REPRODUCTION AND DEVELOPMENT Female leatherbacks nest at an interval of 2 to 3 years, and in Florida the nesting season is from March to July. The eggs are laid at night in clutches of 80 to 85. As many as 11 clutches may be laid in a season with an average internesting period of 10 days. The white spherical eggs are approximately 2 inches in diameter. Incubation takes from 55 to 74 days and emergence of the hatchlings occurs at night. The turtles are believed to reach maturity in 6 to 10 years.
RANGE AND POPULATION LEVEL The leatherback turtle is distributed worldwide in tropical and temperate waters of the Atlantic, Pacific, and Indian Oceans. It is also found in small numbers as far north as British Columbia, Newfoundland, and the British Isles; as far south as Australia, Cape of Good Hope, and Argentina.
The major nesting beaches are located in Malaya, Surinam, French Guiana, Mexico, and Costa Rica.
A NEW NESTING AREA was discovered in 1977 on the western end of St. Croix, U.S. Virgin Islands. Regular United States nesting is restricted to Florida, Culebra, Puerto Rico, and St. Croix, U.S.Virgin Islands.
Atlantic Coast nests have been recorded from Flagler Beach to Miami with the majority of records from Palm Beach and Martin Counties. On the Gulf Coast sightings are common in March and April.
The world female breeding population is estimated at 29,000 to 40,000. The number of leatherback nests in Florida is at 80 to 100 annually. Whole nesting at Sandy Point National Wildlife Refuge in the U.S. Virgin Islands is 200 to 250 nests annually. In Culebra, Puerto Rico, there are 100 nests annually. The number of females involved is uncertain
HABITAT The leatherback is the most pelagic of the sea turtles; it is often found near the edge of the continental shelf. In northern waters they are reported to sometimes enter shallow estuarine bays. Leatherbacks require sandy nesting beaches backed with vegetation and sloped sufficiently so that the crawl to dry sand is not too far. A suitable depth of coarse, dry sand is important, because the female first excavates a pit for her body and then must reach moist sand before she can make the proper flask-shaped nest. The preferred beaches have proximity to deep water and generally rough seas.
CRITICAL HABITAT Virgin Islands. A strip of land 0.2 miles wide (from mean high tide inland) at Sandy Point Beach on the western end of the island of St. Croix beginning at the southwest cape to the south and running 1.2 miles northwest and then northeast along the western and northern shoreline, and from the southwest cape 0.7 miles east along the southern shoreline.
REASONS FOR CURRENT STATUS The decline is considered primarily to be the result of overutilization by humans, mostly through consumption of the eggs, although the meat is also eaten on occasion. Exposure and vulnerability while nesting make the turtles highly susceptible to overuse. Increasing beach development and utilization are also detrimental, as sea turtles require relatively undisturbed beaches for nesting. Artificial lights have been shown to distract hatchlings away from the sea. Predation on the hatchlings by natural predators is extensive. Further losses occur through drowning when the turtles become caught accidentally in the nests of commercial shrimping and fishing trawlers.
MANAGEMENT AND PROTECTION Suggested conservation measures include efforts to curtail the loss of leatherbacks in fishing or shrimping trawls, protection of nesting beaches from egg collectors, and a limitation on development of nesting beaches.