That nest is getting ready to hatch.
Look at ‘em all. Are you kidding me?
Goodness! Each year from late July to November, tiny
sea turtle hatchlings seemingly vanish into the vast ocean along Florida’s coast.
The sea turtle lost years includes the time from which the turtles emerge from their nests,
crawl down and enter into the ocean, and then they swim off shore.
Bound for destinations unknown, for decades researchers were left to guess where the hatchlings
journeyed during their lost years. We don’t really know what they do, where
they go, in part because it’s really difficult to access those offshore waters. That life
history stage has been historically understudied. Before now, we just called them “the lost
years” and kind of threw up our hands. Depending on the species, sea turtles can
spend anywhere from 2 to upwards of 8 years at sea.
We had to just wave goodbye to a turtle off the beach, and then see it again several years
later when it came back into shallow, coastal waters. But now researchers are beginning to unravel
the mysteries of the sea turtle’s lost years. For this youngest stage of sea turtle, it’s
really important for us to understand where they are, when they’re there, so we can
better understand perhaps what potential impacts humans might have on these turtles.
Where do sea turtles go during their lost years? And how are new technologies helping
to solve this oceanic enigma? Major funding for this program was provided
by the Batchelor Foundation, encouraging people to preserve and protect America’s underwater
resources. And by Diver’s Direct, Emocean Club, inspiring the pursuit of tropical adventures
and scuba diving . And by the Do Unto Others Trust.
Sea turtles have roamed the planet’s oceans for 100 million years.
The group the turtles are in as a whole has existed since the dinosaurs existed.
Just in the past few decades, sea turtle populations have declined in certain locations, due to
poaching, destructive fishing practices, loss of habitat, water pollution, and other pressures.
There’s issues that these sea turtles can’t overcome without a little bit of help, and
a little bit of conservation. There are six species of sea turtles found
in the United States, and those are protected under the U.S. Endangered Species Act.
It’s just a tremendously complicated problem to manage.
And to do that you need knowledge. And to gain the knowledge you have to go out and
do research projects like the ones we’re doing.
Founded in the late 1970’s by Dr. Llewellyn Ehrhardt, the Marine Turtle Research Group
at the University of Central Florida was established to better understand coastal sea turtles.
There’s a green just north of here, I think. But I want to know where the loggerhead is.
Today, under the leadership of Dr. Kate Mansfield, the research group’s scope has broadened
to include the whole life history of sea turtles, from egg to adult, with study sites in the
Atlantic and the Gulf of Mexico. So what I’m trying to do is create a center
where we have the early reproductive history we have the inwater work, where we’re catching
those new recruits to the coastal environment, the larger juveniles. And then we have my
offshore work, where I’m looking at the early dispersal and movements and behavior
of the lost years. So I’m trying to tie that all together in a cohesive research program
where we have a whole life history approach. One of Kate’s study sites is in the Archie
Carr National Wildlife Refuge along Florida’s Atlantic coast. The 248-acre refuge was established
in 1991 to protect sea turtle foraging & nesting habitats along this developed barrier island.
The Archie Carr National Wildlife Refuge is one of the most important nesting beaches
in the Western Hemisphere. We get more turtle nests in a 13-mile or 20-km stretch of beach than any other place in the U.S.
Thirty years ago only 8,000 sea turtle nests were laid in the refuge each year. But in
2013, it saw over 20,000 nests. There’s this really incredible exponential
population growth that can be directly attributed to something like the Endangered Species Act.
And to the protection that the refuge provides itself.
The Marine Turtle Research Group monitors around 13 miles of coastline in the refuge,
and has generated more than 30 years of data from these important habitats.
The life cycle of a sea turtle begins after a nesting female lays her eggs in the sand,
typically on a tropical beach. Six to eleven weeks later hatchlings emerge.
In the Archie Carr National Wildlife refuge, sea turtle nests are laid in the sand nearest
the dunes and a turtle can lay more than 100 eggs per nest, upwards of 3-5 times per season,
depending on the species. When the hatchlings all hatch out of the eggs,
it’s really cool, because they all work together to get out of the nest. So what they
do is that all the little hatchlings push the sand behind them as they go. And so it
kind of just makes this elevator where the sand just is rising beneath them. This whole
process takes like maybe two or three days for them to get to the surface.
Most likely they’ve evolved to emerge at night where visual predators may not be out
as much. And the sand looks like it’s boiling with
all these little hatchling heads and flippers. And if all goes well, the hatchlings will
race toward the sea -an innate behavior they’ve been re-enacting for millennia.
They’ll focus on the lightest horizon so in a natural setting it’s the ocean horizon
even on a moonless night, the back dune area is very dark, pitch black but there’s a
lighter horizon and that’s where those hatchlings are meant to go, is to the ocean.
These first few minutes after they hatch are a dangerous time for the tiny turtles.
The biggest threat to small hatchlings on the nesting beach, as they emerge from
the nest, crabs, raccoons, birds may pick them off.
And in some highly developed coastal areas, sea turtles may mistake beachfront lighting
for the horizon and run toward the lights along busy streets, rather than the ocean.
Along the Archie Carr National Wildlife Refuge, where there is less beachfront lighting from
homes and businesses, most hatchlings know just where to go.
And they all run down the beach and into the water as fast as they can.
But even in the water, they are not safe from potential predators.
Once they get into the water, near shore reef fish, barracuda, snapper, a lot of other species,
may eat them. And birds may also pick them off because they’re swimming at the sea
surface. So there are a lot of near shore predators, coastal predators, that they have
to get through in order to get offshore No one knows how many hatchlings survive their
first day. Some experts estimate that as few as one in 10,000 turtles will reach adulthood.
It is an extremely low survivability Once in the water, they disappear into the
open ocean. What follows, is a period known as “the Lost Years”, since until recently,
the exact whereabouts of the sea turtles during that time was largely a mystery.
These turtles are hardwired to swim as soon as they hatch.
They get in that water and they just swim for the horizon.
To get offshore, hatchlings have a long way to go in a short time.
They just swim like little windup toys. Through that 24-hour swimming frenzy, that they
swim as fast as they can. They’re getting as far away as quickly as possible, from the
coast. What they’re trying to do is get into the
currents. And they keep swimming until they encounter
some good habitat for them. One of the longstanding hypotheses is that
the turtles do associate with sargassum. And they receive benefit from associating with
this floating macroalgae. And that provides two essential things. It’s
a place to hide from predators, and it’s a place to find something to eat.
Sargassum floats freely in the Gulf of Mexico and in the Atlantic, providing a critical
habitat for sea life. The sort of base of the food chain is this
drifting sargassum algae. It’s basically this golden oasis out in
the ocean. Sargassum habitat is known to be transient,
and can move depending on particular oceanic features.
We typically have to go into blue water, we have to go into oceanic water, which means
that we have to move off the continental shelf, for the most part. In the Gulf of Mexico,
we are going out off of Louisiana anywhere from tens of miles offshore to upwards of
a 100 miles offshore in order to encounter this habitat, which is ideal for the smaller
turtles. In the Gulf of Mexico the warm, blue, salty
waters of the Gulf collide with the Mississippi River’s cold, murky outflow of fresh water.
Along this rip, an undulating ribbon of sargassum develops into what is known as a “weed line.”
That’s where turtles will get pushed to, and that’s where fish will collect, and
crabs and things that turtles like to eat. Anything from microscopic up to a whale will
be around these weed lines. They’re really neat environments.
It’s along the weedlines that form between the Loop Current and the Mississippi River,
where Dr. Kate Mansfield and her research team are hoping to find 1 to 2 year-old sea turtles
that drift with the sargassum. Researchers believe young turtles in the Gulf
of Mexico swim from nesting grounds in Central America and ride along the Gulf of Mexico
Loop current into North America. We look for very long lines of sargassum and
we’ll just take the boat and cruise along. We’ll look for little dark objects in the
sargassum, things that look like floating coconuts, or an upside down flip-flop.
Once we do decide that yeah that’s a turtle, then a lot of things do happen at once.
Where is he? (unintelligible)
Once the turtles are on board, the work up begins.
So from the time that we capture the turtles and bring them on board, we’ll put them
in our cabin. Keep them shaded, and we’ll work them up. We’ll take basic information
on the turtles: how long they are, how wide they are, how big their heads might be. And
we will weigh them as well. We’ll then also insert little tiny chip or pit tag into their
flipper. Those little implanted pit tags are like the
ones the vet uses microchipping your dog or cat. Those are really wonderful tools, and
they’re a forever tag. It’s so we can identify those turtles later
if they’re recaptured. We take tissue samples, we will take scute
samples, if they happen to poop on board, we’ll take fecal samples.
The researchers also gather sargassum with the creatures that live inside, from the
same areas where they found the turtles floating in the weedline. This will help them to better
understand what the turtles eat during their lost years.
We are finding little crustaceans, little crabs, little fish, some fish larvae, it’s
a real variety. Very little is known about these little turtles,
so anything that we can collect we try to do.
In the future, experts hope to compare the stable isotope ratios collected from the turtles’
tissue to those of the prey items living in the sargassum.
So the stable isotope analysis gives us a general idea of where the turtles have been
and what they might have been eating. And it’s real kind of cutting edge science
Once the work up is completed, the team begins the process of satellite tagging the small
turtles -something that up until recently was thought impossible.
For a number of years, the satellite tag technology just wasn’t small enough to be able to put
on the backs of little turtles swimming long distances.
The tags themselves had very large batteries that were required to communicate with the
overhead satellites. So there was too much weight and too much
drag on the turtles. And only several years ago did a company,
come up with a solar powered, tiny little tag for birds, that we were able to have them
modify slightly to be able to use in a marine environment, and use on the backs of tiny
little turtles. Kate and her collaborator, Dr. Jeanette Wyneken
from Florida Atlantic University, spent a lot of time making sure the tags were just
right. Working with endangered and threatened sea
turtles, we wanted to make sure that what we were doing to the turtles would not unduly
harm their ability to survive in the wild, would not affect their growth, would not affect
their feeding behavior. Once they found a satellite tag that would
work, they needed to figure out how to attach the tags to the rapidly growing sea turtles.
We’ll prep the shell really well. We’ll sand down the shell, make sure that there
are no bits and pieces that can peel. There were no previous methods. Traditional
hard epoxies that are used on larger sea turtles, may stay on for a year, two years, three years,
those hard epoxies don’t allow for the turtles to grow. There’s not flexibility to those
harder attachments. So Kate and her team had to be creative to
find a solution. The sea turtle shells, in general, for loggerheads
and hawksbills and other species, they’re made of keratin. They have this outer keratin
layer. It’s the same thing as our fingernails and toenails.
The turtles are growing and they shed the thin layers of keratin, as they grow.
We were having trouble initially, with putting tags on turtles using a variety of different
attachment methods. We tested all of this in the laboratory. And the tag attachments
were falling off within one to two weeks. They would have a little tiny bit of shell
attached to it. So we finally put two and two together, and realized that we could seal
the keratin, or seal the shell with acrylic nail fill
The acrylic nail fill delays the natural peeling process by sealing the sea turtle’s shell,
but without harming the animal. That nail acrylic is really critically important
to keep the tag on as long as possible. The next step, with these turtles, unlike
the green turtles, there’s this vertebral ridge, what we need to do is build up the
sides, so we’re going to put two strips of old wet suits on to the shell, we’re
going to glue it with hair extension glue, and we’ll let that cure for just a couple
of minutes, it’s very fast. And then we’ll attach the tag with aquarium silicone.
This method allows the tags to stay on for several months before they naturally slough
off. This gives the experts the chance to collect longer-term data on the movement of
the turtles. What they came up with this solar-powered
little transmitter and attachment technique took years of lab work and it really goes
to their persistence. She’s learned an awful lot about it and
is really a pioneer with these very small turtles.
Shell composition can vary by species, so they had to use a different method to attach
satellite tags to green turtles. For the green turtles, their shell is very
different, and feels different. The shell is almost like Teflon.
The green turtles seem to have a little more of waxy coating on their carapace.
And anything that we would put on the turtle would just fall right off within less than
a week. So we ended up testing a number of other different options. And came up with
a very simple solution which is just a flexible boat adhesive, and it works pretty well.
Once the turtles are tagged, the team waits an hour or so for the adhesives to dry.
The animals are then released in the same general area where they were captured. One of the long-standing hypotheses about
these young oceanic stage turtles is that they tend to just drift. They get offshore
and they’re passive drifters for a number of years, we don’t know how long.
And so we release the drifter at the same time that we release the turtle with the satellite
tag. And then compare the tracks and see how they differ. And they definitely do differ
quite a bit over time. The turtles, they’re actually actively moving
to different a habitat. Which would probably make sense.
Because these oceanographic features, these weed lines and convergence zones they disappear.
And they move. And they actively seek out other
big hunks of sargassum where they’re going to find food. And that’s just a matter of
survival, looking for food. But to prove that is pretty unique.
Young sea turtles Kate satellite-tagged in the North Atlantic Ocean provided the first
conclusive evidence detailing what happens to sea turtles during their lost years.
They can cover tremendous distances. And sort of ride the big ocean highways of
these currents, coming back around, making trips that last years, and covering thousands
and thousands of miles. So they’re really world travelers
And the sea turtles didn’t just travel far. I think it’s astonishing how quickly they
travel when they’re released. We had turtles that after maybe one or two
weeks were already up off North Carolina when Kate released them off the coast of Florida.
And so traveling hundreds upon hundreds of miles in two weeks is unheard of for most
species. But for turtles, it’s practically normal. It’s not even really surprising
but it’s really cool to see it. Data on the sea turtles her team captured
and tagged in the Gulf of Mexico is still emerging but revealed no less surprising preliminary
results. Here is a map from the turtles that we tracked
this year in the Gulf of Mexico. We’re seeing a real mix of behaviors.
A number of the turtles that we tagged have dispersed fairly far from where we initially
released them off of the coast of Louisiana. These data are the first in-water captured
sea turtles that have been satellite tagged. So it’s really the first information on
where the turtles are going, what they’re doing, how they’re interacting with their
physical environment in the open ocean. The key message is, the lost years are no
longer lost years. We have some ideas now. 698.
While Kate’s team has gained insight into the lost years of sea turtles in the North
Atlantic Ocean and the Gulf of Mexico, there is much left to learn.
It’s still a great mystery. And it’s kind of neat. Because we’re asking
some really basic, fundamental, almost naturalist questions about the life history and the behavior
of the turtles, that haven’t been answered yet.
Once they grow to about dinner plate size, sea turtles leave their open ocean home and
migrate to coastal areas. So we don’t know how long the Lost Year
time frame is, that oceanic stage. But after several years, depending
upon the species, the turtles will then recruit into near shore habitats as larger juvenile
sea turtles. They’re programmed to turn around and head
back into shallow water. Except for the leatherbacks. They’ll stay out there their whole lives.
Those species that do migrate to the coast have grown large and fast enough to avoid
near shore predators, like sharks. And that’s a place where there is more food
items and shelter places that are appropriate for a little bigger turtle.
We don’t know how long that juvenile coastal phase is, but they will reach maturity, depending
upon species, in 20 to 30 years. As they approach sexual maturity, the teenage
years, they’ll start migrating to a nesting beach.
After they’ve mated offshore, pregnant females come to shore to lay their eggs along the
beach; an ancient ritual that repeats itself with each new generation.
Most turtles lay their eggs on the nesting beach where they themselves were hatched.
They remember and imprint on that beach. The life cycle comes full circle.
And start that process over again. Major funding for this program was provided
by the Batchelor Foundatio, encouraging people to preserve and protect America’s underwater
resources. And by Diver’s Direct, Emocean Club, inspiring the pursuit of tropical adventures
and scuba diving. And by the Do Unto Others Trust.
