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Sea Turtles

Sea Turtles. Maia McGuire, PhD Sea Grant Extension Agent. Sea turtle, terrapin or tortoise?. Where does it live (ocean, fresh water or land)? Can it retract its flippers and head into its shell? All lay eggs on land. All are reptiles. Some fresh water “turtles”. Softshell turtle

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Sea Turtles

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  1. Sea Turtles Maia McGuire, PhD Sea Grant Extension Agent

  2. Sea turtle, terrapin or tortoise? • Where does it live (ocean, fresh water or land)? • Can it retract its flippers and head into its shell? • All lay eggs on land. • All are reptiles.

  3. Some fresh water “turtles” • Softshell turtle • Alligator snapping turtle • Diamondback terrapin • Red-eared mud slider www.enature.com

  4. Land “turtle” • Gopher turtle www.enature.com

  5. Turtle anatomy • Carapace (upper shell) • Plastron (lower shell) • Scutes (plates that make up the shell) • Medial, lateral, marginal http://zygote.swarthmore.edu/turtle.html

  6. Sea turtles • Common characteristics • Types • Life history strategies • Threats • Conservation

  7. Sea turtle characteristics • Cannot retract flippers, head into shell • Salt glands behind eyes secrete salt (“tears”) • Nesting females return to the beach where they hatched (summer months) • Sex of turtle hatchlings is determined by temperature (warm= female; cool = male)

  8. Loggerhead turtle • Named for its large head • Adults:200-350 lbs, carapace about 3’ long • Main foods are crustaceans, clams, etc. • Mature in 12-30 yrs • Adults stay close to shore, feed in estuaries or on continental shelf • Reddish-brown carapace

  9. Loggerheads are the most common nesting sea turtle in Florida • Nests contain 100-125 eggs • One turtle nests 4-7 times per season, every 2+ years • Eggs incubate for 60 days • Hatchlings are 1.5-2” long • Listed as a threatened species (U.S.)

  10. Green Sea Turtle • Named for its green body fat • Adults:300-350 lbs, carapace about 3’ long • Main food is seagrass • Mature in 20-50 yrs • Olive-brown carapace • Formerly hunted for soup

  11. Nesting green turtles in Florida are federally listed as an endangered species • Many green turtles are infected with fibropapilloma virus • Nests contain 110-115 eggs • One turtle nests 2-7 times per season, every 2+ years • Eggs incubate for 60 days • Hatchlings are 1.5-2” long www.turtles.org

  12. Leatherback turtle • Back is covered with leathery skin, with 7 ridges running down the back • Largest of the sea turtles—adults are 4-8’ long and weigh 500-1500 lbs • Main food is jellyfish • Can dive to 3000 feet • Can regulate body temperature National Marine Fisheries Service

  13. Some leatherbacks (30-60) nest in Florida each year • Nests contain 80 fertile eggs & 30 unfertilized eggs • One turtle nests 6-9 times per season, every 2-3 years • Eggs incubate for 65 days • Hatchlings are 2.5” long • Leatherback turtles are federally listed as an endangered species www.unc.edu

  14. Hawksbill Turtle • Named for its beak • Adults:100-200 lbs, carapace about 2.5’ long • Main food is sponges • Mature in 3-5 yrs in captivity • Patterned carapace • Formerly hunted for its shell (tortoiseshell) NOAA

  15. Nest in the tropics; only a few nests are found in Florida each year • Nests contain 160 eggs • One turtle nests 2-4 times per season, every 2+ years • Eggs incubate for 60 days • Hawksbill turtles are federally listed as an endangered species

  16. Kemp’s Ridley • Rarest sea turtle in the world • Adult carapace is 2-2.5 feet long, weighs 85-100 lbs • Main food is crabs • Shell is olive-gray http://www.cccturtle.org/species.htm

  17. Nests in daytime • Only nests on one beach (Mexico)—mass nesting called “arribada” (arrival) • Each turtle lays 2 clutches per year, each year • Nests contain 105 eggs • Eggs incubate for 55 days • Hatchlings are 1.5” long • Federally listed as an endangered species

  18. Early life history strategies • Hatchlings swim out to the Gulf Stream • Young turtles are carried around the Atlantic Ocean by oceanic currents for as long as 10-15 years • Young turtles are often found in floating mats of Sargassum seaweed • Less than 1% probably survive 1 year; 1 in 10,000 may reach maturity

  19. Threats • Natural • Threats to eggs • Raccoons • Storms/flooding • Predators (of hatchlings) • Ghost crabs, sea birds, sharks, fish • Predators (of adults) • Sharks, killer whales

  20. Human threats • Alteration of beaches/shorelines • Artificial lighting • Beach driving • Fishing gear • Boat strikes • Poaching • Marine debris (plastics, balloons)

  21. Conservation efforts • Lighting ordinances • Habitat conservation plans • Turtle excluder devices • Volunteer turtle patrols • Satellite tagging www.cccturtle.org

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