It looked like a limitless bowl of mushroom soup. It often looks like that: but yesterday it was a peculiarly violent kind of soup, restless, forbidding, white-flecked and much colder than gazpacho. It snapped at my feet venomously, forcing me back up the beach. Clouds promising snow stretched down to the horizon.

In Suffolk, the sea lacks the sense of melodrama you find on the rocky coasts: but in the big winds, it still tossed up clouds of Guinness-froth. Gulls passed confidently over the uneasy surface: a flight of three cormorants moved low between the waves.

Sea. We've got a lot of it on this island. We seek it out at the least excuse: even on this grim-looking day, the Bank Holidaymakers were out in force, the caravan site was doing good business and muffled-up Brits were marching about: and there will be plenty more sea pilgrims arriving today.

We think a lot of the big wet stuff in this country: proud that our teeming seas surround every bit of our island. So you'd expect us to be pretty good at looking after it, wouldn't you? After all, the Government says it is fully committed to marine protection. But we're hopeless. Have a guess: how much of our seas do you think are protected?

Imagine all our seas as an Olympic-sized swimming pool: how much of it have we saved? The answer is one teabag floating on the surface of that Olympic pool - less than one square mile in every 100,000. All kinds of mayhem can be wrought down there, out of sight: and that is precisely what is going on. And there's nothing to stop it.

The sea is a dwindling source of wonders. I have still managed to see a few of them in this country: 20ft basking sharks, dolphins leaping clear of the water, more dolphins cruising a few feet from the shore, rafts of sea duck, skies ringing with the cries of kittiwake, and perhaps most dramatic of all, the aerial bombardment of the seas by spear-billed flocks of gannet.

Conservation organisations are pushing hard at the view that the Government needs to take action. Naturally they have some hard suggestions. The RSPB has identified more than 70 sites, all of them near the shore, that are important for wildlife. One problem is that there isn't a mechanism to protect them. The sea, it seems, is the last frontier: out there, you can still taste freedom from responsibility and accountability.

WWF is calling for a network of marine reserves in the North Sea, the mushroom soup I was gazing out on with a wild surmise. It says that 30 per cent of the North Sea needs to be protected if fish stocks are to recover. The marine ecosystem is in desperate need of a little more resilience. Some much-fished species have declined by 90 per cent since 1990: that is to say, in times when we already have the facts of the overfishing before us.

It is impossible to look out at the surface of the sea without wondering what is underneath. This is not the most rewarding bit of conservation, in terms of giving humans things to see: but I am richer for knowing that there are still extraordinary beasts in the three quarters of the planet where we cannot walk. I would feel richer still for knowing that they were protected. It's all very well being part of a nation full of romantic notions about the sea: but a little practical work is needed as well.

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