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 snakeMarine 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 speciesAll derived from Colubrid ancestor; colubrids evolved 40 mya; Laticotids evolved from colubrids 30 myaLocation: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 AustraliaHabitat:Primarily tropical; coastal estuaries, coral reefs, open sea; 33-36oC
4 Sea SnakesBehavior: Often schooling in aggregations; Not aggressive but human fatalities have occurredPrey: Feed on small fish or squid, which are killed with powerful venomPredators (few): sharks, snapper, grouper, crabs, saltwater crocodiles, raptors; they descend to escapeVenom: 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 glandDeveloping a flattened paddle-shaped tail and a laterally compressed body.Reduced metabolic rate and increased tolerance for low oxygen levelsLungs- greatly enlarged; hydrostatic organGaseous 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 waterNot much known about breedingHowever, olive sea snake breed in spring; seasonal courtship displaysBanded sea krates forming mating groupOlive 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 longEggs laid and incubated on landTropical and subtropical
8 Marine Iguanas Marine lizard endemic to Galapagos islands Herbivorous: graze on seaweedsSalt-glands on nose to eliminate excess saltRecently observed feeding on land for first timeThey return to land to escape predators.Marine IguanasThese 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.
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 groupMostly tropical and subtropical
11 Taxonomy Class Reptilia Order Chelonia- warm to temperate and boreal seas ex. leatherback, ridley's, kempsOrder Chelonia-F. Cheloniidae- green, flatback, hawksbill,loggerheadF. Dermochelidae- leatherbackreduced shell, dermal bone scutes composeshellF. Emydidae- diamond back terrapinHawaii species- green, hawksbill, leatherback, Olive Ridley
12 Endangered-facing a very high risk of extinction in the wild Conservation StatusInternational Union for the Conservation of Nature (IUCN), also called the World Conservation UnionThe 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 wildVulnerable -facing a high risk of extinction in the wildThreatened-close to qualifying in one of the above categoriesWhen 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 flatbackClass: Reptilia: ReptilesOrder: Chelonia: Turtles and TortoisesFamily: Chelonidae: Marine TurtlesScientific Name: Natator depressusDiet: sea cucumbers, soft corals, jellyfishSize: < 1 m in lengthConservation Status: vunerableHabitat: near continental shelf, shallow, soft bottom sea bedsRange: northern part of Australia
14 Green turtleClass: Reptilia: ReptilesOrder: Chelonia: Turtles and TortoisesFamily: Chelonidae: Marine TurtlesScientific Name: Chelonia mydasDiet: seagrass and algaeSize: ~500lbsConservation Status: threatenedHabitat: high energy ocean beaches, convergence zones in the pelagic habitat, benthic feeding grounds in relatively protected watersRange: throughout world in all tropical and subtropical oceans
15 hawksbillClass: Reptilia: ReptilesOrder: Chelonia: Turtles and TortoisesFamily: Chelonidae: Marine TurtlesScientific Name: Eretmochelys imbricataDiet: ShellfishSize: cm ( in)Conservation Status: EndangeredHabitat: coral reefs, rocky coastsRange: Tropical Atlantic, Pacific and Indian Oceans; Caribbean
16 LoggerheadClass: Reptilia: ReptilesOrder: Chelonia: Turtles and TortoisesFamily: Chelonidae: Marine TurtlesScientific Name: Caretta carettaDiet: CrustaceansSize: cm ( in)Conservation Status:VulnerableHabitat: coasts, open seaRange: Temperate and tropical areas of the Pacific, Indian and Atlantic Oceans
18 reduced shell,dermal bone scutescompose shell7 dorsal and 5ventral dermal bones
19 Adaptation to the Marine Environment Physiology:Poikilothermic (cold blooded)Skin has scalesSpeed- 35 mphBreath holding- 2 hrs, when sleeping or restingMaturity yrs for greenCannot retract heads like terrestrial turtlesLacrimal gland- salt secretion (drinks seawater)
20 AnatomyHas both internal and external skeleton- provided protection and support for organsFused ribsPowerful sense of smell- find natal beachNo ears, but can perceive low frequency sound and vibrationsMale & 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 maleGreen sea turtles migrate as far as 800 miles from feeding area to nest in Northwestern Hawaiian IslandsEgg laying behavior- return to same beach (natal beach)
22 Front flippers dig pit, rear flippers carve out burrow Kemps Ridley nestingUsually nest at nightFront 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 lightArtificial lights- confuse hatchlingsTurtle nestCross section
24 Clutch size- about 100 eggs & covers pit with sand Leatherback hatchingKemps Ridley hatchlingsClutch size- about 100 eggs & covers pit with sandEgg incubation- 2 months depending upon speciesSex determined by temperature- males lower temp, females higher temp
28 Factors Affecting Green Sea Turtle Population Hawaii nesting femalesFrench Frigate Shoals in the Northwest Hawaiian chainHuntersFisheriesMarine DebrisCoastal Development and Habitat DegradationFibropapilloma
29 Commercial Value Meat Eggs- nearly forbidden in all countries with nesting beachesSoupJewelryLeatherConvention 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 ActRiding or harassing- $100,000 fine + prison timeBringing turtle products into Hawaii- $20,000 + prison timeFishing regulations-Shrimp Trawlers - incidental catch by commercial shrimp fish nets: drowned 10,000 turtles each yearDrift nets, gill netsTurtle Excluder Device (TED)Increase sea turtle populations:Ranching- eggs or hatchlings from wild populationsFarming- originally from wild populations,for breeding stock
31 Catch Statistics (1987) FAO yearbook on Fishery Statistics 3100 metric tonsWestern Central Atlantic- 1200Eastern Central PacificSouth East PacificWestern Central Pacific- 258North West PacificEastern Central AtlanticEastern Indian OceanWestern Indian OceanMediterraneanSouth 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 breathMay be due to pollutants, blood parasites, or habitat changeKaneohe Bay (1991)- >50% infected
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