>> That nest is getting ready
to hatch.
>> Look at 'em all.
>> Are you kidding me?
>> Goodness!
>> NARRATOR: 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.
>> NARRATOR:
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.
♪ ♪
>> NARRATOR: Depending
on the species, sea turtles can
spend anywhere from two to
upwards of eight 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.
(cheering)
>> NARRATOR: 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.
>> NARRATOR:
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 Divers Direct--
Emocean Club,
inspiring the pursuit
of tropical adventures
and scuba diving.
And by the Do Unto Others Trust.
>> NARRATOR: 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.
>> NARRATOR:
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.
>> NARRATOR: There are six
species of sea turtles found
in the United States,
and those are protected
under the U.S.
Endangered Species Act.
>> So 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.
>> NARRATOR:
Founded in the late 1970s
by Dr. Llewellyn Ehrhart,
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.
>> NARRATOR:
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 in-water 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.
>> NARRATOR:
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
and 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-kilometer stretch
of beach than any other place
in the U.S.
>> NARRATOR: 30 years ago,
only 8,000 sea turtle nests
were laid in the refuge
each year.
But in 2013 it saw
over 20,000 nests.
>> So it'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.
>> NARRATOR: 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 11 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 three to five 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.
>> NARRATOR: And if all goes
well, the hatchlings will race
toward the sea--
an innate behavior
they've been reenacting
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.
>> NARRATOR: 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.
>> NARRATOR: 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.
>> NARRATOR:
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.
>> NARRATOR: 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.
>> NARRATOR: 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.
>> NARRATOR: To get offshore,
hatchlings have a long way to go
in a short time.
>> They just swim
like little wind-up toys.
>> Through that 24-hour swimming
frenzy, they swim as fast
as they can so 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.
>> NARRATOR: 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.
>> NARRATOR: 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.
>> NARRATOR: 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.
>> NARRATOR: It's along
the weed lines that form
between the Loop Current
and the Mississippi River
where Dr. Kate Mansfield
and her research team are hoping
to find one- to two-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?
♪ ♪
(cheering)
>> NARRATOR:
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
a 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.
>> NARRATOR: The researchers
also gather sargassum
with the creatures that live
inside it, from the same areas
where they found the turtles
floating in the weed line.
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.
>> NARRATOR: 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.
>> NARRATOR: 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.
>> NARRATOR:
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.
>> NARRATOR: 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 little 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.
>> NARRATOR: 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.
And 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.
>> NARRATOR:
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 wetsuits
onto 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.
>> NARRATOR: 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
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.
>> NARRATOR: 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 it feels different.
The shell is almost like Teflon.
>> The green turtles seem
to have a little more
of a waxy coating
on their carapace.
>> And anything that we would
put on the turtle would just
fall right off within a...
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.
>> NARRATOR: 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 longstanding
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
to see how they differ.
And they definitely do differ
quite a bit over time.
>> The turtles,
they're actually actively moving
to different 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.
>> NARRATOR: 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.
♪ ♪
>> NARRATOR: 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.
>> NARRATOR: 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.
>> NARRATOR: 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.
>> NARRATOR: 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.
>> NARRATOR: 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.
>> NARRATOR: 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.
Captioned by Media Access Group
at WGBH, access.wgbh.org
>> Major funding for this
program was provided
by the Batchelor Foundation.
Encouraging people
to preserve and protect
America's underwater resources.
And by Divers Direct--
Emocean Club,
inspiring the pursuit
of tropical adventures
and scuba diving.
And by the Do Unto Others Trust.