SCOTT SIMON, HOST:
A startling event's taking place in the Pacific Northwest. Starfish are melting. They're victims of what's called wasting disease. It has killed 25 percent of the starfish populations in certain areas since 2013. The starfish literally appear to melt until their arms fall off. Researchers at Cornell University dove into the mystery and discovered what they believe is the virus. We're joined now by Drew Harvell who's a member of that Cornell team.
Thanks very much for being with us.
DREW HARVELL: Yeah, thanks for having me, Scott.
SIMON: This sounds awfully ugly.
HARVELL: Well, it's been ugly. It's been a really tough year and it's been the kind of event we've never seen before.
SIMON: Yeah and starfish of course are extraordinary animals, but I don't even want to speak as if the damage is limited to starfish, is it? They're part of a whole system that gets damaged.
HARVELL: Well, sort of the term keystone predator was coined for this particular species of ochre star and changing its abundance will cause ramifications through the whole food chain.
SIMON: Changing its abundance is Ph.D.-speak for dying, isn't it?
HARVELL: Yeah (laughter), right - dying by the millions and that's not even the most of it. The most of it is there's over 20 species that are affected.
SIMON: Are urchins, for example?
HARVELL: The urchins are likely to respond by increasing hugely with the removal of all these stars, which would normally be eating them so...
SIMON: And that has ramifications too, doesn't it?
HARVELL: Well, it sure does. It's what we call a trophic cascade, when you take away the really big top predator and that allows the herbivores to increase out of control and mow down all the algae in the kelp forests. We don't know that's what will happen, but it is certainly one of the hypotheses we're watching for.
SIMON: Do warmer ocean temperatures contribute to this?
HARVELL: Well, we think climate change or this warming exacerbates it or makes it worse. We have evidence from lab experiments that stars kept at warmer temperatures died sooner and at our field sites in the San Juan Islands the warmer sites had much higher mortality rates, so even though temperature didn't probably trigger the beginning of the outbreak in 2013, it made a lot worse.
SIMON: Sounds as if the beaches are going to be lonelier.
HARVELL: You know, the beaches are going to be lonelier. I was kayaking this summer on Vancouver Island and the full rainbow of ochre stars were there. They were purple and orange and yellow, and thousands of them - and they're not there now so it does feel lonely.
SIMON: Drew Harvell is a researcher at Cornell University.
Thanks so much for being with us.
HARVELL: Well, thanks for having me, Scott. Transcript provided by NPR, Copyright NPR.