For years the Leatherback turtle's travel patterns
have been anything but predictable. These sea voyagers are rarely found alive on
beaches and enjoy a life of ocean travels. Now, marine biologists are releasing
clues into the secret lives of these nomad turtles.

Minutes after hatching, male Leatherbacks enter
the water and will not return to the beach...ever. Females only become beached
when laying their eggs. The Leatherback is the world's largest living turtle
and can grow to a monstrous size. The biggest one ever recorded was found
washed up on a beach in Wales. The turtle weighed more than 1900 pounds and was the
measured over 9 feet long.

But working against their size is the fact that these turtle shells are just
tough, oily skin rather than a hard. From birth these turtles face a battle for
survival. Females usually lay their eggs on the same beach at which they were
born. But many of these eggs are collected before they are even hatched. The
few lucky enough to hatch now face the dangerous outside world. Some will
become prey to hovering birds of prey as they make their way to the shore line.
These tiny creatures begin swimming in the vast ocean, and once again most will
become dinner to birds and other sea creatures. This leaves only a handful of
baby turtles able to survive to maturity. Once they hit maturity they are faced
with their biggest threat, man. Many drown as they become caught up in long-line fishing nets. For
these reasons alone, the Leatherback has been placed on the
endangered species list.

Marine biologist, Barbara Block, and her
colleagues at PLos Biology, decided to research the wonderings of these
turtles in hopes of discovering a pattern of travels which could then help
provide information on ways to help save this endangered species from human
harm. Block and company electronically tagged forty-six females during
three field seasons at Playa Grande in Costa Rica. Playa Grande is the largest known nesting colony in the eastern
Pacific.

After being tagged, the turtles were monitored
from January
24, 2004 to July 5, 2007. During that time period these females leatherbacks
embarked on rapid migration directed to the south that crossed through the
equatorial region. Once south the turtles dispersed throughout the South
Pacific Gyre following slower winding paths. The turtles, though
wondering, stayed in this area of the South Pacific for the remainder of
the tracking period.

What is interesting is what looks to be just
aimless wonderings, these travels followed an even more powerful tow, that of
the ocean currents. When PLos Biology examined the Leatherbacks southward patterns they
discovered the turtles were moving with motion of the ocean. The animals were
at the liberty of the ocean currents, but the biologists were able to identify
the most widely used currents. Leatherbacks responded greatly to strong zonal
currents by increasing their southward speed, probably to maintain their
south/south-west headings and to avoid being pushed too far eastward or
westward from their destination in the South Pacific Gyre.

In 2004, the Leatherbacks covered a maximum of
10,645 miles spanning the western coast of South America.
By 2007, the tracked turtles covered only a maximum of 4,815 miles. Researchers
believe this decrease occurred because Leatherback females only mate every two
to three years therefore the long trek back to the

Protecting the nest sites for the Leatherback is
vitally important but now with these new details about their migration, it is
also vital that their movement at sea be protected just as much. Now,
international management agreements can be put in place to protect these
endangered species.

Pictured above is the Leatherback turtle
home-range utilization distribution for all years three combined. Boundaries of
the ETPS, corresponding to the exclusive economic zones of Costa Rica, Panama, Ecuador, and Colombia, are shown as dashed blue lines. The green polygon
comprises the region with the lowest climatological in the South Pacific Gyre.

For more information on the group of Leatherback
turtles that were tracked, visit PLos Biology's journal at: http://biology.plosjournals.org/perlserv/?request=get-document&doi=1...

Share