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Marine Reptiles Saltwater crocodile Marine iguana

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1 Marine Reptiles Saltwater crocodile Marine iguana
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 turtle

2 Sea Snakes Yellow- bellied sea snake Sea Snakes
Snakes are cold-blooded (poikilotherms). Consequently, their distributions are restricted to warm waters and sea snakes are only found in the Indo-Pacific region. There is concern that if a sea-level canal were constructed across Panama, they could become introduced to the Caribbean. Sea snakes inhabit estuaries, coral reef areas and the open sea and they are often found in large schooling groups. Normally, sea snakes are quite docile and donÕt pose a threat to humans. They have powerful venom which they use to incapacitate fishes or squid. Human fatalities have occurred and these are most common when the snakes wash up on beaches and humans handle the reptiles. They have few natural predators other than sharks, saltwater crocodiles and eagles. Yellow- bellied sea snake

3 Sea Snakes Diversity: Location: Habitat:
Laticodtidae- krates- 5 species (1 is fw in Solomon Islands) Hydrophidae- 54 different species All derived from Colubrid ancestor; colubrids evolved 40 mya; Laticotids evolved from colubrids 30 mya Location: Laticotids- live from east coast India to Japan and come to the tip of Cape York (Australia) Hydrophiids- found from south tip of Africa to India to South East Asian Islands to Japan to north half of Australia Habitat: Primarily tropical; coastal estuaries, coral reefs, open sea; 33-36oC

4 Sea Snakes Behavior: Often schooling in aggregations; Not aggressive but human fatalities have occurred Prey: Feed on small fish or squid, which are killed with powerful venom Predators (few): sharks, snapper, grouper, crabs, saltwater crocodiles, raptors; they descend to escape Venom: 2-10 times as toxic as that of a cobras

5 Sea Snakes Adaptations to life in the sea
Osmoregulation: skin is impermeable to salts; salts eliminated by sublingual gland Developing a flattened paddle-shaped tail and a laterally compressed body. Reduced metabolic rate and increased tolerance for low oxygen levels Lungs- greatly enlarged; hydrostatic organ Gaseous exchange - lungs and the skin. Developing salt excreting glands under the tongue. 2.Developing a flattened paddle-shaped tail and a laterally compressed body making it an efficient swimmer. 3.Reducing its metabolic rate. Sea snakes are capable of remaining submerged for up to 2 hours by decreasing its metabolic rate and developing an increased tolerance for low oxygen levels. After one breath at the surface, it can dive again. A sea snake also has valve-like flaps over its nostrils to stop water flowing into the lungs. 4.The lungs of sea snakes are greatly enlarged, extending to the base of the tail enabling a large volume of oxygen to be stored in the lungs. 5.Parts of the lung are believed to function as a hydrostatic organ regulating the snake's buoyancy. 6.Gaseous exchange occurs through both the lungs and the skin. Up to 22% of the oxygen is supplied from the sea water through the skin and all excess carbon dioxide is lost into the sea.

6 Sea Snakes Reproduction: Krates are oviparous and lay eggs on land
Hydrophiids are viviparous and produce young in the water Not much known about breeding However, olive sea snake breed in spring; seasonal courtship displays Banded sea krates forming mating group Olive Sea Snake

7 Saltwater crocodiles Largest living crocodilians: 6-7 m long
Saltwater crocodiles are the largest of living crocodilians and adults can reach 6-7 m in length. These seagoing animals may travel thousands of miles in the ocean. They are wide-ranging and may move into freshwater areas as well. They havenÕt entirely left land and must return to lay their eggs which are incubated in a terrestrial nest. Their poikilothermic nature means that their distributions are limited to warm areas. Diets include fishes, invertebrates and vertebrates. Largest living crocodilians: 6-7 m long Eggs laid and incubated on land Tropical and subtropical

8 Marine Iguanas Marine lizard endemic to Galapagos islands
Herbivorous: graze on seaweeds Salt-glands on nose to eliminate excess salt Recently observed feeding on land for first time They return to land to escape predators. Marine Iguanas These are the only marine lizards and they are endemic to the Galapagos Islands off Ecuador. Marine iguanas have flattened tails that assist them in swimming and they have adapted to an aquatic life. Their primary diet are algae that encrust the rocks around the islands. Iguanas dive to feed on the algae and in the process, their bodies undergo substantial cooling. After diving and feeding bouts, they must warm themselves on land to raise their body temperature. During feeding they accumulate a lot of salt that is excreted via specialized salt-glands on their noses. Recently, iguanas have been observed feeding on terrestrial vegetation. The stresses of El Ni–os may have driven them to forage ashore.

9 Marine Turtles (Honu)

10 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

11 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 Hawaii species- green, hawksbill, leatherback, Olive Ridley

12 Endangered-facing a very high risk of extinction in the wild
Conservation Status International Union for the Conservation of Nature (IUCN), also called the World Conservation Union The Convention on International Trade in Endangered Species (CITES) The United States Fish and Wildlife Service. Endangered-facing a very high risk of extinction in the wild Vulnerable -facing a high risk of extinction in the wild Threatened-close to qualifying in one of the above categories When people talk about the status of animal species—the current state they are in, or how well they are doing in the world—they rely mostly on three sources: the International Union for the Conservation of Nature (IUCN), also called the World Conservation Union; the Convention on International Trade in Endangered Species (CITES); and the United States Fish and Wildlife Service. All three of these organizations conduct field studies and population surveys and gather information on animal populations from local sources. By coordinating with many other groups, they determine how many individual animals of a certain species there are in the world. This is usually an approximation, not an exact number, because it would be hard to be absolutely sure that every single animal was counted. Once the number of the population has been determined, then that species is given a term to describe its status, such as "endangered” or "threatened,” although the different agencies may use different terms.

13 flatback Class: Reptilia: Reptiles Order: Chelonia: Turtles and Tortoises Family: Chelonidae: Marine Turtles Scientific Name: Natator depressus Diet: sea cucumbers, soft corals, jellyfish Size: < 1 m in length Conservation Status: vunerable Habitat: near continental shelf, shallow, soft bottom sea beds Range: northern part of Australia

14 Green turtle Class: Reptilia: Reptiles Order: Chelonia: Turtles and Tortoises Family: Chelonidae: Marine Turtles 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

15 hawksbill Class: Reptilia: Reptiles Order: Chelonia: Turtles and Tortoises Family: Chelonidae: Marine Turtles Scientific Name: Eretmochelys imbricata Diet: Shellfish Size: cm ( in) Conservation Status: Endangered Habitat: coral reefs, rocky coasts Range: Tropical Atlantic, Pacific and Indian Oceans; Caribbean

16 Loggerhead Class: Reptilia: Reptiles Order: Chelonia: Turtles and Tortoises Family: Chelonidae: Marine Turtles Scientific Name: Caretta caretta Diet: Crustaceans Size: cm ( in) Conservation Status:Vulnerable Habitat: coasts, open sea Range: Temperate and tropical areas of the Pacific, Indian and Atlantic Oceans

17 leatherback Class: Reptilia: Reptiles Order: Chelonia: Turtles and Tortoises Family: Dermochelidae: Marine Turtles Scientific Name: Dermochelys coriacea Diet: sea jellies and salps Size: lbs Conservation Status: endangered Habitat: pelagic water Range: tropical seas, oceanic islands, Atlantic, Pacific, & Indian Ocean

18 reduced shell, dermal bone scutes compose shell 7 dorsal and 5 ventral dermal bones

19 Adaptation to the Marine Environment
Physiology: Poikilothermic (cold blooded) Skin has scales Speed- 35 mph Breath holding- 2 hrs, when sleeping or resting Maturity yrs for green Cannot retract heads like terrestrial turtles Lacrimal gland- salt secretion (drinks seawater)

20 Anatomy Has both internal and external skeleton- provided protection and support for organs Fused ribs Powerful sense of smell- find natal beach No ears, but can perceive low frequency sound and vibrations Male & female- difference in tail size; males tail extends past rear flippers, females is shorter

21 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)

22 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

23 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

24 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

25 Prey

26 Prey Sea grass and Algae- adult green sea turtle
Epiphytes on sea grass, Sponges, fish, crabs, conch- loggerheads (suction feeders) Gelatinous zooplankton: siphonophores jellyfish Crustaceans, mollusks, echinoderms- Ridley

27 Hatchlings- birds, mammals, crabs
Predators Eggs- skunks, raccoons, pigs, lizards, crabs, ants, beetles, fungal and bacterial infections Hatchlings- birds, mammals, crabs Adults- sharks, humans

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

29 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

30 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 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) Increase sea turtle populations: Ranching- eggs or hatchlings from wild populations Farming- originally from wild populations, for breeding stock

31 Catch Statistics (1987) FAO yearbook on Fishery Statistics
3100 metric tons Western Central Atlantic- 1200 Eastern Central Pacific South East Pacific Western Central Pacific- 258 North West Pacific Eastern Central Atlantic Eastern Indian Ocean Western Indian Ocean Mediterranean South East Atlantic

32 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

33 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

34 Turtle Excluder Device

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