For years, it has been one of the biggest mysteries in marine biology: What is killing the starfish?<\/p>\n
Since 2013, billions of sea stars, an elegant ocean species commonly known as starfish that are a key part of the environment along the coast of California and other states, have been dying. The animals have suffered from a disease that causes parts of them to shrivel and melt away.<\/p>\n
In some places 90% of the sea stars died from the gruesome ailment, which is known as \u201cwasting disease.\u201d It has affected more than 20 species of sea stars found in the northeast Pacific Ocean from Alaska to the Baja California peninsula in Mexico, including Monterey Bay, the Sonoma Coast and other parts of the California shoreline, including the most susceptible sunflower sea stars.<\/p>\n
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Drew Harvell, a University of Washington affiliate professor in the School of Aquatic and Fishery Sciences and an adjunct professor at Stanford, holds a sunflower star at the University of Washington Friday Harbor Laboratories. (David O Brown\/Cornell University)\u00a0<\/p>\n
On Monday researchers at the University of British Columbia and the University of Washington said they have found the culprit: A strain of bacteria called Vibrio pectenicida.<\/p>\n
The bacteria, a distant cousin of the bacteria that can cause cholera in humans, has been known to harm coral and shellfish. In four years of research, which the scientists published in the journal Nature Ecology and Evolution,<\/a> the researchers found it causes otherwise healthy sunflower sea stars to melt and die.<\/p>\n \u201cIt\u2019s just heartbreaking to watch them die,\u201d said co-author Drew Harvell, a University of Washington affiliate professor in the School of Aquatic and Fishery Sciences, and an adjunct faculty member at Stanford University\u2019s Oceans Department. \u201cSunflower sea stars are enchanting creatures and they\u2019re quite interactive. At feeding time, they will come toward you. If you throw clams to the stars, they can catch them. It\u2019s so gratifying to finally have an answer.\u201d<\/p>\n Between 5 and 6 billion sea stars on the West Coast have died, according to some estimates<\/a>.<\/p>\n The loss of so many led to a population explosion of sea urchins \u2014 the prickly species that sea stars commonly eat \u2014 along the West Coast over the past decade. And because sea urchins eat kelp, the big growth in the urchin population caused a decline in kelp forests along California\u2019s coast, which are key habitats for sea otters, fish and other species.<\/p>\n \u201cWhen we lose billions of sea stars, that really shifts the ecological dynamics,\u201d said Melanie Prentice, an evolutionary ecologist at the University of British Columbia and a lead author on the paper.<\/p>\n Some populations of sea stars have begun to slowly bounce back, although it varies widely by location on the West Coast, said Mike Murray, director of veterinary services at the Monterey Bay Aquarium.<\/p>\n \u201cThere is some evidence of recovery,\u201d Murray said Monday. \u201cI\u2019m seeing more sea stars than I remember seeing back in 2015 and 2016.\u201d<\/p>\n Researchers in California on Monday called the new study significant.<\/p>\n \u201cThis is great work. I am impressed,\u201d said Pete Raimondi, a professor of ecology and evolutionary biology at UC Santa Cruz. \u201cThis research is quite strong.\u201d<\/p>\n Both Raimondi and Murray said the findings raise new questions for marine biologists to pursue. The type of bacteria already exists in the ocean. What triggered the massive die-off? Does the same bacteria affect other species of sea stars? That type of bacteria does well in warm waters. Has climate change played any role?<\/p>\n \u201cBacteria is everywhere in the ocean,\u201d Raimondi said. \u201cThe question is what made it go rogue?\u201d<\/p>\n Murray agreed.<\/p>\n \u201cSomething happened to trigger it,\u201d he said. \u201cMaybe it was changes in water temperature, changes in PH, or something else. Those kinds of things could trigger a cascade of events.\u201d<\/p>\n The decline of one species of sunflower sea stars has been so dramatic that in 2023, NOAA, the National Oceanic and Atmospheric Administration, announced it would decide whether to list them as threatened under the Endangered Species Act.<\/a><\/p>\n On Monday environmentalists urged the agency to move forward with that step.<\/p>\n In this photo provided by the Hakai Institute, healthy populations of sunflower sea stars are found in the Knight Inlet fjord of the Central Coast of British Columbia, Canada, in 2023. (Grant Callegari\/Hakai Institute via AP)<\/p>\n Researcher Alyssa Gehman from the Hakai Institute in British Columbia counts and measures sunflower sea stars in the Burke Channel on the Central Coast of British Columbia, Canada, in 2023. (Bennett Whitnell\/Hakai Institute via AP)<\/p>\n In this photo provided by the Hakai Institute, with a lack of predatory sunflower sea stars, sea urchins proliferate in Hakai Pass, British Columbia, Canada, in 2019. (Grant Callegari\/Hakai Institute via AP)<\/p>\n In this photo provided by the Hakai Institute, a sunflower sea star is reduced to goo by sea star wasting disease at Calvert Island, British Columbia, Canada, in 2015. (Grant Callegari\/Hakai Institute via AP)<\/p>\n In this photo provided by the Hakai Institute, Hakai Institute research scientist Alyssa Gehman checks on an adult sunflower sea star at the U.S. Geological Survey\u2019s Marrowstone Marine Field Station in Washington state in 2021. (Kristina Blanchflower\/Hakai Institute via AP)\n<\/p>\n Show Caption<\/p>\n 1 of 5<\/p>\n In this photo provided by the Hakai Institute, healthy populations of sunflower sea stars are found in the Knight Inlet fjord of the Central Coast of British Columbia, Canada, in 2023. (Grant Callegari\/Hakai Institute via AP)<\/p>\n Expand<\/a><\/p>\n \u201cHats off to the dedicated researchers who\u2019ve identified what killed billions of these extraordinary sea stars in the Pacific,\u201d said Catherine Kilduff, a senior attorney at the Center for Biological Diversity. \u201cWith this new information, I\u2019m hopeful we\u2019ll be able to stop the sunflower sea star\u2019s decline and get their populations back up so they\u2019re thriving again. This hard-won discovery can help entire ecosystems and it shows why research funding and species protection is so important. The federal government needs to stop dragging its feet and provide the safeguards these sea stars desperately need to survive.\u201d<\/p>\n Researchers said the discovery could help lead to other techniques to help sea stars bounce back, including finding sea stars in the wild that are resistant to the bacteria, breeding them in captivity and releasing them into the wild.<\/p>\n Already, some captive breeding programs have proven successful at the California Academy of Sciences, Moss Landing Marine Labs<\/a>, and the University of Washington\u2019s Friday Harbor Lab, among others.<\/p>\n Along some parts of the California coast, from Marin to Mendocino, scientists have been replanting kelp and working to remove overgrown urchin populations<\/a> to help restore kelp forests that were depleted when sea star populations crashed.<\/p>\n![\"In](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2025\/08\/Sea_Star_Disease_78169.jpg\")
In this photo provided by the Hakai Institute, with a lack of predatory sunflower sea stars, sea urchins proliferate in Hakai Pass, British Columbia, Canada, in 2019. (Grant Callegari\/Hakai Institute via AP)\u00a0<\/p>\n<\/p>\n
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