Wait for a date with a skate

As you read this, I will be in Scotland trying to pull the plug out of the sea. At least, that's how experts describe the experience of hooking a giant skate and trying to haul the damn thing off the bottom.

The common skate has very little in common with the one you eat with chips or as raie au beurre noir, depending on your financial status. A better name would be uncommon skate.

The ones you buy in fish shops are usually thornback rays, which are prolific little breeders living in shallow water. The "common" skate, by contrast, is a solitary critter at home where it's dark and deep. You need 2lb of lead just to get a bait to the fish, and winching that lot up in a fast tide is tougher than two hours of step aerobics.

Winding up a line may be the only sport I get all weekend, for hunting giant skate demands endless patience. All my companions, from the Big Game Club of Scotland, have captured a whopper or two. But if we nobble one between us, they'll be pleased. Two, and they'll be delighted. Three, and it's out with the whisky. (Actually, the whisky will be flowing anyway, because we are fishing such a remote spot that it's impossible to return to port, and so we are sleeping on the 52ft boat overnight.)

Their boat, called Magnum, is a story in itself, for the club have built it all themselves. It's cost about pounds 100,000, though its value is nearer pounds 200,000. Magnum will be available for charter, but the club really want to prove that Scotland is an unexplored haven for monsters of the deep.

One member has already set a world record with a 410lb porbeagle shark. But the club are convinced that there are even bigger shark, along with exotics such as swordfish and tuna. "We've even had an unconfirmed report of a shoal of hammerhead shark," says Murdo Gunn, one of my drinking (sorry, fishing) companions.

"Until now, we haven't had a boat capable of reaching some of the farther marks, and charter skippers usually want to get back by 5pm. Now we can get to unfished grounds and stay out for a week or more," he says.

Surprisingly, fish will not figure high on our menu this weekend. For giant skate, which can grow to more than 200lb and be as large as a dinner table for 10, the name of the game is conservation. Until recently, the world record was only 140lb, and several club members had caught larger ones. But they refused to kill a skate merely to claim a record.

You can't eat it (something to do with build-ups of mercury or other unpleasant things in the flesh, I'm told). Even Russian trawlers, which will sell a piece of driftwood covered with barnacles as a rich source of proteins and vitamin E, throw back common skate.

Every skate is tagged and released. "These fish are worth more to the local economy alive than dead," Gunn says. The tagging allows scientists at Glasgow Museum to identify movements and growth patterns.

Finding big skate is not easy, tempting them to take a bait is tricky, but hauling them up is like playing tug of war with a bus. The skate's flat shape enables it to create a suction pad to the sea bottom. You heave and heave, and after about 30 minutes, if you're lucky, it will give up. Then you slowly wind up - in a fast tide, it's like being hooked to an open parachute - only for the fish to zoom back down to the bottom the moment it detects light. Your muscles aching with the effort, your back hunched like Quasimodo, you start again. And again. And again.

Everyone tells me it's great fun. Next week, if I'm lucky, I'll tell you the truth.