STC Sea Turtle Blog

Satellite tracking identifies risk zones for leatherback turtles

The last large populations of the leatherback turtle are at risk because their migratory routes in the Atlantic Ocean converge with the locations of industrial fisheries, a new study shows.

Photo by Tamar-Ibana

Photo by Tamar-Ibana

Sea Turtle Conservancy (STC) is one of ten organizations that worked together to publish the study which provides insight into the complex patterns of movement by leatherback turtles in the Atlantic and their overlap and accidental capture by industrial longline fisheries for pelagic (open ocean) species such as tuna and swordfish.

Between 1995 and 2010, a total of 106 leatherback females from populations throughout the Atlantic were equipped with satellite tags and tracked over extended periods of time.  Satellite tracking data revealed that leatherbacks display complex patterns of movement in national coastal and international waters and use the waters of 46 of the 97 countries bordering the Atlantic. By overlaying the turtles’ tracks with information on fishing effort, researchers were able to identify nine areas where high risk of capture by fisheries exists, four in the North Atlantic and five in the South Atlantic. Sea Turtle Conservancy’s Technology and Research Specialist Dan Evans is a co-author on the report.

Maps of the daily locations of the turtles revealed that Atlantic leatherbacks use both deep sea international waters (more than 200 nautical miles from land) and coastal national waters, either seasonally or year-round, in a complex pattern of habitat use.

About 16,600 female leatherbacks breed in the Atlantic each year, and while some populations are doing well, accidental capture in longline and other fisheries remains an important conservation threat because fishing effort is intense. More than 4 billion hooks – equivalent to 730,000 hooks per day – were set throughout the entire Atlantic Ocean by industrial fisheries between 1995 and 2010, the study shows.


Leatherback turtle by Dan Evans, STC

Leatherback turtle by Dan Evans, STC

“Fewer than 1,000 females nest in Florida each year, but the coastal waters of the eastern United States represent one of the nine high risk areas for leatherbacks in the Atlantic during April – June and October – December,” said Marydele Donnelly, Director of International Policy for STC.  “The findings of this study have significant policy implications. Multinational collaboration will be needed to reduce leatherback capture through changes in fishing equipment, fishing methodology, and seasonal closures of some areas to fishing.”

leatherback-adopt2The study results from the collaborative efforts of 10 data providers that have tracked leatherback turtles in the Atlantic Ocean since 1995 through the Trans-Atlantic Leatherback Conservation Initiative (TALCIN).

The article, ‘Pan-Atlantic analysis of the overlap of a highly migratory species, the leatherback turtle, with pelagic longline fisheries,’ is published in Proceedings of the Royal Society B.

Other contributing authors on this report include: S. Fossette, Department of Biosciences at Swansea University; M.J. Witt, Environment and Sustainability Institute, University of Exeter; A.C. Broderick, Center for Ecology and Conservation, University of Exeter; P. Miller, Center for Investigation and Marine Conservation, Uruguay; M.A. Nalovic, Virginia Institute of Marine Science; D. Albareda, Aquamarina, Del Besugo 1525, Pinamar, Buenos Aires 7167, Argentina, Jardín Zoológico de la Ciudad de Buenos Aires, Republica de la India 3000,Buenos Aires 1425, Argentina, and Regional Program for Sea Turtles Research and Conservation of Argentina; A.P. Almeida, ICMBio–Reserva Biológica de Comboios, Linhares, Brazil; D. Chacon-Chaverri, Asociación LAST, Apdo 496-1100, Tibás, Costa Rica; M. S. Coyne,, Durham, NC; A. Domingo, Dirección Nacional de Recursos Acuáticos, Constituyente 1497, Uruguay; S. Eckert, WIDECAST and Biology and Natural Resources Department, Principia College; A. Fallabrino, Karumbé – Av. Rivera 3245 (Zoo Villa Dolores), Uruguay; S. Ferraroli, Rue Victor Hugo, France; A. Formia, Wildlife Conservation Society; B. Giffoni, Fundação Pró-TAMAR, Rio Vermelho, Salvador, Bahia, Brazil; G. C. Hays, Department of Biosciences at Swansea University, Center for Integrative Ecology, Deakin University; G. Hughes, 183 Amber Valley, P/Bag X30, Howick 3290, South Africa; L. Kelle, WWF, French Guiana; A. Leslie, WWF International, Switzerland; M. Lopez-Mendilaharsu, Karumbé – Av. Rivera 3245 (Zoo Villa Dolores), Uruguay and Fundação Pró-TAMAR, Rio Vermelho, Salvador, Bahia, Brazil; P. Luschi, Department of Biology, University of Pisa in Italy; L. Prosdocimi, Regional Program for Sea Turtles Research and Conservation of Argentina and Laboratorio Genética de la Estructura Poblacional, Departamento de Ecología, Genética y Evolución, FCEN, Universidad de Buenos Aires, Capital Federal, Buenos Aires, Argentina; S. Rodriguez-Heredia, Regional Program for Sea Turtles Research and Conservation in Argentina and Fundación Mundo Marino, Buenos Aires, Argentina; A. Turny, WWF French Guina; S. Verhage, WWF Gabon; B.J. Godley, Center for Ecology and Conservation University of Exeter.