Findings highlight the uniqueness and high biodiversity value of the Pitcairn Islands as one of the least impacted in the Pacific, and suggest the need for immediate protection. The islands are one of the most remote places on Earth and have escaped overfishing and pollution that has damaged many other regions of the world’s oceans.
The islands and atolls (Ducie, Henderson, Oeno, and Pitcairn) are situated in the central South Pacific, thousands of miles from any continent, halfway between New Zealand and South America.
An international team of scientists have carried out the first underwater surveys of the deep and shallow waters around the islands, best known for their connection to the mutiny on the Royal Navy ship, Bounty, in the 18th century. Some of the mutineers settled on Pitcairn and around 50 of their descendents still live there, governed as a British overseas territory.
The researchers conducted the first surveys of the deep habitats around the Pitcairn Islands using drop-cameras at 21 sites from depths of 78 to 1,585 m. The scientists found healthy coral reefs and an abundance of fish, around half of them not found anywhere else in the world.
A key indicator of the water's good state were the number of top predators like sharks that the scientists recorded. They accounted for over half of the biomass at Ducie Atoll, one of the least disturbed locations.
Perhaps the most significant discovery was down to the purity of the water. The scientists found a type of coralline algae living deeper than anywhere else on earth.
"It lives at 382m that's more than 100m deeper than the previous record, because of the clarity of the water," co-author Dr Enric Sala told BBC news.