Sunflower sea stars are now critically endangered, the International Union for Conservation of Nature (IUCN) announced. IUCN is known for overseeing the Red List of Threatened Species worldwide.
This many-legged star of the sea could be seen in coastal waters in Northern America. But during El Niño and the Warm Blob, a microorganism that triggers sea star wasting disease took root, and several types of sea stars died as ocean temperatures rose along the western coast from 2014-2016.
The sunflower star was badly damaged - this aquatic behemoth is now scarce, although some organisms have since recovered. Scientists predict that a whopping more than 5 billion sunflower stars declined from this epidemic, representing over 90 percent of their total population worldwide.
Sunflower sea stars are now nearly absent in Mexico as well as the contiguous United States, the scientists say. No stars have been seen in Mexico since 2016, none in California since 2018, and only a handful in Oregon and Washington since 2018. https://t.co/DngXifqWq3
— Dr. Drew Harvell (@DrewHarvell) December 11, 2020
Kelp forests on the West Coast are on the brink of missing the main species that has helped hold these habitats in balance with the sunflower star approaching extinction. These types of forests are now dealing with booming colonies of of urchins, and helping to preserve and rebuild sunflower star populations is more critical than ever. The University of Washington and the Nature Conservancy are now working to develop a captive breeding program to re-introduce sunflower sea stars into the wild.
Dr. Drew Harvell, a Cornell University professor of aquatic ecology and a key figure in the sunflower star's story, explained that the sunflower star is among the most vulnerable type of starfish infected by multiple pathogens. She said the species has quickly transpired from being the most prevalent starfish on the west coast to being critically endangered.
In 2016 and 2019 publications, Harvell's group warned no signs of a population recovery since the outbreaks.
Warming seas closely related to die-off sea star
Since 2013, about 20 sea star organisms between Mexico and Alaska have been destroyed by a sea star wasting disease. Although several organisms have started to recover, a paper released last year in Science Advances showed that the vitally significant predatory sunflower star has not. Indeed, along a 3,000-kilometer (approximately 1,864 miles) radius between California and Canada, the population has declined by 80 to 100 percent.
The study team, headed by Cornell University and University of California (UC), Davis, reported the downturn by researchers and citizen scientists utilizing evidence from more than 10,000 dives and thousands of deep ocean trawls done by the National Oceanic and Atmospheric Administration (NOAA). They also noticed that die-offs from the sunflower star were strongly associated with global average temperature surges.
The die-off of the sea star started as a major underwater heatwave the same year, however since ocean temperatures are not standardized, scientists were unable to ascertain if hotter water actually impacted the sea stars and rendered them more vulnerable to disease wastage, the New York Times explained.
The current study confirms the theory that heat helped cause the epidemic by illustrating that the sunflower stars started to die closely after temperatures spiked.
The causing of coral viruses, a parasite threatening frog and toad species, and the infection that wiped out two-thirds of saiga antelope have all been correlated with hotter temperatures.
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