Loggerhead sea turtle (Caretta caretta)

Loggerhead sea turtle
(Caretta caretta)

TAXONOMY AND NAMING

Class : Reptilia
Order : Testudines
Family : Cheloniidae
Genus/species : Caretta
Common names :
English : Loggerhead sea turtle
Spanish : Tortuga boba
French : Caouanne

Loggerhead sea turtle (Caretta caretta)© © N. Pilcher MRF

ANATOMY AND MORPHOLOGY

The average loggerhead measures around 90 cm (35 in) in carapace length when fully grown. The adult loggerhead sea turtle weighs approximately 135 kg (298 lb), with the largest specimens weighing in at more than 450 kg (1,000 lb). It is the world’s largest hard-shelled turtle. The skin ranges from yellow to brown in color, and the shell is typically reddish brown. No external differences in sex are seen until the turtle becomes an adult, the most obvious difference being the adult males have thicker tails and shorter plastrons (lower shells) than the females.

DISTRIBUTION AND LIFE HISTORY

The loggerhead sea turtle is found in the Atlantic, Pacific, and Indian Oceans, as well as the Mediterranean Sea. It spends most of its life in saltwater and estuarine habitats, with females briefly coming ashore to lay eggs. The loggerhead sea turtle has a low reproductive rate ; females lay an average of four egg clutches and then become quiescent, producing no eggs for two to three years. The loggerhead reaches sexual maturity within 17–33 years and has a lifespan of 47–67 years.

The loggerhead sea turtle is omnivorous, feeding mainly on bottom-dwelling invertebrates. Its large and powerful jaws serve as an effective tool for dismantling its prey.

Loggerhead sea turtle (Caretta caretta)©IUCN red list

THREATS

Many human activities have negative effects on loggerhead sea turtle populations. The prolonged time required for loggerheads to reach sexual maturity and the high mortality rates of eggs and young turtles from natural phenomena compound the problems of population reduction as a consequence of human activities. Annual variations in climatic temperatures can affect sex ratios, since loggerheads have temperature-dependent sex determination. High sand temperatures may skew gender ratios in favor of females. In addition, tropical Cyclones have a significant impact on hatchling loss. The associated storm surges push water higher up the beach, flooding nest and drowning the embryos.

Loggerhead sea turtles were once intensively hunted for their meat and eggs ; consumption has decreased, however, due to worldwide legislation. Despite this, turtle meat and eggs are still consumed in countries where regulations are not strictly enforced. Fishing gear is the biggest threat to loggerheads in the open ocean. They often become entangled in longlines or gillnets.

PROTECTION AND CONSERVATION STATUS

The species is recognized as vulnerable on the IUCN Red List. Since the loggerhead occupies such a broad range, successful conservation requires efforts from multiple countries.

CITES : yes_Annex I

SPAW Protocol : yes since 1991_Annex II

USA endangered species Act  : 1970

ab 1. International convention and protection for loggerhead sea turtles

Sea turtle national protection status in SPAW parties ©SPAW RAC

Bibliography

Aguirre, A. ; Susan C. Gardner ; Jesse C. Marsh ; Stephen G. Delgado ; Colin J. Limpus ; Wallace
Kyle S. Van Houtan and Oron L. Bass (2007). "Stormy oceans associated with declines in sea turtle hatching". Current Biology Vol 17 No 15. Cell Press Journal.
N. Mrosovsky & Jane Provancha (1992). "Sex ratio of hatchling loggerhead sea turtles : data and estimates from a 5-year study". Canadian Journal of Zoology. 70 (3) : 530–538. doi:10.1139/z92-080.
Nichols (September 2006). "Hazards Associated with the Consumption of Sea Turtle Meat and Eggs : A Review for Health Care Workers and the General Public". EcoHealth. 3 (3) : 141–53.
Spotila 2004, p. 178