I took a class in Marine Biology, and I loved it. True I only got a B in the class, but I read every word in that book in the beginning the last two weeks the reading was so extensive I failed to complete it, and I rented the book instead of buying it. I had to return it. That was sad. I would have loved to keep it. Of course I am a geek. I very often keep my books. I was reading through my geography book, and someone told me they would rather sit in a room with white walls and stare than read a geography book.
I am fascinated with turtles, so I enjoyed writing about Leatherback Sea turtles. I hope you enjoy the information.
Leatherback Sea Turtles:
D. Coriacea is listed on Appendix 1 of CITES, which makes
export/import of this species (including parts) illegal.
The Leatherback
Sea Turtle is the largest of the sea turtles. It can grow to Six and a half
feet, and weigh up to 1,400 pounds. Unlike other marine turtles it has a
carapace that is covered with skin and oily flesh. The Leatherback turtles have
been around for 110 million years in one form or another. They began during the
crustaceous period. They are a close relative to the other six species of sea
turtles that still exist today.
Leatherback
mothers lay eggs, and leave them to hatch. The infant Leatherbacks face the
same challenges as other sea turtles as they try to make it to the sea. It must
be like running a gauntlet. There are a variety of predators ready to eat them.
This is if humans have not already eaten the eggs. Once at sea they face predation
from cephalopods, sharks and other large fish. They don’t have a hard shell,
but as adults they face fewer predators. They can be quite aggressive if
attacked at sea.
They do long
distance migrations from cold water to tropical beaches where they hatch. They breed in water, and the males once they
hatch and reach the ocean will never return to land. The females will return to
lay eggs. They mate every two to three years, and fertilization is internal. Multiple
males breed with a single female which doesn’t appear to provide the
offspring’s with any advantages. They do not always return to the place where
they were hatched, but may choose another beach in that region. They like
beaches with finer sand, because their shells are soft and plastrons are easily
damaged by hard rocks. They nest at night, and prefer to nest on a beach near a
forest. Their night vision on land in poor. The dark forest and the moonlit
ocean help the female with directions. She makes the nest above the high tide
line, and digs it with her flippers. She will lay about nine clutches of eggs
in a breeding season of around 110 eggs each. 85% will be viable. She covers
her nests and disguises it by scattering sand. The eggs hatch in 60 to 70 days.
The nests ambient temperature determines the sex of the babies.
They live mainly
in the open ocean. They can travel from Indonesia to the US which would be
about 12,000 miles. Their prey is jellyfish, so they are in deeper water during
the day and more shallow water at night. They are undaunted by cold water or
deep water. They also feed on tunicates and cephalopods.
One reason they
are endangered is because plastic bags float and resemble jellyfish. It is
estimated that a third of the Leatherbacks have ingested plastic. It obstructs
their digestive tract, and inhibits their ability to get nutrients they need.
This stops growth which effects sexual maturity and limits reproduction. This
is the best case scenario. The worst case is that they starve to death.
Their life span
is undetermined. It is believed it is somewhere between thirty and eighty
years.
They are the
largest living sea turtle and as such the turtle excluder’s devises can be
ineffective with mature adults. It was
reported that 1500 mature females were caught accidentally annually in the
1990’s. Pollution like chemicals can be fatal. A high level of phthalates has
been measured in their egg yolks.
Work Cited
Leigh Henry: WWF Marine Turtle Leatherback Turtle.
http://worldwildlife.org/species/leather_turtle
Leatherback Sea Turtle.
En.wikipedia.org/wiki/leatherback_turtle
Leatherback Sea Turtle.
www.bagheera.com/inthewild/van_anim_turtle.htm
Nancy Haydon; Why is the Leatherback Sea Turtle
Endangered. http://www.ehow.com/about_7229211
_leatherback -sea-turtle-endange…
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