Loggerhead Sea Turtle
Loggerheads were named for their relatively large heads, which support powerful jaws and enable them to feed on hard-shelled prey, such as whelks and conch. The most common sea turtle in U. S. coastal waters. the loggerhead sea turtle was listed as threatened throughout its range on July 28, 1978, under the Endangered Species Act of 1973, and has received Federal protection since that time.
Description: The adult loggerhead has a slightly heart-shaped, reddish-brown carapace (top shell of a turtle) consisting of five or more pleural scutes and a yellow plastron (bottom shell of a turtle). Adult males are distinguished by long tails that extend beyond the rear carapace in addition to a narrowing of the carapace that tapers towards the rear.
Hatchlings have light to dark gray/brown shells. Their flippers are dark brown with white edges and their belly is a faded yellow.
Diet: Loggerheads are carnivores, subsisting on crustaceans, fish, and other marine animals. The hatchlings feed on small animals living in the sea grass-like algal mats called sargassum, where they spend their early developmental years. Juveniles and adults eat mostly bottom dwelling invertebrates such as whelks, other mollusks, horseshoe crabs, and sea urchins. Their powerful jaws are designed to crush their prey.
Size: Loggerheads in the southeastern U.S. weigh an average of 250 lbs (113 kg) and are generally about 36 inches (92 cm) long.
Habitat: Loggerheads can be found hundreds of miles out to sea or in inshore waters — bays, lagoons, salt marshes, creeks, ship channels, and the mouths of large rivers. Coral reefs, rocky places, and ship wrecks draw large amounts of marine life and are great feeding areas.
Loggerheads nest on ocean beaches and occasionally on estuarine (where a river meets the sea) shorelines with suitable sand. Nests are typically made between the high tide line and the dune front.
Most loggerhead hatchlings originating from U.S. beaches are believed to lead a pelagic (open sea) existence in the North Atlantic for an extended period of time, perhaps as long as 10 to 12 years, and are best known from the eastern Atlantic near the Azores and Madeira.
As mentioned previously, post-hatchlings take cover in floating mats of sargassum, but once they reach a certain size, these juvenile loggerheads begin "recruiting" to coastal areas in the western Atlantic where they become "benthic" feeders in lagoons, estuaries, bays, river mouths, and shallow coastal waters. These juveniles occupy coastal feeding grounds for a decade or more before maturing and making their first reproductive migration.
Typical Lifespan: Scientists believe that loggerheads are long lived and could live to 50 years or more.
Range: The loggerhead sea turtle is a wide-ranging species, occuring throughout the temperate sub-tropical and tropical regions of the Atlantic, Pacific, and Indian Oceans. In the Atlantic, the loggerhead turtle's range extends from Newfoundland to as far south as Argentina.
In the eastern Pacific, loggerheads have been reported as far north as Alaska, and as far south as Chile. In the U.S., occasional sightings are reported from the coasts of Washington and Oregon, but most records are of juveniles off the coast of California. The west coast of Mexico, including the Baja Peninsula, provides critically important developmental habitats for juvenile loggerheads. The only known nesting areas for loggerheads in the North Pacific are found in southern Japan.
Adult loggerheads are known to make extensive migrations between foraging areas and nesting beaches. During non-nesting years, adult females from U.S. beaches are distributed in waters off the eastern U.S. and throughout the Gulf of Mexico, Bahamas, Greater Antilles, and Yucatán.
Life History and Reproduction: Female loggerheads reach maturity at about 35 years of age. Every 2-3 years, they mate in coastal waters and then return to nest on the very same beach where they were hatched, called the "natal" beach. The nesting season begins in April and ends in September, with the peak in June. They emerge onto the beach at night every 14 days, laying an average of 4 clutches containing roughly 100 – 120 eggs in each. Sex of hatchlings is determined by incubation temperature. Warmer temperatures result in the great majority being females and cooler temperatures produce mainly or only males.
The majority of loggerhead nesting occurs in the western rims of the Atlantic and Indian Oceans, primarily in Oman, the United States, and Australia. The greatest nesting concentrations in the U.S. occur on beaches from North Carolina through southwest Florida, and minimal nesting extends westward to Texas and northward to southern Virginia.
Of the loggerhead nesting activity within the southeastern U.S., about 80% occurs in six Florida counties (Brevard, Indian River, St. Lucie, Martin, Palm Beach, and Broward Counties). In Brevard and Indian River Counties, a 20 mile section of coastline from Melbourne Beach to Wabasso Beach comprises the Archie Carr National Wildlife Refuge (ACNWR), which is the most important loggerhead nesting area in the western hemisphere. Nesting densities of 1,000 nests per mile (625 nests per km) are recorded for beaches within the ACNWR.
Threats: Loggerhead turtles have long been hunted for their eggs and for leather. Other threats include:
- Loss or degradation of nesting habitat from coastal development and beach armoring
- Disorientation of hatchlings by beachfront lighting
- Excessive nest predation by native and non-native predators
- Degradation of foraging habitat
- Marine pollution (including oil spills) and debris
- Watercraft strikes
- Incidental take from channel dredging and commercial trawling, longline, and gill net fisheries.
- Directed harvest – The migratory nature of loggerheads severely compromises conservation efforts once they move outside U.S. waters, however, since legal and illegal fisheries activities in some countries are causing high mortality on loggerhead sea turtle nesting populations of the western north Atlantic region.
Loggerhead sea turtles are protected by various international treaties and agreements as well as national laws such as the U.S. Endangered Species Act (ESA).
In 2008 NOAA's National Marine Fisheries Service (NMFS) and the U.S. Fish & Wildlife Service (USFWS) updated the recovery plan for the loggerhead turtle.
Bycatch of loggerhead turtles (accidental capture by commercial and sport fishermen) is being reduced by fishing gear modifications (i.e. use of TED’s or turtle exclusion devises), changes to fishing practices and closures of certain areas to fishing during nesting and hatching seasons.
Many coastal counties and communities in Florida, Georgia, and South Carolina have developed lighting ordinances to reduce hatchling disorientations.
Important U.S. nesting beaches have been and continue to be acquired for long-term protection.
Regular monitoring of loggerhead turtle populations by NMFS and USFWS, and further research on the biology, life cycle, and migration patterns is needed to help develop effective conservation methods.
US Fish & Wildlife Service
NOAA Fisheries Office of Protected Resources
Mamanuca Environment Society