The leatherback (Dermochelys coriacea), the green (Chelonia midas) and the loggerhead turtle (Caretta caretta) regularly occur in the Mediterranean basin
Caretta caretta is the most abundant species of marine turtles in the Mediterranean Sea and the knowledge of its biology represents a crucial point to evaluate the impact of different fishing activity in different areas.
Loggerhead turtle can reach considerable dimensions (the largest weights 140 kg. and measures circa 120 cm whereas the smallest measures 80 cm). Caretta Caretta spawns always in the same beach where it was born. The nesting period is from June to August, months in which the females reach the beach to spawn. The brood contains about 120 eggs and for the ones that hatch (60%) it takes about 50 days. Like many turtles, Caretta caretta has temperature-dependent sex determination (TSD). The sex of hatchlings is determined by egg temperature during the middle third of incubation. Generally, temperatures of 24 to 26 ºC tend to produce all males and temperatures of 32 to 34 ºC tend to produce all females.
Named for their huge heads and powerful jaws, loggerhead turtles are the largest hard-shelled sea turtles alive today. They have a heart-shaped carapace, which is often covered with commensal organisms such as barnacles and algae. Generally, the carapace is a reddish-brown with olive tones; there are five pairs of pleural scutes, the first pair touching the cervical (neck) scute. Green sea turtles (Chelonia mydas) and hawksbill sea turtles (Eretmochelys imbricata) have only four pairs of pleural scutes on the carapace; the first pleurals do not touch the cervical scute. The plastron is cream to yellow. The skin of males is more brown and the head more yellow than those of females. Males also have wider carapaces and a long curved claw on each forelimb. Loggerhead sea turtle hatchlings tend to be dark brown to reddish brown on the carapace The average adult Caretta caretta in the Mediterranean Sea is smaller than the average adult in the Atlantic Ocean. Loggerhead sea turtles differ from other sea turtles in having relatively large heads and reddish coloration.