Tuesday, June 1, 2010

No iPod, but lots of isoPods

Memorial Day weekend brought gray skies and extra-low tides to the Puget Sound area. The conditions were excellent for beachcombing at Carkeek Park--foul weather kept crowds at bay, and the low tides revealed all sorts of squishy, squashy, scuttling, and secretive seashore creatures.

Ochre sea stars in neon orange and purple clung to the undersides of rocks amid a welter of barnacles and mussels. Also nestled among the rocks were a multitude of green anemones and what looked to be a painted urticina (a red and green anemone that can live for up to 60 years). A red-orange blob of what might have been a reclusive octopus lurked deep inside a crevice. If you stood close to a big rock, you could hear the clicks and whispers of barnacles scrabbling inside their shells.

Life in the tidal zone is packed tighter than a subway car at rush hour. The first photo shows a limpet, which clings to a rock; tiny barnacles, in turn, cling to the limpet.

I especially liked the teeming zoo I found under a looseleaf-sized thin slab of red slate. It was dense with tiny mussels, hermit crabs the size of peas, and weird worms that I think were sand or pile worms. (A field guide suggested gently pressing the worm behind its head to cause it to evert its "sharp black pincers," a suggestion I found it easy to ignore.)

The best critter hidden under the slab was a rockweed isopod, a marine cousin of the pill bug and the sow bug (those little gray army-tank minibeasts that live in your yard and are sometimes called roly-polies or potato bugs). This one, as you can see, was bright olive green.

Apparently the isopod wears this color most frequently but can also be black, pink, or tan, depending on what color its background is. It's also called Vosnesensky's isopod. Which is a lot of name for a little guy like this to tote around, even if it can grow to be 2 inches long.

Vosnesensky was some Russian guy who studied marine isopods on the west coast in the mid-1800s. And he got to have one named after him. Some people have all the luck.

Apparently there is a similar species in the southern regions of the coast that looks much the same but has "round eyes instead of kidney-shaped" ones. Remember that if you ever go eye to eye with an isopod.

The birds were out in force, too. Crows poked and probed at the rocks, as did gulls, feasting on the bounty laid out by the extra-low tide. A bald eagle circled over the beach. The song of a Swainson's thrush spiraled up from the woods, and this cheerful song sparrow piped away in a shrub near the entrance to the beach.