There is actually a story behind this one. A few years ago my Wife and I were walking the Stanley Park seawall and just west of Siwash rock noticed that the tidal rocks were almost completely covered with purple sea stars. This is a very common species in our local waters. There were tens of thousands of them. They completely covered the rocks.
In the last couple of years there has been a huge die-off of Sea Stars on the west coast of North America. It appears to be caused by a virus. There have been other die-offs that may or may not be related and I’ve also read that it may be a virus that is present in all Sea Stars but has become lethal lately for some reason. Research is ongoing. I’ve read estimates of the die-off between 80% to 98%.