Fishing Lines: Lured by a taimen in outer Mongolia

Do any readers know the Mongolian for: "I think a pinch of cardomon would spruce up that boiled camel nicely," or "Do you have anything bigger than a labrador for me to ride on?" or "The snow is falling through a hole in the yurt roof on to my sleeping bag"?

Sentences like these - and the correct pronunciation of them - will prove invaluable to me in a month's time, when I head off to a remote region of Mongolia in pursuit of a taimen.

This is not going to be a five-star trip, staying in Ulan Bator's finest, though I'm told the capital is quite an experience. A friend who visited it found a restaurant with a sign on the door saying, "Closed for lunch".

But Ulan Bator (a trading centre producing carpets, textiles and vodka, according to my encyclopaedia) is just a stop along the way. After that, our small party flies on to Morun, pronounced Moron by those who know. From there we board one of those small planes that people tell horror stories about. If all goes well, we land a couple of hours later at a nameless airstrip, where our regular transport awaits - the tiny Mongolian ponies, which take us to our riverside camp.

Eight of us are staying in a yurt with Mr Batso. Yurts are large circular tents with a permanent fire going because at night, it gets so cold (often -30F) that the river starts to freeze.

It's primitive as hell. Our party leader, John Bailey, who runs a small travel company, has warned us what to expect. His first words of advice were: take some food unless you want two weeks of boiled fish, with the occasional straggly spud or dollop of rice. The group has appointed me chef, on the principle that I look like the one who has most to lose by suffering two weeks of slop.

Cooking and the cold are not our only worries. The best fishing is two or three hours by miniature pony. John, an experienced rider, says that it left his bottom feeling as if it had been scrubbed with a cheese grater.

On the plus side, it looks highly likely that we will catch the rarest and largest member of the salmon family. John captured taimen up to 40lb last year, but lost the big ones. We're going there with tough stuff: powerful rods, strong reels, 30lb lines. And we may well need them. Taimen certainly grow to 100lb, probably 150lb and possibly 200lb. From John's pictures, it seems they are a mixture of the reddish sockeye and the silver Atlantic salmon but darker than both: quite slim, with a hunter's head. Their favourite food is tundra mice, which migrate across the rivers at dusk.

And that's about as much as is known about the taimen. Whether they are flourishing or declining, where and how they breed, their migration patterns and their lifespan - all a mystery. Taimen are so rare that only a few museums have even a picture.

I would love to bring back a whopper for the Natural History Museum, but I fear it may miss out. The idea of lugging a 100lb salmon on ponyback for three hours is not worth contemplating. Even if I got it back to camp, it would have to stay outside the yurt and then, knowing my luck, the wolves would probably snaffle it.

I wonder if the scientists would settle for a scale.