Wednesday, March 18, 2015

Star light, star blight

Santa Cruz, California tidepool--wikimedia

I happened to be looking at an old copy of one of our local weeklies, and so came across this distressing news. Apparently many of the sea stars (or starfish as we always called them) along the Pacific Coast are having a hard time of it, suffering a wasting disease, which has been mysterious for some time, but which there is now a hypothesis about. Scientists postulate that it may be a virus called a densovirus that is doing the damage. You can find a whole lot more about sea star wasting disease at this UCSC website.

The results for the poor sea stars are not pleasant, neither to experience nor behold. I'll spare you the intermediary details, but the end result, as Brendan D. Bane describes it in his Good Times article, is that the sea star "deliquesces into disorganized pulp". And, although die-offs have happened before, the scale of this one is unprecedented, with twenty sea star species affected so far and covering a range from Alaska to Mexico. We're talking millions of sea star remains here, people.

The article interested me for a couple of reasons. First, who doesn't like starfish or would wish them to come to harm? Well, unless you happen to be their prey, I guess, but even here, sea stars often are key to the health of a small ecosystem, culling creatures like mussels and sea urchins to keep their populations within sustainable limits.

An ochre sea star eating a mussel in Central California-Wikimedia

But a secondary reason came up at my book group last night, where people began talking about the health of the Monterey Bay, which apparently has dead zones where no living organisms exist, caused in part by poorly oxygenated waters being kicked up from the deeps. Niina Heikinnen reports in Scientific American's Climatewire that though there's long been awareness of the vulnerability of coral reefs, it's taken longer to understand the vulnerability of the Pacific Coast of North America.  My friends also brought up the starving seal pups that have been washing up in skyrocketing numbers this year in the Bay. Warmer waters mean that the parent seals have to go out to deeper waters for food, where the baby seals can't follow them. I know, I know--you wish I hadn't told you.

So the case of the wasting starfish seem less like an anomaly and more like part of a larger ominous trend. The densovirus has been found in seventy year old dried sea stars kept in museum cases--it can exist in apparently healthy sea stars, which act as a kind of host for it. But factors in the modern environment, like pollution, warming waters and so on may be making it harder for sea stars to fight off the virus.

The Monterey Bay still looks beautiful. But as with much in life, things can be quite different--under the surface.

"USA-Santa Cruz-Natural Bridges State Beach-4" by Eugene Zelenko-wikimedia


  1. Yes to both, Kathleen. I think sometimes the bigger perils are easier to grasp when we think of small living things.

  2. There does seem to be a hope that subsequent generations may develop a resistance to the virus, Nancy, and slowly repopulate.