The 11 Most Threatened Sea Turtle Populations

Bycatch was consistently ranked as one of the greatest threats to sea turtle populations globally. Here, several green turtles were accidentally captured by a single net off the coast of Brazil. © Projeto Tamar Brazil – Image Bank

The following list was published in The State of the World's Sea Turtles Report Vol. 7 in 2012 and represents the 11 most threatened sea turtle populations in the world.  This analysis was made possible by the priority-setting efforts of the Burning Issues (BI) Working Group of the IUCN Marine Turtle Specialist Group, which created a framework for delineating sea turtle populations globally (Regional Management Units, or RMU's) and then evaluated, compared, and organized sea turtle RMU's within the context of a conservation "priorities portfolio".

The RMU framework breaks down globally distributed, widely migrating sea turtle species into smaller, biogeographically defined units above the level of a single nesting beach yet below the level of species. RMUs are functionally independent subpopulations that include breeding adults, as well as juveniles. RMUs vary in their levels of risk and threat, as well as their conservation status, and thus provide a more suitable scale for developing strategies for research and conservation than do global-level species assessments.

For more information on the priority-setting initiatives that undergird this assessment, see the SWOT Report article: “Getting our Priorities Straight.”

See also related SWOT Report article: The 12 Healthiest Sea Turtle Populations

Hawksbill Turtles (Eretmochelys imbricata)

East Atlantic Ocean

Key nesting sites: Republic of the Congo, São Tomé and Príncipe.

This poorly studied, small population nests at only a few sites scattered along the West African coast. It is under severe threat from coastal net bycatch and consumption of eggs and meat, as well as from exploitation of shell material for handicrafts and jewelry.

East Pacific Ocean

Key nesting sites: El Salvador, Nicaragua, and Ecuador.

Until a few years ago, marine turtle experts knew virtually nothing about this population. Thanks to recent collaborative efforts by regional conservationists to locate and protect them, hawksbills appear to be hanging on in the East Pacific. However, their use of habitats previously unknown to scientists (mangrove estuaries), extremely low numbers, and severe threats of coastal by-catch and egg consumption earn them a spot on this list.

Northeast Indian Ocean

Key nesting sites: India, Sri Lanka, and Bangladesh.

Like loggerheads and olive ridleys in this region, this hawksbill population has been depleted by severe threats. Compounding these problems, the size and status of this population is poorly known, making monitoring and conservation work very important for its continued survival.

West Pacific Ocean

Key nesting sites: Malaysia, Indonesia, and the Philippines.

Hawksbill populations worldwide have declined, in large part because of enormous demand for their beautiful shells, which provide “tortoiseshell” material used to make highly valuable handicrafts and jewelry. This hawksbill population, in particular, has suffered greatly because of exploitation of its shell material. Although international trade of hawksbill products is illegal, it continues to be a major threat to hawksbills around the world, especially in this region. In addition, future climate change effects could be another serious issue for this population.

Leatherback Turtles (Dermochelys coriacea)

East Pacific Ocean

Key nesting sites: Mexico, Nicaragua, and Costa Rica.

This population is one of the most well studied in the world, so its 90 percent decline in the past 20 years is very well known. However, despite decades of conservation efforts at key nesting sites, leatherbacks remain scarce in the East Pacific. Historic egg consumption, as well as coastal and high-seas by-catch, caused this population’s fall; now coastal development looms as the newest threat to its survival.

Loggerhead Turtles (Caretta caretta)

Northeast Atlantic Ocean

Key nesting site: Cape Verde

Although relatively abundant, Cape Verde loggerheads have a limited distribution and have been threatened for decades by consumption of meat and eggs, as well as by-catch in Cape Verde and in feeding areas along the African mainland coast.

Northeast Indian Ocean

Key nesting sites: Sri Lanka, Bangladesh, and Myanmar.

This very small population has not been monitored consistently, so we do not know much about it. These turtles make this list because they are under high threat, mostly because of fisheries by-catch in trawls and nets, as well as ongoing development of coastal areas where they nest.

North Pacific Ocean

Key nesting site: Japan

The trans-Pacific migrations of loggerheads between reproduction sites in Japan and feeding areas in Hawaii and Mexico are among the best known for ocean going animals. However, by-catch throughout their range— especially in Japan and Mexico—coupled with coastal development at nesting sites in Japan has caused this population to decline. International conservation efforts give hope for the future of loggerheads in this region.

Olive Ridley Turtles (Lepidochelys olivacea)

Northeast Indian Ocean (arribada population)

Key nesting site: India

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Northeast Indian Ocean

Key nesting sites: India and Sri Lanka

Given the massive numbers of olive ridleys that nest in a few locations in India each year, the place of olive ridleys among the most endangered populations in the world might seem hard to believe. However, because of extremely intense pressures from trawl by-catch and consumption of turtle eggs and meat, the seemingly abundant ridleys have declined dramatically region wide—both at mass nesting sites and at beaches where turtles nest in smaller numbers. More recently, development of major shipping ports along the coast of India has become a major cause of concern for these populations.

West Indian Ocean

Key nesting sites: India and Oman.

Although olive ridley nest sites are scattered all along the western coast of India and in other countries, olive ridley turtles nest only in small numbers throughout the region. They have been declining because of intense trawl by-catch and consumption of turtle eggs and meat, especially in India. In addition, these ridleys are threatened on land and in the water by coastal development and shipping.

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This article originally appeared in SWOT Report, vol. 7 (2012). Click here to download the entire article as a PDF.

See related SWOT Report article: The 12 Healthiest Sea Turtle Populations