>>NARRATOR: Sharks have
fascinated mankind

and held it in awe
for centuries.

However, most people
only know the few species

that sometimes
come in contact with humans.

>>Most of the living species
of sharks on the planet

live in the deep sea.

Of the, say, 500 species
of sharks living

that we know of now,

between 55% and 60% of them

live their whole lives deeper
than 700 feet deep.

>>It's a totally, totally
different environment.

>>The information that we have

for a lot of these deepwater
species has been restricted

historically to a handful of
specimens that exist in museums.

If you compare what we know
about deep sea sharks

to these coastal species,

we're years behind them and
we're still playing catch-up.

>>NARRATOR:
These rarely seen animals

range from the very large

and prehistoric-looking
bluntnose sixgill shark...

>>They're just so cool.

These sharks have these big,
shiny, emerald-colored eyes;

they're just gorgeous.

>>NARRATOR: ...to the small
and bioluminescent

green lanternshark.

>>That is such
a cool little dude.

>>NARRATOR: Until now,
relatively little research

has been conducted
on the sharks of the deep,

leaving many
questions unanswered.

>>That's the last domain
in shark research.

It's just wide open.

>>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,

inspiring the pursuit of
tropical adventure scuba diving.

>>NARRATOR: On a sunny day in
October, a team of scientists

is busy loading up
the R.V. Weatherbird

for a ten-day research cruise.

Their destination: the northern
Gulf of Mexico.

The goal: to find out
if the BP oil spill

has impacted the bottom-dwelling
sharks and other fishes

in the deep sea.

>>One of the real
unfortunate parts

about the
Deepwater Horizon blowout

was that after it happened,
everybody said,

"Well, all right, this thing
occurred at a mile deep.

Well, what ecosystems
are being affected?"

And for the most part,
we had to say we don't know

because so little
of it had been studied.

I think the primary reason

that this work hasn't been done
before is just the expense.

It's logistically difficult
to work in the deep sea,

especially with big animals.

>>NARRATOR:
In April of 2010,

the explosion of
the Deepwater Horizon rig

set off the largest accidental
marine oil spill

in the history
of the petroleum industry.

Over the course of
nearly three months,

roughly 4.9 million
barrels of crude oil

gushed out of the well
and into the Gulf of Mexico.

Never before had an oil spill
occurred at such depth,

leaving many to ponder the long-
term impacts of the spill.

To better understand what fishes
live in the deep waters

of the northern Gulf and how
they may have been impacted,

Dr. Dean Grubbs, together
with a team of scientists,

began regular research trips
shortly after the spill.

To capture a variety of animals,

the scientists use a combination
of traps and long lines.

>>We're setting out
a long line.

It's designed to basically allow
us to pinpoint habitats

at different depths.

So, we've got five
different hook sizes,

and that allows us to catch
relatively small fishes

all the way up to
15-, 16-foot sharks,

sometimes on the same line.

And then, we also have
interspersed along here

three different types of traps.

The idea of the traps is,
they'll catch some fish

that won't get caught on the
hooks, and they'll also catch

some of the
invertebrates that we want

that are lower down
on the food chain.

We'll let this stay out there
for about four or five hours,

and we'll come back and haul it.

So, we're going to set three
of these back to back,

going from shallower to deeper
until we've set the third one;

we'll return to the first one
and pick it up.

>>NARRATOR:
The experts begin their work

on the eastern slope
of the Continental Shelf

in an area that is thought to be
less impacted by the oil.

From here, they will slowly work
their way southwest

into the deeper waters
of the DeSoto Canyon.

The Desoto Canyon is
an erosional valle

that cuts through
the broad Continental Shelf

in the northern part
of the Gulf.

The oil spill occurred in the
southwest portion of the canyon.

>>And, of course, the currents
and the wind took the oil

north into the Louisiana,
Mississippi region

and everything.

And so, basically, it blew it
right up the DeSoto Canyon.

>>NARRATOR: After a few hours,
it's time for the scientists

to start hauling the lines
and traps back onto the boat.

And it doesn't take long before
they have a nearly 15-foot

bluntnose sixgill
shark on the line.

>>No matter what
book you look in,

they'll tell you it's a rare
large deepwater shark.

Well, everywhere I've gone
and tried to catch them,

I've caught them.

I don't think they're that rare.

They seem to be quite common
worldwide in tropical

to subtropical oceans at 200
to maybe 1,000 meters deep.

They're definitely exciting;

they're the biggest
sharks we catch.

We've caught probably a dozen or
more that are over 15 feet long

in the Gulf of Mexico,
up to 17 feet long.

>>They only have one dorsal
fin, and their jaw structure

is a little different than some
of the other sharks--

huge, sawblade-like teeth.

If you look for a tooth that
resembles a living shark species

in a fossil record
from 200 million years ago,

it looks just like
the sixgills from today.

And so, that shark
that we're looking at

out on the deck of the boat
likely looks exactly like

the shark that was swimming
around 200 million years ago

before most of the dinosaurs
were on the scene.

So, the first one I caught,
to me, you know,

that's as if I just
pulled up a T-rex,

brontosaurus or something.

>>NARRATOR: After taking
some basic measurements

and a tissue sample,
the shark is tagged...

>>4-3-0-5, p-zero-zero-4.

>>NARRATOR:
...and let go.

Early on, the experts also catch
a lot of other fish,

including a small shark species
known as the Cuban dogfish.

While the scientists do release
large sharks like the sixgill,

most of the other fish
can't be let go.

>>It would be great
if all of our research,

we could just tag and release
everything,

get all the information
we needed from that.

Unfortunately, that's not
the way it is.

>>NARRATOR: Since so little is
known about the life histories

of many of these fishes and how
they may have been impacted

by the oil spill,

scientists need to collect
and dissect specimens.

>>These are the dorsal fin
spines from this Cuban dogfish,

Squalus cubensis.

This is the first dorsal spine,
this is the second.

>>Most people probably don't
realize that some sharks

have spines on their dorsal
fins.

Most sharks don't.

>>NARRATOR:
The shark species

that have spines in front
of their fins

record growth bands
on these spines,

similar to the growth rings
on a tree.

Counting these bands allows
scientists to age the animals.

>>Age information is important

for determining the maximum age
of the species

and also determining age
at maturity.

This is important
in a management context;

we need to know
what age they are

when they first start
reproducing

and also for population level
estimates.

>>NARRATOR:
At some of the study sites,

the animals come up
ravaged by isopods,

scavengers that attack dead
and dying animals in the sea.

>>They make quick work
of a carcass.

It's a bony fish; there'll be
nothing but a skeleton left

if you leave it
down there too long.

And if it's a shark,
a lot of times it'll be just

an empty skin sack with no
tissue, no meat, no muscle left.

They're efficient.

>>NARRATOR: As the scientists
move their lines and traps

into deeper water, the species
they catch start to change.

>>So, that's what we are
calling Squalus mitsukurii,

and it's really similar
to the little Cuban dogfish,

Squalus cubensis, we were
catching earlier in the trip.

>>NARRATOR:
These two types of sharks,

as well as certain bony fishes,
are among the primary species

for the oil-spill related
studies.

They make for good sentinels
because they are caught

in large quantities and in areas
that are thought to be

more or less affected
by the spill.

>>That's one of the two species
of hakes we get

that are really common.

There is a shallow water hake,
Urophycis floridana,

that we get predominantly
between 200

and about 400 meters or so

and then about 400 meters, we
start getting Urophycis cirrata.

And so, those are two
of our sentinel species

that we are using
sort of to look for spatiall

and depth-mediated differences
in exposure to oil and mercur

and all those kinds of things.

>>NARRATOR: To study the
potential impacts of the oil,

the scientists analyze the
animals for signs of exposure

to polycyclic aromatic
hydrocarbons, or PAHs.

PAHs are not only some of the
most toxic components of oil,

but they also take a long time
to break down.

>>So, this is
Urophycis cirrata.

We are going to take a couple
of different samples on it.

First, it's going to be blood.

We are looking at the effects
of the oil spill

or any toxicity in general.

So now, I'm going to go
after the bile and liver.

We are using those again
for metabolites of toxins.

So, that was the liver there...
this large pink.

And associated with the liver

is the gallbladder,
which is usually...

in this fish,
it's kind of bulbous.

It's almost always green
or brown,

and it has almost a neon green
tint to it,

the bile
within the gallbladder does.

And it's time-
and light-sensitive,

so we try to get it
as quickly as possible

and put it in
a light-sensitive container

and then it goes
immediately on ice.

Then it goes for
the rest of its processing.

>>NARRATOR: All the toxicology
samples taken from the animals

are worked up in a lab at the
University of North Florida.

>>Looking to see if, one:

Is there evidence that the PAHs
have been taken up

in the food chain
of these animals?

Then second:

Are they just getting
sequestered in the liver

and disappearing, or are they
actually being metabolized?

And then, if they are being
metabolized, the next step is

to start looking at sublethal
effects, chromosome damage,

things like that from the PAHs.

What we have seen so far
is that, yes,

the closer you get to the oil
spill site,

the higher the rate of
occurrence of these PAHs.

We also see increases in rates
of metabolism

as you get closer to the site.

And there's also some real
preliminary evidence

that the deeper you go
into DeSoto Canyon,

the higher the prevalence of
exposure to these PAHs.

But even so far, with the ones

that University of North Florida
folks have analyzed to date,

the levels of metabolism still
seem pretty low.

They're not at a level that is
shocking for most of these taxa.

And so, it's hard to draw too
many conclusions at this point

about what the overall effect
of this exposure will be.

You also have to understand that
with these deep sea fishes,

their metabolism
is so slow anyway.

So, it will take
some time to see

if this cycles
through the food web

and see if there are any kind
of sublethal effects

on reproductive success or any
of those kinds of things.

>>Brenda just passed me
a Urophycis cirrata,

so it's my turn
to take samples from it.

So, I'll take a fin clip to look
at the animal's DNA.

We try to take as many samples
from every animal that we catch

as possible, including taking
samples for researchers

at other institutions.

>>At times, there are, you
know, 30 different samples

that will get collected
from one animal, you know.

So, we are trying
to make the most use

out of sacrificing
these animals.

>>So next, I'll take a sample
of white muscle

for mercury analysis.

>>NARRATOR:
In addition to containing

trace amounts of mercury
in the oil,

oil spills may create an
environment that is conducive

to the transformation of mercury
into a more toxic form

that is easily absorbed
by animals.

This monomethylmercury
bioaccumulates up the food chain

and is highly toxic.

>>Just going to cut a little
piece off of this mercury sample

to put in a vial for stable
isotope analysis.

The stable isotopes tell us
where in the food web

the animal is feeding.

>>NARRATOR: Collecting this
information gives scientists

a better picture
of the overall food web

and whether or not the oil spill
may have changed it.

This oil spill-related
research is conducted

as part of a larger effort
by the Deep-C Consortium.

>>We were interested
in connectivit

between the coastal area
and the deep sea,

but in order to really
understand that we have

to connect all of these
different disciplines

in a really truly
integrated way.

We have a slew
of people involved,

from geomorphologists to
physical oceanographers,

chemical oceanographers.

Our group is
a fisheries' ecology group.

And then modelers and so forth.

Once we started getting going

and people started talking
to each other, all of a sudden,

they started finding
natural connections

between the different groups,

and that's what we are after is
the integrating all the pieces

of the puzzle.

>>From the oil spill
perspective,

it's the things that are
well-known

that are most important because
they're the things

that we can get plenty of
samples of in order to be able

to say quantitatively whether
there was an effect of oil

on these taxa or not.

But from my scientific
interest in the deep sea,

it's the rare things
that really get you excited.

>>And there is no shortage
of amazing critters

coming up on deck.

>>So, this is Scyliorhinus
retifer.

It's a chain catshark.

Absolutely beautiful,
just fantastic.

We caught him in a trap.

They do pretty well
in captivity,

so we are keeping him
in this tank.

And hopefully we'll be able to
take him back alive.

>>NARRATOR: While some animals
are beautiful,

others are rather creepy.

>>Hagfish intrigue me
because that's still

one of the kind of the holy
grail of ichthyology is

that we still don't know much
about the ecology and biolog

of hagfish.

Most people don't want to work
on them because they're nasty!

I mean, they're slimy.

You know, I mean, that's what
hagfish are known for.

They seem to produce more slime
than their body weight.

You know what I mean?

It's ridiculous.

>>NARRATOR:
Along with the hagfish,

another otherworldly creature

gets caught in the traps
at depths below 500 meters.

>>Giant isopods are awesome;
they're such a cool critter.

I mean, isopods
by and large worldwide

don't get bigger than this.

I mean, you know most...
most people's...

the isopod most people are
familiar with are the pill bugs,

the roly-polys you find in
your garden or in your yard.

I mean, this is like a roly-poly
that gets this big, you know,

and eats everything that comes
down and around it.

You know, it's terrifying
to think about it

if you were down there.

I mean, I could just
see them all

crawling across
the bottom after you.

They're really cool.

Yeah.

Look like a stormtrooper
from "Star Wars"

if you look at them head on.

We're not even catching
the biggest ones.

I can imagine the big ones are
just outside of our traps,

trying to get in, but they can't
fit through the door.

>>NARRATOR:
And it's not just the isopods

that get larger at depth.

>>Giant snake eel is the
biggest of the snake eels.

They get, you know, well over
six feet, seven feet long.

The crazy thing about them

is that they actually were just
described in the 1980s.

Such a cool, cool creature.

I mean, most snake eels are only
this big and that big around.

These things get enormous.

They're feisty, they're tough.

Snake eels are typically
burrowers.

I'd love to see
what it looks like

on the bottom where they are.

I mean, it's terrifying
to think about them.

They must be just these big,
giant snake eel heads

sticking out of the mud,
you know.

They're definitely the things
of a horror movie, you know.

>>NARRATOR: To make the most
of their limited time at sea,

the scientists work
around the clock.

>>At $10,000 a day almost, I
want to work 24 hours a day.

I don't want that ship sitting,
doing nothing at all.

And so, they bring
two captains onboard

so that they shift in and out

and can keep working
around the clock.

And, of course,
for us to get sleep,

we have to do the same thing.

The way we get people sleep is
that we divide the science crew

into two teams for setting
all of our gear.

And so, one team will set
all of the gear

and the other team will sleep.

And then, when it comes
time to haul that gear,

everybody gets up
and hauls together.

The processing of the animals we
catch is so labor-intensive,

it requires
everybody we have on board.

And then, when we're done
hauling that gear,

the next team will set and the
previous team will get to sleep.

>>NARRATOR:
This means that at times,

scientists work
up to 28 hours straight

before they get
a few hours of sleep.

>>I think that ability to work
around the clock

and on little sleep has a lot
to do with what I like to call

"pent-up research aggression,"

which is, we spend so much time
locked in our offices,

reading papers,
working on the computer,

and when we get a chance to come
out here and do this stuff,

we just go hog-wild as far
and as fast as we can.

>>It's deepwater work,
it's exciting!

You don't know what's
going to come up,

so that keeps
the adrenaline going.

>>NARRATOR: One animal
few people have ever seen

is a tiny bioluminescent shark
that was caught in a trap.

>>So, this is Etmopterus
virens, the green lanternshark.

It's one of the smallest species
of sharks there is, period.

Beautiful little creature.

It's probably the most beautiful
shark I've ever caught.

They're called a lanternshark
because their whole bell

is covered in photophores,
actually produces light.

The point of the light is
essentiall

to obliterate their silhouette.

They seem to exist between 300
and 1,200 meters deep,

and there's not much
light but there is some.

We commonly refer to the
area as the twilight zone.

>>NARRATOR:
Another shark species

the scientists frequently catch
in deeper waters

is the gulper shark.

>>Really cool sharks,
big green eyes;

slimy, though, really slimy,
slimy sharks.

>>NARRATOR:
The gulper shark,

as well as its cousin,
Squalus mitsukurii,

which the scientists caught
in slightly shallower water,

is poorly defined taxonomically.

>>Because the deep sea
environment

is relatively constant
worldwide,

you have a lot of species that
have worldwide distributions.

But because they look
pretty similar,

they've all been called
one species.

But often, when you start
looking at these things closer,

you find that
they're species complexes.

>>It wouldn't surprise me if,
within the next five years,

Squalus mitsukurii
wasn't divided

into seven species
in different regions.

With these animals in hand, we
can actually photograph them,

look for morphological
characters

that differentiate them
and take genetic samples

to see if they're
the same species or not.

And by and large,
we've found that they aren't.

Same thing with the gulper
sharks; the gulper sharks

are a taxonomic mess worldwide.

And a lot of the taxa,
especially the sharks,

the bigger fishes fall
into that category.

And there are new
things out there too;

I mean we caught a skate on one
of our previous cruises

that appears to be
a new species.

This is a big animal.

It looks completely different
than anything else,

and it's gone undetected
for so long.

>>NARRATOR: In addition
to studying how old they get,

the scientists are also
interested in learning

more about the reproductive
processes of deep sea sharks.

Shark species use several
different modes of reproduction.

While some are egglayers,
others give birth to live pups.

>>We've got
a gulper shark here.

They only have one offspring
per pregnancy.

That's very low for fishes; even
among sharks that's fairly low.

So, we don't know what
their gestation period is.

It's likely to be pretty long.

A cousin of the gulper shark
has a two-year gestation,

so if these guys
are comparable--

and that is a big if--

they may only have
one pup every two years.

Extrapolate that over the life
and you'll, you know,

quickly realize
the ability of each female

to contribute to the population
is limited.

Looks a lot like the mom.

This is where the yolk sac is
attached, and that's the...

that's the rest of the yolk
that will carry this thing on

for the rest of embryonic
development.

>>NARRATOR: Knowing how old
the animals can get,

at what age they start
to reproduce

and how many offspring
they may have

allows scientists to inform
life history models

for the animals.

This information is an important
tool for fisheries managers.

While deep sea sharks aren't
currently targeted

by any fisheries
in the United States,

their numbers have declined
in other parts of the world.

>>We've seen in Australia,
we've seen in the Azores

and Portugal and other places

that where deepwater fisheries
have developed

either targeting deepwater
sharks or not targeting them

but catching them as by-catch,
they've quickly collapsed.

>>NARRATOR: Over the course
of this trip, the crew deployed

53 longline and trap sets,
covering stations ranging

from 75
to over 2,000 meters deep.

They caught almost 800 fishes
and invertebrates,

which will add to their
ever-growing database

of deep sea animals in this part
of the Gulf of Mexico.

>>The information that will
come out of the work

is just phenomenal.

They've already identified some
very interesting differences

in community structure
that nobody knew about,

and so they'll be able
to get at the essence

of what makes those
communities so different

based on the behavior
of the animals.

It's absolutely cutting edge.

It's marvelous work.

>>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,

inspiring the pursuit of
tropical adventure scuba diving.