Between 2013 and 2015, the US Pacific Northwest and western Canada experienced a mass mortality of sea stars. The Sunflower Star (Pycnopodia helianthoides), a previously abundant predator, began to show signs of a wasting syndrome in early September 2013, and dense aggregations disappeared from many sites in a matter of weeks. REEF surveyors certainly noticed, and the decline was reflected in the REEF database. The authors of a new publication just out in the journal PeerJ used the REEF database to document the decline at a regional scale. In addition to the dramatic decline in Sunflower Stars, they found a four-fold increase in the number of Green Sea Urchins (Strongylocentrotus droebachiensis). The sea urchin increase also resulted in declines in kelp canopy coverage. This type of ecological change, where a change in one species impacts many others, is known as a trophic cascade. Because of the long-term and wide-spread nature of the REEF survey program, our data have proven invaluable in documenting the impacts of the seastar wasting disease. The study was conducted by Jessica Schultz, Ryan Cloutier, and Isabelle M. Côté from Simon Fraser University and the Vancouver Aquarium. Visit www.REEF.org/db/publications to see this and all of the 60+ scientific publications that have included REEF Volunteer Fish Survey Project data.
