Marine Turtles

Marine Reptiles Some reinvaded the oceans, but still breathe air: Turtles (Order Chelonia) Snakes (Order Squamata) Iguanas (Order Squamata) Crocodiles (Order Crocodilia) Saltwater crocodile Marine turtle Marine Reptiles (Sea Snakes) Marine Reptiles include sea snakes, saltwater crocodiles, marine iguanas and sea turtles. Sea snakes are a group of true snakes that have completely adapted their life-histories to live in the sea. Sea snake Marine iguana

Marine Reptiles Ectotherms (“cold-blooded”), so mostly in warmer waters, seasonal in temperate waters Cold stunning – Turtles too far north when water temperature suddenly drops (<50°F) Get lethargic, immobile, float to surface, wash up on beach Fatal if not warmed

Marine Turtles

History Found in fossil record 200 mya (Triassic) Common in Cretaceous (130 mya) Present day genera originated 60 (Eocene) and 10 mya (Pleistocene) Not a very diverse group Mostly tropical and subtropical

Taxonomy Class Reptilia Order Chelonia- warm to temperate and boreal seas ex. leatherback, ridley's, kemps   Order Chelonia- F. Cheloniidae- green, flatback, hawksbill, loggerhead F. Dermochelidae- leatherback reduced shell, dermal bone scutes compose shell F. Emydidae- diamond back terrapin

Anatomy Dorsal shell = carapace Ventral shell = plastron Head does not retract carapace plastron

Anatomy Female Male

Adaptation to salt water Lacrimal glands-modified tear ducts!

Green turtle Scientific Name: Chelonia mydas Diet: seagrass and algae Size: ~500lbs Conservation Status: threatened Habitat: high energy ocean beaches, convergence zones in the pelagic habitat, benthic feeding grounds in relatively protected waters Range: throughout world in all tropical and subtropical oceans

Kemp’s Ridley Scientific Name: Lepidochelys kempii Diet: mollusks, crustaceans, jellyfish, fish, algae or seaweed, and sea urchins. Size: 100lbs Conservation Status: highly endangered Habitat: shallow water benthic feeder Range: Gulf of Mexico, Texas

Olive Ridley Scientific Name: Lepidochelys olivacea Diet: jellyfish, tunicates, sea urchins, bryozoans, bivalves, snails, shrimp, crabs, rock lobsters, and sipunculid worms Size: >100lbs Conservation Status: highly endangered Habitat: shallow marine waters Range: Indo-Pacific, S. Atlantic NOAA NOAA

Hawksbill Scientific Name: Eretmochelys imbricata Diet: Shellfish Size: 76 - 91 cm (30 - 36 in) Conservation Status: Endangered Habitat: coral reefs, rocky coasts Range: Tropical Atlantic, Pacific and Indian Oceans; Caribbean

Loggerhead Scientific Name: Caretta caretta Diet: Crustaceans Size: 76 - 102 cm (30 - 40 in), 300 lbs Conservation Status: Vulnerable Habitat: coasts, open sea Range: Temperate and tropical areas of the Pacific, Indian and Atlantic Oceans NOAA

Flatback Scientific Name: Natator depressus Diet: sea cucumbers, soft corals, jellyfish Size: < 1 m in length, 200 lbs Conservation Status: vunerable Habitat: near continental shelf, shallow, soft bottom sea beds Range: northern part of Australia

Leatherback Leatherback Largest species (7 ft, 1200 lbs) Family: Dermochelidae: Scientific Name: Dermochelys coriacea Diet: sea jellies and salps Size: 1500 lbs Conservation Status: endangered Habitat: pelagic water Range: tropical seas, oceanic islands, Atlantic, Pacific, & Indian Ocean Leatherback Largest species (7 ft, 1200 lbs) Global, widest distribution Dive deep (up to 4000 ft) “Warm-blooded” (counter-current circulation, fat)

Reproduction Mating- at sea Migration- occurs in late spring; female is accompanied by male Green sea turtles migrate as far as 800 miles from feeding area to nest in Northwestern Hawaiian Islands Egg laying behavior- return to same beach (natal beach)

Front flippers dig pit, rear flippers carve out burrow Kemps Ridley nesting Usually nest at night Front flippers dig pit, rear flippers carve out burrow

Egg tooth- used to chip away at shell Group effort to get out of nest- emerge at night (safer) and head towards brightest light Artificial lights- confuse hatchlings Turtle nest Cross section

Incidental Marine Turtle Catches

Marine Debris- plastic bags, soda can plastic rings, fishing line, oil and tar Costal development and habitat degradation- noise, light, beach obstructions- affect nesting habitat

Fibropapilloma- virus in Green turtles Affects ability to feed, see, move about, or breath May be due to pollutants, blood parasites, or habitat change Kaneohe Bay (1991)- >50% infected

Clutch size- about 100 eggs & covers pit with sand Leatherback hatching Kemps Ridley hatchlings Clutch size- about 100 eggs & covers pit with sand Egg incubation- 2 months depending upon species Sex determined by temperature- males lower temp, females higher temp

Predators

Factors Affecting Green Sea Turtle Population Hawaii- 100-350 nesting females French Frigate Shoals in the Northwest Hawaiian chain Hunters Fisheries Marine Debris Coastal Development and Habitat Degradation Fibropapilloma

Commercial Value Meat Eggs- nearly forbidden in all countries with nesting beaches Soup Jewelry Leather Convention on International Trade in Endangered Species (CITES): turtle commerce prohibited in countries that signed agreement

Protection and Management Law enforcement- in Hawaii, turtles protected under Endangered Species Act Riding or harassing- $100,000 fine + prison time Bringing turtle products into Hawaii- $20,000 + prison time

Protection and Management Increase sea turtle populations: Ranching- eggs or hatchlings from wild populations Farming- originally from wild populations, for breeding stock

Protection and Management Fishing regulations- Shrimp Trawlers - incidental catch by commercial shrimp fish nets: drowned 10,000 turtles each year Drift nets, gill nets Turtle Excluder Device (TED)

Turtle Excluder Device

How do marine turtles regulate salt in their body? Inquiry What is a natal beach? What advantage is there in turtle hatchlings leaving in a group rather than individually? Are the consequences for harassing a turtle adequate? How does the fibropapilloma virus effect green sea turtles? What is a TED? How do marine turtles regulate salt in their body?