The IUCN Red List classifies Green sea turtle as an endangered species. In recent decades, sea turtles have moved from unrestricted exploitation to global protection, with individual countries providing additional protection, although serious threats remain unabated.
All populations are considered threatened. More dangerous are unintentional threats, including boat strikes, fishermen's nets that lack turtle excluder devices, pollution and habitat destruction. Chemical pollution may create tumors, effluent from harbors near nesting sites may create disturbances; and light pollution may disorient hatchlings.
With chemical pollution present, there is a development of tar balls that is often eaten by green sea turtles in a confusion of their food. Tar balls cause the green sea turtle to intake toxins that can block their guts, displace the liver and intestines causing swelling of the tissue.
Habitat loss usually occurs due to human development of nesting areas. Beach-front construction, land reclamation and increased tourism are examples of such development. An infectious tumor-causing disease, fibropapillomatosis, is also a problem in some populations.
The disease kills a sizeable fraction of those it infects, though some individuals seem to resist the disease.
It is distinguished from other sea turtles for the carapace with four pairs of costal scutes, a single prefrontal plate on the head, which is robust, voluminous and rounded, the tip of the horny beak of the upper jaw is not curved into a hook and the shields of the carapace never imbricates.
The male differs from the female due to the more robust tail and the longer nails of the forelimbs.
The color of the shell is brown-olive, with yellow or marbled streaks and spots. Young specimens are more uniformly brown-olive, with yellow-edged limbs. The adult is up to about 140 cm long, with a weight that can reach 500 kg.
Its lifestyle is similar to that of the common turtle, from which it differs above all for the impressive migrations, even of 2000 km, which by the thousands the adults make in groups moving from the areas where they stop to feed to those of mating and laying.
It is considered the most suitable for swimming among living turtles. It feeds mainly on marine phanerogams and for this reason it is found above all in areas rich in submerged prairies. The breeding season runs from July to March.
The female mates and lays eggs every 2-3 years: on the beach, she digs 5-7 holes with her flippers in which, at intervals of 10-15 days, she lays about 100 white and soft shell eggs, for a total number seasonal of about 500 units. The incubation lasts 50-60 days, depending on the climatic conditions.