Loggerhead Sea Turtle

(Caretta caretta)

General Characteristics

The loggerhead is named for its very large head which is proportionately larger than any of the other species and measures approximately 25 cm (10 in.), with two pairs of prefrontal scales. The carapace (shell) is heart shaped with five pairs of costal scutes, and reddish-brown in color. Their plastron is yellowish-brown. 

Size

The carapace of the loggerhead measures approximately one meter (3 ft. 3 in.), in length and can weigh up to 150 kg. (330 lbs.). Their front flippers are shorter and thicker than the other species and have two claws. Their rear flippers can have two or three claws.

Habitat

Loggerheads are found in all temperate, subtropical and tropical waters throughout the world and inhabit a large northern to southern range. For example, in the western hemisphere they are found as far north as Newfoundland and as far south as Argentina. This species prefers to feed in coastal bays and estuaries, as well as in shallow waters along continental shelves.

Diet

Loggerheads are primarily carnivorous and have very powerful jaw muscles that allow them to crush the shells of their prey. They mainly eat horseshoe crabs, clams, mussels, and other invertebrates living on the ocean floor.

Nesting

Similar to other species, it is difficult to determine the age of sexual maturity for loggerheads; however, studies have estimated it to reach maturity between 16-40 years. A female will nest between four and seven times per season with an inter-nesting period of approximately 12 to 14 days; however, she will not lay every year, instead at intervals of two years or more.  Each female will lay between 100 to 130 eggs in each nest, which will then incubate for approximately 60 days.  The majority of the nesting within the American Continent occurs in the south-eastern United States. However, nesting has been reported in Central America and the northern tip of South America.

Hatchlings

Loggerhead hatchlings have a dark-brown carapace and are distinguished by the pale brown on the margins of their flippers. Their front flippers are much shorter than the length of their carapace, which measures around 45 mm (1.8 in.).   

Migrations

Adult loggerheads are known to make considerable migrations between foraging areas and nesting beaches. For example, satellite tracking of adult females in the south-eastern United States has shown that when they are not nesting, they are distributed off the coast of eastern U.S. and throughout the Gulf of Mexico, Yucatán Peninsula, Bahamas and the Greater Antilles. These results are being compared to the distribution of commercial fishing and dredging activities for better management.

Current Status

The World Conservation Union (IUCN) classifies the species as Endangered, facing a very high risk of extinction in the wild in the near future.

Threats

The most significant threats to the loggerhead are coastal development, marine pollution and commercial fisheries, primarily shrimp trawling. 

Population Trends

In general, loggerhead populations have been declining; however, there are some cases of increased nesting activities such as in southern Florida.

Inter-American Sea Turtle Convention

Cooperative efforts from a variety of governmental as well as non-governmental organizations to conserve distinct sea turtle populations inhabiting the American Continent have existed for many years.  The Inter-American Convention for the Protection and Conservation of Sea Turtles (IAC), which entered into force in May of 2001, provides an opportunity for dialogue and action favoring sea turtle management.  The IAC is the only international body establishing legal instruments and guidelines that commit the Parties to, among others, protect and conserve populations of sea turtles and their habitat, reduce incidental capture and foster international cooperation for research and management of sea turtles. Currently, eleven countries- Belize, Brazil, Costa Rica, Ecuador, United States, Guatemala, Netherlands Antilles, Honduras, México, Peru and Venezuela – are Signatory countries, meanwhile two more, Nicaragua and Uruguay, have sent in the necessary instruments for accession to the Government of Venezuela, the official depository nation.

Sources:

Caribbean Conservation Corporation & Sea Turtle Survival League (www.cccturtle.org)

NOAA Fisheries Office of Protected Resources (www.nmfs.noaa.gov/pr/species/turtles)

Pritchard, P.C.H. and J.A. Mortimer. 1999. Taxonomy, External Morphology, and Species Identification, p. 21-38. In: K.L. Eckert,

K.A. Bjorndal, F.A. Abreu G. and M.A. Donnelly (Editors), Research and Management Techniques for the Conservation of Sea

Turtles. IUCN/SSC Marine Turtle Specialist Group Publ. No. 4. Washington, D.C.

Wider Caribbean Sea Turtle Conservation Network (www.widecast.org)

Published by:

Pro Tempore Secretariat of the Inter-American Convention for the Protection and Conservation of Sea Turtles (IAC), San Jose, Costa Rica, April 2005

Edited by:

Belinda Dick

English Translation:

Belinda Dick

Photo Credits:

Loggerhead - Projeto TAMAR, Brazil

Hatchling - Jacey Biery, 2003

Juvenile loggerhead fitted with satellite transmitter, North Carolina, USA – Matthew Godfrey

Illustrations:

Tom McFarland