Chelonia mydasSpecies Description
Weight: 300-350 pounds (135-160 kg) for adults; hatchlings weigh 0.05 lbs (25 g)
Length: 3 feet (1 m) for adults;hatchlings are 2 inches (50 mm)
Appearance: top shell (carapace) is smooth with shades of black, gray, green, brown, and yellow; their bottom shell (plastron) is yellowish white
Lifespan: unknown, but sexual maturity occurs anywhere between 20-50 years
Diet: seagrasses and algae
Behavior: females return to the same beaches where they were born ("natal" beaches) every 2-4 years to lay eggs, generally in the summer months
Green turtles are the largest of all the hard-shelled sea turtles, but have a comparatively small head.
Adult green turtles are unique among sea turtles in that they eat only plants; they are herbivorous, feeding primarily on seagrasses and algae. This diet is thought to give them greenish-colored fat, from which they take their name.
While nesting season varies from location to location, in the southeastern U.S., females generally nest in the summer between June and September; peak nesting occurs in June and July. During the nesting season, females nest at approximately two-week intervals. They lay an average of five nests, or "clutches." In Florida, green turtle nests contain an average of 135 eggs, which will incubate for approximately 2 months before hatching
Habitat
Green turtles primarily use three types of habitat:
- beaches for nesting
- open ocean convergence zones
- coastal areas for "benthic" feeding
Adult females migrate from foraging areas to mainland or island nesting beaches and may travel hundreds or thousands of kilometers each way. After emerging from the nest, hatchlings swim to offshore areas, where they are believed to live for several years, feeding close to the surface on a variety of pelagic plants and animals. Once the juveniles reach a certain age/size range, they leave the pelagic habitat and travel to nearshore foraging grounds. Once they move to these nearshore benthic habitats, adult green turtles are almost exclusively herbivores, feeding on sea grasses and algae.
Critical habitat
- beaches for nesting
- open ocean convergence zones
- coastal areas for "benthic" feeding
Adult females migrate from foraging areas to mainland or island nesting beaches and may travel hundreds or thousands of kilometers each way. After emerging from the nest, hatchlings swim to offshore areas, where they are believed to live for several years, feeding close to the surface on a variety of pelagic plants and animals. Once the juveniles reach a certain age/size range, they leave the pelagic habitat and travel to nearshore foraging grounds. Once they move to these nearshore benthic habitats, adult green turtles are almost exclusively herbivores, feeding on sea grasses and algae.
Critical habitat
Critical habitat was designated in 1998 for green turtles in coastal waters around Culebra Island, Puerto Rico.
The green turtle is globally distributed and generally found in tropical and subtropical waters along continental coasts and islands between 30° North and 30° South. Nesting occurs in over 80 countries throughout the year (though not throughout the year at each specific location). Green turtles are thought to inhabit coastal areas of more than 140 countries.
In U.S. Atlantic and Gulf of Mexico waters, green turtles are found in inshore and nearshore waters from Texas to Massachusetts, the U.S. Virgin Islands, and Puerto Rico. Important feeding areas in Florida include the Indian River Lagoon, the Florida Keys, Florida Bay, Homosassa, Crystal River, Cedar Key, and St. Joseph Bay.
In the eastern North Pacific, green turtles have been sighted from Baja California to southern Alaska, but most commonly occur from San Diego south. In the central Pacific, green turtles occur around most tropical islands, including the Hawaiian Islands. Adult green turtles that feed throughout the main Hawaiian Islands undergo a long migration to French Frigate Shoals in the Northwest Hawaiian Islands, where the majority of nesting and mating occurs.
Population Trends
The green turtle is globally distributed and generally found in tropical and subtropical waters along continental coasts and islands between 30° North and 30° South. Nesting occurs in over 80 countries throughout the year (though not throughout the year at each specific location). Green turtles are thought to inhabit coastal areas of more than 140 countries.
In U.S. Atlantic and Gulf of Mexico waters, green turtles are found in inshore and nearshore waters from Texas to Massachusetts, the U.S. Virgin Islands, and Puerto Rico. Important feeding areas in Florida include the Indian River Lagoon, the Florida Keys, Florida Bay, Homosassa, Crystal River, Cedar Key, and St. Joseph Bay.
In the eastern North Pacific, green turtles have been sighted from Baja California to southern Alaska, but most commonly occur from San Diego south. In the central Pacific, green turtles occur around most tropical islands, including the Hawaiian Islands. Adult green turtles that feed throughout the main Hawaiian Islands undergo a long migration to French Frigate Shoals in the Northwest Hawaiian Islands, where the majority of nesting and mating occurs.
Population Trends
The two largest nesting populations are found at:
- Tortuguero, on the Caribbean coast of Costa Rica, where 22,500 females nest per season on average
- Raine Island, on the Great Barrier Reef in Australia, where 18,000 females nest per season on average
In the U.S., green turtles nest primarily along the central and southeast coast of Florida where an estimated 200-1,100 females nest annually.
In a 2004 Green Turtle Assessment, the Marine Turtle Specialist Group (MTSG) of the IUCN classified green turtles as endangered globally. Analyses of historic and recent abundance information by the MTSG indicates that extensive population declines have occurred in all major ocean basins over approximately the past 100-150 years. The MTSG analyzed population trends at 32 index nesting sites around the world and found a 48-65% decline in the number of mature females nesting annually over the past 100-150 years.
Threats
- Tortuguero, on the Caribbean coast of Costa Rica, where 22,500 females nest per season on average
- Raine Island, on the Great Barrier Reef in Australia, where 18,000 females nest per season on average
In the U.S., green turtles nest primarily along the central and southeast coast of Florida where an estimated 200-1,100 females nest annually.
In a 2004 Green Turtle Assessment, the Marine Turtle Specialist Group (MTSG) of the IUCN classified green turtles as endangered globally. Analyses of historic and recent abundance information by the MTSG indicates that extensive population declines have occurred in all major ocean basins over approximately the past 100-150 years. The MTSG analyzed population trends at 32 index nesting sites around the world and found a 48-65% decline in the number of mature females nesting annually over the past 100-150 years.
Threats
- harvest of eggs and adults (historically, though the practice continues in some areas of the world)
- incidental capture in fishing gear
- fibropapillomatosis (disease)
- general threats to marine turtles
Information & Photo : nmfs.noaa
- incidental capture in fishing gear
- fibropapillomatosis (disease)
- general threats to marine turtles
Information & Photo : nmfs.noaa
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