Rising sea temperatures caused by climate change will profoundly affect the fish population in the North Sea as mullet and squid replace cod, plaice and sole, research by Wageningen Marine Research has found.

“Cold water species are beginning to find it too hot in the North Sea,” marine research ecologist Karen van de Wolfshaar told broadcaster NOS. “That can affect other species as well, because their prey will be leaving for cooler areas. Other species will need more food because the higher temperatures make them use more energy,” she said.

Fishermen are already discovering species usually found in hotter climes in their nets, such as squid and langoustine.

There are no rules or quota in place for these “new” species, Christien Absil of fish quality label MSC told the broadcaster. “It looks as if a species will have to be overfished before we will get some sort of policy,” she said.

According to Van de Wolfshaar, it is important to find out the volume of the newcomers and set out quota recommendations for them.

Absil also warned that overfishing could lead to a collapse of the fish stock in the North Sea. “North Sea herring was almost wiped out in the Seventies and it took five years to come back. That had a profound effect on the fishing industry,” she said.

Meanwhile, 90 percent of the exotic fish caught in the North Sea is exported abroad. “The Dutch should value the new species more,” fisherman Hendrik Kramer said. Kramer, who promotes sustainable fishing, caught a lot of squid during the pandemic. “I helped to keep me going. But what would be really sustainable is if it could be eaten here,” he said.