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Mariana Island Sea Turtles. Background. Populations of sea turtles have been around since the time of the dinosaurs but their numbers have been drastically reduced since interactions between humans and sea turtles began.
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Background • Populations of sea turtles have been around since the time of the dinosaurs but their numbers have been drastically reduced since interactions between humans and sea turtles began. • In addition to direct harvest, population declines have more recently been driven by factors such as incidental capture in commercial fisheries, habitat degradation, introduction of feral predators on nesting beaches, and marine pollution.
Sea turtles are endangered! • Hawksbill and green turtles protected in CNMI by law under the Endangered Species Act • Turtles still illegally hunted today at unknown levels • Limited information available on turtles in the CNMI on which to base management decisions and recovery efforts, especially on hawksbills Photo by: Laura Williams
Near shore Turtles of the Marianas Green sea turtle Chelonia mydas Haggan betde Hawksbill turtle Eretmochelys imbricata Haggan cari
Hawksbill vs Green Turtle Hawksbill Turtle Two pairs of prefrontal scales Green Turtle One pair of prefrontal scales
Offshore Turtles of the Marianas Leatherback turtle Dermochelys coriacea Loggerhead turtle Caretta caretta Olive Ridley turtle Lepidochelys olivacea
Sea turtles are ReptilesWhat does that mean? • They breathe air from the water’s surface • They are cold-blooded which means they get their body heat from the environment rather than making their own • Their skin has scales • They lay eggs
What do sea turtles eat? It depends on the kind of turtle… Loggerhead vs. Leatherback • Some have finely serrated jaws adapted for vegetarian diet • Others have jaws adapted for crushing and grinding • Or they have narrow heads and pointy jaws adapted for getting food out of crevices in coral reefs • While still some have very delicate scissor-like jaws
Carnivore, Herbivore, or Omnivore? • Green turtles: algae and seagrass • Hawksbills: sponges, shrimps, and squid • Leatherbacks: jellyfish • Loggerheads & Ridleys: crabs, lobsters, jellyfish, & vegetation Photo by: Peter Bennett
How fast and far can sea turtles swim? • Most turtles can swim for short bursts to 20mph, but some green turtles have been clocked up to 35mph! • They can swim for long distances, some travel up to 2500 miles!
How long can sea turtles hold their breath? It depends… • On their size, adult turtles can hold it for 2 hours while they sleep but when they are active they usually come to the surface every 15-20 minutes • On the species, hawksbill turtles can’t hold their breath for as long as leatherback turtles
How many eggs do sea turtles lay and what do they look like? • Depending on the kind of turtle they can lay between 100 and 180 eggs per nest @ 3-6 nests per season • They are the size of ping-pong balls (unless you are a leatherback and then they are the size of billiard balls • They are leathery and flexible (unlike a chicken egg) so when they are dropped into the nest they do not break
Nest Inventory • Eggs incubate under the sand for 2 months • After they hatch we count the number of hatched and unhatched eggs to calculate the hatch success rate
Photo by: PIFSC/NOAA Escape from Predators! Photo by: Mark Sullivan Photo by: Mark Sullivan
Indigenous hand-capture method Photo by: Lynne Michael Photo by: K. Hayashi Photo by: K. Hayashi
Flipper tagging Nearshore Tagging • Return address on tags: SPREP, P.O. Box 240, Apia, Samoa Photo by: Joe Ruak Photo by: Lynne Michael Photo by: Joe Ruak Photo by: Lynne Michael Photo by: K. Hayashi Photo by: K. Hayashi
PIT tag scanning and application • A Passive Integrated Transponder (PIT) tag is smaller than a penny and is inserted inside the flipper • It can last up to 75 years and usually remain much longer than metal flipper tags in animals. Photo by: Lynne Michael Photo by: Lynne Michael
Tissue biopsy samples • Skin samples are taken for DNA lab tests • From this we can tell who CNMI sea turtle’s family members are and what other countries they are from
Measuring turtle shells • Measuring a turtle’s shell length and width • Allows scientists to measure how quickly or slowly a turtle grows between captures Photo by: Lynne Michael Photo by: Lynne Michael
Measuring weight and taking photos • Preparing to measure a turtle’s weight on a scale • Photographing a turtle’s face gives us the turtle’s “fingerprint” each pattern is unique Photo by: Mark Michael Photo by: Lynne Michael
Satellite tagging & tracking Photo by: Shawn Wusstig
Migration routes & recapture locations of sat tagged Guam green turtles
Photo by: Shawn Wusstig Why do we satellite tag turtles? • To learn more about sea turtle movements and behavior. • We have found that turtles travel great distances from foraging grounds to nesting beaches. • Passing through the waters of many countries has highlighted the migratory nature of sea turtles, and the need for the Pacific region to work together to strengthen conservation initiatives.
Things you can do in your community to help sea turtles… Volunteer with TAGS (Turtle Advocate & Guardian Society), TASI Watch (MINA), or get involved with KHS Marine Biology Club!
Myrtle says… dispose of trash properly and walk the beach, don’t drive it YES! Photo by: www.ethicalocean.com OH NO!
Myrtle says… treat animals with respect: do not crowd, attempt to feed, ride, touch, or harass OH NO! YES!
Myrtle says…please don’t keep us as pets, we are much happier swimming and eating in the wide open spaces of the ocean! OH NO! YES!
Myrtle says…if you find a stranded, sick, or injured turtle call DLNR-DFW, 911 or crime stoppers at 323-PARA so we can get a doctors help! These kids did! Thank you! I don’t feel well…
For More Help! Mariana Islands Sea Turtles www.ihaggan.com NOAA Sea Turtles www.fpir.noaa.gov Turtle Trax www.turtles.org International Sea Turtle Society www.seaturtle.org Internet resources Volunteer with Tasi Watch or TAGS Report sea turtle strandings: 911 323-PARA 664-6000 (DFW)