脆弱天堂 18

Tuna are predators.

They herd smaller fish to the surface, where they can be picked off one by one.

They are high-speed fish - the cheetahs of the ocean.

They're also the wildebeest

They herd together in their thousands

And undertake epic migrations across the Pacific in search of their prey.

If these animals lived on land

They'd be famous for providing the greatest wildlife spectacle on Earth.

Instead, they're better known as a filling for a sandwich.

In an ocean with no marine reserves, migratory fish have nowhere to hide.

Up to two kilometres long and 200 metres deep

"purse seine" nets are designed to encircle schools of tuna.

A fisherman checks his nets

Breathing air pumped down a tube from the vessel above.

It's not only tuna that get caught in these nets.

A lone turtle was in the wrong place at the wrong time.

She can only hold her breath for a few minutes

And the path to the surface isn't clear.

She begins to panic.