Andrew Fairlie, who runs the only restaurant in Scotland with two Michelin stars, and Tom Kitchin, award-winning chef and guest judge on BBC's MasterChef, are among those who say the electrocution is being carried out by fishing boats out to make a fast buck.
"This idiocy must stop," they declare in a joint letter to the Sunday Herald (see right).
Shocking the seabed forces razor clams out of their burrows so that thousands can be harvested relatively easily. But it also kills marine wildlife, breaking the spines of fish, causing internal bleeding and respiratory failure.
The fishing industry wants the practice to be legalised, though only after further research and under proper regulation. For their part, Scottish ministers promise they will tighten the licensing rules for razor fishing.
Razor clams (Ensis) are regarded as a gourmet delicacy, and have a soft, sweet flesh much favoured by chefs. There is a lucrative market for them across Europe and in the Far East. They can be harvested using dredged suction pumps, or traditionally by hand.
But now fishing boats are increasingly turning to electro-fishing. Catches have rocketed from 46 tonnes valued at £74,218 in 1995 to 903 tonnes worth over £2.5 million in 2012. Government scientists attribute the huge increases in recent years to electro-fishing, suggesting that as many as half are now being illegally harvested.
Since 2010, a dozen boats have been caught and fined up to £2000 for electro-fishing around Scotland. But critics argue that the fines are "puny" and have not deterred the fishermen or dented their profits.
"I was absolutely shocked when I looked into the methods that were being used to harvest razor clams," said Fairlie, who runs the famed restaurant at the luxury Gleneagles Hotel in Perthshire.
He added: "Unless our suppliers can guarantee that any spoots [razor clams] we receive are caught in a sustainable manner we will remove them from our menu - and I would urge any other chef to follow suit."
Tom Kitchin, chef at The Kitchin restaurant in Leith, Edinburgh, agreed. "As chefs we should be responsible," he argued. "We have to do this sustainably, and if we have to pay a premium, then we have to pay a premium," he said. Illegally electrocuted spoots were "against our philosophy" and had never knowingly been served in his restaurant.
Fairlie and Kitchin have both signed the letter to the Sunday Herald describing electro-fishing as "one of the most damaging ways of catching food mankind has devised". Other signatories are Charlie Cornelius, who runs the Iglu organic restaurant in Edinburgh, Charlotte Maberly, a food lecturer at Queen Margaret University, and the food writers Richard Bath, Alex Renton and the Sunday Herald's Joanna Blythman.
Renton, who co-ordinated the joint letter, pointed out that unregulated electro-fishing also put divers' lives in danger. "I'm worried at any fishing that risks human lives and the health of Scottish seas," he said.
But the industry body, Seafish, pointed out that another form of electrical fishing for flatfish by trawlers in the southern North Sea had been legalised. Its research suggested that electricity was "less environmentally intrusive" than other fishing methods.
"We would therefore welcome further research to allow for an accurate and objective portrayal of the activity based on scientific findings," said Seafish's sustainability adviser, Bill Lart.
"Electrical fishing for razor clams is an illegal fishing method under European Union rules and Seafish does not condone its use until proper legislation and fishery management measures are in place."
According to the Scottish Fisheries Minister, Richard Lochhead, officials would continue to tackle illegal activity and the harm it caused. "The Scottish Government does not support the practice of electro-fishing or any relaxation of the rules governing it," he said.
"Marine Scotland intends to introduce new razor-fishing licence conditions by April 2014, which will deliver a comprehensive and stringent suite of conditions to minimise the risk of electro-fishing."