We were on the Oregon last summer. There on the beach of Brookings, the predatory starfish anchored at the lowest level of the rocks waiting for the tide to come back in. The rest of the rocks were heavily encrusted with mussels - millions upon millions of the them. There was also a red tide warning. Pity too, I would dearly loved to have had a bucket of those mussels, drenched in butter and lemon, and thick slices of garlic bread all washed down with a fine white wine.
Our family used to buy our clamming licenses every winter and we'd drive down to Long Beach early in the morning to dig our limit of razor clams. I can remember the sadness we experienced the first time we heard of a red tide warning. It really affected the whole western side of the state of Washington. Like our beaches had suddenly been rendered unclean. This was in the 1970's.
Red tide seems to be a more or less permanent fixture now during the warm months of the year. Starfish prey on shellfish and their food sources for shellfish have been under stress for decades. I recall reading that the phytoplankton responsible for algal bloom are responding to warmer water temperatures. Since the 70's the waters have become warmer still. I'm dubious that the starfish die-off started in the much colder coastal waters of Puget Sound and has worked its way down the coast, rather than from Mexico and California upward. I'd be more inclined to look at what has changed for the worse in the food chain from the starfish downward.