Cod fish in the North Sea off the United Kingdom were once heading towards extinction.

But these fish are now recovering, thanks to years of conservation measures, according to a report in The Guardian.

The North Sea was once one of the world’s great fisheries. But due to overfishing, stocks of cod there plummeted by 84% between the early 1970s and 2006.

It was nearly as bad as the total collapse of the Grand Banks fisheries off Canada in the early 1990s (which has still not recovered).

But the fate of Canada was averted thanks to tough but necessary actions such as:

• Decommissioning fishing boats

• Ban on catches in nursery areas

• Limits on days when fishing is allowed

• Larger holes in nets to allow young cod to escape

In 2001, parts of the North Sea were closed to cod fishermen under emergency European Union rules. Cod fishing was banned for 12 weeks during the crucial spawning period in a desperate bid to revive dangerously depleted stocks.

Some of these measures hit fishermen hard, but there was no choice as their catch of cod was dwindling away (anyway).

Now, all these efforts have paid off.

The stock of cod has increased by fourfold since its lowest point in 2006. And last month, North Sea cod was awarded sustainable status by the London-based Marine Stewardship Council.

Sustainable North Sea cod in supermarkets will carry the MSC’s blue label. To obtain the MSC certification, fishermen are also required to protect cold water corals from damage by trawlers.

On a global level, overfishing is still a major threat.

The United Nations Food and Agriculture Organisation says that 90% of the world’s fisheries are either being fully exploited, or are at risk of collapsing. This is what makes the turnaround of North Sea cod a rather rare but inspiring example of how conservation can work.

Mike Park, chair of the Scottish Fisheries Sustainable Accreditation Group, told The Guardian, “This is a testament to the power of collective action. The years of commitment to rebuilding North Sea cod has shown that fishermen are responsible and can be trusted to deliver stable and sustainable stocks.”

Lyndsey Dodds, head of UK marine policy at WWF, agreed that the improvement in cod stock showed what was possible when the fishing industry, managers and scientists worked together. But she added that the recovery remains fragile and work to sustainably manage fish stocks must be continued.

Up till now, about 90% of cod in the UK has been imported, mostly from Iceland and from Norwegian and Russian boats fishing in the Barents Sea, which have all gained MSC sustainable certification in recent years. But now cod caught and landed in the UK will also be labelled sustainable.

UK citizens eat about 70,000 tonnes of cod a year – 1kg per person. Industry group Seafish estimated there are over 10,000 takeaway fish and chip shops in the UK, serving about 380 million meals a year.