Studying Sea Star Wasting

image of sea star

Massive-scale monitoring and research of the sea star wasting disease is happening along the West Coast because of collaborations between University scientists, state and federal agencies, non-profit organizations, school groups, and the general public.  These collaborative research and citizen efforts are essential for understanding the causes and consequences of the sea star wasting disease.


Sea star wasting syndrome has been impacting west coast populations of sea stars since summer 2013. Research by Cornell University scientitist Ian Hewson and a number of collaborators provides evidence for a link between a densovirus (SSaDV) and sea star wasting syndrome, but there is still much work to be done before this mysterious disease is fully understood.  Scientists are now working to understand the causes for this disease outbreak, such as possible environmental triggers like warmer waters. 

“Wasting Syndrome” is a general description of a set of symptoms that are found in sea stars.  Symptoms can progress rapidly- sometimes within days.  Lesions and tissue decay appear on the arms and body of the sea stars.  Eventually, parts can fall off (such as an arm separating from the body) and lead to death.  It’s important to recognize that these are also symptoms of unhealthy stars when they are in a stressful environment—such as being stranded too high in the intertidal on a hot day. The current outbreak along the West Coast is “true” wasting disease, meaning that sea stars have these extreme symptoms while in suitable “healthy” habitat.  


Effects can be devastating on sea star populations.  Two of the hardest hit species are also top predators, called “keystone species” in the rocky reef systems:  the ochre star “Pisaster ochraceus” and the sunflower star “Pycnopodia helianthoides”.   Ecological monitoring groups have documented Wasting in Pisaster ochraceus from Alaska through California; see interactive map at  Two common attributes for many of the sites are: (1) the period prior to Wasting was characterized by warm water temperatures, and (2) the effects are dramatic.  Some evidence from the few areas in California where we have both intertidal and subtidal survey data suggests that the effects of wasting syndrome may be more severe in the subtidal.


PISCO investigators are quantifying the extent of sea star wasting and ecological impacts, as part of our long-term ecosystem research program.  PISCO and the Multi-Agency Rocky Intertidal Network collaborate to track the progression of the sea star wasting syndrome.  Initially, much of the research effort focused on documenting the progression of sea star wasting along the West Coast of North America and across a range of sea star species. Now, we are assessing the ecological consequences from the loss of these species.  In particular, we are focusing efforts on understanding changes in ecological communities where sea stars have been affected and the population replenishment rates of young sea stars.

Get most recent updates at

Check out's podcast video, featuring PISCO investigator Pete Raimondi (UC Santa Cruz) talking about coast-wide efforts.


Because this wasting syndrome is so extensive along the West Coast, assistance from educational institutions, non-profit organizations, and other groups is critical to helping track the spread of the disease in the intertidal and subtidal.  These contributions:

  • provide essential data on areas that have not yet been surveyed to-date, or have been under-surveyed.
  • improve our ability to track the spread and impact of the syndrome on sea star populations and aid in documenting recovery. 

To get involved: