Sea turtles remain wide ranging marine reptiles whose seven living species include the flatback, green, hawksbill, leatherback, loggerhead, Kemp's ridley, and olive ridley, and these animals are now the focus of concerted conservation and research efforts.
The IUCN Red List classifies two sea turtle species as critically endangered and three as vulnerable, and all species appear on CITES Appendix I restricting international trade, as reported in conservation assessments.
In US waters, every sea turtle population is listed as either threatened or endangered under the US Endangered Species Act, and NOAA Fisheries works with partners on recovery, monitoring, and bycatch mitigation in commercial fisheries.
Bycatch remains a leading contemporary threat, and studies indicate that turtle excluder devices have reduced sea turtle bycatch in shrimp nets by about 97 percent, while longlining and imprecise fishing methods continue to cause incidental deaths.
Other major threats cited in conservation reports include illegal take of turtles and eggs, loss and degradation of nesting and foraging habitat from coastal development, vessel strikes, oil pollution, and entanglement in marine debris such as plastics.
Light pollution on nesting beaches disorients hatchlings, driving them away from the sea, and markets for eggs, meat, and tortoiseshell sustain illegal harvest in some regions, though some communities have shifted to ecotourism to protect nesting sites.
Biology Behavior And Research Findings
Sea turtles have streamlined bodies and paddlelike flippers, and adults of most species cannot retract their heads or limbs into their shells, which increases swimming efficiency but limits terrestrial protection.
Adult males and females are similar in overall size, but adults can be distinguished by tails and cloacal position, with males bearing longer tails that extend past the hind flippers.
Size varies by species, with leatherbacks the largest, reaching over one meter in carapace length and several hundred kilograms, while Kemp's ridleys and olive ridleys are among the smallest hard‑shelled species, as summarized in species accounts.
Sea turtles migrate long distances between feeding grounds and nesting beaches and use magnetoreception, including a bicoordinate magnetic map and a magnetic compass sense, to navigate ocean basins and return to natal beaches.
Reproduction depends on temperature dependent sex determination, and research summaries report that warmer nest temperatures bias hatchlings female while cooler sands produce males, making nesting sands a key variable under warming conditions.
Juveniles spend early years in pelagic habitats, often sheltering in floating sargassum mats, while adults move into coastal foraging grounds; diet shifts occur, for example green turtles become primarily herbivorous as they mature.
Researchers have documented unexpected traits, including biofluorescence observed in a hawksbill turtle and widespread commensal relationships with barnacles that can increase drag and affect turtle energetics.
