They aren’t pretty: Sea stars that look like acid was poured on them are clinging to rocks at the bottom of Howe Sound.
Sick starfish (or sea stars) are sadly a common sight for Jessica Schultz, research coordinator for the Howe Sound research program at the Vancouver Aquarium.
“It looks like the sea stars are melting,” Schultz said of the ones with sea star wasting syndrome, which is contributing to the reduction in sea stars in Howe Sound and along the coast of B.C.
“Basically they lose their body pressure so they kind of get a deflated look to them and they develop lesions, so their body wall ruptures and their organs start spilling out a little bit – it is quite gruesome,” she said. “At later stages they basically dissolve and turn into what looks like a pile of white bacterial goo.”
Schultz is looking at the disease’s impact on other marine life.
The disease first appeared in the sound between August 2013 and January 2014 and is still present today, though it is not as prevalent – “probably because a lot of the sea stars are gone,” Schultz said.
The disease hit about 20 of the more than 25 sea star species in the sound.
Schultz said it could be viral, but researchers don’t yet know the whole story. “Whether it is temperature or ocean acidification, no one is quite sure yet, there is no obvious pattern,” she said.
The disease is not isolated to Howe Sound. Sick sea stars have been seen from California all the way up the coast to Alaska, according to Schultz.
The sea star is important because of the impact it has on the rest of the marine ecosystem.
“A lot of sea stars are predators, so when they are suddenly gone, it can change other levels of the ecosystem,” Schultz said, adding she is focusing her research on invertebrates, while fellow Aquarium researcher Laura Borden is looking at how the lower number of sea stars impacts kelp.
Reseachers have noted an explosion in the number of sea urchins as the sea stars waste away. Normally the sunflower sea star eats urchins.
Sunflower stars are opportunistic eaters that will consume anything they can, according to Schultz, so a lower number of stars has an impact on much of the marine environment. For example, because urchins eat kelp, there has been a resultant drop in kelp, Schultz said.
Although some researchers have whispered about localized extinction of the sea star, Schultz believes it is too soon to draw that conclusion.
“We saw a huge number of juvenile sunflower stars last summer,” she said.
“I think they are still here and I think there is a huge chance that they’ll recover, but it is hard to say.”
Her study will be ongoing, and she expects to publish a report on her work in a few weeks.
