# Marine warming and cephalopod population surges > Live situation record from CLSTR: https://clstr.news/situations/marine-warming-and-cephalopod-population-surges > Updated: 2026-09-18T17:47:22.000Z. Sources: 4. Developments: 2. Rising ocean temperatures in the UK and North Sea are driving significant shifts in marine ecosystems, specifically through the proliferation of cephalopod populations. In the UK, an intense marine heat wave off the coasts of Devon and Cornwall has triggered the largest octopus bloom recorded in 75 years. Water temperatures have risen up to 9 degrees Fahrenheit above normal, allowing larvae to survive and reproduce. This has resulted in octopus landings increasing by approximately 7,700 percent, though it has simultaneously reduced catches of scallops, lobster, and crab. The warming has also attracted predators like bluefin tuna, sharks, and dolphins to the region. Similarly, in the southern North Sea, water temperatures have increased by approximately four degrees Celsius over the last century. This warming, combined with an abundant food supply, has allowed cephalopod eggs to hatch successfully in previously too-cold waters. The decline of the cod population, a primary predator of these species, has further contributed to the surge. In Flemish marine fishing, squid and octopus now represent more than one-fifth of the total catch. ## Timeline ### 2026-09-18: North Sea warming triggers surge in octopus and squid populations Warming North Sea temperatures are causing a population explosion of squid and octopuses as cod populations decline and warmer waters facilitate cephalopod breeding. 2 sources. https://clstr.news/cluster/north-sea-warming-triggers-surge-in-octopus-and-squid-populations ### 2026-09-12: Marine heat waves trigger massive octopus bloom off UK coast A massive octopus bloom off the UK coast, driven by intense marine heat waves, has reached its largest level in 75 years, significantly altering local marine ecosystems and fishing markets. 2 sources. https://clstr.news/cluster/marine-heat-waves-trigger-massive-octopus-bloom-off-uk-coast --- Cite as: Marine warming and cephalopod population surges. CLSTR, https://clstr.news/situations/marine-warming-and-cephalopod-population-surges