Search for the Great Sharks

Across 400 million years

Long before and long after the dinosaur ruled the continents

the sea has remained

the unchallenged domain of the shark.

Yet recently, another species has begun to intrude.

Lords of the land, we enter the ocean as potential prey.

But of 370 shark species, only about 30 attack humans.

Most, like the bottom shark maturing in an egg case

are small or harmless.

Other young, however, born live from larger sharks

are so aggressive they often devour one another

inside their mothers before birth.

Now an extraordinary expedition begins

to probe the true nature of these mysterious creatures.

Can we learn to live in their midst

or will the shark ever remain

our most frightening enemy in the wild?

Renowned marine biologist Eugenie Clark

never feared sharks and at 70 still swims among them.

I was nine when I saw my first live shark.

It was at the old New York Aquarium

and they looked so beautiful.

I had my nose pressed up against the glass.

I wanted to be in there with them.

It never occurred to me that they were dangerous.

Dr. Clark believes sharks hold

important secrets of survival which can benefit humankind.

They have an incredible immune system...

perhaps the strongest in the animal kingdom.

They can fight off diseases

including malignant cancer.

There are substances derived from sharks

that can put some cancers in remission.

Dr. Clark feels that sharks deserve protection

an opinion shared by her friend Rodney Fox

despite a great white shark attack

that nearly tore Rodney in half.

462 stitches later, he launched a career

leading expeditions into shark-infested waters.

After my shark attack in 1963

I really hated sharks

but, after studying them for just a short time

I've come to really appreciate them.

However, I'm really keen on these trips

to find an effective shark repellent.

The central question is:

Why do some sharks attack humans?

In the hope of finding out

Dr. Clark and Rodney Fox now embark on three expeditions

to study the feeding and attack behavior

of the great sharks.

...but today we're going to be using the leopard shark...

Work begins at California State University, Long Beach

where Dr. Don Nelson is testing a new shark repellent.

...namely when the chemical is evenly disbursed in the water.

A natural shark repellent

discovered by Dr. Clark has proven impractical

leading to a search for a synthetic alternative.

Effective in the lab

the new chemical must now be tested

in the wild.

In the Catalina Channel off Southern California

the team enters waters

home to sea lions, a favorite prey of many large sharks.

Some scientists believe

that sharks often attack humans in error

mistaking swimmers for sea lions.

Preying upon the less fit among their quarry

sharks perform a vital evolutionary service

and perhaps bear large responsibility

for the sea lions' remarkable speed and agility.

Experiments with the new repellent

begin in a notorious hunting ground of blue sharks

adjacent to the kelp forests.

By spreading a chum of ground mackerel

they hope to create a drifting scent trail

leading sharks directly to the boat.

As a safeguard against shark bites

Rodney Fox will don a special chain-mail suit.

Yet, as the scars across his chest and back suggest

the suit would offer little protection

against sharks as large as great whites.

Marine biologist Rocky Strong

will release a new repellent using a pressurized squirt gun.

Divers

stand by, please.

I feel like a knight in shining armor.

Wait till you put that helmet on.

My students, who know I'm in my seventies

raise their eyebrows

when they hear I'm diving with sharks again.

While Dr. Clark and Rodney Fox observe from a steel cage

a safety diver in chain-mail will serve as lookout

and attempt to lure the sharks with bait.

Hello. This is Mandy.

Can you both hear me?

Loud and clear

Rodney, what is the visibility like?

It's pretty good at the moment.

I don't see any sharks yet.

Our safety diver is almost in position.

The plan is to distract the sharks with the bait

giving Rocky Strong a chance to fire the repellent.

Unexpectedly, the first arrivals are not sharks.

Genie, do you see what I see?

The food offerings draw

a flock of shearwaters, masters of underwater flight.

They're eating our shark bait.

Any sharks?

Not yet.

Here comes

the first one, Genie.

We've got three beautiful blue sharks around us now.

Make it four.

Though they rarely exceed ten feet

blue sharks travel and can attack in packs.

Ranging widely, often feeding in a frenzy

the blue serves as our most common image

of a lethal shark.

There's a five-footer close to us.

Rodney's tempting it with bait.

How close to the front of the cage are they coming?

Watch out!

It's got my hand!

His hand suddenly seized by the shark

Rodney struggles to pull free.

I was feeding him

and he nearly swallowed my hand.

At least the chain-mail

kept him from biting through.

Ok, I see Don now.

While the shark's attention

is on bait

Dr. Nelson approaches with a tagging spear.

In the future

if the shark is caught

the tag will reveal its range, territory

and growth rate.

The repellent test begins with a mild concentration

released into the shark's mouth.

Oh, no, Genie.

He's coming back.

I think maybe he likes the stuff.

As Rocky Strong returns to the boat

to reload with a stronger solution

of the repellent, Rodney leaves the cage

to assist the safety diver in keeping the sharks near.

As I was trying to keep the sharp around

by waving the bait at him, I lost one of my fins.

And while trying to get it back on, I started sinking.

I dropped the weights on the outside of my suit

and tried to reach the buoyancy inflator

but it was out of reach, and I couldn't get to it.

I knew then that I'd have to take off the air tanks

and risk dislodging my helmet

in order to inflate the vest

or I was certainly going to die.

Rodney, do you read me?

Help me! Somebody help me!

Rodney manages at last

to inflate his vest and reach the surface

where a safety diver rushes to his aid.

It was pretty frightening

to be in the water and suddenly he's not there

and to realize that your close friend

is going down in that depth

and there wasn't any way we could help him.

I thought we'd lost Rodney.

I couldn't find my inflator.

Uh, really, I thought I was going to die.

You all right?

In the end

tests of the repellent prove disappointing.

While the search for a defense against sharks continues

the master of the sea prevails.

Along the coast of western Australia

a team sets out on a rare mission

to locate one of the sea's most elusive creatures...

the giant whale shark.

On occasion whale sharks have been sighted near Ningaloo Reef

but the reason for their appearances is unknown.

Dr. Clark and Rodney believe they may be able

to solve the mystery and advance science...

a prospect that draws a photographic team

from National Geographic magazine.

We planned this expedition based on the theory

that whale sharks would come to feed

on a massive bloom of plankton triggered by coral spawning

and that was the key because we knew

that certain species of coral in Ningaloo Reef

spawn for a brief few minutes one or two nights a year

about a week after the march full moon.

Our first task was to locate

an area of good spawning activity

so that we would know exactly where to begin our search

for whale sharks in the morning.

Builders of vast undersea structures

corals are not plants but colonies of tiny animals.

Only recently, science has found that they often reproduce

by releasing a storm of eggs and sperm