{
  "id": 5653615,
  "title": "Octopus Clinging to a Risso’s Dolphin May Offer Clues to Southwest England’s Remarkable Octopus Boom",
  "url": "https://urgent.news/2026/09/04/octopus-clinging-to-a-rissos-dolphin-may-offer-clues-to-southwest",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-04T22:06:00.000Z",
  "source": {
    "name": "Discover Magazine",
    "slug": "discover-magazine",
    "url": "https://www.discovermagazine.com/octopus-clinging-to-a-risso-s-dolphin-may-offer-clues-to-southwest-england-s-remarkable-octopus-boom-49640"
  },
  "original_language": "en",
  "account": "Off the coast of Berry Head in Devon, Bill Coulson captured an unusual sight on camera. A common octopus (Octopus vulgaris) was clinging to the back of a Risso's dolphin, much like a passenger who forgot to disembark. This unique encounter occurred amid the greatest surge in octopus populations seen off southwest England in at least 75 years, a phenomenon researchers term a bloom.\n\nScientists are examining the implications of this population boom on the marine food web, from crabs and lobsters consumed by octopuses to Risso's dolphins, which prey on cephalopods including octopuses, squid, and cuttlefish. Bill Coulson, a marine biologist, said the photos offer valuable insights into the feeding habits of Risso's dolphins and the evolving marine environment around our coasts.\n\nThe octopus boom has been particularly pronounced in recent years. A report by the Marine Biological Association surveyed over 120 divers and snorkelers, with 96.5% reporting sightings of octopuses off southwest England, and 55.4% encountering them at depths of 33 feet or less. The presence of octopuses has been linked to declines in local crab, lobster, and scallop catches, with some fishing crews reporting damaged catches and lost income.\n\nFurthermore, octopus eggs and juveniles have successfully bred in British waters, suggesting the influx began south of Britain and was carried northward by currents from the breeding grounds around the Channel Islands and northern France. Warmer seawater may have contributed to the octopus's northward migration.\n\nRisso's dolphins, which typically inhabit deep waters near continental shelves and slopes, have been increasingly venturing into coastal waters less than 65 feet deep. Previous research has identified the curled octopus (Eledone cirrhosa) as the most important prey species for Risso's dolphins in British waters. A recent study examining preserved samples from 72 dolphins stranded between 1992 and 2016 found that these animals belong to one genetic group spanning the sampling locations. This genetic analysis further revealed six distinct mitochondrial DNA sequences unique to dolphins around the British Isles, indicating a lack of population structure in the region.\n\nResearchers from the Marine Biological Association and the Risso's Dolphin Project South West are encouraging the public to report octopus and dolphin sightings through Facebook or iNaturalist. This information can help researchers track the movement patterns of these species and gain a better understanding of the factors driving the current population boom.",
  "summary": "Learn how a photograph of an octopus riding a Risso’s dolphin connects the encounter to southwest England’s largest octopus bloom in at least 75 years.",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}