By Damian Carrington
An expedition has revealed the unique underwater treasures of the Pitcairn Islands. The discovery increases the pressure on the UK government to create the world’s largest marine protection area around the Pacific sea.
The islands are one of the most remote places on Earth, thousands of miles from any continent, and have escaped overfishing and pollution that has damaged many regions of the world’s oceans. Just 53 people live on the islands, many descendents of the sailors behind the famous mutiny on the Bounty in 1790, but it is the marine life that attracted National Geographic’s Pristine Seas expedition. Its results, including new species of fish, were published in the journal Plos One on Friday.
“The remoteness means it has been preserved as pristine as possible,” expedition leader Enric Sala told the Guardian. “As soon as you jump in the water and the bubbles clear you are surrounded by sharks.” Top-predators like sharks are virtually fished-out in many parts of the seas but the expedition found they dominated the marine ecosystems around the four Pitcairn Islands. Grey reef sharks were the most common predator, followed by whitetip reef sharks and black trevally, while the plant-eating fish were dominated by chubs, unicornfish and whitebar surgeonfish.
The waters are also extremely clear. “We couldn’t believe it. The water was so clear we could see for 75 metres,” said Sala. That clarity meant coral reefs thrived far deeper than usual, down to 100 metres, a world record. Another light-dependent organism, crustose coralline algae, was seen at 382m depth. Over 80 species of fish, coral and algae were recorded at Pitcairn for the first time.
The team also did the first surveys of the deep habitats around the Pitcairn Islands by dropping cameras down to 1,600 metres, revealing rare species such as the false catshark and several species never seen before.
“This is one of the most intact marine ecosystems on the planet and right now it is in danger,” said Sala, adding it provides an irreplaceable view of how coral reefs function without extensive human interference.
The Pitcairn islanders have backed a plan to declare a protected zone of over 830,000 sq km around the islands, which if created today would be the biggest in the world. Sala points out that while about 15% of land has some kind of protection, only 3% of the oceans have any environmental rules.
The Pitcairns are a British overseas territory and campaigners are optimistic that the UK Foreign Office’s current assessment of the proposal will see the marine park approved, particularly after US president Barack Obama pledged on 17 June to protect 780,000 km2 of ocean around uninhabited south Pacific Islands. “The arguments are pretty clear and there seems to be momentum now, so it makes sense for the UK to lead the way,” said Sala.
However, the Environment Audit select committee of MPs criticised the government in January for failing protect the exotic species living on the string of isolated islands that make up the last vestiges of the British empire. It noted that there are more endangered species living in the Pitcairns than people.