Government scientists from the Centre for Environment, Fisheries and Aquaculture Science (Cefas) have found squid are now being caught at 60 per cent of its 76 survey stations in the North Sea, compared with 20 per cent in the 1980s.
Fish such as cod and haddock, which live in colder waters, are heading further north and away from British waters. Their populations have already been hampered by warming sea temperatures.
Cefas, which has been monitoring North Sea fish populations for more than 100 years, said its models for 2025 and beyond suggest seawater temperatures off the UK may continue to rise and attract fish that currently live in warmer, Mediterranean waters.
"UK consumers enjoy eating quite a limited range of seafood, but in the long-term we will need to adapt our diets," said Cefas' Dr John Pinnegar.
"In 2025 and beyond, we may need to replace cod and other old favourites with warm-water species such as squid, mackarel, sardine and red mullet."
Cefas' research will be presented at the British Ecological Society annual meeting in Liverpool later today.