Sea turtles have navigated the world’s oceans for over 100 million years, important to marine ecosystems. They inhabit tropical and temperate waters worldwide. Their long history makes their current vulnerable status concerning.
Early Population Declines
Human interaction with sea turtles led to substantial population reductions long before formal conservation efforts. Exploitation for meat, eggs, and shells dates back at least 13,000 years, with early indigenous harvesting likely sustainable. By the 18th century, commercial exploitation emerged.
The consumption and trade of sea turtles intensified with the colonization of the New World, as whalers and explorers used them as a source of fresh meat during long voyages. Turtle meat and soup became a popular delicacy in Europe by the late 19th century, with demand peaking between the 1950s and early 1970s.
The hunting of hawksbills for their shells, known as bekko, began in Japan in the 1600s and led to plummeting populations by the mid-1800s. These historical practices resulted in significant declines, with some estimates suggesting over 2 million olive ridley sea turtles were captured in Mexico alone between 1965 and 1970. Caribbean hawksbill populations are now estimated to be at most 10% of their pre-Columbian levels, illustrating the profound impact of these early, widespread harvests.
Official Endangered Species Listings
Formal recognition of sea turtles’ imperiled status began in the late 20th century through legislative acts and international agreements. The U.S. Endangered Species Act (ESA), signed into law in 1973, provided a framework for protecting species. The leatherback sea turtle was among the first, listed as endangered in 1970 under the ESA’s predecessor, then re-listed under the ESA upon its enactment.
Following this, the loggerhead sea turtle was listed as threatened in 1975, and the olive ridley sea turtle was designated endangered in 1978. The green sea turtle also received ESA protection in 1978, with some populations listed as endangered. In 2016, the green sea turtle’s status was refined, with 11 distinct population segments (DPSs) identified, some listed as endangered and others as threatened.
Concurrently, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), in force since 1975, quickly included sea turtles. By 1981, all sea turtle species were placed on CITES Appendix I, effectively banning commercial international trade in sea turtles and their products.
Key Threats Leading to Endangerment
The decline in sea turtle populations stems from several human-induced threats. A primary concern is fisheries bycatch, where hundreds of thousands of sea turtles are accidentally caught each year in fishing gear such as shrimp trawls, longlines, and gillnets. Since sea turtles must surface to breathe, many drown when entangled, with loggerhead and hawksbill turtles being particularly vulnerable.
Habitat loss and degradation also contribute significantly to their endangerment. Coastal development directly impacts nesting beaches, while artificial lighting disorients hatchlings, leading them away from the ocean. Degradation of foraging grounds, including seagrass beds and coral reefs, diminishes their food and shelter.
Pollution, including plastic ingestion, chemical runoff, and oil spills, poses another threat. Sea turtles often mistake plastic debris for food, and they were among the first marine species documented to ingest plastics.
Climate change presents a growing challenge, with rising sea levels threatening to inundate nesting beaches and increased sand temperatures altering the sex ratios of hatchlings. Changes in ocean currents, also influenced by climate change, can affect food availability and migratory patterns. Despite legal protections, direct exploitation persists in some areas through illegal poaching for meat, eggs, and shells. These combined pressures have collectively pushed sea turtle populations to their endangered status.
Current Conservation Status
Currently, nearly all sea turtle species are classified as endangered or threatened globally by organizations such as the IUCN and CITES. While their situation remains precarious, concerted conservation efforts are underway.
These initiatives include the establishment and protection of nesting sites, the implementation of Turtle Excluder Devices (TEDs) in fishing nets to reduce bycatch, and the operation of rehabilitation centers for injured turtles. Although some sea turtle populations have shown signs of recovery due to these interventions, most species continue to face vulnerability from persistent human-related threats.