Marine Turtles (Honu)

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Marine Turtles (Honu)
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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
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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
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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

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Flatback
Class Reptilia Reptiles Order Chelonia
Turtles and Tortoises Family Chelonidae Marine
Turtles Scientific Name Natator depressus Diet
sea cucumbers, soft corals, jellyfish Size lt 1
m in length Conservation Status
vunerable Habitat near continental shelf,
shallow, soft bottom sea beds Range northern
part of Australia
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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
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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
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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 StatusVulnerable Habitat coasts,
open sea Range Temperate and tropical areas of
the Pacific, Indian and Atlantic Oceans
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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
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• reduced shell,
• dermal bone scutes
• compose shell
• 7 dorsal and 5
• ventral dermal bones

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Adaptation to the Marine Environment
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)
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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
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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)
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Kemps Ridley nesting
Usually nest at night Front flippers dig pit,
rear flippers carve out burrow
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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
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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
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Prey
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Prey
Sea grass and Algae- adult green sea
turtle Epiphytes on sea grass, Sponges, fish,
crabs, conch- loggerheads (suction
feeders) Gelatinous zooplankton siphonophores j
ellyfish Crustaceans, mollusks, echinoderms-
Ridley
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Predators
Eggs- skunks, raccoons, pigs, lizards, crabs,
ants, beetles, fungal and bacterial
infections Hatchlings- birds, mammals,
crabs Adults- sharks, humans
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Factors Affecting Green Sea Turtle Population
Hawaii- 100-350 nesting females French Frigate
Shoals in the Northwest Hawaiian chain

1. Hunters
2. Fisheries
3. Marine Debris
4. Coastal Development and Habitat Degradation
5. Fibropapilloma

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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
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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
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Catch Statistics (1987) FAO yearbook on Fishery
Statistics 3100 metric tons Western Central
Atlantic- 1200 Eastern Central Pacific-
864 South East Pacific- 305 Western Central
Pacific- 258 North West Pacific- 190 Eastern
Central Atlantic- 153 Eastern Indian Ocean-
50 Western Indian Ocean-
37 Mediterranean - 20 South East
Atlantic- 10
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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
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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)- gt50 infected
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Turtle Excluder Device
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Inquiry

1. What is a natal beach?
2. What advantage is there in turtle hatchlings
   leaving in a group rather than individually?
3. Are the consequences for harassing a turtle
   adequate?
4. How does the fibropapilloma virus effect green
   sea turtles?
5. What is a TED?

How do marine turtles regulate salt in their body?