In April 2014, Oregon began to experience a massive die-off of sea stars (Pisaster ochraceus) in near-shore environments. The cause of the depletion was named Sea Star Wasting Disease. This affliction was characterized by twisting arms, then deflation and/or lesions, lost arms, losing grip on substrate, and finally disintegration. A proximate cause of wasting was likely the “Sea Star associated Densovirus”, but the ultimate factors triggering the epidemic, if any, remain unclear. Although warm temperature has been proposed as a possible trigger, Sea Star Wasting Disease in Oregon populations increased with cool temperatures.



It is estimated that the adult population of purple sea stars had been depleted by up to 80 percent by the end of 2014, leading to a dramatic disruption of the balance of predator and prey species in Oregon's rocky intertidal habitats. However, in fall 2015, researchers began to see an explosion of new juvenile sea stars along the coast, suggesting that the species was recovering.

For the latest information on sea star wasting disease, visit

A 2016 journal article by researchers at Oregon State University documented the progression of sea star wasting in Oregon, the potential ecological consequences, and the beginning of population recovery, Click here to read the article.

The Oregon Marine Reserves program conducts intertidal monitoring, which includes surveys of sea star wasting and recovery.