Image copyright Thinkstock

The traditional British fish supper could be replaced by the likes of squid as the waters around the UK's shores grow warmer, say government scientists.

Squid and fish that thrive in warmer waters, such as sardines and anchovies, are flourishing around the North Sea, according to fisheries data.

Squid are now being caught at 60% of survey stations in the North Sea, compared with 20% in the 1980s.

But the likes of cod are heading north, away from British waters.

Dr John Pinnegar, of the Centre for Environment, Fisheries and Aquaculture Science (Cefas), which has been monitoring North Sea fish populations for more than 100 years, said models for 2025 and beyond suggested that seawater temperatures off the UK may continue to rise.

Fishing boats are now catching species that have not been caught in the area before.

Mediterranean alternatives

"Twenty or 30 years ago we hardly saw squid in our surveys," he told BBC News.

Dr Pinnegar, programme director for marine climate change at Cefas, said summer squid fisheries had expanded around the Moray Firth in north-east Scotland, as part of efforts to reduce over-fishing of more traditional species such as haddock and cod.

"A lot of the things we see increasing in abundance around the UK are marine animals that would probably originally [be] thought of as being Mediterranean or characteristic of the Bay of Biscay, or around Portugal or Spain," he added.

"They're now increasing in UK waters because the waters are getting more conducive for those sorts of species, whereas other species are shifting the centre of their distribution towards the north of the UK."

Image copyright Thinkstock Image caption Cod numbers have been slow to recover after overfishing, meaning much of the cod we eat in the UK is imported

Long-term data shows the centre of distribution of cod has moved north towards Norway, whereas plaice is moving across the North Sea from the Netherlands towards Scotland.

Currently, squid catches off the UK tend to be exported to other countries, but Dr Pinnegar, who is presenting data on trends in stocks at the British Ecological Society's annual meeting in Liverpool on Monday, believes that may change.

"Maybe consumers might like to choose species that are distributed in our own waters rather than importing some of this," he said.

"There are quite a lot of species that seem to be increasing - things like red mullet, anchovies, sardines, John Dory, squid - all of these are quite nice to eat but they are the kind of thing you would have normally have eaten on your holiday to Spain or Portugal."

A study earlier this year found that squid appeared to be benefiting from climate change, at the expense of finned fish, and they have been identified as a valuable alternative fishing target, particularly in the North Sea.

Worldwide catches of squid, octopus and cuttlefish (cephalopods) have increased considerably over the last two decades.

Efforts are under way to understand more about the sustainability of populations before they become the target of large-scale fisheries.

Figures show that the annual mean sea surface temperature in the North Sea has risen from about 10 degrees Celsius in the early 1980s to a record 11.7 degree Celsius in 2014.

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