Conservation International says the leatherback turtles in the east Pacific Ocean that nest on the western beaches of Costa Rica are among the 11 most threatened populations in the world.
Leatherbacks (Dermochelys coriacea) also nest in Mexico and Nicaragua.
Top sea turtle experts from around the globe announced the results of the first comprehensive status assessment of all sea turtle populations globally in a paper published this week in the online science journal, PLoS ONE, said Conservation International. The study, designed to provide a blueprint for conservation and research, evaluated the state of individual populations of sea turtles and determined the 11 most threatened populations, as well as the 12 healthiest populations, it said.
The organization also characterized the olive ridley turtle population in the east Pacific Ocean as one of the healthiest. These turtles (Lepidochelys olivacea) have nesting sites in Mexico, Nicaragua and Costa Rica.
Despite decades of conservation efforts, leatherbacks in the East Pacific have declined by 90 percent in the past 20 years due to egg consumption and being caught by fishermen, said Conservation International. Coastal development looms as the next threat to their survival, it added.
On the other hand, the oliver ridley turtles have been harvested for meat, eggs and skin in the past, and resulted in shocking declines in the seemingly endless abundance of these turtles in the east Pacific, said the organization. Although some mass nesting sites have not recovered, others have held strong and remained incredibly abundant; the biggest rookery in the world hosts hundreds of thousands of nesting females each year, it added. Serious threats still exist in this region, especially due to fishing, but this is presently the most abundant sea turtle population on the planet, the organization said.
However, the oliver ridley turtles in the West Indian Ocean that nest in India and Oman and those in the northeast Indian Ocean that nest in India and Sri Lanka are considered among the 11 most threatened populations, according to Conservation International.
The organization produced maps showing the endangered and successful populations all over the world.
Four of the seven sea turtle species have populations among the world’s 11 most threatened. Almost half of these populations are found in the northern Indian Ocean, specifically on nesting beaches and in waters within exclusive economic zones 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 United States to South America) and east Atlantic Ocean off the coast of west Africa.
“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 Bryan Wallace, director of science for the Marine Flagship Species Program at Conservation International 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.” He was quoted by the organization in a release.
The accidental catching of turtles in trawler nets can be reduced by using a turtle excluder that works like a trap door that allows the air-breathing turtles to leave before they are drowned. These devices have dramatically reduced turtle deaths from shrimp trawler nets in the United States.
However, Costa Rican shrimp is banned from the United States because of the failure of officials here to enforce the use of excluders.