For years, a puzzling question has haunted marine biologists: What is causing the deaths of starfish? Since 2013, billions of these beautiful sea stars, essential to many coastal ecosystems, have been perishing. They suffer from a condition known as “wasting disease,” which makes their body parts shrink and disintegrate.
This tragic loss has hit the sunflower sea star hardest, with some areas seeing 90% mortality. Over 20 species of starfish along the coasts of California and beyond have been affected, from Alaska to Mexico.
Recently, researchers from the University of British Columbia and the University of Washington identified a strain of bacteria, Vibrio pectenicida, as the main culprit. Surprisingly, this bacteria is related to the one that causes cholera in humans. In a comprehensive study published in Nature Ecology and Evolution, they revealed that it ravages otherwise healthy sunflower sea stars.
Drew Harvell, a co-author of the study, expressed the heartbreak of witnessing such widespread death among these captivating creatures. He noted how engaging they can be, often responding to food tossed their way. “It’s gratifying to finally have an answer,” he said.
The sheer scale of the problem is staggering. Estimates suggest that between 5 and 6 billion sea stars have died along the U.S. West Coast. This massive die-off has led to a rapid rise in sea urchin populations, as these spiky creatures rely on starfish as a primary food source. The unexpected surge in sea urchins has severely damaged kelp forests critical for various marine life, including fish and sea otters.
Melanie Prentice, an evolutionary ecologist at the University of British Columbia, highlighted how the decline of sea stars alters the balance of marine ecosystems. Some areas are seeing gradual signs of recovery, though the situation varies greatly. Mike Murray, director of veterinary services at the Monterey Bay Aquarium, noted a rise in starfish sightings compared to 2015 and 2016.
Experts emphasize that the study raises pressing new questions. Why did a bacteria previously harmless suddenly become deadly? Environmental conditions, such as rising sea temperatures or changes in acidity, might have triggered this shift. Understanding these dynamics could be crucial in addressing this unsettling crisis.
In light of the continuing decline of the sunflower sea star, NOAA is contemplating whether to classify the species as threatened under the Endangered Species Act. Environmentalists urge swift action to create policies that ensure the survival of these sea stars.
Despite the grim circumstances, efforts are underway to foster recovery. Some initiatives focus on breeding sea stars resistant to the bacteria. Successful programs at institutions like the California Academy of Sciences are working to replenish populations. Additionally, scientists are replanting kelp and managing overcrowded urchin habitats along the California coast to help restore balance in marine ecosystems.
This ongoing detective work underscores the nature of scientific inquiry—sometimes theories don’t pan out, but each lesson learned drives progress. As Mike Murray put it, “That’s the way science works. Sometimes we undervalue failures. We learn from them.”
Understanding the challenges faced by sunflower sea stars not only sheds light on a specific species but highlights broader themes of ecological balance and the impact of human actions on the environment. By exploring these dynamics, we can better protect vulnerable species and the ecosystems they support.
For more insight on marine biology challenges, check out NOAA’s official report.
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Starfish, sea stars, Monterey Bay, NOAA, climate change
