A blockbuster scientific study that tracked ocean-going leatherback turtles may help save the endangered reptiles whose numbers have plummeted as commercial fishing continues to take a toll.
John Roe, a biology professor at The University of North Carolina at Pembroke and reptile expert, is the lead author of a satellite-tracking study that began more than two decades ago and included 15 scientists from leading universities and institutes. The study tracked 135 leatherback turtles as they trekked across the Pacific Ocean. It was released online on Jan. 8 by The Proceedings of the Royal Society B (Biological Sciences) of London and will be published in print form on Feb. 22.
The leatherback population has declined by 90 percent since 1980 due in large part to longline fishing vessels hauling them in as “bycatch.” Using GPS to track the travels of the world’s largest ocean-going turtle, it may be possible to untangle them from the multi-billion dollar fishing industry, Roe said.
“The high profile of this paper helps the turtles’ cause; it’s a huge industrial issue,” Roe said. “It’s an important study, and many conservation groups are behind it.”
The study represents “the largest compilation of satellite-derived position estimates with fisheries information to predict times and locations of bycatch risk for any species of marine vertebrate.” Roe analyzed huge volumes of data, which gives “strong evidence of predictable time and location of leatherback movements” all of which “make the problem of leatherback bycatch more manageable.”
Some of the participating scientists work for the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service, which is responsible for the stewardship of the nation’s living marine resources and their habitat.
“Leatherback turtles travel thousands of miles to and from nesting sites, and their movements are predictable,” Roe said. “They follow jellyfish, their sole food source, and fishermen follow similar patterns.”
It’s difficult to get data from the industry on leatherbacks hooked on longlines, but fishermen do not intentionally catch the large turtles, which can damage their equipment.
The study, which began in 1992 and ran through 2008, is a remarkable cooperative effort among many groups who tag turtles, according to Roe.
“Knowing that many people are putting satellite transmitters on turtles, we were able to collaborate with them to get a better picture of what’s going on in the ocean,” he said.
Universities represented in the ongoing research are UNCP, Indian-Purdue University at Fort Wayne, Cornell, Duke, Stanford, Maryland and Drexel. Institutes participating were NOAA and the Leatherback Turtle Conservation Trust. Funding came from the Lenfest Oceans Program of the Pew Charitable Trust, the tagging of Pacific Pelagics Program, Drexel’s Betz Endowment and the Schrey Endowment of Indiana-Purdue.
Several leading international turtle scientists were co-authors, including the study’s senior scientist James Spotila of Drexel, Stephen Morreale of Cornell, and Frank Paladino of Indiana-Purdue, who is Roe’s mentor.
“I was able to maintain a relationship with this group from my time as a post-doctoral fellow,” Roe said. “I pushed the study forward and crunched the numbers.”
As lead author, Roe is also the spokesman for the paper, and interest in the study has been high. Thus far, BBC News, Nature World and Science Daily have reported on it. Roe has done an interview with WHYY, Philadelphia public radio.
Roe said acquiring more data would narrow the field of collisions between turtles and fishing vessels. A related study of leatherbacks in the Atlantic will be published online in the coming months.
“Turtles and whales are in the spotlight globally,” Roe said. “There has been success in some areas like shrimping on the East Coast of the Atlantic where turtle excluder devices have been incorporated in nets. But leatherbacks are not coastal turtles and remain in deep water, which makes regulation more difficult.”
The study identified hot spots of conflict. In the eastern Pacific, leatherbacks are at the highest risk in the South Pacific Gyre, an enormous ocean eddy past the Galapagos Islands and south of the equator. In the western Pacific, the highest potential for bycatch is near nesting beaches of northwest New Guinea.
In Pembroke, Roe stays busy with his students tracking box turtles, a terrestrial species that is North Carolina’s state reptile. Roe, who joined UNCP’s faculty in 2010, earned his doctorate from the University of Canberra, Australia. He has studied turtles and snakes Down Under, across the Pacific and from Michigan to North Carolina.
“I expect to have some papers on box turtles ready for publication in a year, and I am looking at some turtles of conservation concern in the Lumber River,” he said. “There is no shortage of interesting reptiles.”
To contact Roe, email firstname.lastname@example.org or call (910) 775-4081.