Monday, May 14, 2012

Spring Low Tides

The Spring low tides of the past month along with excellent weather have made beach exploration excellent.

Spotted Aglaja Aglaja ocelligera (Spotted Bubble Shell)
Predator on other bubble shell snails - has not radula and simply inhales victims

Shaggy Mouse Nudibranch - Aeolidia papillosa
Egg laying...any season
Feeds on anemones, sequesters both stinging cells and algal cells from anemone for own use in defense and also to add some solar power

Graceful Cancer Crab Cancer gracilis
With eggs

Graceful Cancer Crab Cancer gracilis
With eggs

Black Bubble Shell Snail Melanochlamys diomedea
Laying eggs
Feeds on nematode worms and is prey of Spotted Aglaja

Fish Eggs on Red Seaweed, likely Sculpin Eggs

Mottled Anemone (Painted Anemone) Urticina crassicornis

Sunflower Star Pycnopodia helianthoides

Sea Stars on piling under ferry dock

Rough Piddock Clam Zirfaea pilsbyri
having fallen out of burrow undercut by water movement

Red Rock Crab feeding on Helmet Crab

Sea Pen Ptilosarcus gurneyi
Under ferry dock
member of octocorals - eight tentacles on each polyp
Withdraws into sand when not feeding
Produces blue-green light when stroked
Feeds on plankton and is prey of Striped Sea Slug and other sea slugs

Jointed Three Section Tube Worm (bamboo tube worm)
Spiochaetopterus costarum
palps extending from tube remove waste from tube
feeds using cilia to produce water current and captures food with mucus balls

SpinyPink Scallop Chlamys hastata
Sponge grown on top of shell help protect scallop from suction using predators
has well developed eyes

Fifteen Scaled Worm Harmothoe imbricata
Often found in tubes of other worms
Female broods eggs beneath her scales until young are capable of swimming away
Ambush predator on other invertebrates

Leather Star Dermasterias imbricata
Feeds on anemones and other inverts
has smell of burnt gunpowder

Geoduck Clam

Pigeon Gullimot
only Alcid that nests in Puget Sound proper

Sea Lemon (unidentified species)  Dorid nudibranch that feeds on sponges

Sea Pen (see above)

Hairy Hermit Crab molting

Horse Clam

Spinynose Sculpin Asemichthys taylori
Common on Seattle beaches but often mistaken for Tidepool Sculpin
this sculpin has 1 to 4 rows of scales above lateral line, whereas Tidepool Sculpin has no scales

Slimy Snailfish  Liparis mucosus
Uncommon visitor to Seattle beaches, generally subtidal
Little known of natural histroy

Friday, May 11, 2012


Moonsnails, a quite large, carnivorous snail found locally, Apparently, they are great in chowder, but not so much pan fried. I was on the beach with some fabulous Beach Naturalists and a couple of questions arose: 1) how do they eat?  2) how do they move--like, what good is all of that slimy stuff? I will work on the eating part in this post.

Moonsnails eat all types of clams but they demonstrate a strong preference for our native littleneck clams. These clams live several inches down in the sand, and the moonsnail has become very efficient at digging for them.  First it thrusts part of its big, slimy foot into the sand, inflates the "anchor" with water, then pulls itself into the sand.  It keeps doing this until it reaches the clam, then armageddon ensues, at least for the clam.

Upon reaching the clam, the moonsail enfolds the clam in its foot, manipulating the clam as needed.  Moonsnails get at the clam in a couple of different ways:  drilling or creating a gap

To drill, the moonsnail manipulates the clam so that its hinged side is close to the snail's mouth.  Once the clam is in position, the moonsnail uses an "accessory boring organ" that exudes carbonic anydrate (acid) to soften the shell so that the moonsnail's raspy tongue can drill a hole in the shell and the clam can be eatedn from the inside out.  There is mention of a frankenstein-ish approach wherein the moonsnail sucks the clam out through its own siphon, but just a mention.

Drilling is a lot of work, however.  It's much easier if the moonsnail just wraps its foot around the clam, encases it in foot mucus, and then waits for the clam to suffocate, thereby crating a "gap" in the shell through which the moonsnail can enter.  Researchers who actually study this stuff (kinda like watching grass grow) report that it is not unusual for a moonsnail not to drill, but to suffocate.  Even better if a gaper clam has been chosen for dinner--the gap gives the moonsnail a natural "in" whereby it can simply insert its radula and begin hacking away at the clam--no suffocation needed.

Contributed by Gretchen Frankenstein