The southern tip of the African continent.
Sailors once called this "The Cape of Storms"
These waters seem forbidding and without life.
But just below the surface,
one of the world's greatest wildlife spectacles
is about to emerge.
Rising up from the depths,
appears to be one giant creature.
But appearances can be deceptive.
This is one single animal,
but millions. It's a massive shoal of sardines
100,000,000 little fish are about to begin 1000 mile journey
up the African coast.
And on course to intercept them are armies of deadly predators.
Tens of thousands of them.
If they will find the sardines
one of nature's greatest confrontations will take place.
This is Massive Nature.
But why here ?
And why now ?
In an attack of this scale,
the life of every single little fish will be on the line.
So, at the moment of impact, is it all over for these sardines ?
Or did some still have a change to save themselves ?
And are these sardines the only ones in danger ?
Because even hungry predators have predators of their own.
Dolphins and sharks are deadly enemies.
Will they turn on each other ?
It's a moment when life hangs in the balance for both predator
and prey.
The future of all these animals would depend on a chain of events
that begun 6 months ago,
more than 1000 miles down the coast.
Our story starts in deep water,
off the southern tip of Africa, on the Agulhas bank
a safe place for sardines.
It's their nursery.
Here hundreds of millions of tiny fish are growing,
breeding and multiplying.
They're safe here, for now.
But they can't stay here forever.
Before long , something will set them on a journey up the coast of Africa.
And that something is food.
In winter a cold current sweeps 1000 miles up the coast
carrying with it the sardines plankton food.
When the time comes, the sardines will have no choice, but to follow.
Their dangerous journey will take them past Bird Island
It's the world's largest colony of fish-eating gannets.
Here, 100000 birds are gathering to breed.
Timing is critical.
Although they'll have almost 6 months to raise their chicks before the sardine shoal passes by,
not all will be ready.
And while the gannets await the sardine's arrival
on a nearby island, 7000 cape-fur seals are gathering to breed.
With such massive numbers in this colony
the seals can't simply wait for the sardines to arrive
they'll need to start hunting closer to home.
And that could put the gannet chicks in real danger.
The first great storms of winter trigger a big change in the ocean currents.
The life-sustaining plankton is swept out of the sardine's nursery.
And with billions of new mouths to feed, the massive shoal sets off on its epic journey.
Sheer numbers force the sardine shoal to follow their food,
even if it means leaving the safety of these deep waters.
As the shoal begins its incredible journey
hundreds of miles up the coast, yet another animal is preparing to join the hunt.
Common dolphins thrive in the seas along the coast of Africa
They're social, playful animals,
but also intelligent and cunning hunters.
These dolphins will, in fact, be the brains behind this whole sardine hunt.
Because if they don't find the fish, then none of the other predators will, either.
Somehow, they sense the sardines are on the move
and they mobilize their own massive force.
They bound together into a huge armada
5000 strong, a dolphin super pod,
assembled with the soul purpose of hunting down sardines.
But in these numbers, they can also become a target.
For in these same coastal waters are sharks.
They're normally solitary hunters, except when there's a dolphin super pod on the move.
Now they too gather in their thousands, and begin their search for the dolphins.
But will these sharks find the dolphins, before the dolphins find the sardines ?
Halfway through their journey, and still safe in deep water,
the shoal moves on relentlessly.
Each little fish is blissfully unaware of the gathering of predators
Amassing in their honor.
On Bird Island, the gannet chicks have hatched.
These young birds must fatten up fast,
and learn to fly soon, if they are going to join the sardine hunt.
They'll need these fat reserves to tide them over
until they can learn to fly with the rest of the colony,
and that will make them a target.
Nearby, at the seal colony,
a new generation of predators is about to take to the water.
And all these pups will soon be learning their own survival skills.
As the numbers swell, the pressure mounts on the seals, too.
And, like the gannets, they will be forced to leave these islands, in search of food.
When that time comes, these young pups will have to fend for themselves,
in ever more dangerous waters.
The odds seem to be stacking up against the sardines
but for now they're safe, so long as they remain in deep water.
And even if they were to be found here, being part of the massive shoal
means the odds of survival are good.
But shoaling comes at a cost.
Hiding in the middle, a fish may be safe, but there's precious little food here.
So each fish must take its turn at the edge of the shoal, where it can feed,
but where it also risks becoming food.
Being part of the massive shoal, also makes them easier to find.
And there's one predator with a plan to do just that.
A few hundred miles off the coast, the dolphin super pod is now on the move.
With so many mouths to feed, their search is becoming desperate.
They're now using a combination of intelligence and sonar
to try and locate the sardine shoal.
Highly organized, they set up a sweeping front
a line of scouts, several miles wide, to scan the sea for signs of the sardines.
But as a dolphin's sonar beams out
they alert their presence to their predators.
It's exactly the signal these sharks are waiting for.
Around Bird Island, the food is running out.
The gannets must join the sardine hunt, and the fledglings will have to follow.
They've been preparing for this moment for weeks
now it's time to put their wings to the test.
With hungry seals nearby, now it's literally fly, or die.
One the gannets are gone, the seals must follow.
But they're not all ready to live.
Pups born late in the season, are to small and weak to join the crowd.
And these waters are dangerous, for those who go alone.
And, until the sardines are found, these are very dangerous waters.
The gannets now spot the dolphins, and start to track their movements,
while the seals follow on from below.
The fate of all these animals now rests with the dolphin's success
at hunting down the shoal of sardines.
So, where on earth are they ?
With just 24 hours to go, nature now starts working for the predators.
The cold food-rich current is letting the sardines out of deep water,
and into the shallows,
at waterfall bluff.
It's the perfect spot for an ambush.
Until now, the sardines have remained out of range of most predators
but if they're caught in these shallow waters, they'll be at their most vulnerable.
It's dawn, the most dangerous time for the sardines.
Overnight, they've been feeding at the surface,
protected by the cloak of darkness.
But with the sunrise, they need to dive to safety.
And it's now, that finally, the dolphins track them down.
These waters may be shallow for sardines, but the dolphins are at their limit of their diving range.
They must be quick, before the shoal is lost to the deep.
So, how will they catch them ?
It's a race against time. The shoal is sinking fast.
But these dolphins have a remarkable plan.
An individual can only hold its breath for a few minutes at a time.
So, the dolphins work as a team,
relaying to the surface, to breathe.
By constantly blowing bubbles into the shoal,
the dolphins confuse the sardines.
Eventually, they manage to isolate and disorient a group.
And bring it to the surface.
The result is a bait ball,
a swirling, churning mass of terrified fish.
They're still 20000 strong,
but now, they're all in serious trouble.
With just seconds to go,
the dolphins have got the sardines exactly where they want them.
And just before the attack, they set their sonar to stun mode.
Now, every single little fish is at risk.
Each , instinctively searches for the safety of the crowd,
but in a bait ball, nowhere is safe.
Still, the dolphins must keep the bait ball near the surface, in close diving range.
They can't do that and attack in the same time.
They need help.
And right on queue, guided by the dolphin's sonar, the sharks have arrived.
With literally thousands drawn to the feeding frenzy,
the dolphins are now in great danger
The sharks approach from below, and start their attack.
But at the final moment, their focus changes.
The bait ball becomes their target, too.
Instead of attacking the dolphins, these sharks become their allies.
Sharks don't need to surface for air,
and they now lead the attack from below the bait ball.
The sardines only escape route is closed.
So, is it all over for the bait ball, or these sardines still have a chance ?
If they can spread out thinly, just below the surface
they'll present no clear target for the predators.
But once more, the dolphins are ahead of the game.
They split into platoons, some circling around the sardines,
leaving others free to continue the attack.
It's a deadly alliance of predators,
a pincer movement, dolphins attacking from the side,
as sharks lunge from below.
Things are looking bad for the sardines,
and there are about to get much worse.
from the skies above, the gannets roar down, like fish-seeking missiles.
Hitting the water at 60 mph, and plunging to a depth of 20 feet
The attack brings more birds to the bait ball.
Soon, there's thousands of them, raining death from above.
But there's still one predator missing from the scene.
The fur seals.
And now, the last group of hunters arrive, for their share of the killing.
But, will the gannets, or the sardines be their target ?
Like the sharks and the dolphins,
the seals and gannets ignore each other, when they found a bait ball.
This bait ball faces extinction.
With so many predators, every single fish will be eaten.
Day after day, bait balls like this are created and destroyed by these predators.
But the sardine story doesn't end here.
Though huge, the bait ball is just a small part of this massive shoal.
Becoming separated, was what made those fish vulnerable.
But even in a shoal of this size, they're still not entirely safe.
The army of allied predators may have disbanded,
but the danger still remains.
Now the food-rich currents are pinning them in the shallows,
where their predators can easily attack.
Sharks have no need for the dolphins here.
And in these shallows, the fish now face another enemy.
A 20 ton Bryde's whale can swallow 10000 sardines
in a single gulp.
Those fish that have survived all these attacks
must face one final challenge.
Trapped in these warm shallow waters, the fish begin to suffocate
victims of their own massive numbers.
But just as it looks like the end for every single sardine,
nature takes the reigns.
Once again, the currents change, steering them out of the shallows
and releasing them back into the safety of the deep.
The Africa sardine is a gambler.
It plays the number's game and wins.
Although millions die, millions more survive.
And they ride the currents back to their nursery grounds,
where, next year, they will rise again,
as the greatest shoal on earth.