Text by Victoria Schlesinger; images by Jane Kim.
SPOTLIGHT SPECIES: OCHRE SEA STAR
Arm days
Perhaps this spring you’ll make it to the coast and find yourself calmed by the waves cresting and crashing ashore, a drama that repeats and repeats. But consider the sea star: relentless pounding as a way of life—not so tranquil. Scientists have examined how ochre sea stars (Pisaster ochraceus) nonetheless hold on. As one of the largest rocky intertidal species, they take an outsize beating. One study found that the stars changed shape over three months in response to their exposure to waves. The greater the waves’ velocity, the more slender and lighter-weight the star’s arms become. The thinking goes that a wave’s lift and drag lessens with this arm size. A skinny-armed pisaster is telling you something about the waves on that bit of coast.
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