Atlantic Salmon: Lost at Sea

- In the North Atlantic and the great rivers

that pour into it, there is a legendary fish

whose future is now on the brink.

The Atlantic salmon.

It travels thousands of miles from river to sea,

facing great risks and then returning back again.

- There's something very special about the salmon.

It's homing to its place of its birth.

- Once salmon leave the streams of their birth,

they live a phantom, unknown life at sea.

Magically they reappear some years later,

called back to the very river where they were born.

Whole communities once flourished

on this bounty from the sea,

but now something mysterious

and deadly is happening to them.

- We know that we send out a lot of smolts to sea each year

and they're just not coming back.

- This is my way of life, it's my family's way of life,

and it's part of the fabric of Scotland,

and you know, we want it to continue

for many generations to come.

Somewhere on the salmon's epic journey,

these remarkable fish are now dying in huge numbers.

- There's a mystery of smolts either not coming back,

and it's very important to understand

where this mortality is occurring.

- In the last 30 years, returning populations

of wild Atlantic salmon have dropped by 70%.

To save these salmon, first we must find out

what is happening to them.

For some, the problem is clear.

- Principally, the problem is that we have been killing

too many fish for too long.

Government and scientists don't accept it,

they don't recognize it.

- Others believe there's more to understand.

- The ocean's really a big unknown for salmon.

We have these big picture ideas of what goes on,

but we really don't know any of the details.

I just implore anyone

that can influence what's going on at sea to do so.

Pick up that ball and run with it.

With livelihoods at stake,

and a natural wonder in danger of vanishing,

now scientific detectives race to solve the mystery,

and for the first time ever,

an international team heads out into the North Atlantic

to find why the wild Atlantic salmon is lost at sea.

Our relationship with salmon is ancient and powerful.

The oldest known image of one is carved 25,000 years ago

on the ceiling of a cave in France.

The Romans when they invaded northern Europe

marveled at its acrobatics

and called it salar from the Latin saliere, the leaper.

Standing stones carved with its image

are one of the few remnants that an ancient people,

the Picts, left behind over 1000 years ago.

- We're here at Glamis in the precincts of the Kirk,

and here next to me is the great Glamis stone,

which is world famous,

largely because of this etched salmon,

wild Atlantic salmon.

Now this was probably carved by a Pictish engraver

about 12 to 1300 years ago.

The Picts were here in Scotland in the seventh,

eighth, and ninth centuries,

and their culture focused on the natural environment

in a very special way.

If you look above the salmon,

you'll see what people, I think incorrectly,

describe as a serpent.

I don't think it's a serpent at all,

I think it's an eel.

And the thing about the eel and the salmon

is that both migrate.

They're fish that cross human boundaries.

They're fish that pay no attention to political frontiers.

They travel the oceans, the eels as we know

go to the Sargasso Sea to spawn

and where their young are born and then they come back,

and the salmon come here, and they spawn,

and then the small fish go to sea to get big.

So this sense of the community based culture

attributing to these remarkable animals

an almost mystical sense of wisdom and understanding

which they themselves were unable to grasp.

For millennia, around the North Atlantic,

people awaited the annual return of the great fish.

In Ireland and Scotland, the salmon fishery

was a way of life.

It fed whole communities.

The ancient fishing village of Claddagh

at the mouth of Galway Bay in the west of Ireland

dates to pre-Christian times,

and so valued were the fish to the town of Galway

that a watchtower was built in the mid-1800s

to announce the return of the salmon to the Corrib River.

Salmon not only filled stomachs, it fed dreams.

Taking this great fish on a gossamer line

was soon a lifetime's thrill.

Upper classes embraced a new sport

and great estates flourished.

Here in the heart of Scotland, salmon angling was born.

Fishing the wide Spey river required its own rules.

A custom fly rod and a unique cast

to reach pools where the great fish, fresh from the sea,

had gathered.

- My family has run and owned and organized fishing here

for centuries, not just decades,

and my children have caught their first fish on the river.

I could show you the point where everyone

caught their first salmon, it's an iconic moment.

- 20 years ago, as many as 3000 salmon were taken

on this stretch of river.

Today, catches are now less than 1000.

The fish are no longer there,

and it's gone from harvesting a surplus

to worrying about whether there are any fish at all.

The local economy is massively influenced

by what goes on in this river.

And even in the best of days,

it can be quite an elusive salmon,

but at the moment it's particularly elusive.

Good luck, I'll see you a few more years.

On both sides of the Atlantic,

great salmon rivers are losing their fish.

In the late 1800s a daughter of Queen Victoria

and her husband the Governor General of Canada

came to the Grand Cascapedia,

bringing the sport of salmon angling across the Atlantic.

The river teemed.

Soon dignitaries and tycoons were attracted

to this beautiful, remote area,

for some of the largest of the species came to this river.

But that was over a century ago, and much has changed.

On the great fishing rivers all around the Atlantic rim,

salmon are disappearing fast.

In the last two decades, some new unknown disaster

has emerged.

Somewhere on the journey between

young salmon heading out to sea

and adults returning to spawn

their numbers are being decimated.

For scientists, the race is on to find the cause,

but if they fail, this magnificent creature

may soon be gone.

- We had a recent, massive decline in the return rates

of wild Atlantic salmon from the ocean to the rivers,

and the key is to find out where and when

the mortality is occurring

that is causing the salmon to decline.

Right now I must admit I'm totally flummoxed.

- Over the course of all the different environments

and over the course of the life cycle of the salmon,

there's a lot of different threats

that can be impacting its productivity.

A wide range of things are happening

in the fresh water side.

In the ocean, salmon are dying in the ocean

at relatively high rates,

higher rates than we've seen prior, and we don't know why.

- But today, researchers are tracking salmon

at every stage of their remarkable life's journey.

The many thousand mile migration

from river to sea and back again.

It's a challenging journey of discovery.

Salmon evolved in the ocean,

and for millennia, this was their home.

Their life in rivers began after the last ice age,

when huge glaciers and sheets of ice

covered much of the northern hemisphere.

And when the Earth warmed, the ice started to melt.

As the glaciers retreated, they gouged out the earth,

causing deep trenches that turned into rivers.

One of the first fish to colonize these new cold rivers

was the Arctic chard, a close relative of the salmon.

They still thrive in the Arctic today.

As the ice retreated, ancestral salmon

pioneered new rivers all over the North Atlantic,

safe havens to lay their eggs.

Over time they adapted to each river

as a genetically distinct population,

and today, no two rivers

hold the exact same genetic strain of salmon.

In a clear, protected stream, buried in the gravel,

are salmon eggs.

This is where life begins.

It is now early spring and the eggs are hatching.

Less than 1% of these eggs will survive

to make their way to the sea.

These newborns remain in their rocky nest

for up to 12 weeks.

Once they have consumed their surrounding egg sacks,

they are ready for the next chapter of their lives.

Feeding voraciously on microscopic life.

Within a few months, they are transformed

with distinct markings to help them blend in with the river.

They dart up to the surface to catch a variety of insects.

They will remain in the rivers for one to six years,