July 1, 2008

Loggerhead Turtles Return To Sea After Rehabilitation

Conservationists at Blue Reef Aquarium, Newquay, successfully rehabilitated two loggerhead turtles, which became stranded on UK and Irish coasts this year.

"Dink" and "James" were found on the shore last winter. Both turtles underwent six months of rehabilitation at Blue Reef, and were recently returned to the sea off a beach in Las Palmas, Gran Canaria.

"It was absolutely beautiful. Let's hope no more turtles get stranded, but if they do we know we can look after them," said Blue Reef Aquarium curator Matt Slater.

Dink and James were both microchipped so they can be easily identified if they ever wash on to the coast again.

"I hope they will be OK," Mr Slater mused. "In their lifetime, things will change a lot. The future for turtles in general is not great."

Overall, 23 endangered loggerheads were washed up onto the coast this year, an unprecedented number.

When Dink and James arrived at Gran Canaria, they were checked over at the Wildlife Recovery Center of Tafira, where about 150 injured turtles from around the Canary Islands are taken each year.

"Seventy-five percent of the sea turtles that we receive have been hurt because of man's activities," said Pascual Calabuig, the center's director.

"We see turtles damaged by hooks, nets, pollution, oil and plastic bags. Turtles damaged by boats are the worst to recover. We try to patch up their shells with fiberglass, but survival rates are low."

"Through diagnosis, treatment, operations, protein-rich food, fluid and antibiotics, we help save 80% of the turtles that we receive," said Mr Calabuig.

Habitat loss and climate change continue to threaten the livelihood of turtles.

Loggerheads breed on the beaches of the Mediterranean, West Africa, Brazil and along the south-east coasts of the US. Florida has the largest loggerhead population.

"Within 24 hours hatchlings swim into the open water of the Atlantic Ocean," explained Peter Richardson, biodiversity program manager at the Marine Conservation Society.

Loggerheads circle the ocean currents. For example, from nesting beaches in Florida, they follow the Gulf Stream across the Atlantic to Madeira, and then head south to the Canary Islands and Cape Verde Isles, before heading back to the south-east coast of the US.

"They join the North Atlantic Gyre's circulatory system for three to five years before coming inshore. They then gradually move towards a nesting beach in the vicinity of where they were born," said Mr. Richardson.

"We are not 100% sure how turtles navigate this route. They have some geo-magnetic understanding, for broad-scale navigation, and can use chemical cues coming off of islands, such as windblown dust, as a homing device."

Although scientists say they are unsure as to why loggerheads continue to be stranded on UK and Ireland coasts, they think the large number discovered this year can be attributed to the extreme weather systems in the region this year.

"From December to February we had strong and persistent south-westerly winds towards UK shores. Small or compromised turtles in the north-east Atlantic may have drifted off-course because of this," explained Mr. Richardson.

Loggerheads are unable to raise their body temperature, and therefore are unable to survive in cold waters.

"At 15C (59F) the turtles stop feeding and at 10C (50F) they shut down."

Unable to feed, the loggerheads became lethargic and drifted inland.

Another cause for the large number of loggerheads found on the coasts could be linked to a rare unseasonable jellyfish bloom at the end of November.

"Juvenile loggerheads are opportunistic feeders. The jellyfish may have attracted them off their normal course. Then they may have got caught in a weather system and blown over."

"It may simply be because there are more hatchlings in the open water," said Brendan Godley, a conservation biologist at the University of Exeter.

"The Florida population of loggerheads has increased since the 70s because of good conservation. The more hatchlings there are out there, the more likely that some may be stranded."

James was discovered on Blackrock Beach, Bude, on January 26. After that conservationists spotted Dink one week later at Putsborough Beach, Wollacombe.

"They were both in a poor state when they arrived," explained Mr Slater. "James was particularly bad. It was touch and go for a while.

"Being a larger, more powerful turtle, James is thought to have battled the strong currents, which left him exhausted. Dink, being younger, probably endured less stress as he just drifted on the current and arrived inland faster."

Both turtles had hypothermia. James was suffering from pneumonia, dehydration and a lung infection when he was found.

The water temperature of their rehabilitation tanks was increased from 10C, the temperature of the UK sea in January, to 25C.

"As a result, their metabolism speeded up and they are able to heal faster," said Mr Slater.

"James was put on a course of antibiotics and anti-fungals to cure infection. When he first took food by himself, after two weeks of tube feeding, we knew he was on the road to recovery."

After six months of recovery, both Dink and James were released on a beach at Las Palmas, Gran Canaria, on June 23.


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