Ocean Oasis

I cannot stay away.

Coming home to Baja California for me-

-is like walking across a thousand miles of sand-

and finding a pool of water.

It's an oasis for my heart.

A few very special places in the world-

are havens for life.

Resources and shelter draw living creatures from far and near.

These places are rare. We call them oases.

Of them all, this is one of the most extraordinary.

This is my home.

It is a hot, dry peninsula, 700 miles long-

and surrounded by ocean.

It is called Baja California.

I'm Exequiel Ezcurra.

I work here as an ecologist.

Today, some fellow naturalists and I will take you to places we love-

-to discover the answer to a single question:

Why does this land and this sea create an oasis?

One simple answer to that question is that there's plenty to eat.

Mercedes Guerrero studies whales that are drawn here to feed.

The whales eat floating sea life called plankton.

They find it here in huge concentrations.

Dolphins too are drawn here in tens of thousands-

to feed their high energy lives.

Dolphins trap the schools of fish near the surface.

Birds can see the commotion from miles away and join in.

Whales follow by listening for the action underwater.

I have learned to recognise these humpback whales as individuals-

by their special markings.

We study them to see how they live and even how they die.

The sharks did not kill this humpback-

but we don't know what did.

I am saddened by the death of this whale.

But in this circle of hunger and life-

even the greatest lives end.

And I know that this whale's body-

-will give new life to others.

The ocean oasis is a magnet to life.

Enriqueta Velarde studies the birds-

-that return each year to Rasa Island.

It's amazing.

Almost all the Herman's gulls and elegant terns in the world-

come here to Rasa to breed.

The gulls arrive first, to establish their nest sites-

-travelling from as far away as Canada.

The terns migrate from coastal Chile and Peru.

As many as half a million birds-

-pack into this tiny island at once.

It may seem curious that the terns nest-

-in the middle of the gulls' colony. But by living among the gulls-

-the terns gain protection from predators.

The gulls tax the terns-

-by stealing some of the food they bring in from the ocean.

Just imagine-

-the birds of Rasa catch 65 tonnes of fish each day-

one sardine at a time.

That points to one conclusion.

This ocean must be incredibly productive.

Iliana Ortega works here as a naturalist.

This is my community.

Much of my work is to show people the diversity of the wildlife-

and to explain its biology.

For instance, it's important to get to know sharks...

...like these hammerheads.

They don't threaten us, they usually eat squid.

But with grey sharks, there is tension.

They'll eat almost anything.

You know, humans are much more dangerous to sharks-

than they are to us.

When you spend time with sharks you begin to understand them.

And learn to respect them.

But you have to command their respect too.

See? They're always testing you.

I admire sharks.

They're a vital link in the chain of life.

Like wolves, they weed out the sick and the injured-

-leaving behind only the healthiest of their prey to reproduce.

At night, the sharks' sophisticated senses of vibration-

-and electro-conductivity serve them best.

They move faster, become more excited-

and leave, in search of prey.

I will not follow.

Throughout the night, other predators stalk the oasis.

The moray eel is almost blind-

-but it can smell like a bloodhound.

The scorpion fish is camouflaged by day-

-but not from something that can smell it.

Daylight returns.

The frog fish begins its day.

Cornet fish stir from their slumber...

...and life rises to the morning.

Some animals come to the oasis for reasons other than hunger.

They come to breed.

These elephant seals migrate here twice each year-

from the northern pacific.

A round trip of 6000 miles each time.

The mothers transform their thick blubber into milk.

And the milk is incredibly rich.

Just imagine, the babies put on eight pounds a day!

A male as big as a truck sees a smaller trespasser.

In this fight over the territory where the females gather...

...bulk is power.

Elephant seals may look ugly and awkward to us-

-but they are powerful predators.

Soon they will return to the sea-

-where they spend 90% of their time-

-diving to depths of up to 1500 feet.

Ospreys are usually solitary, except here.

The abundant mullet in the ocean oasis-

-attracts so many of these fish hawks that they crowd the cliffs-

-sometimes building their nests less than a hundred metres apart.

Whenever I see them using those claw like beaks so gently-

-I can't help wondering whether instinct and emotions-

are really so different after all.

Is this what we call sibling rivalry?

The chicks are always hungry-

-so the adult osprey are always fishing.

Underwater, other life is also busy breeding.

These Creole fish are broadcast spawners.

Milt and eggs burst into the water-

and mix right there.

Schools of mackerel dash in to feast-

but many eggs survive.

Other fish produce fewer eggs, but tend them carefully.

A female sergeant major lays her eggs on the rocks-

-and the male spends weeks guarding his nest-

until the eggs hatch-

-chasing off everything else that wants a snack.

Because life in the oasis is so crowded-

-the reef here reminds me of a city.

A moray can smell something tasty.

But the baby leather bass has a refuge-

-she's specially adapted to shelter among the venomous urchins.

But other fish may threaten her sanctuary.

A hogfish attacks one of the urchins.

Its neighbours mill around, waiting for scraps-

and careless mistakes.

In this city, you better watch out when crossing the street.