Can't see me, I'm disguised.

The camouflage fails when the seaweed is wet and the crab is not.

Kelp crab, Pugettia producta.

But he's wearing a sea lettuce hat. That should help to disguise him, right?

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El camuflage no funciona cuando el alga está mojada y el cangrejo no lo está.

Foto: un cangrejo "kelp", Pugettia producta.

Pero lleva un sombrerito hecho de lechuga marina. Eso le servirá de disfraz, ¿no?

Messy crab, with a hat.

Three weeks ago, wading in the eelgrass beds at the bottom of the tidal plain, I saw hundreds of egg masses, pink and yellow, and their parents, opalescent nudibranchs and bubble shells. A couple of days ago, the tide was even lower, and I spent two hours making figure-eights in the same area. And there were no pink and yellow eggs, no nudibranchs, few bubble shells.

Everything has its own season.

This week, the beds are full of blue anemones, sea stars, and crabs. Unusual crabs: crabs I'd never seen before.

For example, this little guy.

He's less than an inch across.

He is completely covered in algae or diatom fuzz, and is wearing a comparatively huge barnacle on his back. Good for camouflage; not so good for the purpose of identification.

The carapace is triangular, with a long cap protecting his head area. It's hard to tell if it's smooth or bumpy, but the edges are wavy, rather than toothed like the shore crabs' carapaces, or sharp, like the kelp crabs. His pincers are bluish*, with orange tips; the legs are also tipped with orange.

I've been examining the photos in the Encyclopedia with a lens, trying to find a match. The closest I can find is the sharpnose crab, Scyra acutifrons, which grows to just under 2 inches across. Adult males have long pincers, but the females are similar to this one. Or maybe he's a juvenile decorator crab, Loxorhynchus crispatus. These grow to about 5 inches across the carapace.

Both these crabs "decorate" their shells, adding algae, anemones, barnacles, diatoms, what have you. And in both species, the males have long pincers, while the females' pincers are about the length of the legs.

Here he is upside-down, and struggling to right himself. From here, he looks like a male, with the narrow plate on the abdomen.

Here's how I saw him at first, under a foot of water:

Under the water, the diatom fuzz is more apparent. His pincers are definitely blue. His eyes look blue, too.

Do you recognize this crab? Can you help with the ID?

*The blue coloring could also be because he is young, and his skin is semi-transparent, so the blue blood shows through.

Rainy day crab watching

All day Sunday it rained, sometimes in buckets. That's three solid days, much appreciated. And a good time to stay inside and watch my crabs.

Just crabs

"Patch"

These shore crabs are babies still, some so small I hadn't even seen them until this week. I have discovered some, long ago, as small as a sand grain, unseen until they scuttled sideways in an entirely un-sandlike way. The largest of the half-dozen in the aquarium now, Patch, is maybe half an inch across the carapace.

Small or not, they are feisty. Often they sit by the glass, watching me as I watch them. If I aim a finger their way, they lift warning claws; "I'm going to pinch you!"

Patch was by the glass wall, facing me, as usual. But when I approached him, he made no move. Even a finger on the glass by his face made no impression. Odd.

Three hours later, I stopped by again. Now he had his back to the glass, and lying beside him was his old molted shell. No wonder he wasn't interested in anything else; he had urgent business to attend to. The shell was an obvious size smaller than he is now.

I lightened up the photo to make him more visible. Even so, his camouflage is perfect against the sand. Once he'd hardened up, he buried himself so that only his eyes - two sand grains among thousands - showed up.

(The lines at the bottom of the photo in the sand against the glass are worm tunnels. There are at least two different species of worms there, still only visible with a lens. They'll grow.)

A smaller cousin, with his latest building project

Even the tiniest of the crabs, a white-topped cutie about an eighth of an inch across, is a hard worker. Mostly, they're digging new quarters under stones or shells. I watch them backing down the holes, then crawling back up, pushing a load of sand with their pincers. (Tiny Tim - "TT" - moves a grain or two of sand at a time.) The pile is pushed up and far enough away so it won't slide back, and the crab goes back for the next load. Sometimes they surface carrying a stone or a shell in both pincers. Once I saw a crab carry up a snail larger than himself, holding it high overhead until he was on neutral territory, then giving it a good toss. "And stay out!"

In the photo above, the green crab is clearing out a burrow under the stone on the left. The oyster shell on the right is half-buried in the sand, standing on edge, narrow rim upwards. The crab somehow lifted that big white whelk shell up and balanced it between the rock and the rim of the oyster shell. Quite a feat, I thought, and went for the camera.

And when I got back, he had added those two stones, the pink one and the white one, also on the rim. I have no idea how he did it without tipping the whole arrangement onto the ground. He has a steadier hand than I, that's for sure!

Hermit crabs and "True" crabs

Hermit crabs are social beings. They rarely fight, except briefly over some exceptionally prized snack; they climb over each other, take rides on each others' shells, discuss shell economics peacefully, even between different species. And, like human teens, when one gets a new outfit, it starts a general rush.

It works like this: Jim's shell is a bit too tight; he's been growing. So he convinces Sally to pass down hers. She's willing, but then she needs a new outfit. She asks Tom and Pete for theirs; no, they're not ready. She finds a suitable empty and puts it on. But Tom and Pete now begin to notice how their shells are tight, or scratchy, or the wrong shape, and off they go to find someone willing to share. The idea snowballs, until hermits are queueing up; as each one takes the latest one available, the next hermit in line grabs his cast-off. And so it goes until they're all satisfied.

I happened to watch a threesome sorting out shells. It went fine until two were fitted, but the largest was stuck with a shell too small, so she went off with a bare belly, looking for a bigger suit. It's an urgent search, that usually goes off without a hitch. But the hermit is vulnerable in this state; all her weapons are in front, and the back end is tender and appetizing to fish, gulls and other birds, eels and octopuses. And crabs.

When I went back to check, the naked hermit was stranded up a blade of eelgrass, with a big shore crab at the bottom. She dodged back and forth and eventually managed to drop off onto a rock behind the crab. Safe for now.

I came to look later, and after a search, found her. The big crab had her in his pincers; he'd eaten her belly already. She wasn't moving.

I don't know why this makes me sad and annoyed at the crab; I find no problem with anemones eating copepods, or hermits emptying out barnacles. Or, outside my door, robins and worms, spiders and assorted flies. Maybe it's because of the face contact with hermits and crabs; they seem to be connecting with me, at least noticing me and responding.

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Wandering around the web, I discovered another intriguing fact about hermit crabs. I'll post about it as soon as I've read up on it.

Turning over stones

Summer has come (when? I must have missed it) and gone. The geese are on the move again, and the nights are cold. Yesterday the clouds threatened rain. We went to Boundary Bay anyhow, in hopes that the sun would be shining there. It was. For a while.

High tide

Is this a snake, lizard or log?

Another snake-ish piece of driftwood

The tide was almost at its peak, leaving us a thin strip of beach, mostly rocky, to walk along. We poked among the stones, searching for crabs. The small grey crabs on the northern end of this beach are shy creatures; they scuttle for shelter as soon as the light hits them. Here, towards the southern tip, some hide; but last time I was here, I found green crabs that stand their ground and offer battle, waving their pincers menacingly. I poked at one with a fingertip, and it grabbed and held on. I lost that round.

The next time, I used an edge of a clamshell; the tiny, half-inch crab was more than willing to attack it over and over again.

I dare you!

On guard

I found other crabs this time, small, thoroughly camouflaged ones. They neither ran for shelter not waved pincers. They didn't need to.

Blending in

We passed a long stretch of lugworm egg cases, (Here, and here.) interspersed with coiled piles of fecal castings, tiny and large. Among the far-too-plentiful invasive battilaria snails, I was pleased to discover a few miniature, fatter ones, probably native to the area.

And, turning over barnacled rocks to see if I could get a good look at something that twisted and flashed out of sight, I found a pair of these:

I don't know what they are. This is the large one, and the white piles beside it are small barnacles. They were both soft to touch, and shrunk away from my finger, just a bit. The jelly-like flesh is transparent, brown, with greenish stripes inside the gel, not on the surface. The creamy top disappeared inside after I had touched it. They both had tiny bits of sand glued to their skin, shining like jewels in the sunshine. (Click on the photo to get the full effect.)

They look to me like anenomes, closed in for low tide. * But they are in the wrong place, on rocks just at the high tide line. And I have never seen an anenome so small, nor alone like these two were.

So I've got another week of Googling and reading and leafing through indexes to do. Any hints would be greatly appreciated.

It was getting close to supper-time. We turned back.

It was raining when we got to the car.

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* Update: Hugh Griffiths identified them for me in the comments; they are Diadumene lineata, reported in the Exotic Species Guide (San Francisco). Thanks Hugh!

Hiding in Plain Sight, continued

Continued from yesterday: a walk along Boundary Bay.

I am still learning the ropes with this digital camera. So my focus on this walk along the shore was on seeing what it would do outside, in bright sunlight. I snapped wildly as we went along, at anything and everything, from scenery to the little puddles left by the tide. Even this, which I think is a roller from an ancient wringer washer.

The beach was almost deserted, the tide well out. Not a seagull in sight. And this area was mostly bare of eelgrass. Nothing to see, really, but sand and sky. I turned over a stone with my toe, and tiny crabs scuttled away from the sudden light, buried themselves in the sand again. I investigated a few more puddles and saw movements, something tiny and pale, visible for only a moment. Bending down low, I could see pinkish shrimp-like creatures, almost transparent. I took photos, without much hope of getting anything through the reflecting surface of the water.

Farther on, I found a light-coloured snail and practiced on it.

At home, I blew up my photos and looked them over. I got the shrimp! Yay!

Pale and blurry they may be, but still; I can see their little eyes and the curve of the body. Encouraging.


And that snail? He had company. There is a crab beside him that I hadn't even noticed, looking straight at it on the beach, possibly because he's wearing camouflage colours. And barnacles, and limpets in several colours, another snail. Going back to the "shrimp" photo, I realized I was also seeing something that looks like a white tube with tentacles on the end; some kind of a worm. And something starfish-purple.

Click on the photos to see them full size. For comparison, the snail is about a centimetre ( almost half an inch) long, the "shrimp" about half that.

I brought home a handful of dead eel-grass from the high-tide line, and a bit of plain sand. Looking at it through my hand microscope (40x), I discovered that it was full of worms, some large enough to see segments, the intestines and a whip-like tail, some so small that they seemed barely more than a lively thread.

Nothing to see but sand? I will never say that again.

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Checking the blogs yesterday, I ran across a photo posted by GrrlScientist, submitted by an underwater photo site, of a Leafy Sea Dragon. Absolutely stunning! And what an example of camouflage! (Copyrighted: you'll have to click on the link to see it.)

Jeff writes,

"Sea Dragons are arguably the most spectacular and mysterious of all ocean fish. Though close relatives of sea horses, sea dragons have larger bodies and leaf-like appendages which enable them to hide among floating seaweed or kelp beds. ...

...Leafy Sea Dragons are very interesting to watch-- the leafy appendages are not used for movement. The body of a sea dragon scarcely appears to move at all. Steering and turning is through movement of tiny, translucent fins along the sides of the head (pectoral fins, visible above) and propulsion derives from the dorsal fins (along the spine). Their movement is as though an invisible hand were helping, causing them to glide and tumble in peculiar but graceful patterns in slow-motion. This movement appears to mimic the swaying movements of the seaweed and kelp. Only close observation reveals movement of an eye or tiny fins."

He has many more photos; beautiful, all of them. Go over and browse.

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Next: eagles, same day.