Atlantic loggerhead turtle

Loggerhead turtles occur within the warmer portions of the Atlantic, Indian, and Pacific oceans, as well as the Mediterranean and Caribbean seas. Within the Atlantic Ocean, they feed from Brazil to Canada, with the greatest concentrations found along the coasts of Mexico, Cuba, the Bahamas, and along the coast of North America from the Mississippi River along the Gulf coast and up the U.S. east coast to the Canadian Maritime Provinces. They rarely venture far from mainland shores, usually occurring in water less than 60 meters in depth.

Nesting occurs in warm temperate and subtropical regions on open sandy beaches above the high-tide mark in front of well-developed sand dunes. Nesting along the U.S. coast is mainly along the Atlantic coast from Florida to North Carolina, with about 90% occurring within six coastal counties in Florida. Nesting within the U.S. also occurs along the coast of Texas, Florida’s Gulf coast, and in small numbers in Virginia. They have even been documented nesting as far north as New Jersey, with one nesting record from Island Beach State Park. In Florida, nesting on urban beaches is strongly correlated with the presence of tall objects (trees, buildings), which apparently shield the beach from city lights.

Loggerhead turtles may inhabit open seas more than 500 miles from shore, mostly over the continental shelf, and in bays, estuaries, lagoons, creeks, and mouths of rivers; mainly warm temperate and subtropical regions not far from shorelines. Adults occupy various habitats, from turbid bays to clear waters of reefs. Subadults occur mainly in near shore and estuarine waters. Hatchlings move directly to sea after hatching, often floating in masses of sea plants for 3-5 years. Adults are frequently observed around wrecks, underwater structures, and reefs where they may find prey.

Loggerhead turtles eat a variety of marine invertebrates including crabs, mollusks, sponges, and jellyfish. They also feed on plants and slow-moving or dead fish. Adults forage primarily on the bottom of the ocean but may also take jellyfish from the surface. Young turtles feed on gastropods, crustaceans, and sea plants concentrated at the surface.

Within the southeastern U.S., loggerhead turtles mate between late March and early June. Nesting occurs between late April and early September, but peaks in June. Females may lay 1 to 9 clutches of about 45-200 eggs (averaging 120 eggs per egg laying session) at intervals of about 2 weeks, every 2-3 years.

They nest primarily at night, often at high tide. Eggs hatch in 7 to 11 weeks. Egg mortality may result from predation, beach erosion, invasion of clutches by plant roots, crushing by off-road vehicles, or flooding by sea water or excessive rainfall.

The gender of hatchlings is affected by incubation temperature, with warmer temperatures resulting in a higher number of females and cooler temperatures producing mainly males. Hatchlings emerge from the nest a few days after hatching, typically during darkness. Of every thousand hatchlings, only a few are believed to survive to adulthood.

Once they reach water, male hatchlings will never return to land while females will only do so to nest.

Loggerhead turtle populations have been decimated by overharvesting of adults and eggs, loss of nesting habitat, interactions with fisheries, and entanglement or ingestion of marine debris. Their populations are currently a small fraction of their historical size. Because of this, loggerheads were listed as federally threatened in 1978 and in 1979, listed as endangered by the state of New Jersey. The total global population is perhaps 100,000 adult females.

Loggerhead turtles are currently faced with many threats such as the direct exploitation for food (including eggs), incidental take (chiefly by drowning in shrimp trawls), oil spills, habitat degradation (such as beach development), beachfront lighting, ocean pollution (including marine debris, which may be ingested), and dredging (direct kills and injuries). Beach cleaning operations can destroy nests or produce tire ruts that inhibit movement of hatchlings to sea. Additional threats include predation and trampling of eggs and young by raccoons and feral mammals, crushing of eggs or young by vehicles or humans, collisions with boats and intentional attacks by fishermen. Long-term threats include sea level rise which, coupled with inland urbanization, may reduce available nesting beaches. Since sexual differentiation depends on incubation temperature, there is concern that global warming may result in an imbalance in the sex ratio. Annual mortality due to drowning in shrimp nets has been estimated at 5,000-50,000 in the southeastern U.S.; an additional 550-5,500 may die each year from other human activities.