Marine heatwaves reshape Britain's seas as native fish head north and sunfish surge

Britain’s marine life is shifting as sustained heatwaves reshape sea conditions, with colder-water species moving north and warm-water fish appearing more often. The Guardian reported a skipper in the English Channel mistook a pair of sunfish for a signal because they were beating their fins conspicuously farther north than usual. The Met Office called 2025 “exceptional,” with heatwave conditions lasting roughly three-quarters of the year in parts of British waters, and 2026 is following a similar pattern. A Brighton charter boat captain, Kurt Lander, says cod have become scarce—down from hundreds a year to about one or two in summer—and he’s seeing more sunfish, bass, combers and triggerfish. Scientists link redistribution to warmer seas, noting temperature preferences such as sharks at 61–63°F.