Fishing lines: I'm not a cheat - I'm just looking

That protector of traditional values and bastion against Johnny Foreigner, the Daily Mail, found a new target this week - anglers who use electronic devices to locate fish.

That protector of traditional values and bastion against Johnny Foreigner, the Daily Mail, found a new target this week - anglers who use electronic devices to locate fish.

Though the newspaper didn't actually call for all fishermen using a Smartcast watch to be slung into prison ships, its message was clear: employing sonar technology to pinpoint fish is cheating, and that's not British.

However, it is not merely a matter of switching on your watch and holding out a net for the fish to jump into. The Smartcast comes with a float fitted with a sonar scanner, which is activated when it gets wet (offering endless opportunities for fun in the bath). The sonar pulses scan the water below (it can work to a depth of 75ft) and transmit digital images back to the watch screen, showing both the bottom of the lake or river and any fish. It even shows the depth at which fish are swimming.

Now if that's cheating, I'm a teapot. The device, which costs £110, is simply an echo sounder. Every charter boat fishing for cod and conger, bass and brill around our coast line uses one. As well as finding fish, it isolates wrecks and sandbanks.

Fish don't stay in the same place. They swim around. Echo sounders save hours of fruitless fishing by pinpointing areas where is something to catch. They offer an additional bonus: punters can see fish on the bottom, even if they can't catch them.

That is perhaps the key point. It is pretty pointless fishing where there isn't a fish for yards (and, in some cases, miles).

Great Slave Lake in Canada's Northwest Territories is 290 miles long, the fifth largest lake in North America. In places, it is more than 1,000ft deep. When I visited, thank goodness our guides had echo sounders. Imagine: we could have been fishing at the wrong part of the lake, with every fish a car-drive away (except it was so wild you couldn't get even 4x4s up there).

For freshwater fishing, especially in large, deep waters, echo sounders are crucial. The very big trout called ferox that live in deep Scottish and Irish lakes would be impossible to locate by chucking out a bait at random and hoping it landed on a hungry fish.

Even if it did, it wouldn't mean you had your ferox. All an echo sounder does is to show that there is a fish about. If it had a dodgy curry the night before, has just had a row with the wife, is worrying about GM water fleas or pondering the meaning of life, it's not going to snaffle your bait.

The Smartcast comes (surprise, surprise) from the US, where lake anglers would not venture out without an echo sounder. When I went ice-fishing on Lake Mille Lacs in Minnesota, the anglers had not only coloured echo- sounders that pinged when a fish came close, but even underwater cameras that enabled you to watch the fish catch (or ignore) your lure. Cheating? No, just evening out the odds a bit.