The effects that diet, salinity and temperature contribute to Seastar Wasting Disease in Pycnopodia helianthoides and field surveying Pisaster ochraceus

Abstract

This study investigated Seastar Wasting Disease (SWD) in both Pycnopodia helianthoides and Pisaster ochraceus, involving field surveying, diet, temperature and salinity experiments. SWD describes a set of symptoms that has been seen in sea stars and it is most easily recognized by the presence of white lesions, tissue deterioration and eventually death. The pathogen and disease mechanism is still poorly understood and there have been scattered incidences of SWD reported for the last 50 years, however the current epizooitic has persisted for nearly a year, and has afflicted sea stars on over 3000 miles of coastline. Our study showed that increasing water temperature and decreasing salinity both independently correlate with increasing rates of symptoms appearing on Pycnopodia helianthoides. Field surveying of Pisaster displayed a strong correlation between temperature at the field site and percentage of sea stars showing lesions. Prevalence of SWD increases with seasonally warming temperatures and it is imperative to explore the mechanisms of this relationship and what ecological implications this entails.