Transcript Marine Reptiles - cloudfront.net

Marine Reptiles
Saltwater crocodile
Marine iguana
Sea snake
Marine turtle
Sea Snakes
Yellow- bellied sea snake
Diversity:
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Sea Snakes
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:
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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:
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Primarily tropical; coastal estuaries, coral reefs, open sea;
33-36oC
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
Sea Snakes
Adaptations to life in the sea
1. Osmoregulation: skin is impermeable to salts;
salts eliminated by sublingual gland
2. Developing a flattened paddle-shaped tail and
a laterally compressed body.
3. Reduced metabolic rate and increased
tolerance for low oxygen levels
4. Lungs- greatly enlarged; hydrostatic organ
5. Gaseous exchange - lungs and the skin.
Reproduction:
Sea Snakes
• 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
Olive Sea Snake
Saltwater crocodiles
• Largest living crocodilians: 6-7 m
long
• Eggs laid and incubated on land
• Tropical and subtropical
Marine Iguanas
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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.
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
Class Reptilia
Order Chelonia- warm to temperate and boreal
seas ex. leatherback, ridley's, kemps
Order CheloniaF. 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
Conservation Status
1. International Union for the Conservation of Nature (IUCN),
also called the World Conservation Union
2. The Convention on International Trade in Endangered
Species (CITES)
3. The United States Fish and Wildlife Service.
1. Endangered-facing a very high risk of
extinction in the wild
2. Vulnerable -facing a high risk of extinction in
the wild
3. Threatened-close to qualifying in one of the
above categories
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
Class: Reptilia: Reptiles Green turtle
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
hawksbill
Class: Reptilia: Reptiles
Order: Chelonia: Turtles and Tortoises
Family: Chelonidae: Marine Turtles
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
Class: Reptilia: Reptiles
Order: Chelonia: Turtles and Tortoises
Family: Chelonidae: Marine Turtles
Scientific Name: Caretta caretta
Diet: Crustaceans
Size: 76 - 102 cm (30 - 40 in)
Conservation Status:Vulnerable
Habitat: coasts, open sea
Range: Temperate and tropical areas of the
Pacific, Indian and Atlantic Oceans
leatherback
Class: Reptilia: Reptiles
Order: Chelonia: Turtles and Tortoises
Family: Dermochelidae: Marine Turtles
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
• reduced shell,
• dermal bone scutes
compose shell
• 7 dorsal and 5
ventral dermal bones
Physiology:
Poikilothermic (cold blooded)
Skin has scales
Speed- 35 mph
Breath holding- 2 hrs, when sleeping or resting
Maturity- 10-50 yrs for green
Cannot retract heads like terrestrial turtles
Lacrimal gland- salt secretion (drinks seawater)
Anatomy
Has both internal and external skeletonprovided 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
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)
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 nestemerge at night (safer) and head
towards brightest light
Artificial lights- confuse hatchlings
Turtle nest
Cross section
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
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
Eggs- skunks, raccoons, pigs,
lizards, crabs, ants, beetles,
fungal and bacterial infections
Hatchlings- birds, mammals,
crabs
Adults- sharks, humans
Hawaii- 100-350 nesting females
French Frigate Shoals in the Northwest Hawaiian
chain
A. Hunters
B. Fisheries
C. Marine Debris
D. Coastal Development and Habitat Degradation
E. Fibropapilloma
• 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
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 regulationsShrimp 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
Catch Statistics (1987) FAO yearbook on Fishery
Statistics
3100 metric tons
Western Central Atlantic1200
Eastern Central Pacific864
South East Pacific305
Western Central Pacific258
North West Pacific190
Eastern Central Atlantic153
Eastern Indian Ocean50
Western Indian Ocean37
Mediterranean 20
South East Atlantic10
Marine Debris- plastic bags, soda can plastic
rings, fishing line, oil and tar
Costal development and habitat degradationnoise, 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
Turtle
Excluder
Device