We are pleased to announce the results of the first comprehensive status assessment of all sea turtle populations globally in a paper published today in the journal PLoS ONE. The study, designed to provide a blueprint for marine turtle conservation and research, evaluated the risk and status of each of the 58 marine turtle “Regional Management Units” and determined the 11 most threatened populations (listed below), as well as the 12 healthiest populations, and 12 “critical data needs.” The full paper is available here.
The 11 Most Threatened Sea Turtle Populations are:
- Olive ridley turtles (Lepidochelys olivacea) in the West Indian Ocean
- Key nesting sites: India and Oman
- Loggerhead turtles (Caretta caretta) in the Northeast Indian Ocean
- Key nesting sites: Sri Lanka, Bangladesh and Myanmar
- Olive ridley turtles (Lepidochelys olivacea) arribada population in the Northeast Indian Ocean
- Key nesting sites: India
- Olive ridley turtles (Lepidochelys olivacea) in the Northeast Indian Ocean
- Key nesting sites: India and Sri Lanka
- Hawksbill turtles (Eretmochelys imbricata) in the Northeast Indian Ocean
- Key nesting sites: India, Sri Lanka and Bangladesh
- Hawksbill turtles (Eretmochelys imbricata) in the East Atlantic Ocean
- Key nesting sites: Congo and Sao Tome et Principe
- Loggerhead turtles (Caretta caretta) in the Northeast Atlantic Ocean
- Key nesting sites: Cape Verde
- Hawksbill turtles (Eretmochelys imbricata) in the East Pacific Ocean
- Key nesting sites: El Salvador, Nicaragua; Ecuador
- Leatherback turtles (Dermochelys coriacea) in the East Pacific Ocean
- Key nesting sites: Mexico, Nicaragua and Costa Rica
- Loggerhead turtles (Caretta caretta) in the North Pacific Ocean
- Key nesting sites: Japan
- Hawksbill turtles (Eretmochelys imbricata) in the West Pacific Ocean
- Key nesting sites: Malaysia, Indonesia and Philippines
The report was co-authored by more than 30 MTSG members from 6 continents and more than 20 countries with diverse expertise in all aspects of sea turtle biology and conservation. The work is the latest product of the MTSG’s “Burning Issues” initiative, and was supported by Conservation International (CI) and the National Fish and Wildlife Foundation (NFWF).
We found that four of the seven sea turtle species have populations among the world’s 11 most threatened. Almost half (five) of these populations are found in the northern Indian Ocean, specifically on nesting beaches and in waters within Exclusive Economic Zones (EEZs) of countries like India, Sri Lanka, and Bangladesh. Other areas that proved to be the most dangerous places for sea turtles were the East Pacific Ocean (from the U.S. to South America) and East Atlantic Ocean (off the coast of west Africa).
“The report confirms that India is a home to many of the most threatened sea turtles in the world,” said Dr. B. C. Choudhury, MTSG regional vice chair, head of the Department of Endangered Species Management at the Wildlife Institute of India, and a contributor to the study. “This paper is a wake –up call for the authorities to do more to protect India’s sea turtles and their habitats to ensure that they survive.“
The study also highlights the twelve healthiest sea turtle populations in the world, which are generally large populations with increasing trends under relatively low threats, as well as twelve “critical data needs” where more research is urgently needed.
“Before we conducted this study, the best we could say about sea turtles was that six of the seven sea turtle species are threatened with extinction globally,” said Dr. Bryan Wallace, MTSG regional vice chair, Director of Science for the Marine Flagship Species Program at CI, and lead author for the paper. “But this wasn’t very helpful for conservation because it didn’t help us set priorities for different populations in different regions. Sea turtles everywhere are conservation-dependent, but this framework will help us effectively target our conservation efforts around the world.”
The seven sea turtle species comprise 58 biologically defined populations, called regional management units (RMUs), as described in a publication earlier this year. To determine the most threatened RMUs, we scored traits like population size, population trends, rookery vulnerability, and genetic diversity as well as threats of fisheries bycatch, human consumption of turtles and their eggs, coastal development, pollution and pathogens, and climate change for each RMU.
“We are excited by the clarity this new study provides by identifying areas around the world that are most important for sea turtle conservation,” said Dr. Claude Gascon the Chief Science Officer and Executive Vice-President of NFWF. “This report is a guide for scientists, conservationists, policy makers, and funders to determine where conservation resources can be allocated to improve the status of these threatened populations.”
The most significant threats across all of the threatened populations are fisheries bycatch, the accidental catch of sea turtles by fishermen targeting other species, and direct harvest of turtles or their eggs for food or turtle shell material for commercial use.
“This assessment system provides a baseline status for all sea turtles from which we can gauge our progress on recovering these threatened populations in the future,” explained Roderic Mast, Co-Chair of the MTSG, CI Vice President, and one of the paper’s authors. “Through this process, we have learned a lot about what is working and what isn’t in sea turtle conservation, so now we look forward to turning the lessons learned into sound conservation strategies for sea turtles and their habitats.”
We are excited to have this publication available after several years of work by many MTSG members, and hope that it will be used to inform future investments in marine turtle conservation. We will be updating the Burning Issues section of this website with additional information and supplemental resources in the near future, so please check back soon.