Four fish : a journey from the ocean to your plate

Whether it's wild or farmed, fresh or tinned, in batter or a bento box, we're eating more fish than ever before.

But what's the story behind the fish on your plate? Award-winning writer and lifelong fisherman Paul Greenberg takes us on a culinary journey through the oceans, telling the stories of the fish we eat the most: salmon, cod, bass and tuna.

He visits Norwegian mega farms that use genetic techniques once pioneered on sheep to grow 500,000 tons of salmon a year.

He travels to Alaska to see the only Fair Trade certified fishing company in the world.

He investigates the pollutants that cause mercury build-up in seafood; discovers how Mediterranean sea bass went global; meets a Polish emigre on the Shetland Islands who may have saved the cod; and, gets sea-sick chasing blue fin tuna off Hawaii.

Throughout, Greenberg poses the questions many of us ask when confronted with a seafood menu or a supermarket shelf: Which fish can I eat without worrying?

What does overfishing mean? What's the difference between wild, farmed and organic?

Should humans domesticate fish as we have animals - or stop eating from the sea altogether?Fish, Greenberg shows, are the last truly wild food we eat - for now.

By understanding fully how it gets to our dinner table, we can start to enjoy fish in a way that's healthy for us - and good for the world that exists off our coasts.