Here's a link with the actual science on the subject: http://www.eeb.ucsc.edu/pacificrockyintertidal/data-products/sea-star-wasting/
The first paragraph at the link:
Sea star wasting disease is a general description of a set of symptoms that are found in sea stars. Typically, lesions appear in the ectoderm followed by decay of tissue surrounding the lesions, which leads to eventual fragmentation of the body and death. A deflated appearance can precede other morphological signs of the disease. All of these symptoms are also associated with ordinary attributes of unhealthy stars and can arise when an individual is stranded too high in the intertidal zone (for example) and simply desiccates. True wasting disease will be present in individuals that are found in suitable habitat, often in the midst of other individuals that might also be affected. The progression of wasting disease can be rapid, leading to death within a few days, and its effects can be devastating on sea star populations. The proximal cause of the disease, when pathological studies have been done, is typically a bacterium (vibrio), although a recent wasting event on the east coast of the United States has been attributed to a virus. The ultimate cause is not clear although such events are often associated with warmer than typical water temperatures as was the case for the major die off in southern California in 1983-1984 and again (on a lesser scale) in 1997-98. Following the 1983-1984 event, the ochre star, Pisaster ochraceus, was virtually absent along southern California shorelines for years.
That won't stop people from falsely claiming a link to Fukushima.