Oyster Blog — Tideflat Critters

Sea urchins are echinoderms, and are related to sea cucumbers and sea stars. They're covered in protective spines, use tube feet for locomotion, and normally feed on algae. Sea urchin gonads, known more appetizingly as uni, are a popular food in Japan. The little urchin above lived up to its name by stabbing Oyster Fan underneath her thumbnail, leaving a shard of its spine lodged in her cuticle. Cute. Technically, this urchin is a Stronglyocentrotus droebachiensis. But if that was too much gobbly-gook for you, just call it a green urchin. Below: a close up photo of a sea urchin...

Humming toadfish are also known as plainfish midshipmen, California canary fish, or bullheads. The fish are nocturnal, and bury themselves in sand during the day, unless they're manhandled for a photograph. During mating season, male toadfish contract their swim bladder muscles to produce a low, humming sound. Female toadfish, in turn, develop increased acoustic sensitivity during the mating season, and are attracted by the humming sound. The toadfish hum can last for up to an hour, and is loud enough to be heard by oyster pickers and other humans. Midshipman fish also have light-producing photophores, which they use to attract...

Hood Canal has had a tremendous barnacle set this year. The little guys are everywhere! Barnacles attach head first to rocks, shells, pilings, boats, buoys, etc. When the tide is in, their feathery legs, called cirri, sweep through the water for phytoplankton. Although they look like mollusks, barnacles are actually crustaceans, like shrimp and crab. They spend their infancy as free-swimmers and molt several times during their lives, which is why you occasionally find free-floating barnacle drifting through the water. When they're safely in their home they're very sharp, and count as the number one reason why you should always...

Mystery solved! And it wasn't actually that great a mystery. The egg cases below were laid by a drill snail, a voracious oyster predator. The beautiful orange drill snail in the middle of the photo is native to the Pacific Northwest... the two drab-looking snails on either side of it are non-native Japanese drill snails. Here's a better photo of Japanese drills. On an unrelated note: normally, after four or five hours of work on the beach—bent over at the waist in blinding summer sun or soaking winter rain—even the most ardent tideflat fan is happy to call it quits....

Pictured here is the Eccentric Sand Dollar, Dendraster excentricus, also known as the Pacific or West Coast sand dollar. The name 'eccentric' sounds intriguing...and makes you want to hang out with the scientist who came up with it...until you learn that it just refers to the fact that these little guys have an 'off-center' pattern. Sand dollars are echinoderms and in the same phylum as sea stars and sea cucumbers. Like sea stars, they have 5-part radial symmetry. They're covered in tube feet, which give the live animals a beautiful purple color. Tube feet and cilia on the bottom direct...