North Sea cod

North Sea cod populations have been battered by overfishing and the warming of the region’s seas. Photograph: Graham Turner for the Guardian

Stringent catch controls were imposed on the species in 2006 after two decades of overfishing pushed cod populations to the brink of collapse. But a recovery of North Atlantic stocks has led the MCS to nudge cod into their amber category for fish that can be occasionally eaten.

This month, the Marine Stewardship Council, which sets standards for sustainable fishing, began an assessment of the health of North Sea populations. This could lead to the cod gaining certification for sale in British high streets, as has happened with Scottish haddock and Cornish hake.

Related: North sea cod stocks bounce back, analysis shows

Almost all cod sold in the UK’s fish and chip shops – 50, 000 tonnes-worth – comes from the Arctic Sea. “It is encouraging to see this change in scoring from the MCS, ” the council’s North Atlantic director, Toby Middleton, said. “The signs of improvement are there.”

“It’s fantastic to see this fishery finally off the red list, ” said Samuel Stone, an MCS fisheries officer. “While this is certainly a milestone for North Sea cod, the job is not done yet. Efforts of recent years need to continue in order for the fishery to head towards the green end of the spectrum.”

North Atlantic cod are large predatory fish with three distinct dorsal fins on their backs. Famed for their white flaky meat, they can grow to at least two metres and weight up to 91kg.

Between 1996 and 2006, annual cod catches in the North Sea plummeted from 80, 000 to 20, 000 tonnes. But after the imposition of strict catch controls, cod stocks made a parallel recovery over the next eight years – from an estimated 20, 000 tonnes to 70, 000 tonnes.

The worst culprits in the cod population collapse were fishermen from Denmark, Norway and the UK, according to Oceana, an ocean advocacy group.

“Cod lives close to the ocean floor and so it was particularly affected by bottom trawling, which is the most destructive type of fishing, ” said Lasse Gustavsson, Oceana’s executive director. “When you drag a huge net along the sea floor, you plough it up and catch everything there. Selective fishing is not an option in those circumstances.”

Almost all cod sold in the UK’s fish and chip shops – 50, 000 tonnes-worth – comes from the Arctic Sea. Photograph: Alamy

Rukayah Sarumi, Oceans campaigner at Greenpeace UK, said: “The government needs to start rewarding those who fish in a sustainable way by putting them at the front of the queue for fishing quota, instead of continuing to let the industry’s biggest players plunder our seas.”

As well as overfishing, the decline of North Atlantic cod was exacerbated by warming oceans in western shelf areas of the North Sea basin, which reduced the fishes reproductive success.

“This is one of the key reasons why we want stocks in a healthy position as soon as possible, so they are as resilient as they can be, going into threats like climate change, ” Stone said.

The MCS cautions that cod numbers may never again reach the peak levels of the 1970s and 80s, and Stone recommended against a mass rush to the chippie just yet. “We are not saying you should avoid it but equally we are not saying it is the best option, ” he said. “It has been toted as a very occasional eat.”