Extreme heat cooks shellfish alive on Puget Sound beaches

A record-shattering heat wave June 26-28 coincided with some of the year's lowest tides on Puget Sound. The combination was lethal for millions of mussels, clams, oysters, sand dollars, barnacles, sea stars, moon snails, and other tideland creatures exposed to three afternoons of intense heat.

A shellfish farmer on Little Skookum Inlet in south Puget Sound reported the muddy sand on his beach reaching 135 degrees.

“It was a Murphy’s Law of extreme heat and the lowest tides of the year at the same time,” said Megan Dethier, the University of Washington Friday Harbor Laboratories director.

“This was so far above normal,” she said. “The fact that it’s killing mussels, which are some of the toughest creatures around, is really striking.”