Loggerhead turtle (Caretta caretta)
|French:||Caouanne, Tortue Caouanne|
|Spanish:||Cayuma, Tortuga Boba|
|Size||Adults: 75 - 160 kg (2)|
Record weight: 227+ kg (2)
Length: 80 - 100 cm (2)
Record length: 122+ cm (2)
Classified as Endangered (EN) on the IUCN Red List 2007 (1). Listed on Appendix I of CITES (3), and Appendix I of the Convention of Migratory Species (CMS or Bonn Convention) (4).
The loggerhead is one of the most widespread of all the marine turtles and also the most highly migratory, with individuals known to cross the Atlantic and Pacific Oceans (2). This turtle's common name comes from its relatively large head, which contains powerful jaws (5). The carapace of the adult turtle is a reddish-brown colour, whilst the underneath (or plastron) is more yellow in appearance (6).
Found throughout the world in subtropical and temperate waters, loggerheads are the most common turtle in the Mediterranean Sea (7) and western North Atlantic Ocean (2). Nesting occurs in more temperate regions than for other sea turtle species and the largest breeding population is currently found in the southeastern United States from North Carolina throughout Florida (2).
Inhabit coastal waters (7), but may also be found on the open ocean where they tend to float near the water's surface (5).
Adults are primarily carnivorous, using their powerful jaws to crack open crustaceans such as crabs and even seemingly impenetrable molluscs such as the queen conch (Strombus gigas) and giant clam (Tridacna spp.) (7). Loggerheads may reach sexual maturity at around 35 years old, and females appear to nest an average of three to five times in one breeding season, returning to breed every couple of years (8). Nesting occurs at night throughout the summer; females drag themselves out onto beaches beyond the high-tide mark and dig nests (around 40 centimetres deep) into which around 100 eggs are laid (2). Hatchlings and small juveniles appear to spend some time in pelagic environments, often drifting amongst rafts of sargassum (brown algae) and/or flotsam in the open ocean before migrating to benthic habitats in shallower, coastal waters (6).
Long-distance migration makes loggerheads particularly vulnerable to accidental capture by commercial fisheries (bycatch), and turtles can become caught in shrimp trawler nets or entangled in longlines, leading to mortal injuries or death by drowning (7). Fisheries captured 32,000 loggerhead turtles in the Atlantic and 10,500 in the Gulf of Mexico in 1987 alone (7). Loggerheads are unlikely to be deliberately hunted for their meat, which is not considered a delicacy, but eggs are collected in many parts of the world (7). Habitat loss or disturbance, particularly developments on nesting beaches, is the main threat to this species (9).
Loggerheads are nominally protected throughout most of their range and international trade is prohibited by their listing on Appendix I of the Convention on International Trade in Endangered Species (CITES) (3). Nesting occurs on relatively few protected beaches however, and increased protection remains a conservation priority. In Oman, if locals must collect eggs, they are encouraged to only take them from below the high water mark, thus securing an income without harming the turtles' survival chances (9). Turtle Excluder Devices (TEDs) fitted to shrimp trawlers can help prevent bycatch by only allowing shrimp-sized objects to enter the nets, and these are now being adopted by many of the world's fisheries (7).
For more information on the loggerhead turtle see:
Authenticated (11/7/02) by Mike Frick, Caretta Research Project.
- Benthic: the lowermost region of a marine habitat, the bottom.
- Bycatch: in the fishing industry, the part of the catch made up of non-target species.
- Carapace: the top shell of a turtle. In arthropods (insects, crabs etc), the fused head and thorax (the part of the body located near the head) also known as ‘cephalothorax’.
- Carnivore: flesh-eating.
- Crustaceans: diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles.
- Molluscs: a diverse group of invertebrates, mainly marine, that have one or all of the following; a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.
- Pelagic: inhabits the open oceans.
IUCN Red List (March, 2008)
- Frick, M. (2002) Pers. comm.
CITES (March, 2008)
CMS (June, 2002)
- Burnie, D. (2001) Animals. Dorling Kindersley, London.
Turtles.org (June, 2002)
WWF Species Sheets (March, 2008)
NOAA fisheries (March, 2008)
WCMC Species Sheets (March, 2008)