On the trail of the grayling; fishing lines

Walking along the banks of Derbyshire's river Dove, it's easy to see why Izaak Walton thought: "I could get a book out of this." With a rare flash of good taste, the Peak District authorities have refused to allow a plethora of cafes, ice cream vans, picnic spots and souvenir shops. If Walton came back tomorrow, apart from looking bloody silly in those baggy trousers, he would find that the Dove and surrounding countryside have changed little. Even the grayling are still big.

The grayling are one reason why I'm here. There are a few others. The Dove is one of the few rivers where you can guarantee to see the dipper, a delightful white-chested bird that thinks it's a fish and can actually walk along the bottom of a river. I also want to talk to John Bailey about taimen, the largest fish of the salmon family, which live in Mongolia and are rumoured to grow to 150lb.

John runs a company called Angling Travel, and one of the trips he organises is a weekend's grayling fishing tuition on the Dove, staying in (you've guessed it) the Izaak Walton Hotel. This is slightly less exotic than some of his other jaunts, which include sturgeon fishing on the Volga, mahseer in India, trout in Chile, char in Greenland - and taimen in Mongolia.

But we're here for grayling, an underrated and understated fish so lovely that Walton called it The Lady of the Stream. It is slim, with a few small trout-like spots and mainly silver shot with lilac and pink. The most distinctive feature is a huge dorsal fin, so large that it looks as if it has been stolen from a fish three times as large.

For years, trout anglers condemned grayling as pests. Frederick Halford, doyen of trout fishermen, wrote of a conversation between two trouters, where one told of his dream: the last pike in the river Test would be choked by trying to eat the last grayling. But a useless little lump of fat and bone on their backs called the adipose fin means grayling get a ticket into the royal box. Trout and salmon have one and are called game fish: roach, perch and pike don't so they are called coarse fish. Don't worry if you don't understand this, because neither do I.

Grayling now have their own supporters' club: the Grayling Society, which is an extremely well-run group with its own newsletter. The fish has an added benefit (unless you're a grayling) of being extremely good eating. My mother likes them better than trout.

The six on this weekend's trip have never caught a grayling before. But in the Dove's crystal waters, they all see plenty of fish, some running well over 2lb. Grayling at this time of year are pernickity creatures. They are not chasing flies on the surface, but sitting glumly on the bottom wondering when the weather's going to perk up. When an angler's artifice comes trickling past their noses, they are more likely to twitch a fin and let that little tempter float on past. If they do take, they usually reject the fly before a fisherman has time to react. It's wildly frustrating but totally addictive.

This stretch of the river is popular with walkers: sturdy boots, woolly hats and determined strides, their maps of the Peak district contained in a little plastic bag to keep out the damp. But many pause on their journey to watch a fisherman fail miserably to deceive the clearly-visible fish. One little girl asks her parents: "Why can't that man catch those fish?" You can almost hear the angler's teeth gnashing.

But there are ways to catch them, and Bailey is usually pretty nifty at nailing grayling. But you'll have to wait until next week to find out whether the beginners managed to catch any - and to find out more about those taimen.

Angling Travel, Orchard House, Gunton Park, Hanworth, Norwich, NR11 7HJ, tel 01263 761602.