Sea Stars Observed after Massive Epidemic
(Oct 22, 2015)
In 2014, the Pacific Coast of North America was hit by a mysterious epidemic that wiped out millions of sea stars, marking the largest marine animal disease event in recorded history. The disease caused these organisms to physically waste-away — hence its name; sea star wasting disease.
Looming questions researchers are trying to answer include: Do environmental conditions trigger the disease? Will sea stars recover? Will other environmental stressors, such as ocean acidification, impact sea star recovery?
Working to help answer these questions is Jenna Sullivan, a PhD student at Oregon State University in Dr. Bruce Menge’s lab. Her research is integral to understanding population-level impacts resulting from sea star wasting disease and in helping understand another major marine issue — ocean acidification. ODFW’s Marine Reserves Program is helping to support Jenna’s research.
Jenna’s research includes working in and around the Cape Perpetua Marine Reserve. “The support provided by the Marine Reserves Program is integral to my continued ocean acidification research,” she explains. We are only in the infancy of understanding the impacts that changing ocean conditions—such as lower pH levels—have on marine organisms. Meanwhile, Jenna’s work is giving us a glimpse of how sea star populations are currently doing.
So, how are the sea stars doing?
“The stars are back! At most of the sites our lab monitors along the Oregon Coast — at Cape Perpetua, Cape Foulweather and Cape Blanco — sea star density is actually higher now than it was before sea star wasting disease hit,” explains Jenna. She explains that, “… if you go out on the intertidal rocks, you probably won’t see many unless you know where to look. The high population numbers are actually from a record number of baby sea stars in the intertidal.” Scientists refer to these small, baby sea stars as recruits. “Depending on the site, density of sea star recruits (those smaller than about the size of a penny) is between about 5 and 200 times higher than it was in 2014.”
Jenna cautions that, “we still aren’t sure what is driving this pattern, and recruitment is patchy across sites. We also don’t know how these new recruits will fare as they mature in the context of sea star wasting. Currently, symptoms of wasting are still present at all of our sites but at low percentages (mostly below 10%). We will keep tracking population and disease dynamics throughout the winter and hopefully follow this cohort of new recruits as they mature.”