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Caroline Rogers Sea Turtles. 2 Introduction Air breathing reptiles Inhabit temperate to tropical seas Range in size from less than 100lbs (olive ridley)

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Presentation on theme: "Caroline Rogers Sea Turtles. 2 Introduction Air breathing reptiles Inhabit temperate to tropical seas Range in size from less than 100lbs (olive ridley)"— Presentation transcript:

1 Caroline Rogers Sea Turtles

2 2 Introduction Air breathing reptiles Inhabit temperate to tropical seas Range in size from less than 100lbs (olive ridley) to 1300lbs (leatherback) Shell consists of carapace (upper portion) and plastron (lower portion) No teeth but have beak like jaws

3 3 Introduction No external ears but have skin covered eardrums Good vision in water Excellent sense of smell Earliest sea turtle fossil 150 million yrs old 100+ yrs ago they traveled the sea in great numbers (too many to count) Habitat destruction and demand for their meat, eggs, leather, and shells has caused population destruction. Dubose Griffin

4 4 Growth Theorized that baby turtles spend their time in sargassum mats Move to adult feeding grounds when they reach dinner plate size 15 to 50 years to reach sexual maturity Thought that some can live over 100 yrs

5 5 Behavior Generally solitary Feed during the day Can sleep on surface or on the bottom Males very rarely return to land Females return to land only to nest

6 6 Mating Mate prior to female nesting emergence Males court a female by nuzzling the head, biting the neck, and/or biting the rear flippers If female receptive the male latches on with front claws and does the nasty Females may mate with several males before laying her eggs Egg clutches may be fertilized by several males

7 7 Nesting Females return to natal beach to nest Often emerge a few yards from their last nesting site Usually at night After finding suitable dry sand she digs a nest with her flippers Eggs are flexible and covered in mucus Mathew Godfrey Adhith Swaminathan

8 8 Nesting Female fills in hole and disguises the nest by flinging sand everywhere When done she crawls back to the water Nesting season in U.S. is April through October Abdulmaula Hamza

9 9 Incubation The hotter the temperature the faster the eggs will develop Warmer temperatures will result in more females Cooler temperatures will result in more males Vulnerable to predation from digging animals and humans Kate Mansfield

10 10 Mathew Godfrey Kellie Pendoley Emergence Babies us “caruncle” (egg tooth) to break open shell Dig out of nest as a group Emerge during cooler temps (night or during rain) Move to brightest horizon (hopefully ocean not lights) Many predators on beach: birds, crabs

11 11 Hatchlings Swim out to sea to find seaweed mats May live in the mats for years Many predators: birds, sharks, fish Only one in 1,000 survive Mary Wozny

12 12 Navigation How do sea turtles migrate 100 to 1000 miles and find their way back to their natal beach? They do not see well out of water so landmarks is unlikely Theory: They are able to detect the intensity and angle of the earths magnetic field.

13 13 Sea Turtle Species Green sea turtle (Chelonia mydas) Hawksbill (Eretmochelys imbricata) Leatherback (Dermochelys coriacea) Loggerhead (Caretta caretta) Robert von DamDouglas Shea Matthew Godfrey Marco Affronte

14 14 Green Sea Turtle Chelonia mydas Named for green colored fat under its shell Single pair of prefrontal scales (scales in front of eyes) Small head Carapace is bony with non- overlapping scutes Four lateral scutes Body nearly oval 4 nonoverlapping lateral scutes

15 15 Green Sea Turtle Description Variable shell colorations Carapace length is 3.5 to 4 ft Weigh between 300 and 400 lbs Largest ever recorded was 5 ft and weighed 871 lbs Kevin Moses

16 16 Green Sea Turtle Diet Changes throughout life Less than 8-10 inches: worms, crustaceans, sea grasses, and algae 8-10 inches and larger: sea grasses and algae Only sea turtle that is herbivorous as an adult Caroline Ridgers

17 17 Green Sea Turtle Habitat Near coastlines and bays Areas with sea grass beds Rarely seen in open ocean Found in all temperate and tropical waters Robert von Dam

18 18 Green Sea Turtle Nesting Nest at two or more year intervals Nest three to five times per season Lay ~115 eggs per nest Eggs hatch after ~60 days Mary Wozny

19 19 Green Sea Turtle Nesting Sites

20 20 Green Sea Turtle Status and Threats United States: Endangered International: Endangered Greatest threat is from commercial harvest for eggs and food. Used for leather and small ones stuffed for souvenirs Commercial trawling increasing threat Estimated population: 88,520 nesting females

21 21 Hawksbill Eretmochelys imbricata Named for hawk-like beak Smaller sea turtle Head small with two pairs of prefrontal scales Bony carapace with overlapping scutes Four lateral scutes Body elliptical in shape

22 22 Hawksbill Description Carapace is yellow, brown, or orange Carapace length is 2.5 to 3 ft Weigh between 100 and 150 lbs Claudia Townsend

23 23 Hawksbill Diet Narrow head and beak-like jaws enable it to get into narrow cracks and crevices Feed on sponges, anemones, squid, and shrimp. Jason Buccheim

24 24 Hawksbill Habitat Found around coastal reefs and rocky areas. Also frequent lagoons and estuaries Found in tropical and subtropical waters worldwide (most tropical sea turtle) Michael Coyne

25 25 Hawksbill Nesting Nest at two or more year intervals Nest two to four times per season Lay ~115 eggs per nest Eggs hatch after ~60 days Johan Chevalier

26 26 Hawksbill Nesting Sites

27 27 Hawksbill Status and Threats United States: Endangered International: Critically Endangered Harvest for their shell is greatest threat Estimated population: 22,900 nesting females

28 28 Leatherback Dermochelys coriacea Named for its shell which is composed of a tough rubbery skin that covers many tiny bony plates Carapace is large, elongated, and flexible with seven ridges that run the length of the turtle

29 29 Leatherback Description Carapace is black or dark grey with pale spots Carapace length is 4 to 6 ft. Weigh between 550 and 1,500 lbs Largest one ever recorded was almost 10 ft (including head and tail) and weighed 2,019 lbs Karumbe

30 30 Leatherback Diet Have very delicate jaws Papillae help to trap food Feed almost exclusively on jellyfish Karumbe

31 31 Leatherback Habitat Found primarily in the open ocean Known to be active in water down to 40F (only reptile known to be active at such a low temp) Most widely distributed sea turtle Inhabit oceans worldwide as north as Alaska and as south as South Africa

32 32 Leatherback Nesting Nest every one to three years Nest six to nine times per season Lay ~80 fertilized eggs (30 smaller unfertilized) Eggs hatch in ~65 days May change nesting beaches but stay in same region Matthew Godfrey

33 33 Leatherback Nesting Sites

34 34 Leatherback Status and Threats United States: Endangered International: Critically Endangered Incidental commercial harvest and pollution are greatest threats –Pollution such as plastic bags and balloons are mistaken as jellyfish Estimated population: 35,860

35 35 Loggerhead Caretta caretta Named for its very large head Carapace has large non-overlapping scutes Carapace is heart shaped Five lateral scutes

36 36 Loggerhead description Carapace is reddish-brown in color Carapace length is 2.5 to 3.5 ft Weigh up to 350 lbs Alan Rees

37 37 Loggerhead Diet Strong jaws allow it to crush animals with shells Feed on clams, muscles, horseshoe crabs, and other invertebrates Alejandro Fallabrino

38 38 Loggerhead Habitat Feed along the continental shelves in the shallow water They also feed in estuaries and coastal bays They are found in all temperate and tropical waters of the world Matthew Simonds

39 39 Loggerhead Nesting Nest every two or more years Nest four to seven times per season ~100 to ~126 eggs per nest Eggs incubate for ~60 days Larisa Avens

40 40 Loggerhead Nesting Sites

41 41 Loggerhead Status and Threats United States: Threatened International: Endangered Loss of nesting habitat due to development is the greatest threat Trawling and pollution are other threats Estimated population: 44,560

42 42 Hector Barrios-Garrido Sea Turtle Fishery Threats Hector Barrios-Garrido Janice Blumenthal Michael Coyne Trawling

43 43 Sea Turtle Pollution Threats Lucia Guillen Robson G. Santos Tar

44 44 Habitat Degradation Kate Mansfield Beach Renourishment Lights Moustakas Vasilios Development on Beach

45 45 Sea Turtle Predation Alexander Gaos Alejandro Fallabrino Robson G. Santos Rats Dogs Zoe Bass Shark

46 46 Resources Hillis-Star, Zandy-Marie, Ralf Boulon and Michael Evans. Sea Turtles of the Virgin Islands and Puerto Rico. 25 Oct U.S. Geological Survey Dec. 15, Information on Sea Turtles and Threats To Their Survival Caribbean Conservation Corporation & Sea Turtle Survival League. 15 Dec


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