We’re tracking the secret lives of teenage sea turtles10/08/2018
We are deploying four new satellite tags on teenage turtles in the Turks and Caicos Islands. Knowledge of their mysterious, epic journeys will reveal vital information: where protection is needed
The one question I always ask myself when working with an individual turtle is “Where will you go?”
Dr Peter Richardson
I like turtles. I have been studying and protecting marine turtles for over 27 years. Knowing their ability for epic migrations, the one question I always ask myself when working with an individual turtle is “Where will you go?”
I was once a young Zoology & Psychology BSc graduate, skint, but with a burning interest in primatology. Despite my desire to follow in the footsteps of Fossey and Goodall, my itchy feet took me to the cheapest conservation volunteering option at the time. So, back in the summer of 1990, I signed up to work on a marine turtle monitoring programme on the beaches of Kefalonia in the Greek Ionian Islands. Attenborough had shown me turtles on the telly, but I had never seen one in the flesh. The first time I laid beside an ancient nesting loggerhead under a starlit night on a deserted beach, the rising moon shining in the ooze of her tears, was the last time I thought about a career in the forests of central Africa. It was also the first time I wondered where this ancient reptile would go once she crawled back into the sea.
Since my years in Kefalonia I have set up a number of marine turtle conservation and research projects in Sri Lanka and the Caribbean. MCS led Sri Lanka’s first wildlife satellite telemetry study in 2006. Working with the University of Exeter and the local Turtle Conservation Project, we revealed the foraging grounds used by the green turtles that nest there. Some stayed close to home in Sri Lankan waters, some migrated thousands of kilometres to oceanic islands, while a third of the turtles migrated about 500 km north to the Gulf of Mannar Marine National Park, a large marine protected area (MPA) in the coastal waters of India’s Tamil Nadu. It turns out this distant, Indian MPA is crucially important for the conservation of Sri Lanka’s breeding green turtles.
I am writing in the Turks and Caicos Islands (TCI) preparing to deploy four more satellite tags on green turtles with our Turks and Caicos Islands Turtle Project. MCS established the TCI Turtle Project in 2008 on invitation by the TCI Government. We were asked to follow-up our recommendations made a few years earlier during a collaborative Defra-funded project with the University of Exeter, and Duke University in the USA. The TCI Turtle Project combined biological research, social science and community engagement. Working closely with local fishermen, the TCI Government and our University partners, we changed the archaic fishery legislation and improved the way the traditional TCI turtle fishery is managed. Large green and hawksbill turtles are now protected by law while local people still have access to some juvenile turtles. Hawksbills are fully protected during their eight-month breeding season and capture of any other species of turtle is prohibited.
This work launched the TCI’s first ever satellite tracking study of turtles. Our much-publicised early tracking of adult green and hawksbill turtles changed the way local fishers perceived the turtles they targeted. Migrating turtles were seen not just as the property of the TCI fishers, but a shared Caribbean resource that needs careful management. The tracking data provided much-needed and well-respected evidence to back up our calls for new regulations to protect the larger, breeding turtles. Since the new turtle fishery regulations came into force in 2014, the TCI Turtle Project has hooked up with a new local partner, the Amanyara Resort, and has focused the tracking study on sub-adult (or teenage) green turtles. There are very few studies of teenage turtles, mainly because they do not come ashore like nesting females, so they are much harder to access. So far, we have tracked 13 teenage green turtles, all caught on the Caicos Banks and within the North, Middle and East Caicos Ramsar protected area. We work with South Caicos fishermen Gilbert Jennings and Dave Clare, who have been ‘jumping’ turtles together for over 35 years.
It is a pleasure to watch Gilbert and Dave in action, as Dave uses his years of experience to artfully predict the turtles’ behaviours and position the boat, so that Gilbert can jump them, and carefully bring them aboard. Their considerable skill means we are afforded the rare privilege of attaching satellite tags to these poorly understood teenagers.
So where do the teenage turtles go? Well, most of them stay within the protected area during the tracking, grazing and growing on the lush seagrass meadows, once again showing the importance of MPAs to regional turtle conservation. But some of them have migrated away from the TCI, on what we think are ‘developmental migrations’, a key behaviour rarely recorded. Developmental migrations are still mostly theory, but we think these teenage turtles are seeking the feeding grounds on which they will live for the rest of their lives as adults.
These distant seagrass meadows are likely closer to the nesting beaches on which they hatched, the same beaches they will head to as adults to breed. One teenage turtle, Gilbert, migrated more than 2,000 km north up through the Bahamas and along the USA coast to North Carolina. Perhaps Gilbert hatched on a South Eastern USA beach – our genetic studies show that the nesting population contributes to the TCI turtle grazing collective. Another turtle, Karman, migrated more than 2,200 km to Limon in Costa Rica via Colombia and Panama, before turning back on herself and eventually settling in Colombia’s inshore waters close to Cartagena. Maybe Karman was hatched at Tortuguero in Costa Rica, the region’s largest green turtle rookery. We know that TCI hosts juvenile greens from Tortuguero too. We don’t think these turtles had carried out these migrations before, so were they prospecting for suitable feeding ground to settle on for the rest of their lives?
Three turtles, Dave, Yara and Sea Biscuit all migrated around 500 km to Cuba’s inshore waters, where they all suddenly stopped transmitting mid-migration. We can’t be sure, but we think they were caught by Cuban fishermen there. Cuba once ran a government-controlled and managed turtle fishery, but pressure from the USA led the Cubans to ban the fishery in 2008. Despite this, our turtle biologist colleagues in Cuba tell us there is still a rampant turtle fishery along the impoverished northern coast where our turtles went silent. It is almost impossible to get information from the fishers there because the turtle fishery is illegal. It seems like there may well be a serious problem for migrating teenage turtles in Cuba’s inshore waters, and perhaps there is a need to review the effectiveness of turtle fishing bans in Cuba and elsewhere.
Satellite tracking does tell us where turtles go. Along the way it tells us important truths about distant and disparate habitats turtle populations need to thrive, and where they themselves may be threatened by human activity. Turtle tracking can influence conservation policy, and with good, local promotion, it can also change and improve the way local communities view the conservation needs of the wildlife they live with. That’s why we track turtles. This year we are analysing the TCI teenage turtle data with our friends at the University of Exeter, hopefully for publication later this year, and we will have tagged another four teenage turtles on the Caicos Banks to better understand these enigmatic animals. Who knows where these four turtles will go?! If you want to find out, and experience scientific discovery as it happens, you can track these turtles on www.mcsuk.org
MCS is grateful to all those that have supported the TCI satellite tracking work, including Princess Yachts, The People’s Trust for Endangered Species, the British Chelonia Group and many private individuals who have sponsored tags. If you would like to support this exciting research, please contact firstname.lastname@example.org
This article was written by Peter Richardson, Head of Ocean Recovery (MCS), for our Spring 2018 membership magazine ‘Marine Conservation’. If you’d like to receive our fantastic quarterly magazine straight to your door, you can become a member from as little as £3.50 per month.