SALES of sustainable seafood have soared nearly one-third in just two years, campaigners claim, with the popularity of celebrity chef cookbooks a major factor.

The latest figures show shoppers spent an estimated £403 million on certified sustainable products in the year to April as public awareness and the range on offer increases.

Chefs such as Hugh Fearnley-Whittingstall have been credited with the rise in popularity of 'alternative' fish types such as mackerel, pollack, coley, pouting and whiting.

According to figures from the Marine Stewardship Council (MSC), the global non-profit organisation looking to conserve the oceans, the value of sustainable seafood rose 16 per cent on the previous 12 months and 30 per cent over the two years.

The MSC said that in that time its list of certified products, which stretch to health supplements, pet food and baby food, had reached over 1,100, more than twice the number of those on offer in 2012.

The number of MSC certified fish and chip restaurants in the UK has also doubled this year, while students at 21 UK universities and more than 3,500 schools can choose certified seafood in their canteens.

It comes on the back of research from the Environment Department at the University of York, which found that "a chef’s ethical leanings may influence the behaviour of consumers".

It named Hugh Fearnley-Whittingstall as the front runner in promoting sustainable, while even Gordon Ramsay, who once encouraged people to eat an endangered fish called orange roughy, was the third most influential. Books by Raymond Blanc where ethically-harvested produce figured large was also cited as evidence of a general improvement in the use of sustainable seafood by most chefs in recent years.

Toby Middleton, the MSC's UK programme director, said: "Five years ago, one in five UK shoppers recognised the MSC ecolabel, but now it's more than one in four shoppers.

"When shoppers and diners choose seafood with the MSC ecolabel, they reward the fisheries, retailers, brands and restaurants that are committed to sustainable sourcing, and incentivise others to improve their practices, helping to ensure that the life in our oceans is safeguarded for the future."

Bertie Armstrong, chief executive of the Scottish Fishermen's Federation, said: "With the majority of our fish stocks being in good health and fished sustainably, this is great news for the Scottish industry.

"Popular Scottish caught fish such as haddock, saithe and herring are already certified by the MSC for their sustainability and even just today we have had the good news that other stocks such as monkfish, megrim and West of Scotland langoustine are increasing."

Cate Devine, The Herald's food writer, said: "It's very encouraging to see so many Scottish chippies and restaurants signing up to sourcing MSC accredited fish. The Bay Fish and Chips in Stonehaven, Ondine seafood restaurant in Edinburgh and Gamba in Glasgow are among those who have led the way in ethical sourcing, and they wouldn't do it if they didn't think their customers would support them.

"Traditionally, the Scots diet contained lots of fish, though in recent years that has fallen away.

"I'd like to think these new figures point to a return to a healthier and more sustainable Scots diet."

According to the MSC, seafood is the world's single most traded food commodity, at about 10 times the value of coffee.

Globally, it says, one billion people rely on fish for their main source of protein and around 10 per cent of the world's population depend on it for their livelihood.

In recent weeks, Ikea has declared that it is now the foodservice provider that offers the largest variety of certified seafood globally.