>> 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.