Jeremy Wade's Mighty Rivers - Full Episode 2 - The Danube

But Danube has an unusual claim to fame.

Welling up in Germany's Black Forest, it

runs east along the edge of the Austrian

Alps, swings south across the Great

Plains of Hungary, then cuts through a

dramatic gorge to enter its final phase.

And by the time it emerges from Romania

to empty into the Black Sea, it has

flowed through 10 countries, [music]

which makes it the world's most

international river. But delving into

recent reports, I'm surprised to see

that the Danube is also ranked as one of

the world's most endangered rivers. Now,

Europe has stringent environmental laws.

So to find this of all rivers on an at

[music] risk list, that really is quite

disturbing.

Go online and the Danube is sold as a

river of romantic cities and picture

postcard scenery. But it's time to look

beyond the castles and cruises and find

out what's really going on with this

mighty river.

I'm starting my investigation in Romania

at the less glamorous end of the river.

This is the mouth of the Danube, what

people here know as Mile Zero. Behind me

is the Black Sea. And over there, if you

keep following this shipping channel, is

a vast delta.

The Danube [music] Delta is one of the

largest wetlands on Earth.

It's a vital [music] refuge for

endangered wildlife.

>> [music]

>> Birds flock here in their millions,

and its waters are reportedly home to 84

species of fish.

If there's one part of this river that

[music] ought to be in good shape, it's

here in the delta.

St. George is supposedly the main

fishing hub for the area,

but it feels completely dead.

This place was built with money from

fishing and in its heyday

guess it would have been thronging with

people, but now pretty much a ghost

town.

Something here doesn't add up. A healthy

river should be able to support a

thriving fishery.

>> Hello. Salute. Salute.

>> Niko.

>> They got Jeremy.

>> Are you Are you fishing now?

>> Yes.

>> Okay.

>> Nico tells me that until recently people

here used to hunt a huge and very

lucrative fish.

Beluga sturgeon can grow as big as a

great white shark and live for over a

hundred years.

For millennia, they've been caught for

their meat.

What makes this fish so valuable,

though, are its eggs,

better known as beluga caviar.

Today, people are willing to pay more

than $4,000 [music] a pound for this

ultimate luxury.

But beluga sturgeon have become so rare

that it's now illegal to catch them. So,

is this why there's there's not many

fishermen here today?

>> Because of the sturgeon ban, a lot of

people just left. Since the ban, he's

had to adapt. And so what he does now,

rather than fishing off the river mouth,

he's fishing for other species.

Nico agrees to let me tag along.

As well as seeing what's in his catch, I

want to find out what the story is with

the Danube's few remaining beluga

sturgeon.

We're very close to the bank because out

in the middle there's very strong

current. The fish tend to hug the bank.

They don't have to expend so much energy

to hold their place in the currents.

>> No. Okay.

>> Okay. That's good.

>> Morning. I'll be back.

>> We leave the traps to do their work and

travel deeper into the delta.

Fishing is a bit like taking a blood

sample. If you know what to look for, it

can tell you a lot about a river's state

of health.

>> I've seen lots of um small fish swimming

around, which is a good sign. It shows

that there's productivity. There's

certainly the basis of a good food

pyramid here.

I'm hoping there's going to be bigger

fish feeding on those small ones.

Despite the promising signs, I'm

struggling to get a bite.

Yes, that's a fish. Here we go. This is

a pike. Very recognizable.

Big toothy mouth there. Quite big eyes

as well. They're built for acceleration.

The dorsal fin instead of being in the

middle of the back, it's way down by the

tail here. So that gives them that quick

burst of speed. But as pike go, this one

is tiny.

As to the health of the river, the jury

is still out.

How you doing?

At least I've done enough to establish

my fishing credentials with Nico. He's

invited me back to his fishing camp.

>> Crap.

>> This used to include sturgeon. Now it's

just other species they can find. And

this is carp. I can see its eye looking

out at me as it bubbles away in there.

Good.

The boiled fish head is better than it

looks. My real interest, however, is in

beluga sturgeon.

>> What was the the biggest one that you

saw or heard about?

>> Right. 360 kilos. Uh that is

I believe that's just a little short of

£800.

He says it was getting off the size of

the boat. So I mean this we're talking

sort of 15 foot fish.

>> So you're saying a fish that that size

now if it was legal you wouldn't have to

work for a year.

Naturally hardup fisherman like Nico are

hoping that the sturgeon will make a

[music] comeback so that the ban can be

lifted.

He says, "When we could fish for [music]

sturgeon, we used to work and we got

results. Now we work harder [music]

but with less results."

As if to underline his point, Niko digs

out an old photograph of another fish.

And I can hardly believe my eyes. That

is an extraordinary picture. This is

absolutely huge. It's a Wales catfish.

Niko says he caught the fish about 15

years ago with a rod and line. This

weighed well clear of 250 lbs and it's

about one and a half times the length of

him. That is one of the biggest Wells

catfish that I've heard about and

certainly seen a picture of.

I've no idea if giant catfish are still

out here.

Maybe our nets will spring [music] a

surprise.

You got it.

>> Da.

>> Nothing. Just a stick.

>> Nothing.

>> Nothing. Nothing.

>> The fishing [music] season has only just

opened.

There should be plenty to catch.

>> Nothing in this one.

The empty nets are a real surprise to

me,

>> but not to Nico.

>> Although this is a good spot, [music] he

says year after year, the the number of

fish is just going down, going down,

down, down.

>> Nikico says the underlying problem is

the decline of the beluga sturgeon.

If you stop people fishing for the

beluga sturgeon, they're bound to then

turn to other fish to make a living

[music] and that's going to increase

pressure and it's going to cause a

decline in those other species. And that

is what's happened [music] and that is

what is continuing to happen.

It all sort of makes sense

to the casual observer. The Danube Delta

looks [music] healthy.

Below the surface though, the picture

isn't so rosy.

What puzzles me is why after more than

10 years of protection, beluga sturgeon

are not turning up in [music] bigger

numbers.

To find out what's going on, I've pulled

some strings.

One of the few people in Romania allowed

to catch sturgeon is fish biologist Dr.

Radu Suchu. I'm rather I'm very

>> and I'm lucky to be invited to join him.

>> This is the best fishing ground for

sturgeon in the whole venue.

>> For the last 18 years, Radu [music] has

been keeping tabs on sturgeon numbers.

>> You see how it works? Sides of the net.

You see?

>> Yeah. I see that. Yeah.

>> There are two lines. There's a line with

floats. There's a line with lead

weights. The float line, if you look,

it's not on the surface. Basically, this

operates right down on the bottom.

[music] So, where the boy is, that's

about 35 ft of water. The net is about

6t [music] deep, but it's the 6T on the

bottom of the water. Our deep set

[music] net is well placed to catch

sturgeon, which typically move along the

river bed.

>> You are actually the [music] best

assistant I've ever had.

>> Well, there we go. [laughter]

Adult sturgeon swim up river to lay

their eggs. Our aim today is to

intercept baby sturgeon as they make

their way down river to the sea.

Sturgeon are covered with these spiky

scoots. So they're very vulnerable to to

nets. All they got to do is touch it and

and move and they're wrapped up.

>> Radu can use the number of babies

[music] we catch to calculate if the

overall sturgeon population is

rebounding or still shrinking.

We're pulling in now.

>> Look at this one.

>> Native crayfish here. That's proof that

we were on the bottom. These tend

[music] not to swim by the surface.

>> Oh, we have a fish.

>> This is a thing called a petra. We sort

of mean stone. It lives down on one of

the rocks. I've not seen these before.

I think we're getting close to the end

here.

>> Yeah.

>> This is [music] a saber fish. Probably

got caught while we were pulling the net

up. That is a nice fish.

>> But no sturgeon.

>> Nope.

>> I'm a little bit disappointed. I was

hoping I would see a sturgeon of some

description.

>> Despite my disappointment, Radu says his

long-term records indicate a fragile

recovery.

>> It is very difficult because of the high

value of the fish. You know, this is the

most valuable animal on the planet. They

fished like hell. Before we had numbers

like 8 12 in one year this number has

tripled.

>> So it sounds like the this fishing ban

is starting to have an effect. I mean

that seems fairly clear from your

numbers.

>> It will take time a bit longer than we

thought in the beginning but it will

have an effect.

[music] However, with a fish as insanely

profitable as beluga sturgeon, [music]

temptation lingers.

Radu also monitors adult fish using

satellite tags. And he says he's got

something interesting to show me.

This is a normal track of an adult

beluga male.

It was coming out of the delta and

heading towards this wintering site in

the Bay of Odessa in Ukrainian waters.

[music]

A track.

>> Next is a very different track picked up

from another of his tagged sturgeon.

>> His record is showing that it was

popping up here after being immo for 2

days. [music]

Suddenly it came to the surface from 62

m to 0 m.

>> So it's like 200 ft.

>> Yeah. And then it moved almost straight

to the bank to this village Novo

Fedorfka and it ended up in Saki at the

railroad station. So it was taking

[music] a train.

>> Clearly this unlucky sturgeon ended up

in the wrong hands.

>> That's very simple. It's poaching.

>> Thwarting the sturgeon poachers is the

job of Romania's Delta Police.

And with a bit of help from Radu, I've

taught my way onto their next patrol.

>> Will be five boats. All the all the

boats will be in a line 300 m apart.

>> Are you armed when you do this?

>> Yes. Just in case we run in some

unforeseen event or someone very

aggressive.

The next day, we set out to find

poachers at the mouth of [music] the

river.

It's a huge area to search. And to make

things harder, the poachers submerge

their nets out of sight.

Our best hope of finding these death

traps is to spread out.

>> [music]

>> So, this is a bit like trolling. This is

what I do occasionally. I'm pulling a

lure behind the boat here. It's just a

weight with some crude hooks attached to

it. And if there's any nets down there,

that's going to snag onto it.

>> They found something.

It looks like a snagged animal.

>> Sadly, [music] this harbor porpus was

unable to free itself. His eyes have

been pecked out. That's the first thing

that seagulls are going to go for.

This is what we didn't want to see.

There's skin missing from the tail. And

that would have been while it was still

alive, just trying to get out of the

net.

>> And there's another grizzly surprise.

>> This is dead sturgeon.

They take so long to to reach maturity

that they are just so vulnerable. Uh you

know, you kill them off like this and

the [music] population just goes totally

downhill.

Within minutes, the body count has

tripled.

There are three different species of

sturgeon here. All illegal to catch and

all listed as vulnerable or endangered.

This is a beluga that's been

cut off in its prime. This is the

world's biggest sturgeon, and this one

met a very untimely end.

This young fish could have lived well

into the next century and produced many

young.

When a species is so close to

extinction, every individual is

precious. I don't think I want to have

another day's fishing like this. I think

it's it's important to see it once, but

um

yeah, not a not a very not a very happy

days fishing.

That's another fish. Another sturgeon.

This one's alive. This one is alive.

[music] Fantastic.

I'm just putting some gloves on because

the scoots are quite sharp. This has

been cut up quite a bit by the net, but

um that's only a flesh wound. But there

we go. It's alive and it's going back in

the water away from the net.

That feels very [music] satisfying. That

would have been a dead sturgeon not uh

very far into the future. So we have we

have in our own small way um changed the

course of history.

[music]

In the past year alone, the Delta police

have fished out over 10 miles of illegal

nets and set free more than a 100

entangled [music]

sturgeon.

The root of the problem, I [music]

suspect, is greed.

If caviar suddenly had no value, if

people weren't prepared to pay lots of

money for it, do you think the problem

would go away and the sturgeon would

recover?

>> I'm not sure if it it would go away

100%. But at least 90% you still have

guys hunting them for the trail. But as

long as the value is down, they wouldn't

risk it.

>> At this less wealthy end of the Danube,

my first impressions were of decline.

Decline in its fish.

>> Nothing.

>> Nothing.

>> And because of this decline in its

fishing communities,

but mixing with the people who live here

and digging a little deeper,

>> it is a flagship species. I believe that

the beluga sturgeon could come back.

>> This is going to swim off quite nicely.

>> There is something about being beside

water that contains

these armored leviathans which is a

world of difference from being beside

water that is basically a lifeless

drain. What I'm starting to see is there

are people who passionately believe that

a living river is something worth

fighting for.

Leaving the delta, I'm heading in land.

With its historic cities and picturesque

countryside, the middle reaches of this

mighty river are well known to

sightseers.

Much less well-known, but crucial for my

investigation is another of the Danube's

great fish, an elusive creature known as

the hookan.

Now, this is a landlocked relative of

the salmon, and it grows to the size of

a man. But since World War II, this fish

has become little more than a memory.

It's like a ghost fish. I'm wondering

what this says about the river and

whether I have any chance at all of

seeing this fish.

I'm eager to talk to anyone who might

remember the hooken,

but apart from the [music] occasional

commercial barge, this stretch of the

Danube is strangely empty.

Hoping to find signs of life, I decide

to check out the backwaters.

The distant ring of an axe [music] draws

me on.

>> See you.

>> Uh Mas

>> can

>> it's very solid. Are are you a

fisherman? Are you a fisherman?

>> Bit by bit, I start to piece things

together. It seems that Yanosh and his

family belong to a tribe of wood carving

gypsies.

He says he used to carve boats for

fishermen who paid him with the fish

they caught from the Danube.

>> I'm straining to pick out one fish in

particular.

But it goes unmentioned.

>> I think I recognize most of those fish,

but have you ever seen a hooken?

really

>> Yanosh says that when he was a boy he

remembers seeing large

>> sturgeon.

>> But as for the hooken

>> he's not sure.

>> He says hooken. They just seem to be

gone. But don't ask me. I don't know

about these things. Ask a fisherman.

>> Before I can resume my search, Yanosh

invites me to try out what he says is

his last ever canoe.

Where do I sit?

>> Here.

>> These days, no one wants a handcarved

boat.

>> This one is destined [music] for a

museum.

>> It's very nice. It's very good.

>> Okay. Okay.

>> I like it. It's stable. I'll take it.

I'll take it. How much?

[laughter]

>> With the hard work done,

>> it's time for a glass of gypsy

moonshine.

[music]

To make room for farms and towns, the

Danub's backwaters have almost all been

drained.

But I've heard about some interesting

ponds [music] just off the river.

During World War II, dozens of American

bombs intended for a Nazi airfield

landed harmlessly off target with

intriguing results. This is a wartime

bomb crater. It's a window into the

groundwater which continues from here

underneath my feet all the way to what

we normally think of as the river over

there across this flat open plane. But

the [music] real significance of all

these bomb craters is that they're now a

lifeline for many [music] of the plants

and animals that once thrived in the

Danub's marshy backwaters.

So this is actually a refuge.

Bombs are normally destructive, but here

they've created [music] something quite

important.

Back on the main river, my search for

the Danub's missing predator is taking

me into more densely populated [music]

country.

Hooken are thought to have abandoned

many of their old haunts because of

pollution.

But so far at least, the water seems

remarkably clean.

>> When you're in a city, the sounds that

you hear tend to be all man-made.

There's voices everywhere. There's

traffic.

But if you come out here, you can

actually hear the voice of the river.

And looking down, I'm very much aware of

the flow of the river, the sheer volume

of water that's passing every moment.

With so much flow, big rivers have an

impressive capacity to clean themselves.

This and the fact that there's no heavy

industry around here should be good news

for the hooken.

But has anyone here even heard of this

fish?

>> Hello.

>> Oh, hi.

>> This is a good spot here.

>> Yeah, it's actually a famous spot.

Budapest city center is one of the best

spots in Hungary. Yeah.

>> It turns out that Lazlo has been fishing

here since he was a boy,

>> and he says there's plenty to catch.

>> Looks like he's even got something.

>> Do you think he'd show us?

>> Yes, of course.

>> What's the Hungarian name?

>> In Hungarian English dictionaries, they

are called nose carp because of that.

[music]

>> So the water here is clean.

>> Yeah, normally it's transparent.

Pollution level is very low. No, there

are more predators here.

>> Do you ever see the hookum here? Have

you ever seen that?

>> Oh, the mysterious fish. Sometimes you

hear a gossip that somebody caught one

over there and then there is another

gossip that someone caught one over

there. I have even traveled to distant

countries to try to catch it, but uh

I've never seen it in Budapest. It will

be my dream.

[music]

With clean water and no shortage of

prey, this stretch of the Danube ticks

two big boxes for the hooken.

Yet, the only place it lives is in

people's dreams.

What its absence is telling me about the

river is still unclear.

One thing I'm getting used to, though,

is the near constant procession of

floating juggernauts.

There's some people doing something in

the bank here. We're just going to uh

check it out.

>> Hello.

>> How do you um

>> I've seen similar kind of thing in the

animals. This is This is gold panning.

>> Imm tells me he started panning on

weekends as a way to relax,

>> but it seems he now has a more romantic

objective. [music]

What he's trying to do at the moment is

make a ring for his girlfriend. He

started on that project about 6 months

ago. He reckons another 6 months, so a

year in total uh to make this uh this

ring. Does she does she know that you're

doing this?

So,

>> right. So, she she doesn't know. So,

what is where does she think you're

going in all your all your spare time?

>> She knows that I'm a a gold panner, but

sometimes I also tell her, "I'm going to

see my parents or or something else."

There's a little bit of subtuge going

on.

[music]

At first glance, Imray's search for gold

has no connection with my search for the

hooken.

But in fact, the presence of both

depends [music] on the precise flow of

the river.

Hooken dislike water that's too

sluggish. And so does Imry. [music]

He needs the current to be a certain

speed to carry the gold particles

downstream from their source.

There's lots of specks, [music] but they

are tiny. They are tiny, tiny.

>> What makes Imry's task extra difficult

is that nowadays the [music] flow of the

river has become unpredictable.

>> He's saying there's a dam that's gone in

up river and [music]

since that happened, it's just changed

the river. The panning spots [music]

have changed.

By next week, the precious gold could

have been carried somewhere else.

Dams are built for many [music] reasons,

not least to improve navigation.

But by changing the river's [music]

natural flow, I wonder if they're making

life hard for the hooken.

If you were just an ordinary person,

you're looking at a river you [music]

you think is exactly the same. But if

this is what you do, you know that

something's [music] happened. You don't

even have to know about the dam. you

just know that something's happened to

the flow. And it has to be the same for

the fish, too. We don't understand

enough about them. But if a dam can so

change the flow of a river that somebody

[music] panning for gold can detect it,

then the hooken have got to be affected.

They are indicators.

They indicate that [music] we've done

something to the river that I need to

understand.

Maybe I'll find the real thing in

neighboring Austria. I'm going to a

place that was once of the heart of the

Hookans range.

[music] Superficially, there's not much

wrong with the Danube here. [music] And

on close inspection, it looks better

suited to hooken than anywhere I've seen

so far.

It's narrower, but it's also faster. The

water's clearer and almost certainly

there's a higher oxygen content. Now,

from my knowledge of the salmon family,

it's this kind of water where they're

much more likely to feel at home.

Hookin are active sight hunters that

thrive in clean, fast flowing water

courses. That's why their presence is a

kind of gold standard for a healthy

river.

This is a nice little bit of slack off

the main push. I mean, the main current

is is running very very strong and fast.

But in here, it's the kind of place that

uh fish might be lurking.

What I'm trying to do is let the lure

sink to the bottom and then just twitch

it, let it sink again, twitch it, let it

sink again, twitch, sink.

One thing that can't be blamed for the

hookan's absence is over fishing.

As a species, hooken have never been

commercially exploited.

And here at least, recreational anglers

are required by law to put them back.

Since nothing is [music] biting though,

I decide to ask around.

>> What fish are you after?

>> Pike.

>> For a hex. Have you fished here on the

Danube? Many years.

>> Yes. Yeah.

>> Since Since?

>> Yes. Little boy.

>> Yeah. What about hookin? Do you see them

at all in the river now?

>> He says he's never seen any hookin in

the river, but he's got a contact who

sounds [music] intriguing.

>> You have a friend who's a specialist.

>> Can you give me his his name and maybe

uh how do I find him? So here's what

>> Fisher Ysef

>> and uh where is he?

>> Rosat.

>> Okay. So that's that's just that's just

down a little way here. Yeah.

>> Nice. Thank you.

>> No fish, but some interesting

information. It seems I need to go and

speak with a certain Mr. Fisher.

Maybe I'm actually going to see the

Danube's elusive ghost fish.

>> The aptly named fishes are eager to show

me something very special.

>> Look at that. What an amazing fish.

>> For decades, hooken have hardly been

seen in the Danube. Just so fantastic.

I've never seen hooken [music] before.

And here they are. They're almost in

touching distance.

>> What we do here, we're keeping [music]

them.

>> Joe and his dad are hooking fanatics.

>> We use them for

>> for years, they've dreamt [music] of

reestablishing a wild population in the

Vakal Valley.

This irrigated pond holds their precious

[music] breeding stock.

That's nice. Here we go.

There. There. There. There.

Look at this. I never thought I would

get to hold one of these in my lifetime.

That's a very very rare fish.

And uh they are just magnificent.

Breeding and raising baby hooken is a

timeconsuming business that costs the

fishers a [music] lot of money.

The fact that you are doing it as

private individuals purely out of

interest and passion that really is

something special definitely if we don't

do it nobody else is doing it

>> bringing the hookan back would [music]

be extraordinary

but for that to happen don't we need to

understand why it vanished in the first

place

so this big decline in the hookum why do

you think that was

>> that the biggest problem is

straightening. In the 17th and 18th

century, the government wanted to do

shipping a little easier and [music] now

it's a huge problem.

>> Starting 300 years ago, it seems that

large stretches of the naturally winding

Danube have been radically

re-engineered.

>> Okay, let me show you.

>> Oh, wow. That's really dramatic. A

surprising amount of change. The red

tier was ideal for hooking. Just a lot

of bends and curves. When you go

further, you see that all the ravel

banks and bends are lost. They were the

most important thing for the hooken to

breed.

>> So, it's a conflict between navigation

and the breeding of the hooken. And by

improving the navigation, it is almost

destroyed the breeding conditions for

the hooken.

>> Definitely correct.

Remarkably though, I'm told that some of

the engineering that destroyed the

hookan's breeding grounds has now been

undone.

And for the fishes, this is creating a

unique opportunity.

When the Danube was straightened for

shipping, side branches like this were

sealed off. But several have now been

reconnected, and these revived

backwaters make an ideal nursery for

young hookin.

The temperature right here is perfect.

It's very clear. There's no waste from

ships. Plus, there's no fishing allowed,

so they can grow up here very safely.

[music]

>> Just as important, though, is that the

Danub's reopened side branches also have

the right conditions [music] for adult

hooken to breed.

Successful breeding for hooken is about

the structure of the riverbed. They need

gravel [music] in order to breed.

>> The thing about gravel as opposed to mud

or [music] silt is the spaces in

between. This allows the water to flow

around the eggs bringing that [music]

all important to dissolved oxygen

without which those eggs would just die.

If you straighten the river, if the flow

is too strong, it washes away those

gravel beds

and you [music] lose the fish.

When I first tried to pick up the trail

of the hooken back in Hungary, I never

imagined that I would see one actually

in the waters of the Danube. And here I

am not seeing one. There's 30 or 40 in

front of me. This could be the beginning

of something very significant.

If the hooken story teaches me anything,

good luck,

>> it's that a tightly controlled river is

not [music] wildlife friendly,

no matter how pretty it looks.

The whole process of control of the

river by humans is something which has

continued and accelerated even until

this day.

>> The thing about rivers is that they're

restless, writhing creatures. They keep

changing their course. So, we lock them

in a straight jacket,

but the fish don't always like that.

Further up the Danube, though, lives an

exception. An aquatic invader that's

wreaking havoc.

In its upper reaches, the Danube is more

than 1,500 miles from the sea. But I've

heard that this part of the river is

being overrun by a saltwater invader.

Oh, there we go. Something just pulled.

Oh, yes. Yeah, I've got something. I've

got something. I've got one.

It may look cute, but according to

reports, it's a destroyer. This is a

thing called a round goi. This shouldn't

be anywhere near here. The Gobi's

natural habitat is on the shores of the

Black Sea amongst rocks. This

interesting arrangement of the pelvic

fins that is for sort of holding itself

to a rock.

>> To find out more about these tiny

[music] invaders, I've arranged to go

fishing with biology professor Jurgen

Gist.

>> Nice to meet you. You will need rubber

boots and special gloves.

>> So, these goies, how do they get here?

>> By ship balanced water. They hump in

water and automatically suck in eggs or

larvi or even adult fish. And when this

water gets [music] released at those

upstream sites, the gobies enter these

areas.

>> So basically right down in the mouth of

the river, they're taking in water just

to create stability for the boat that

then comes up here. They let that water

go.

>> But it's not just water. There's lots of

other stuff in it as well.

>> Exactly. There are very few fish that

can easily move from salt water into

fresh water. But the gobies can cope

very well with fresh water.

>> Today we're fishing both sides of the

river, starting along one of the rare

stretches of completely natural

shoreline.

>> We will do some electro fishing in this

really shallow area.

>> Okay.

Jurgen's net is in fact an electrode

that shocks the water with around 800

volts. Enough to stun any fish within 6

ft.

My job is to scoop them up before they

recover and swim off.

>> Here we go.

>> Oh yeah.

>> It doesn't take long to get some fish

and I'm curious to see what's here. This

is really interesting because within

this natural stretch uh we really

exclusively got native species of fish.

>> So no gobies,

>> no gobies, only native fish, including

this trout.

This is a young fish. So this habitat is

extremely important for the reproduction

of those native fishes.

>> So where are all the gobies?

The opposite side of the river is also

shallow. The big difference is that the

bank here is man-made. [music]

>> In between those boulders, those are the

spots where they are hiding.

>> Okay.

>> Using exactly the same voltage, we

quickly fill our bucket with stunned

fish. You

>> can see

>> they really come out all of these.

>> Oh, they they sink, don't they? Yeah.

>> Yeah. Yeah.

>> The question is, [music]

how many of them actually belong here?

Out of all the fish that we caught here,

there's just one single native species.

[music]

>> That's a chop, isn't it?

>> Yes. But this is totally dominated by

goies.

We find all size and age [music] classes

from the really big adults

to those very small ones.

This is ideal habitat [music] for them.

The tight packed rocks along the banks

hold the river in place.

For native fish, this straight jacket

[music] is an alien environment, but for

the gobies, it's home away from home.

I have noticed a lot of these banks. How

much of the Danuba are we talking about?

>> More than 90%.

>> So, what effect does this have on the

native species? Within the last 10 to 15

years, [music] the entire food web of

this upper Danube region has completely

changed.

It's such a dramatic difference.

>> Hundreds of miles of man-made banks are

allowing the invaders to proliferate.

And worse still, they're gobbling up the

eggs and young of native fish.

What I need to know is [music] whether

there's anything here that eats goies.

Dusk is often the time when predators

stir.

And there's one in particular that could

be very significant.

Just a few feet out, you've got an area

that's about 20t deep. It's the kind of

place where you'd expect to find a

larger fish.

When I think about fish that might be

unaffected by man-made banks, my mind

turns to a beast that can grow bigger

than a man.

It's a fish that guards its nest. So any

gobies after its eggs would end up on

the menu themselves.

If it is still here, then I, for one,

will feel a flicker of hope. Here

we go. Here we go.

Yes. Yes.

I've got the drag really tight because

I don't want the fish running. I just

want to This isn't strong gear. I just

want to get it in.

Ah. Oh god. Still there. It's in close.

It's in close.

There it is. There it is.

Here we go. Here we go.

This, I'm [music] very pleased to say,

is a native species.

>> The Danubian or Wells [music] catfish is

an eating machine.

This is the apex predator of this part

of the river. And uh think about those

gobies. They would just be perfect um

[music] snacks. Not even bite-sized

snacks. They wouldn't need to bite them.

They just suck them in.

For me though, this goi eater is doubly

significant.

In most of the big rivers in the world

now, you won't find [music] iconic

species in the main rivers. You've got

to go to very remote corners on the

[music] river systems. So to get a

decent sized Danubian catfish from the

Danube

actually feels very good.

Perhaps more than any other river in the

world, the Danube [music] is one

continuous picture postcard. How could

anything possibly be wrong? But looking

under the surface, what you've got is a

very complicated story. This is far from

a natural wild river.

What makes me hopeful is the continued

presence [music] of the beluga sturgeon,

the hookan, and the denubian whales

catfish.

That these are still here, still

clinging on is testimony to the fact

that this is still a living river.