“At one time plentiful in nearshore waters, the sunflower sea stars right now cannot be found off the California coast and are rare into Alaska,” said Drew Harvell, Cornell professor of ecology and evolutionary biology, a co-lead author. “Numbers of the sea stars have stayed so low in the past three years, we consider them endangered in the southern part of their range, and we don’t have data for northern Alaska.”
Since 2013, sea star wasting disease has brought about massive mortality in multiple sea star species from Mexico to Alaska. The East Coast has not been immune, as the disease has affected the shores from New Jersey to New England.
“This is likely because this disease has many hosts, and other species that tolerate the pathogen better may spread it to the sunflower star,” he said.
Global warming due to a changing atmosphere is likely a major factor.
“The heat wave in the oceans – a product of increasing atmospheric temperatures – is exacerbating the sea star wasting disease,” said Harvell, a fellow at Cornell’s Atkinson Center for a Sustainable Future. “It’s a lethal disease, and when you add a higher temperature to that, it kills faster, causing a bigger impact.”
The sunflower sea star is large, about the size of a manhole cover, and possesses an enormous appetite. It crawls over the seafloor like a robotic vacuum cleaner, munching on everything in its path.
“In California, Washington and parts of British Columbia, sunflower sea stars keep urchins under control,” said Joseph Gaydos, senior author on the paper and director of UC Davis’ SeaDoc Society program. “Without sunflower stars, urchin populations expand and threaten kelp forests and biodiversity. This cascading effect has a really big impact.”
Scientists from Simon Fraser University and the Hakai Institute confirmed the loss from remote Calvert Island in British Columbia. The ocean warming recorded at REEF locations corresponds to an increase in water temperature by up to 4 degrees Celsius that started in 2014.
Scientists from the National Oceanic and Atmospheric Administration surveyed sunflower sea stars in thousands of deep trawls from Mexico to the Canadian border and recorded 100 percent decline in all states in deep water down to 1,000 meters.
Stanford University also contributed to this research. The study was supported by the National Science Foundation, Natural Sciences and Engineering Research Council of Canada, NOAA and the Department of Commerce.
Kat Kerlin, UC Davis News and Media Relations, 530-752-7704, firstname.lastname@example.org
Jeff Tyson, Cornell University Media Office, 607-255-7701, email@example.com