especially so as it is uncertain at this stage as to numbers from Dassen Island that may be oiled in addition to those from Robben Island. Probably at least several hundred birds from Dassen Island will be oiled. There is an accumulating body of evidence that African Penguins have a strong homing ability. An oiled penguin collected at St Croix Island that was cleaned and released in Cape Town returned to St Croix in about 11 days, travelling the 900 km journey at an average speed of 81 km per day. Algoa Bay off Port Elizabeth supports the second and fourth largest colonies of African Penguins and there is expected to be sufficient food there to temporarily support an additional number of penguins. However, penguins transported there may be back at Robben Island within about 10 days. Breeding birds tend to move rapidly to their home colonies to find their mates. Unless the coastline used by penguins at Robben Island is cleaned within this period, the translocated birds may be oiled. However, even then valuable breathing space would be gained. Mr Moldan on 26 June 2000 was investigating means of clearing the access points for penguins at Robben Island. Large-scale translocation of African Penguins is experimental. It is by no means certain that all will return to Robben Island. This makes it imperative to band as many of these birds as possible, so that their subsequent movements may be gauged. However, even if many birds do not return but remain in Algoa Bay, the objective of saving a significant portion of the overall adult population will have been achieved. It will be necessary that birds are transported in ideal conditions to minimize loses in transit. These conditions should be advised by SANCCOB. Staff of Port Elizabeth Museum will arrange release of all birds flown to Port Elizabeth at Cape Recife. South African Air Force advises that the C47-TP aircraft can maintain a suitable temperature. Adult African Penguins have a relatively high survival rate of about 90-95% per annum. Hence rescue efforts for this species will emphasise keeping as many adults as possible alive. Of birds held in captivity, a satisfactory target would be to release 80% (50% of those caught in the Apollo Sea oiling were released alive). Of unoiled birds flown to Port Elizabeth, it is hoped that as many as 95% might survive the translocation. A lot will depend on the condition of the birds at the time of their transportation. On 21 June 2000, it is estimated that there were 6140 chicks at Robben Island. It is planned to collect as many of these as possible for rearing. On 21 June 2000, an estimated 1052 pairs of penguins at Robben Island were incubating eggs. It is anticipated that these clutches will all be lost. A colony of about 120 pairs of Bank Cormorant, the third largest in South Africa, nested at Robben Island in 2000. By the time of the sinking of Treasure, several pairs had completed breeding but most were still engaged in breeding. On 25 June 2000, many of the Bank Cormorants at Robben Island were oiled. Attempts will be made to catch as many as possible, and to rear all chicks that are orphaned. South Africa’s second largest colony of Bank Cormorants at Clifton Rocks, as well as the colonies at Koeberg Harbour, Vöelsteen and Duikerklip are all at risk from the Treasure oil spill. The colonies at risk number about 284 breeding pairs, 6% of the overall population.
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