Starfish are Experiencing a Baby Boom

You may have heard about the disease which for the last couple of years was ‘melting’ away the north pacific starfish. The cause of this bad sci-fi plot started out as a mystery but scientist soon pinned the pathogen down to  a densovirus. However, it still is unclear what caused the virus to spike, although most theorize that it’s due to our recently abnormally warm waters in the Pacific.However, some of the data is contradictory, so it’s still uncertain to the rapid spread.

“But a few months later, the number of juveniles was off the charts — higher than we’d ever seen.” – Bruce Menge


So just what is a densovirus? Basically it’s a single-stranded DNA virus which infects crustaceans and insects. For sea-stars the virus causes lesions which in turn cause deformation and loss of limbs. Over time the starfish will disintegrate in a white mush.

Oddly enough, starfish on the west coast have been living with the virus for decades with no ill effects until recently with over 20 different species of starfish being affected with this latest terminal variant.

Starfish Baby Boom

The good news is that much higher than average number of juveniles have survived the 2015 summer and winter seasons. The Oregon coast currently has a thriving community of juvenile starfish (or sea stars), with some places seeing populations with as many as 300 times the typical number, researchers said.

“When we looked at the settlement of the larval sea stars on rocks in 2014 during the epidemic, it was the same or maybe even a bit lower than previous years,” study lead author Bruce Menge, a professor of marine biology at Oregon State University, said in a statement. “But a few months later, the number of juveniles was off the charts — higher than we’d ever seen.”

Along the Oregon coast there are areas with 300 time more juveniles than normal.


This high number doesn’t mean that west coast sea stars are out of the woods yet. Perhaps this generation had a high survival rate because there was more food available, the researchers said. After the wasting disease killed off the majority of adult starfish, the young sea stars would have had more mussels and barnacles to eat, the scientists said.

The disease could still make a come back and attack the juveniles but there is reason to be hopeful.


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