In the summer of 2013, a Sea Star was reported with a strange appearance. It was identified as a Star with Sea Star Wasting Syndrome (also known as SSWS). SSWS was not a new occurance, as die-offs had been observed in the 70s, 80s and 90s. However, these die-offs were very localized. Noone realized that this 2013 observation would be the start of the wide-spread Sea Star die-off across the west coast from Alaska to Baja California. This die-off would hit all species of Sea Stars; impacting Ochre Stars (Pisaster ochraceus) and Sunflower Stars (Pycnopodia helianthoides) the hardest.
Hearing about the spread of the SSWS, Feiro Volunteers began to collect Sea Star data, partnered with the long term Intertidal studies by UCSC MaRINe. Thanks to the volunteers quick organizing, Feiro has a database of counted Sea Stars dating back to the end of the year 2013 for Freshwater Bay. We can see that in May of 2014, the volunteers counted 120 Ochre Stars and 7 Sunflower Stars. However, signs of wasting were also being documented and by July of 2014 there would only be 20 Ochre Stars counted, with 9 of those stars showing SSWS symptoms and only 1 diseased Sunflower sighted. The rest of 2014 would continue with low sighting numbers and lots of sick sea stars.
The Freshwater Bay Sea Star surveys continued, with volunteers gathering to count all the stars they could find and measure the arm lengths of Ochre Stars spotted. While numbers remained low, there were some hopeful moments. By the summer of 2015, sick Ochre Stars were minimal. May of 2018 spotted the first healthy Sunflower Star surveyed since the die-off. And in 2023, over 40 Ochre Stars were surveyed along with 3 Sunflower Stars (our highest count yet).
With the excitement of counting so many Ochre Stars, volunteers have also started commenting on the color of Stars being spotted. This year, 2025, we have begun to document the color-morph of the Ochre Stars being surveyed. Ochre Stars can vary in color from Orange, Purple or Brown/Maroon. This data will allow us to monitor the color-morph trend of the recovering sea stars. This year, over 50% of the Ochre Stars surveyed were the purple color-morph.
The cause of why this SSWS die-off was so wide spread is still a bit of a mystery. An initial study hypothesized a relation with a Densovirus, but further study ruled this out. Another study found that an increase in organic matter led to an increase in microbial activity. This was linked to a potential decrease in oxygen for the sea stars. This continues to be studied along with how the warm blob located off the coast may have contributed to the spread.
Feiro continues to report our Sea Star survey numbers to UCSC MaRINe program, and partner with a long-term intertidal survey which allows their biologist to interpret the changes to the Freshwater Bay community resulting from the decline in Sea Stars, as well as document the recovery. Anyone can contribute to this data, including you. Next time you are out tidepooling, beachcombing or snorkeling/scuba diving, take note of how many Stars you are seeing (visit Feiro for practice learning how to identify the different species) and you can submit an observation https://marine.ucsc.edu/data-products/sea-star-wasting/index.html The more eyes making observations, the better the data will be because biologists can’t be everywhere at once.
