In previous
postings we have identified the Sargasso as the likely home to the population
of Atlantic sea serpents or other sea based reptiles. The evidence points in that direction and
finding the turtles also conform to the same pattern is serious confirmation.
I also suspect
that this sea is a remnant of the great equatorial ocean that dominated during
the Age of Dinosaurs. Thus remnant
populations are likely to be located here.
To the best of my knowledge, no one has seriously entered the Sargasso
to look for large animals.
Thus exploration
with clever sensors may be very surprising.
A herd of plesiosaurs would put everything on its head.
Sea turtles
'lost years' mystery starts to unravel
Small satellite-tracking devices attached to sea
turtles swimming off Florida's coast have delivered first-of-its-kind data that
could help unlock they mystery of what endangered turtles do during the
"lost years."
The "lost years" refers to the time after
turtles hatch and head to sea where they remain for many years before returning
to near-shore waters as large juveniles. The time period is often referred to
as the "lost years" because not much has been known about where the
young turtles go and how they interact with their oceanic environment—until
now.
"What is exciting is that we provide the first
look at the early behavior and movements of young sea turtles in the
wild," said UCF biologist Kate Mansfield, who led the team. "Before
this study, most of the scientific information about the early life history of
sea turtles was inferred through genetics studies, opportunistic sightings
offshore, or laboratory-based studies. With real observations of turtles in
their natural environment, we are able to examine and reevaluate existing
hypotheses about the turtles' early life history. This knowledge may help
managers provide better protection for these threatened and endangered
species."
Findings from the study appear today in the
journal Proceedings of the Royal Society B.
A team of scientists from the UCF, Florida Atlantic
University, University of Miami (UM) Rosenstiel School of Marine and
Atmospheric Science, and University of Wisconsin, tracked 17 loggerhead turtles
for 27 to 220 days in the open ocean using small, solar-powered satellite tags.
The goal was to better understand the turtles' movements, habitat preferences,
and what role temperature may play in early sea turtle life history.
Some of the findings challenge previously held
beliefs.
While the turtles remain in oceanic waters
(traveling between 124 miles to 2,672 miles) off the continental shelf and the
loggerhead turtles sought the surface of the water as predicted, the study
found that the turtles do not necessarily remain within the currents associated
with the North Atlantic subtropical gyre. It was historically thought that
loggerhead turtles hatching from Florida's east coast complete a long, developmental
migration in a large circle around the Atlantic entrained in these currents.
But the team's data suggest that turtles may drop out of these currents into
the middle of the Atlantic or the Sargasso Sea.
The team also found that while the turtles mostly
stayed at the sea surface, where they were exposed to the sun's energy, the
turtles' shells registered more heat than anticipated (as recorded by sensors
in the satellite tags), leading the team to consider a new hypothesis about why
the turtles seek refuge in Sargassum. It is a type of seaweed found on the
surface of the water in the deep ocean long associated with young sea turtles.
"We propose that young turtles remain at the
sea surface to gain a thermal benefit," Mansfield said. "This makes
sense because the turtles are cold blooded animals. By remaining at the sea surface, and by associating with Sargassum habitat, turtles
gain a thermal refuge of sorts that may help enhance growth and feeding rates,
among other physiological benefits."
More research will be needed, but it's a start at
cracking the "lost years" mystery.
The findings are important because the loggerhead
turtles along with other sea turtles are threatened or endangered species.
Florida beaches are important to their survival because they provide important
nesting grounds in North America. More than 80% of Atlantic loggerheads nest
along Florida's coast. There are other important nesting grounds and nursing
areas for sea turtles in
the western hemisphere found from as far north as Virginia to South America and
the Caribbean.
"From the time they leave our shores, we don't
hear anything about them until they surface near the Canary Islands, which is
like their primary school years," said Florida Atlantic University
professor Jeannette Wyneken, the study's co- PI and author. "There's a
whole lot that happens during the Atlantic crossing that we knew nothing about.
Our work helps to redefine Atlantic loggerhead nursery grounds and early
loggerhead habitat use."
Mansfield joined UCF in 2013. She has a Ph.D. from
the Virginia Institute of Marine Science and a master's degree from the
Rosenstiel School of Marine and Atmospheric Science at the University of Miami.
She previously worked at Florida International University, through the
Cooperative Institute for Marine and Atmospheric Studies (CIMAS) in association
with the National Oceanographic and Atmospheric Administration and the National
Marine Fisheries Services. She was a National Academies NRC postdoctoral
associate based at NOAA's Southeast Fisheries Science Center, and remains an
affiliate faculty in Florida Atlantic University's biology department where
Wyneken is based.
With colleagues at each institution Mansfield
conducted research that has helped further the understanding of the sea turtle
"lost years" and sea turtle
life history as a whole. For example she and Wyneken developed a satellite
tagging method using a non-toxic manicure acrylic, old wetsuits, and
hair-extension glue to attach satellite tags to small turtles. Tagging
small turtles is
very difficult by traditional means because of their small size and how fast
they grow.
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