New population of Pacific Hawksbill turtles found living in mangroves

Critically endangered turtles normally favour coral and rocky reefs

September 2011: Critically endangered hawksbill turtles have been discovered living among in-shore mangrove estuaries in Central and South America.

Hawksbill turtles are tracked to build up a clear picture of their nesting and breeding habits

The turtles were once written-off as functionally extinct in the eastern tropical Pacific Ocean - where they used to be found among coral and rocky reefs. This never-before-seen habitat adaptation by this population helps explain why the species went undetected in the region for decades.

The findings are the culmination of a three-year grassroots effort to track movements of adult female hawksbills to identify important areas for nesting, migration and feeding in the eastern Pacific Ocean from southern America to Peru. The results mark the most complete set of observations on habitat use by hawksbill turtles in the eastern Pacific to date.

Most endangered turtle species in the world
Widely considered among the most endangered sea turtle populations in the world, little attention had been paid to hawksbill population declines or habitats in the eastern Pacific since the early Eighties, when scientists concluded that they had become ‘rare to non-existent in most localities'.

Long exploited for the commercial trade of its elaborately coloured shell, the hawksbill turtle has faced numerous other threats in the region including egg harvest, coastal habitat destruction, and fisheries bycatch.

Hawksbills were believed to live in the region, but had long evaded detection by scientists, likely due to their unique life-history strategy of moving into these mangrove habitats, which is seen nowhere else in the world and made them extremely difficult to find.

Not even remotely similar to hawksbill habitats elsewhere
‘We were really shocked to see that adult hawksbills weren't even using coral or rocky reefs or any habitats that were even remotely similar to habitats they associate with in other parts of the world,' said scientist Alexander Gaos, who initiated the research, forming the Eastern Pacific Hawksbill Initiative (ICAPO).

This research builds on a ‘rediscovery' of the species in the eastern Pacific based on ICAPO's region-wide effort to identify key nesting sites and in-water sites for hawksbills. Observers found nesting beaches for the hawksbills in El Salvador, Nicaragua, Costa Rica and Ecuador.

‘These findings show that conservation of mangrove estuaries and coastal wetland habitats is important not just for rare species such as hawksbills, but also for the critical ecosystem services these habitats provide,' said Conservation International's Dr Bryan Wallace, a co-author of the study.

Mangrove habitats not only act as nurseries for juvenile marine animals, many of which are important food sources for humans, like fish and crabs, but they also serve as land buffers from storms and natural water filters.

This discovery of the population's reliance on confined mangrove habitats is both bad and good news for these hawksbills. The proximity of these habitats to human communities places the hawksbills under severe threat from rampant egg collection for human consumption and excessive habitart degradation.