Oyster Blog — Tideflat Critters

Chitons are ubiquitous on the beach. We believe the one pictured below is a woody chiton, or Mopalia lignosa. (It may also be a mossy chiton, visit this site if you care about the differences between the two.) Species in the genus Mopalia differ from other chitons in that they eat both animal and vegetable material and are covered in bristly hairs. But even though the woody chiton is capable of eating meat, it still feeds primarily on sea lettuce. Like other chitons, its body is protected by eight overlapping calcareous shell plates, which look like a knight's armor, and...

During last week's geoduck dig Nathan found this horse mussel sticking straight up out of the sand. There are a lot of horse mussels on the beach, but because they live out deep you only see them on really low tides. They're much bigger than the ubiquitous blue mussels: this one was about 5 inches long and they can grow as large as 9 inches long. Like other species of mussel, the horse mussel attaches itself to firm substrates using byssal threads. A horse mussel's periostracum (or thin, outer layer) is covered with long, soft bristles. We have no idea...

A red algal bloom started last week near Hoodsport, and slowly worked its way north. Today it hit the beaches at Hama Hama. Ever since the bloom started we've been getting calls from people concerned about red tide. The water is indeed red, and especially so when all the algae concentrates in still water on an incoming tide, as above. But it's not the scary "red tide" -- this algae doesn't hurt shellfish or the people who eat them. And it's not necessarily a harmful algal bloom (or HAB, the term that's replacing 'red tide' in the scientific parlance), although...

Trifecta! A Pacific oyster, a blood oyster (see earlier post), and a kumamoto. Like the Pacific, the kumamoto oyster (Crassostrea sikamea) originally hails from Japan. Some people think the kumo is a variety of Pacific (Crassostrea gigas) that evolved in isolated bays and estuaries. Kumos can't reproduce in Puget Sound or Hood Canal because the water is too cold, so the only way to grow them in these climes  is to buy seed from an oyster hatchery. In the late 60s, when oyster aquaculture was in its infancy, scientists tried to create an oyster that would grow as fast as...