Jeremy Wade's Dark Waters (2019–…): Season 1, Episode 1 - Italy's Lake Monster - full transcript

In a land dominated
by rock and ice...

There is something very incongruous
about this place.
There's nobody here.

..beasts of all sizes
thrive against the odds.

He's running, he's running.

But one species seems to have
gone missing.

No-one knows where it's gone
and no-one knows why.

I'm Jeremy Wade,
fisherman and adventurer.

For more than 35 years,
I've travelled the globe
hunting for monsters...

Look at this beast.

..but mysteries are still out there.

There's something behind me.



I'm journeying into the unknown
to reveal...

Yes!

..the secrets hidden
in these dark waters.

I'm in Alaska,

home of the world's
longest Pacific salmon runs.

Five species of Pacific salmon have
navigated these waters for millennia.

But one salmon species
is in a class of its own.

Bigger and faster than the rest

and famed for
their incredible feats of endurance,

king salmon are the power athletes
of the salmon world.

The word coming
out of Alaska recently

is that the king salmon
have gone missing.

Now, salmon are born inland
in the rivers.

They then migrate down to the sea,



where they spend a number of years
feeding and growing.

Then they return to the river
where they were hatched

and they spawn
and they carry on the life cycle.

But in the last few years,
the kings have not been returning.

So what has happened to them?

The other four species of salmon
in Alaska,

chum, pink, coho and sockeye,
are doing fine.

So how can just one species
of salmon disappear?

Who or what is taking the kings?

I'm starting my investigation
on the Kenai River

in the south of Alaska.

Thirty years ago a fisherman
landed a king salmon here

that weighed nearly 100lb.

This is the Kenai River.

Now, this used to be the place
to come

and catch king salmon
on rod and line.

Phenomenal numbers of fish.
Also very big fish.

The world record came from here.

But the story is that today
they've all but disappeared.

Having said that,
there's loads of people here,

almost shoulder-to-shoulder,
a rod-length apart, sometimes less.

And I guess they're
catching something,

so I'm gonna go and find out
what that is.

The Kenai is just a couple of hours'
drive from Anchorage

and it's the most heavily fished
river in all of Alaska.

- How's your day been?
- They come in spurts.

Sometimes you get a bunch,
bam, bam, bam, and then nothing.

Do you fish kings as well?
Not any more. The fishing's so bad.

So you used to fish? Yes. Yeah.
Used to fish the rivers for 'em.

They don't come back
like they used to. Right.

So, in its heyday, what was it like?

I caught nine really nice kings
in an afternoon.

But now that...that's totally
unheard of. Absolutely.

He confirms what I've heard.

This famous salmon river
seems to be empty of kings.

But there are other species here.

These fishermen are hauling out
sockeye salmon,

which appear to be running strong.

Why have just the kings vanished?

If the problem was
an environmental one,

then surely all the salmon species
would be affected.

Sockeye salmon are particularly
sensitive to any ecological changes.

So I'm hoping the sockeye
can shed some light

on the health of this river.

It's a bit of a hybrid technique
I'm using here.

I'm using a fly rod and reel,
but on the end, I've got some lead

and a leader about four feet long.

Something like that, and then,
on the end, quite a heavy,
bright fly.

Now, no way can I fly-cast
with those leads.

What I'm doing, I'm just
swinging it out a short distance.

And the idea is that the leads
will just bump on the bottom

and the line gets caught
in the mouth.

And then this will slide along

and it'll hook them
on the outside of the mouth.

I've never fished the Kenai before

and this is
an unfamiliar technique for me,

but it's how most locals
catch sockeye here.

Yes!

Surprising, even with
the resistance of the rod,

it's making headway
against the current.

There it is!
Mind...Mind yourself, mind yourself.

And here it is, it's right in here.

Go on.

Wow.

It's strong. It's strong.

There it is.

So, sockeye salmon.
The salmon are running.

As an indicator of clean water,

this decent-sized sockeye
looks bright,

clear-eyed and bursting with energy,

which suggests
water quality isn't the problem.

So could something be killing off
the king salmon in large numbers?

One predator immediately
springs to mind.

A thousand pounds of aggression
with an insatiable appetite,

the brown bear
is a salmon-eating machine.

I travel across the Cook Inlet

to see if I can find any evidence of
bears over-indulging on king salmon.

I meet up with Matthias Breiter,
an expert in bear behaviour.

He's come face to face
with bears many times

in his 30 years of research,
and he's not taking any chances.

That's a marine flare, so
doesn't matter whether it gets wet.

And you pull it,
and it shoots out a flame

about this long, smokes a lot,
hisses, and it lasts
about seven minutes.

And we've used it on bears

when they try to get into
food caches,

and I've always been able
to drive off bears
easily with it. Right.

So that I don't wave my arms
too much, can I put bug spray
on my face? Yeah, that's fine.

This place is full of bears
and they're all here for the salmon.

One, two, three, four, five.
That's five over at that point.

So, this is a bay
where a river meets the sea,

and at the moment
it's round about high tide

and the tide is gonna
start going out.

When that happens,
there's gonna be,

erm, a number of small channels,

and any salmon that are here
are likely to get stranded.

So that is what the bears
are waiting for.

Bears need to eat
up to 30 salmon a day

if they're to bulk up enough
to survive through the winter.

He's running.
This one's running, he's running,

it's running, it's running.
Fishing has started, I think.

I'm so focused
on the action in front of me

that I don't see
what's coming from behind.

I'm in Alaska,
in bear country.

I'm trying to find
the famous king salmon,

but I'm caught off guard
by a male brown bear.

There's a bear
coming behind us..

They'll pretend to be
not interested in us

and try to get closer and closer.

He's actually a good boy,
walking around us.

So it's fishing time, yeah? Yeah.

Thankfully, the bears are far more
interested in the fish than us...

..so we move closer to find out
what kind of salmon
they're feeding on.

It's hard to tell for sure, but they
don't look big enough to be kings.

Do they go for kings
if they're available?

Well, I'm sure they would

because the fat content
is even higher. I've never seen it.

They spawn in water
that is just simply

too deep for the bears
to fish successfully.

In anything deeper than two feet,
the bears really can't get the fish.

Yes. With kings, they tend to hug
the bottom of the deep water,

and that's sort of beyond... Yeah.
..what the bears can fish in.

Yeah. So, if the bears get kings,

they are spawned-out ones
that are dying. Right.

So that's not going to impact
the spawning, then.

Of all that I've seen, I would say

that king salmon
is the least impacted fish species.

With the kings swimming in water
that's too deep to reach,

the bears can't be blamed
for their disappearance.

But another predator has been
hunting king salmon in Alaska

People.

I head into the heart of the state
to the mighty Yukon River,

where indigenous people have been
fishing for kings for 8,000 years.

They'll know king salmon
better than anyone,

and they will feel the salmon's loss
the hardest.

I land in Galena,

a small, remote community
where the Yukon River

is an important source of food -
in particular, king salmon.

Vehicles parked up. I'm not seeing
any other vehicles on the road.

I haven't actually seen
a person, either,

which is a bit odd,
but I have been to other places

in the world where people do live...

a similar kind of
subsistence lifestyle.

And what's going on is
a lot of those people, they...

A lot of the time, they are
not in the population centre.

They are out. They're on the land
or they're on the water.

I'm lucky to find a ride upriver.

I'm guessing everyone is out fishing,

taking advantage of the salmon runs
and stocking up for the winter.

But the river looks deserted.

It should be lined with fishing camps
at this time of year.

I stop at a small village called Ruby

to see if there are any fishermen
to speak with.

Hello.

People in the village have told me
to talk to Billy McCarthy,

and he's down on his boat
at the moment.

I believe this is him here.

Hello. Hey!

Billy is a native elder
who has lived here all his life.

Nice meeting you.

I can remember as a young kid
that there were so many fish.

Every fish camp along the river
had racks of fish

and there was never a shortage.

Ruby depends very much on
the king salmon. Right.

If the king salmon are not here,
what happens to the village?
What happens to the people?

Well, of course there's all sorts of
fish out there...

..but to me, our main food
is the king salmon.

They're gonna have a tough time.

It's a serious situation.

Subsistence fishermen
only take what they need
to feed their families,

which should protect their precious
resource for future generations.

If the subsistence fishermen are not
catching king salmon here

and if the bears are not eating them,
what else could be wiping them out?

Morning. You started to pull 'em in.

- You got something in there?
- Yeah. Yeah? Yeah.

Is this, sort of, a normal catch
for a night?

This is a very normal catch
for this time of year.

These are predominantly chum.

You'll dry some of that,
you'll smoke some of that...
Yeah, yeah.

I will go and cut some right now
if you'd like to see.

Jake tells me
he is originally from Russia

and has been fishing
this same spot on the Yukon

every day for the past 24 years.

What is the story right now
with the king salmon?

Something is impeding them.

The fish are much smaller
and the runs are just smaller.

This is slightly different
from what I've been hearing so far.

So, reports that they've gone,
that's a bit of an exaggeration.

They're still here, but you say
there is a problem.

Yes. Yes, absolutely.

Do you worry, given that trend,

that they might disappear completely?
Is that a possibility?

I think it's a distinct possibility.

I ask if there are any predators
that might be affecting them.

There are lots of pike
in the river. Pike?

How big have you seen them?
Somewhat around 50 inches.
Right. About 50. OK.

There are stories of giant pike.
Of course, pike do terrible things.

You know, I found entire ducks
inside, and muskrats.

So there's a little bit of
kind of superstitious fear.

Pike are voracious hunters that can
grow up to 50lb, possibly bigger.

Their mouths are packed
with viciously sharp teeth.

Where pike have been introduced,
they've been known

to decimate
established salmon populations.

I'm wondering if that
is what has happened here.

Pike hunt in slow water,

so I'm staying fairly shallow,
at the edge of a tributary.

They are predominantly
visual hunters,

so I'll be using that knowledge
to try to catch one.

I'm fishing a very simple lure.

It's just like a metal spoon,
and that'll just flash and wobble,

so it's sending out
light and vibration.

So anything predatory that's
in the water's gonna go for this.

That was a hit.

There it is again.
There it is again.

I'll net this.

Well, there's definitely pike
in here.

But I need to find pike
bigger than this

to be any real threat to the kings.

OK.

See if I can go out a bit further.

Yes.

Well, that's something small.

Oops!

Let's get it on the bank.

So, this is a pink salmon
or what they call a humpy salmon,

which is the smallest
of the five salmon species.

And "humpy", well... Don't really
need to explain it, do I?

Big humpback. And all salmon
do this thing where

they change colour and shape
when they come into the rivers.

But they've got this rather sort of
ugly, hooked jaw going on.

And I think, maybe, put it back.

Presence of these pinks
and other smaller fish

is maybe not a good sign when
it comes to looking for a monster.

Yes, that's something.
That's something.

It's off! It's off.
See the swirl there.

I saw a flash of colour.
It was greenish.

It was about that long. It wasn't
a big one, but that was a pike.

Anyway, let's...

see if there's more.

Pike are well-known cannibals,

and if there were giant pike
in this area,

they could easily eat
these smaller ones.

I cast further out,
close to the reeds

to see if a monster
could be lurking there.

Yeah. This feels bigger.

Get my feet unstuck
and see if I can...

See if I can just...

beach it quickly before it has
a chance to get off.

It's still not the giant I'm after.

So, that's a pike of
three or four pounds, lots of teeth.

They're not cutting teeth,
they're for gripping something.

So, a fish this size

could swallow something
almost its own length,

but normally, it's gonna eat
something just a few inches long.

So it wouldn't be a serious threat
to adult king salmon,

but they might well make inroads
into the young salmon

on their way down to the sea.

Young salmon can spend
up to two years in fresh water

before heading to the ocean.

During this time,
they are easy pickings

for top predators such as pike.

But this is true
of all salmon species,

and it's only the kings
that are disappearing.

So, this is the Yukon.
Here's the mouth, the delta.

Historically, the king salmon,
they enter the river mouth,

the delta here, they run upstream,
and some of them will be peeling off

on routes going up
the side tributaries to spawn.

But some of them will go
all the way upstream,

all the way, and end up in Canada.

Where I am is here, Galena.
Now, what they're telling me

is that the kings
are showing up here,

but only in a fraction of the numbers
that they should be.

What's interesting is - no problem
with all the other species of salmon.

They are still running strongly.

Now, whatever is causing this decline

is clearly not gonna be
happening upstream.

It's gonna be happening somewhere
down here.

So this is clearly the direction
I need to travel.

I need to go downriver.

I head towards the coast where
the river empties into the sea.

It's where the ocean-dwelling salmon
come back into the river

on their way upstream to spawn.

I stop at a fishing port called
St Mary's, nearer the river mouth,

to find out if the king salmon
are being fished out here

before they even get a chance
to swim upriver.

There is something very incongruous
about this place.

You have this wilderness with nobody
out there and then you've just got

this cluster of buildings, and it's
got a very functional feel to it.

There's a lot of dead machinery
sort of lying around rusting.

But it's also...
It's a bit like a ghost town.

There's nobody here. And, erm...

Believe it or not,
this is 10:00 at night.

It's like it's sort of
one continuous day.

But I do find some late-night
activity down at the docks.

Judging from the rows of containers,

this is a fish-buying station
where locals can sell their catch.

Could a high commercial demand
for kings

be destroying the population?

What do we got here?

Yeah. So, those are chum.

Are you getting kings as well?
We don't buy kings.
You don't buy kings.

So this is all chums here.
Yeah. All chums.

The reason you're not buying kings
at the moment, why is that?
Their low numbers.

But at the moment,
it's not enough to...
Not enough to fish for. Right.

And then the fishing boats
start coming in with the day's catch.

Did you find any monsters?
We're hoping you got some in there.

They're all chums, are they? Yeah.

What's that?
A white fish, like a cisco.

Is that, like, a she-fish? Yeah.

A white fish,
but more importantly, lots of chum.

Their numbers are high enough
for them to be caught
and sold commercially.

Kings aren't being fished for here,
which rules out overfishing

as an immediate cause
for their disappearance.

Hello. How are you doing?
I watch your show.

You're Jeremy Wade, right?
That's right.

You're out in the Yukon!
Hello there.

You know, I've heard that
the kings' numbers are down.

They're pretty low.

So, I mean, does anybody keep
a record of the numbers of fish?

They do it down-river,
right where the mouths meet.

Then they do it up here
where the river's narrower.

So, there's somewhere...

There's somewhere that way
and there's somewhere that way
where they do it. Yeah.

This station where salmon data
gets collected

is definitely worth a visit...

..but before I leave,
I'm offered a local delicacy.

The eggs of the white fish.

Welcome to the Yukon River...

..where fish is abundant
and it's the best.

Good?
That tastes very fishy.

Tastes fishy? Yeah.

That just slipped down.

It's an acquired taste
for a midnight snack,

up here where we are so far north
that in the summer months,

the sun never truly sets.

Days merge into each other.

It's not just a figure of speech.

There's no...
There's very little delineation

in the way of darkness.

It just gets a bit dimmer,

and then the dimmer switch
is turned back up again.

'Morning.

It's a new day, and time to follow
a new lead in this investigation.

I'm hoping the counting station
could be the place

for my first encounter
with a legendary king salmon.

Up, up, up!

I'm on the Yukon River
in Alaska,

trying to discover what could be
taking out the iconic king salmon.

Yeah, this must be the place.

So, it looks like we can't go
any further.

There's a bit of a, sort of,
barrage put across the river.

Erm, something's going on there.
I wonder if it's all blocked off

apart from one channel and, er...

they somehow count them
when they go through.

There's fish in there.
There's fish in here.

You can see the back
sticking out of the water.

So there are fish in here.

Somebody coming down. Hello.

Hello.

Good to see you.
I'm Jeremy. Yeah.

I'm Gerald. Nice to meet you.

Fish biologist Gerald Maschmann
and his crew

worked for
the US Fish and Wildlife Service.

Team leader Matt Larson is going to
show me how the station works.

The floating dam or weir
acts as a barrier

which funnels the fish
through a single opening

leading to a trap
where they are filmed and counted.

There, chum.
You see quite a bit of them
through the weir.

Matt tells me that chums
and pinks are common,

but even down here,
near the mouth of the river,

they're seeing very few kings.

We can go check the trap
if you want.

Absolutely. Yeah? Yeah.

But the summer chum can still
be of use to my investigation.

They're second in size
to the king salmon,

and both chums and kings
run the same rivers at the same time.

I'm hoping a closer look
will offer up some clues

as to why the chums are here
in numbers and the kings are not.

Do I pick out an individual fish

or just make a bit of a lunge
and see what I get?

Let's do the lunge.

One there.

That's a complete miss.

So, there was me thinking
this was gonna be easy.

Right. So I've got to move
fairly quickly. Yeah.

So, underneath...

and then up. Up, up, up, up, up!
There we go.

The crew take data samples
from all species of salmon

to track changes over time.
They're measured...

88540.

..and a scale sample is taken
to record their age.

And...

The data is sent off to be analysed,
and the results so far

are showing no obvious signs
of disease or environmental harm.

Yet in recent years, the numbers
of king salmon running up the Yukon

have dropped to as low as 10%
of what they used to be.

We assess the salmon runs,
try and determine

how many fish are getting upriver
to spawn and what we can do

to make sure that these fish
come back year after year
after year.

So, management is one factor,
but there's also

other extraneous factors
that might affect the numbers.

Absolutely. That's, you know...
The fish go out to the Bering Sea

for three, four, five, you know,
six, seven years.

We don't know what they're doing
out there. It's a big black box.

And so all we can do as managers
is manage what comes in the river.

So, they are not arriving
in the river in significant numbers,
simple as that.

And so maybe it's time to turn
to the other part of the...

the king salmon's life cycle.
That's the five, six, seven years

that they spend in the ocean.

Oceans are not my area of expertise,

so I contact Dr Jan Ohlberger,
who's studying king salmon in Alaska.

He tells me about
some brand-new research.

An interesting study
at the University
of Alaska Fairbanks.

They used satellite tags
on king salmon

to study their migration
and dispersal patterns in the ocean.

Researchers found
that half of the tags

recorded some strange numbers.

They jumped from
an ocean temperature of 45 degrees

up to about 70 degrees
in a matter of seconds.

This showed that the king salmon,
along with its tag, had been eaten -

not by a warm blooded mammal,
and not by a cold-blooded fish.

But a few fish can partially
raise their body temperature,

including salmon sharks.

So, based on these data,
they've identified salmon sharks

as a potentially important predator
on king salmon.

I wouldn't want to guess
how many kings

they actually eat each year
as, sort of, a whole population.

The data is just not there
to make an informed estimate.

Now, that's really interesting.

Salmon shark, as the name suggests,
they eat salmon,

and they are definitely
taking some king salmon.

But whether they are targeting
the large king salmon

and whether they are consuming
significant numbers of them,

I don't know.

But I do know a place
that I can go to

to try and find out.

I head to the one area of Alaska
where salmon sharks

have been reported to congregate
for a mass feeding frenzy.

But do the numbers stack up?

Do there seem to be
enough of them in the water

to significantly make an impact
on the king salmon populations?

With a top speed of 50mph,
the salmon shark is a faster

and more agile relative
of the great white.

I investigated salmon sharks
a few years ago

and I've caught up with Boone Hodgin,

a salmon shark expert
in Prince William Sound.

The sharks congregate in this area,
waiting to ambush

the migrating salmon as they travel
from the ocean into the rivers.

And since it's salmon running season,
the sharks should be here right now.

I'm going to drop a line in the water
to see what's down there.

I prepare myself for battle.

Anticipation tinged almost
with a bit of dread.

There are certain fish...
They are just so powerful

that you almost don't want
to be in contact with them.

If it's a prolonged fight,
then this will just take

some of the strain
off my back and my arms.

I almost want to be
looking back on today,

as long as today is a successful day.

But I have to actually go through
the process of living today first.

It will be fun as well,
if, when it happens.

But it is gonna be mixed in
with some pain, I think.

I'm gonna slap this
around your waist... Yep.

..as the secondary line.
Just in case you slip out,

we can reel you back in. OK.
With shark and all.

Down it goes.

Ten... 20...

At this time of year,
the salmon sharks

could be anywhere
from 20ft to 200ft deep.

What I've been told to expect
is either this will just

get slammed down with no warning

or there will be a slow,
steady increase in tension.

And either one of those two things
could happen at any moment,

or several hours could pass
without anything happening at all.

This is the...the interesting...

..frozen moment
that you get stuck in,
in this kind of, er...

This type of situation.

I keep the bait moving
to attract attention.

Lift it up...

..drop it down. Lift it up...

drop it down.

I thought I felt a bump.

But the bait hasn't been touched.

80... 90...

Lift it up, drop it down.

I try different depths...

A little bit shallow,
about 100ft down.

..and multiple locations.

I'm starting to wonder
if the sharks are here at all.

Then just as my patience
is running out...

Yeah. There is something, I think.

This is an interesting one.

Good-looking? It's a sculpin.

So, that's sitting on the bottom
perfectly camouflaged,

blending in with the bottom
and then something swims by,

opens the mouth...

It's just about to move, I think.
Pop it back.

Not the beast I was hoping
to catch here.

So, two days on the water -
full days, long days -

and not a single sign
of salmon shark.

Not a fin on the surface
and nothing on the sonar either...

..which leaves me
very surprised, puzzled.

In my investigation so far,
the salmon shark seems to be

the most plausible explanation
for the disappearing king salmon.

But if I can't find any sharks,
that theory is blown.

Maybe I've missed the salmon runs
and the sharks have already gone.

The next day, I decide
to switch strategy and equipment

to check the salmon are still here.

Yes.

I don't think this is a salmon.

Wait a minute. Wait a minute.

Coho. Coho. It is a coho.

He's off.

A long-enough glimpse of it
to see what it was.

That was a nice coho salmon.

Here we go.

Coming up to the surface.
There it is. There it is.

This feels... Maybe a better size.

Look at that.

And jumping again.
God, this one's lively.

This one's lively.

Coho, also known as silvers,
are smaller than the kings.

Look at this.

Has this one suffered a shark attack?

It's a thin tooth,
so it's not a shark. Yeah.

More like a sea lion tried
and grabbed it.

There we go.

Yes.

Gosh, it's a nice one.
It is, yeah.

Right, I'm gonna let this, er,
tire out.

There we go.

The colouration on the gill flap
is beautiful.

Such a beautiful fish. Of course,
they change so dramatically,

don't they, once they're in...?
Once they hit the fresh water.

The coho are running, but no kings

and no evidence of salmon sharks
hunting them down.

So while it's known
that salmon sharks do feed on kings,

I don't believe the sharks
can be the cause

of the king salmon's
sudden disappearance.

Then Boone shows me
something interesting.

That's an orca.
Is that off the back of your boat?

It is. When was this?

This was, a few weeks ago.
Are they still around?

Boone says he's seen the number of
resident fish-eating orca,

or killer whales,
rapidly increasing lately.

Bigger and smarter than sharks,
these apex predators

could do serious damage
to any fish population

if they got a taste for it.

But are there enough orca here?

And have they developed a preference
for king salmon above all other fish?

Let's go find some orcas?
Yes, absolutely.

I scan the horizon
for the distinctive

six-foot-high, black dorsal fin...

..and the telltale plume of air

as the orca
breaks the surface to breathe.

I'm looking for orca
in the waters off Alaska

to try to see if they're connected

to the disappearance
of the king salmon.

I think that must have come out of...

And again! Look at that.
Look at that, look at that.

It's like they're putting on
a show for us. It really is.

These astounding creatures
are the true rulers of the ocean.

To power their huge bulk
takes a lot of energy.

But are the kings,
the biggest of the salmon species,

their fuel?

This doesn't look like
predatory behaviour.

At the moment they just appear
to be having fun with us.

They are approaching the boat.

We're sitting here
with the motor idling

and they're coming very slowly
towards us.

It's almost like they are curious.

This is wonderful.

You can see it through the water.
Through the water.

Diving down,
coming right across our stern.

They may not be hunting right now,

but they certainly are here
in surprising numbers.

Suddenly, there is the impression
that this water is full of them.

And so the numbers here...

..are starting to make sense.

There we go.
That was a selfie with an orca.
How often do you get that?

If these orca
really do feed on kings,

there's a chance
the salmon could be here right now.

Once I'm sure
the orca have long gone,

I try my luck...

but catch nothing.

I'm certain I'm on to something
with the orca,

but I still need definitive proof,

something that links them
to the king salmon.

I track down John Maniscalco,

who has apparently
witnessed orca actively hunting.

One time, just right off
the corner of my boat,

this king salmon
leaps out of the water

right towards the boat, dives down,

and this killer whale
just does the same arcing leap

right after it,
dives right under the boat

right after this king salmon.
Huge salmon.

I don't know if it eventually
got that salmon, but I bet it did.

So it was right behind?
It was hot on its trail, yeah.

Have you any way of saying
what particular fish

they might be going for?

Sure,
the studies that some of the guys
have been doing around here,

they'll pick up some of the scales

and some of the other tissue
from the fish

that the killer whales kill

and determined that they feed mainly
on the king salmon around here.

Right. It's a big,
warm-blooded animal.

Probably has to get through
a lot of king salmon

just to keep itself going.
Yeah, a lot of calories there.

Yeah. So, you know,
that's why they think

they target the bigger fish.
Then the king salmon,

they're the biggest of the salmon
that we have around here,

and they'll target the big ones.

So orca are going after king salmon
in these waters.

But are they behind
the kings' disappearance?

It's possible.
That's really hard to say.

A lot of things feed on king salmon,
including humans, out here.

Yeah. So, you know,
with the increased population

of killer whales around here,
they think that...

Some of the researchers think
that they are making

more of a significant dent
in the king salmon population.

It definitely sounds like
they're targeting king salmon,

because, well, why wouldn't they?

They're tasty,
but also very rich food.

However, they're not
all of the picture.

There's lots of other factors.

The fact that resident orca numbers
off Alaska have been on the increase

when other orca populations
are declining

is a critical element
in this mystery.

Has this orca boom
been at the expense of the kings?

Given the dynamic nature
of predator-prey relationships,

perhaps it's not possible
for king salmon

and orca to flourish
at the same time.

The question is - does this spell
the end for Alaskan king salmon?

I need to find out if enough kings
are escaping the orca

to return to the rivers and spawn.

So far I've seen
the other four species of salmon,

but not a single king.
But I'm convinced I'm getting close.

I team up with the Alaskan Department
of Fish and Game,

who are also searching for kings
at the mouths of the rivers...

Anything happening today so far?
Um, we've been picking up
a couple of sockeye,

but we haven't
picked up any kings yet. Right.

And we're about to pull it
right now. OK.

This one's a sockeye.

You're just letting those go? Yep.

So you're only
interested in the kings. Exactly.

Feels like that might be something.
There we go.

Is that a sockeye? Yes. Right.

..but it's just sockeye
after sockeye.

So, still no kings today..

With each net pull, it's looking
less and less hopeful.

Look at that. Look at that.
Look at that.

Finally, a king salmon.

Its survival is so important

that I dare not even remove it
from the water.

So, here we have it.
This is an Alaskan king salmon.

This will be about a 28-pounder.
Very nice-sized fish,

but these things potentially
grow a lot bigger than that.

And this is fresh from the sea,
it's bright silver.

As it progresses upriver,
it will gradually change.

I was starting to think that
I might never see a king salmon.

My investigation has made me realise
that throughout their life cycle

the kings are constantly hunted -

in the early days by pike,
then by humans,

salmon sharks and orca,
each one taking their fill.

Perhaps there's no single cause
for their decline,

but instead
a perfect storm of factors

that has brought this iconic species
to the brink of collapse.

But this shimmering, full-bodied fish

is evidence
that the kings are not lost.

And as long as there are still
some left

to journey upriver and breed...

Off it goes. Fantastic.
It's going the right way. Upriver.

..the kings will one day
rule again.

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