After a Huge Die-Off, Oregon's Sea Stars Are Coming Back

Sea stars, which you rubes probably call "starfish," are one of the coolest things a person will see while tide pooling on the Oregon Coast.

At least, they were, before sea-star wasting disease.

In 2014, when the disease hit Oregon, Oregon State University's school of science wrote that the ochre sea star, also called the purple sea star, "may be headed toward localized extinction in Oregon," with an estimated 30-50 percent of the Oregon population afflicted with the somewhat mysterious disease.

The cause of the wasting disease has been linked to a virus and/or warming ocean temperatures.

"Sea star wasting syndrome is a traumatic process in which, over the course of a week or less, the sea stars begin to lose legs, disintegrate, ultimately die and rot," according to the OSU report. "They sometimes physically tear their bodies apart."

Basically, it's the most horrifying sea star death you can imagine.

But now, PBS Newshour reports, the ochre sea star is coming back in a major way.

Dr. Bruce Menge, a researcher at Oregon State's Lubchenco/Menge Lab, has been conducting surveys of the juvenile population of sea stars around Oregon since April of 2014.

"Menge's team found that sea star wasting cut the juvenile and adult population of purple sea stars by up to 80 percent by the end of 2014," write Newshour. "But then the tides turned."

In some areas, the baby sea star numbers have increased by up to 300 times relative to the previous year.

So, does this mean the wasting disease is over? Well, no. Because as the population of babies booms, adults are still dying from the disease up and down the coast. "If the disease catches hold in the younglings once they mature into adults," writes Newshour, "then the mass die-off may repeat itself."

The sea star population affects an entire ocean ecosystem. The sea stars are predators of sea urchins, and with the stars in decline the urchins have been allowed to overpopulate.

In Washington, a different species, the sunflower sea star, is nearly gone and the sea urchin population has exploded as a result. Sea urchins devour "enormous amounts of algae and mow down kelp forests," according to Newshour.

"If the kelp forest is diminished because of urchins, which may be enhanced because of [sunflower sea star] loss, you'd have a truly fundamental shift in a lot of things, including the fish community," says Pete Raimondi of the University of California Santa Cruz.

But Raimondi doesn't think it's time to totally freak out about the end of sea stars and the total annihilation of the tide pool ecosystem.

It's difficult to monitor sea star populations and it's possible that this die-out is part of the standard ebb and flow of populations. "So it's not to say that things are not going to recover," he says. "In my opinion, they will."

Willamette Week