Efforts by the people of Tristan da Cunha to rescue birds in last year’s oil spill disaster appear to have been a great success, against enormous odds.
A count appears to show little impact on breeding among the island’s endangered rockhopper penguin colonies after the MS Oliva broke up on rocks.
But oil and cargo released into the South Atlantic from the ship have severely damaged the lobster fishery that provides islanders’ main source of income.
Tristanians had to rescue crew members of the MS Oliva when it hit rocks off neighbouring Nightinghale Island on March 16.
They then set up their own clean-up operation for wildlife while they waited more than a week for help to arrive from Cape Town, 1,700 miles away by sea.
The ship broke up in rough weather, discharging 1,500 tonnes of bunker fuel into the sea. The resulting slick reached Tristan and Inaccessible Island, a World Heritage Site.
Now a report by the Royal Society for the Protection of Birds says the breeding population of rockhopper penguins in the area has not suffered as much as anticipated.
But Dr Juliet Vickery, head of international research, says the figures should be treated with caution.
Well over half of the world’s population of Northern Rockhopper penguins breed on the Tristan group of islands.
Approximately 154,000 of them bred on the islands in 2011, but estimates in the 1950s suggest there were ‘millions’ of birds, with two million pairs on Gough alone.
‘It’s a big relief that the initial results of the counts are better than we had anticipated,’ says Dr Vickery. ‘We should not, however, relax our watch. There is much we don’t know about this species.’
She says it is not known how well population trends can be worked out from counts in breeding colonies. There may be longer-term ‘sub-lethal’ effects on breeding.
‘It is vital that we continue to monitor the birds closely for several more years to establish the true impact of the oil spill.’
The oil spill has also caused concern for the important Rock Lobster fishery around Tristan – the mainstay of the island’s economy. The latest evidence shows that catches are way below normal and rotting soya has been spotted on the traps.
Divers found the wreck had broken up considerably over the Southern Hemisphere winter. The Nightingale fishery has closed on expert advice and the quota for the fishery at Inaccessible Island was reduced from 92 to 53 tonnes for 2011/12 season.
An RSPB emergency appeal raised almost £70,000, which will be used to support penguin monitoring, strengthen the islands’ biosecurity, and help Tristan control rats – which could spread to Nightinghale and kill chicks.
Katrine Herian. who works for the RSPB on Tristan, praised islanders for their work: ‘Something really needs to be said about the huge Tristanian efforts in response to this disaster.
‘Without them, this could have been a very different story. While the true impact of the spill won’t be known for some time yet, we can at least know that everything that could be done was done.’