Scientists Identify Bacterial Culprit Behind Massive Sea Star Die-Off
Researchers have pinpointed Vibrio pectenicida as the cause of a decade-long sea star wasting disease that decimated populations along the Pacific coast.
Since 2013, a mysterious wasting disease has led to the death of over 5 billion sea stars along the Pacific coast of North America, from Mexico to Alaska. The epidemic severely impacted more than 20 species, with the sunflower sea star experiencing a population decline of approximately 90% within the first five years.
Recent research has identified the bacterium Vibrio pectenicida as the cause of this devastating disease. The findings, published in Nature Ecology & Evolution, mark a significant breakthrough in understanding the largest recorded marine epidemic in the wild.
The disease manifests as lesions on the sea stars, leading to arm loss and rapid tissue decay. Healthy sea stars typically have "puffy arms sticking straight out," but those affected by the wasting disease develop lesions, and "then their arms actually fall off," explained marine disease ecologist Alyssa Gehman of the Hakai Institute in British Columbia.
The identification of Vibrio pectenicida was achieved through detailed analysis of the sea stars' coelomic fluid—the internal fluid surrounding their organs—where the bacterium was found in high concentrations. This discovery resolves a long-standing question about a serious oceanic disease, according to Rebecca Vega Thurber, a marine microbiologist at the University of California, Santa Barbara.
Understanding the cause of the disease opens avenues for conservation efforts. Scientists are now considering strategies such as breeding sea stars in captivity, exploring natural immunity within populations, and developing treatments like probiotics to boost resistance to the disease. These initiatives are crucial not only for the survival of sea stars but also for restoring entire marine ecosystems.
The decline of sea stars has led to an overpopulation of sea urchins, their natural prey, resulting in the destruction of kelp forests that serve as vital habitats for various marine species. Researchers hope that by addressing the root cause of the disease, they can aid in the recovery of sea star populations and the broader marine environment.