Satellite-tagged turtles take conservation project forward

FRIDAY, AUGUST 19: Laid out on noodles, baking on their backs in the afternoon heat, the rows of green turtles look like sunbathers on a day at the beach.

But this was more like a trip to the doctors for the shell-shocked reptiles.

Plucked from the seagrass meadows of Castle Harbour by snorkellers, they winced their way through a series of tests as volunteers tip-toed across the cluttered deck — taking blood samples, weighing, measuring and tagging.

Movements

It might have been an uncomfortable afternoon for the turtles, but the research is providing new information that will help to preserve their habitat.

The Bermuda Turtle Project has already helped to piece together fascinating details of the life cycle of one of our most iconic marine creatures.

There is no nesting population on the island and turtles spend their early lives floating on open-ocean currents.

Blood tests, carried out by the team, have indicated that Bermuda’s turtles are swept here from all over the Atlantic. Many are from Costa Rica or the Caribbean.

But some have come from as far away as the African coast and in one case, Cyprus.

Nobody is sure how they do it. But the turtles, swept here by accident as juveniles, will ultimately make a staggering return journey to the exact beach where they were born.

“Turtles come here from Nicaragua, from Florida, from west Africa,” said Mark Outerbridge of the Bermuda Zoological Society (BZS).

“They might spend decades together on the same seagrass meadow. Then they leave and they would certainly never see each other again.”

Data on their movements across the Atlantic has been well established, in part by the work of the Bermuda project.

This began in 1968 as an apparently unsuccessful attempt to reintroduce nesting turtles to the island.

The newest phase of the project aims to ‘zoom in’ further on the local movements of turtles within Bermuda.

The island acts as a safe haven during the critical youth development stage — a period of around 20 years, where juvenile turtles grow almost to full size before heading home as they near the age of sexual maturity.

Researchers say our turtles move within a relatively limited field — foraging in no more than a couple of kilometres of ocean.

GPS tags, attached as part of this year’s project, will for the first time pinpoint the movements of each turtle around its little piece of the rock.

Robert Hardy, a telemetry expert with BZS research partner the Sea Turtle Conservancy, said the new tags were accurate to within 10 metres.

During the course of the project — led since 1990 by Florida doctors Peter and Annie Meylan — more than 3,000 green turtles have been observed and fitted with a variety of tags.

Most of them are simply ‘visual tags’ that help to provide information if a turtle is caught by fishermen.

But fitting tags and collecting vital statistics is not a simple process.

The Bermuda Aquarium Museum and Zoo boat Endurance operates as a floating school during the two-week annual project.

Knowledge

Students from across the US, Central and South America, and Bermuda learn from the experts about the lives and habits of turtles as they assist the project.

One of their toughest jobs is to snorkel the perimeter of a 2,000ft net, releasing the turtles caught in the meshing and boating them.

Up to 40 turtles, some heavy enough to require two people to lift them, are caught in a 90-minute session.

Back on board the turtles lie calmly on their backs as the students gather the data.

When they return to their home countries, many will start their own projects.

Dr Peter Meylan said this year’s project was a tremendous success.

“Bermuda is such a great place to study the developmental stage of the lives of green turtles because there is no overlap with other phases. They are not born here and they don’t breed here.

“The data we have collected over the years in the same 40 spots around the island has contributed immensely to the knowledge we have about green turtles.”

The two researchers will publish a paper with the Natural History Museum in New York on the project later this month.

In 1620 Bermuda passed one of the first conservation laws in the world, banning the killing of turtles in our waters.