漂流者 14

Out in the open ocean, they hatch into larvae

and become part of the vast plankton soup

And it's not just fish that depend on the whim of the open ocean to disperse their larvae

Land crabs and other crustaceans do too

But there's a deadline They each have a set number of days to reach new islands

Astonishingly,these larvae are able to home in on the smells and sounds of distant reefs

Out of the millions of larvae that set off only a small fraction will succeed in colonising new islands

Curiously, some freshwater fish also spawn at sea

and use the sea to help their larvae colonise rivers

These freshwater eels in the Solomons began their lives hundreds of miles away

possibly in a deep sea trench off New Guinea

Yet as larvae and then elvers,they made their way into these freshwater pools

and over 40 years,grew into two-metre giants