The sea stars (starfish) along the Sonoma Coast have mostly died off from sea star wasting disease.
This sickness has killed off most of the sea stars in areas from Mexico into Canada. Modern epidemiologists have not been able to determine what is causing the die off.
Some specialists believe that sea star wasting disease is caused by two agents attacking the sea stars at once. It could be like AIDs, where a virus attacks and weakens the immunity of the individual, then a bacterial infection kills them off. Scientists believe that this disease is caused by a combination of a bacteria, a virus or pollution.
Molecular sampling of samples of sick sea stars is now being done at Cornell University under Professor Drew Harwell. Researchers are working to determine if the main cause of sea star wasting disease is a virus or a bacteria. There is no evidence that this disease is caused by radioactivity from the Fukushima nuclear plant.
The problem is that sea stars melt at lesions and fall apart. They can mostly die off in an area in just a few days. This wasting disease has been observed before but never in such a wide range, with so many different sea star species and individuals affected.
Why should this be of concern to the general public? Because sea stars are a keystone species. They have a disproportionate influence on other species and are important to the ecological balance of the rocky intertidal zone. They are voracious eaters, and they love shellfish. They keep the domineering mussels in check, which allows other species like barnacles and algae to survive, which in turn helps increase diversity.
Biologists fear a loss of diversity with the loss of sea stars. The strength of an ecosystem is much based on its diversity.
Sea star populations are being monitored up and down the coast. Their population changes are being determined using established scientific protocols, often with the help of local citizens. This sea star population data are being collected by UC Santa Cruz and Western Washington University, institutions in areas where this disease has been devastating.
The monitoring of the sea stars in Sonoma County is being done through the UC Davis Bodega Marine Lab. Sarah Gravem, a Ph.D candidate under Steve Morgan, is heading up this sea star research project. She has been measuring the population of sea stars for the last year with the help of volunteers.
She is also measuring the changes in the population of mussels and other organisms with which mussels compete. She expects that without sea stars, mussels will dominate the space and crowd out many other species.
Gravem is passionate about our ocean environment. She braves the low tides and waves at all hours (depending when the low tide happens to fall) and under cold and wet conditions to collect different sets of data on these species from the tide pools. This data then needs to be sorted and put into the computer. Bodega Marine Lab professionals volunteer to help her with this essential work in the lab. This research project is the labor of love and the knowledge of the importance of this sea star disease.
Meanwhile, there are now baby sea stars getting established on the Sonoma Coast as Gravem and her volunteers have determined in the tide pools. The hope is that these babies are disease resistant and will thrive and repopulate our rocky shores.