Sea Turtle Species Profiles
Loggerhead Sea Turtle
Scientific Name: Caretta caretta
IUCN/Conservation Status: Vulnerable - According to the International Union for the Conservation of Nature (IUCN), loggerhead sea turtles are listed as Vulnerable. Their status was amended in 2017, from a 2015 study that listed them as Endangered (Casale & Tucker, 2017). However, distinct population segments may be in serious decline. Loggerhead sea turtles are protected in the U.S. under the Endangered Species Act. They are also protected from being harvested in Cuba, Mexico, Bermuda, and the Bahamas. Under the Convention on International Trade in Endangered Species, also known as CITES, loggerhead sea turtles cannot be traded internationally between countries that have signed the agreement (Witherington & Witherington, 2015).
Habitat and Distribution: Loggerhead sea turtles are found worldwide, mainly in temperate waters outside of the tropics. In the summer months, in the United States, loggerheads can be found from Cape Cod, Massachusetts to the Gulf Coast of Florida. In the winter months, loggerheads migrate towards warmer waters and move south or offshore. Young loggerheads may circle the entire Atlantic Ocean in their first 10 years of life and later utilize habitats such as seagrass beds, channels, and rocky reefs.
Diet: Loggerheads are carnivores, known to eat jellies, sponges, crabs, and conch. Post-hatchling and juvenile loggerheads are more opportunistic and will eat a variety of invertebrates including Portuguese man-o-wars, dead insects, and sargassum shrimp. Subadults and adults are more specialized in their diet and will eat mainly crustaceans, such as spider crabs, horseshoe crabs, and queen conch.
Size: An adult loggerheads’ carapace typically measures 78 to 109 centimeters (31 to 43 inches) and can weigh between 150 and 375 pounds. Females will normally grow to be larger than males.
Distinguishing Characteristics: Loggerhead sea turtles have 5 lateral scutes on their carapace, which is a reddish-brown color. As hatchlings, the carapace of a loggerhead has raised scutes, this is thought to potentially make these smaller turtles more difficult to swallow by predators, such as sharks. Adult loggerheads are often found with epibiota, including barnacles and algae, living on their carapaces. These creatures and the loggerheads they live on have a commensalistic relationship, meaning the epibiota benefit from having a surface to live on but the loggerhead remains unharmed. Another defining feature of loggerheads is their broad head and neck, for which they are named. Their strong jaws are used for crushing shells, such as conch, when feeding.
Maturity and Reproduction: Loggerheads reach maturity at about 30 years of age. This species has been seen mating off the coast of southeastern Florida. Most loggerhead clutches have 1 paternity but can have multiple (Witherington & Witherington, 2015).
Nesting: In the United States, loggerhead nesting takes place from North Carolina to Mississippi. The large majority of loggerhead nesting occurs on the beaches of southeastern Florida. Loggerheads do not nest every year, but every 2 to 4 years. In a single nesting season, a female can lay anywhere between 3 and 6 nests. Loggerhead nests average 115 eggs and hatchlings typically emerge after incubating for about 2 months.
Fun fact: the most densely nested loggerhead beaches in the world are on the 9.5 miles of beach Loggerhead Marinelife Center monitors and in northeastern Oman, in the Middle East. Loggerhead nesting on LMC monitored beaches normally occurs from April to October. During the 2020 nesting season, 13,059 loggerhead nests were recorded between Tequesta, Jupiter-Carlin, and Juno Beach (Loggerhead Marinelife Center, 2021).
Conservation and Specific Human Impacts: Loggerhead sea turtles have not suffered from commercial harvest, like some sea turtle species have. However, loggerheads are often impacted by commercial fishing. Juveniles have been found to go after bait on longlines, while subadult and adult loggerheads are adversely affected by trawling, another form of commercial fishing. Being trapped in a trawl can restrict a sea turtle's ability to breathe and therefore often leads to drowning. It is estimated that because of commercial trawling, loggerhead numbers have decreased by tens of thousands. Some specific changes that have been made that positively impact loggerheads include the use of turtle excluder devices, (TED’s) on trawl nets, and requiring longline fishermen to use circle hooks (Witherington & Witherington, 2015).
Local Impacts: During the 2020 nesting season, Loggerhead Marinelife Center researchers documented that boat strikes were the most frequently recorded injury observed on nesting loggerhead sea turtles. (Loggerhead Marinelife Center, 2021). See what our Conservation department is doing to promote Responsible Boating Initiatives: https://marinelife.org/conservation/rbi/
Citations:
Casale, P. & Tucker, A.D. 2017. Caretta caretta (amended version of 2015 assessment). The IUCN Red List of Threatened Species 2017: e.T3897A119333622.
https://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T3897A119333622.en. Downloaded on 09 February 2021.
Loggerhead Marinelife Center. (2021) Loggerhead Marinelife Center Sea Turtle Monitoring 2020 Nesting Season Final Report. 9-16.
Witherington, B., & Witherington, D. (2015) Our Sea Turtles: A Practical Guide for the Atlantic and Gulf, From Canada to Mexico. Pineapple Press, Inc.