UK Seas Near 5C Above Average as Extreme Marine Heatwave Threatens Shellfish
Updated
Updated · bbc.co.uk · Jul 7
UK Seas Near 5C Above Average as Extreme Marine Heatwave Threatens Shellfish
3 articles · Updated · bbc.co.uk · Jul 7
Summary
Sea temperatures around parts of eastern and southern England could reach 4-5C above average later this week, with the Met Office warning of an "extreme" marine heatwave.
Heat domes and persistent high pressure that drove record air temperatures in May and June have warmed shallow waters in the English Channel and southern North Sea, on top of decades of climate-driven ocean warming.
Scientists say the heat can stress or kill seagrass, kelp and shellfish, while favoring warm-water species such as octopus that are already hitting catches of crabs, lobster and scallops in some fishing communities.
Researchers also report longer-term shifts, with cool-water species such as cod moving north and warm-water species increasing around south-west England.
Met Office scientists warn such marine heatwave conditions could become average by the middle to end of the century unless greenhouse gas emissions are cut.
Beyond the octopus boom, what invasive species and new diseases are arriving in Britain's warming coastal waters?
As warming seas replace lobsters with octopus, can UK fishing fleets adapt fast enough to survive?
With cod migrating across borders, how will international fishing treaties be redrawn in a rapidly warming Atlantic?
UK Marine Heatwave 2026: Record Ocean Temperatures Threaten Ecosystems, Fisheries, and Coastal Communities
Overview
In July 2026, UK seas are facing a severe crisis as a persistent marine heatwave drives sea-surface temperatures far above normal. This surge follows an unprecedented European heatwave, intensified by climate change and a heat dome that trapped heat for days. The extreme land temperatures in Europe led to further warming of the surrounding seas, worsening a marine heatwave already present since May. As a result, waters around southern and eastern Britain are especially affected, with record temperatures and significant ecological and economic risks emerging for marine life and coastal communities.