Using all three eyes

The camera sees more - and less - than my eyes do. Flipping rocks along the shore, left-handed, with the camera in the right hand, finger on the shutter button, I disturb crabs, who scuttle quickly under the next-door stone. Flip another; crabs. Another; more crabs. One stops to threaten me, pincers raised. "Come on, see if you dare!" I turn the camera in her direction, and she changes her mind and joins her friends under shelter.

Another stone. More racing crabs. Once they're gone, I see slow movement; flatworms. The camera sees them, unless the light is just exactly right, as brown smears. My eyes see the movement, the merest hint of it, going in a different direction than the slither next to it, the next flatworm.

Whelk egg cases, spiral tube-worms, and flatworms on the underside of a stone.

Wosnesenski's isopods, one lying upside-down for some reason, showing off his 14 legs. And a pair of crabs.

Sometimes, there's a nano-second of flurry, a miniscule splash; a baby sculpin, an inch long, gone to ground, now invisible. Maybe the camera will see him; I won't. But I saw the splash.

Some animals are only recognized, in these surroundings, by their movement. I learn to see them; the merest rise and fall of a limpet under the seaweed gluing herself down to the rock while the light threatens her; the split-second flip-flip-flip of a gunnel, the shrinking of an anemone, the characteristic sideways scuttle of a miniature hermit - snail shells don't move like that without a hermit resident; the writhing of a polychaete worm becoming one with the mud underneath, the squirting of a clam retreating deeper into the mud. The camera never sees those.

Spiral tubeworms, flatworms (the light was right- look for the eyes!) and a limpet, still on the move. I don't know what that tiny thing with the striped back"bone" on the stony patch in the centre is.

My eyes miss the very tiny critters. My reading glasses are in my pocket; they get in the way when I look through the viewfinder, and the light is too bright to see the screen. So I point and shoot, looking for the green square that says the auto-focus has found something interesting. Or find a safe, non-painful (broken barnacles are sharp!) place to kneel so that I can get my head down a few inches from the stones and look through the viewfinder.

White shells, a sea of white shells; must be barnacles. The camera knows better. Waving seaweeds; no, the camera discovers tentacles or antennae. Or a mass of worms.

The camera saw these. I didn't.

This photo includes two masses of ribbon worms; the upper one is a knot of Paranemertes peregrina (p. means wandering), the purple ribbon worm, with a very purple body and a creamy belly; the orange ribbon worm, Tubulanus polymorphus; and the green ribbon worm, Emplecotnema gracile, with its green top and yellow belly.

The lower knot appears to be all green ribbon worms.

And there are three flatworms and a trio of crabs.

Sometimes things are easier; I find an underwater species tossed up to die on the shore. These I can pick up and move to a better background.

Unidentified species of hydrocoral. Notice the yellow "bud" at the tip of the branches.

Habitat for the critters found above. The stripes parallel to the shore are probably old glacier tracks on sandstone.

Sparkly green eyes

Most of the small crabs on the upper intertidal reaches of Boundary Bay were green shore crabs. They were not always green; they can be any colour from white to purple.

Here, on the Campbell River beaches, so far, I have seen mostly purple shore crabs, like this one:

Young purple shore crab, Hemigrapsus nudus.

Since the greens can be purple, and some of the purples are green, they are hard to distinguish at first glance. But the purples have those pretty red or purple polka dots on their pincer arms; the greens don't.

And this one has sparkly green eyes, to boot. Handsome, isn't he?

This may help

Because those crabs were too well camouflaged, here's a marked-up copy of the photo:

Crabs in red, hermits in green, green ribbon worms in yellow.

And there's a full-sized photo on Flickr, here.

Now, I've got to sleep. Tomorrow, my new critter!

Teeming

On the underside of one smallish stone on the White Rock beach, life happens. Abundantly.

Flatworms, flatworm egg masses, barnacles, crabs, hermit crabs, snails, mussels, green ribbon worms, amphipods, and no telling what else.

Examining the photo, I found 6 crabs. Can you find them? And check out the varied colours and patterns of the flatworms while you're at it.

I uploaded a larger photo than usual, to make the search easier. If you right-click on the photo, you get an enlargeable view. (At least, that's the way it works for me.)

And I'm going to be busy the next couple of days, with an urgent assignment and a big garage sale at the same time, so I won't be posting 'till Monday. But then, I've got a beautiful new critter to show you!

Deportation proceedings: Part 2 The accusation

There's nothing cuter than a baby crab.

Case in point; "Smiley". 2009 photo.

Trouble is, shore crabs do very well for themselves in an aquarium; steady temperatures, clean water, ample diet, and no predators, to boot! So they grow up large and strong.

And the bigger a crab gets, the more disruptive he becomes. He digs himself a deep burrow, throwing aside carefully-placed landscaping and piling leftovers on top of his neighbours' land. He then goes out to steal food from whoever has any, and retreats to his hole to eat it all in peace. No sharing! When his hole gets untidy, as it does - he's a messy eater - he abandons it and digs himself a new shelter. Again, he tosses his construction trash next door.

In between, he goes a-hunting. Freshly-molted young hermit is tasty; so is a snail that he can crack between his pincers. He can snatch a speeding amphipod out of the water without a miss. And a nice mouthful of green sea lettuce makes a good garnish. Leftovers are tossed into the current.

But even the non-edible, glued-in-place residents come in for their share of harassment. Enter the burrowing anemone.

"Val", from Campbell River. Nicely healed, growing a sturdy, button-studded column.

Hermit crabs crawl all over the anemones, picking up bits of debris, grooming the tentacles. Sometimes the anemone shuts down for a bit; more often it doesn't. They're friends. Big Patch, the crab, tried to imitate them, but was not welcomed, probably with good reason. I watched on several occasions as the crab approached. When he came within reach of a tentacle, he leaped backwards, as if shocked. He tried over and over, always with the same result. The anemone's stinging cells are good protection.

Revenge is sweet, says Patch.

He dug a hole right next door, and buried the anemone with broken shells and gravel. Val shut down; can't feed under all that heavy construction debris. I raked through the stuff with my fingers, removed the gravel, left clean sand around the base of Val's column.

Patch dug another, deeper hole. Val shut down. I cleaned up. Patch pushed a load of sand halfway across the aquarium and piled it on top. I cleaned up.

Burrowing anemone, White Rock beach.

(On the beaches, most of these anemones cling to rocks, sheltered from tidal sand pile-ups. I accidentally dug up the one above that I found in sand instead, by trying to measure its column depth with a finger. It had nothing to hold it, and rolled out of the sand. A wave caught it and hauled it away, probably food for whatever fish got to it first.

The anemones on the beach in Campbell River, where Val originated, usually anchor themselves in sandstone pits, sheltered by seaweeds. There is very little loose sand for the crabs to move about.)

Cluster of anemones in sandstone, Storries Beach, Campbell River.

Val has anchored hirself to the glass bottom of the aquarium, for safety, but that means only a certain depth of stuff will be tolerated around the column.  Patch kept burying hir.

Eventually, I moved Patch's favourite clam and oyster shells to the far end, re-arranged all the landscaping, plants, rocks and all, so as to leave nothing nearby to be piled on top of Val. Overnight, Patch hauled it all back, and re-buried his enemy.

Patch, showing off his Alpha male, XL pincers. Val in the background, shut down. What's the sense of fighting back?

So: it's time. Patch is too big for his britches, too big for a tank he must share. He's been exiled to a quarantine tank, with a couple of other growing crabs. Next trip to the beach, they're going along. They'll do fine there; they're large and healthy, if a bit spoiled.

Val is sitting in an empty plane, in lonely splendour, waving tentacles happily in the current.

Deportation proceedings, part1

On the beach, they live together amicably, the animals and plants that end up in my aquarium. All but one have come from the upper intertidal shores of Boundary Bay, where shore crabs and hermits (hairy, grainy-hand, and greenmark), worms, clams, mud snails and periwinkles, amphipods and burrowing Nassa snails, and the occasional anemone abound. Val, my one import, comes from Campbell River; on hir beach, we found the same crabs and hermits, snails and worms. So they should do well together in the tank, right?

Not so fast! On the beach, they do tend to separate into zones; there's a wormy patch, with snails on the surface; there's a clean sand patch, with clams underneath and crabs on the surface; there's a snail and hermit area, with worms underground. On our Campbell River beach, there were patches of mostly anemones where the tide pools were full of hermits and snails.

The combinations may be due to water current variations, to the size of the sand grains, to the number of rocks, or the varying salinities and temperatures of any intertidal zone. But personalites may enter into the equation, too.

Hermit crabs get along with each other nicely, even across species lines. They're fine with anemones; they clean up the shells of snails and clams without disturbing their owners. They eat barnacles or worms, but only when they find them already broken. They have no fight with "true" crabs.

Mud snails, periwinkles, and the little Nassas go about their business eating algae and detritus, ignoring anything else. They stay away from anemones, though; the anemones do sting when they're pestered.

But the crabs! A different story altogether. A crab is the top dog on the totem pole, in his own eyes. He'll get along with anything else, as long as it keeps out of his way, gives up its choice tidbits of food, doesn't invade his current hole. Or doesn't look too tasty, like, for example, a newly-molted hermit or a snail small enough to crack like a nut.

Unfortunate hermit, looking for a shell, with a crab waiting below him. Crab dinner.

And a mature male shore crab is the top-doggiest top dog of them all.

Patch, recently molted, grown to his full size, ready for action.

Next: the case against Patch.

Garfield the hermit

Seeing eye to eye with a crab:

"Freckles"

"Peachy"

Did you notice the eyes?

Crabs' eyes are on stalks; the shore crabs' eyes are a graceful paisley shape.

Freckles on a raft of Turkish towel.

Hermit crabs' eyes are stalked, too. But they come in many shapes; round, vertical ellipses, even U-shaped. My hairy hermits have oval eyes with long, horizontal irises, with the pupil at the top; a heavy-lidded, world-weary, Garfield* the cat sort of eye.

"Moi seul sens ce tourment." (See Henri, Paw de Deux)

*Or Henri; watch for 1:30.

Recovery, Part three

One advantage to having many mouthparts, like a crab does, is that they can substitute for hands. So when my poisoned shore crab lost both of his pincers, he didn't have to go on a diet, just because he couldn't pick up his food. Instead, he bent down to the ground to grab things with two big, flat paddles, the third maxillipeds. The second maxillipeds (read "jaw feet") have hooks on the ends; between hooks and paddles, he could cut and tear a salad of sea lettuce, or mash a fish filet. And he still had lots of machinery behind those, for chewing; another pair of maxillipeds, two pair of maxillae (jaws), and a pair of mandibles. No problem.

It did worry me when he molted, and promptly lost his replacement pincers and a pair of legs, too. This is a fairly common reaction to stress, called autotomy; the crab amputates his own limbs, usually just one of the pincers. Two pincers and two legs was a sign that Mr. Crab was at the end of his resources.

Once the tank was completely cleaned out, he seemed happy enough. He didn't lose any more pieces. I made sure to feed him well, putting treats down right in front of him, and turning off the water pump until he'd finished eating.

That was in July. In August, I noticed a tiny bud where one pincer had broken off. He had started the process of regeneration. In mid-September, two pincers were well on their way.

Six-legged crab, with pincer buds. Inside the translucent covering, the developing claws are visible.

Yesterday morning, he molted again. And now he has two pincers, and all eight legs.

The pincers are smaller than the originals that he lost. Next molt should fix that.

The molted shell, showing the buds where the pincers grew.

When he backed out of his old shell, his skin was soft and pliable. He pumped his body full of water to expand the tissues before the shell hardened, leaving him room to grow. The new pincers expanded like balloons, so they are many times the size of the buds they came out of.

The tank looks healthy now; the amphipods are multiplying again, and three tiny hairy hermits are scrambling about happily. I think Mr. Crab will be able to keep those shiny, new pincers this time. It's been almost 48 hours now, and he's still intact.

And the thermometer at the window read 60° F. this evening. The long summer is finally over.

Purple crabs, pink stones, and periwinkles

On Sliammon beach:

Shore crabs, probably purple, so dark the polka-dots barely show.

Most of the crabs we saw this trip, on several Sunshine Coast shores, were much darker than the shore crabs we find at home. The snails looked about the same.

And I'm still only halfway through Day Two, with more wharf photos, the rest of the Sliammon story and the evening sky to go.

How not to be supper

Crabs will eat anything, fresh or old, plant or animal. One of their favourite treats, though, is fresh snail meat, so fresh it's still squirming. My shore crabs spend a good part of their time trying to break through snail shells, not always as successfully as they'd like.

Big male, showing off his snail cracking tool.

Asian mud snails, up on the glass where the crabs can't get them.

These two snails are survivors, and bear their scars proudly. The lower one has had the worst of it; extensive damage near the lip, where the crabs prefer to start work, and a large patch taken out of the upper spiral. Lucky for her that their shells are so thick. Or rather, it's an arms race; if your enemies have humongous shell-cracking pincers, you'd better wear heavy armour and keep it repaired. Climbing walls helps, too.

The snail on the right has patched the big gap in her shell; only the scars remain.

Lips, patched and freshly broken.

The snails won this round.

Backsides, buttons, and a beautiful beast

My intertidal invertebrates are like birds in the bush; always presenting themselves at odd angles, so you see a shoulder, or the top of a back, or a foot. And from that, you're supposed to say, "Aha! There's Ma Crab hiding in the sea lettuce!" Or, more likely, "Was that leg from a hermit or a crab?"

As for taking photos ... Can you identify these?

1:

Warm-up. This one should be easy.

2:

There are two very different kinds of animals here. Can you see the second?

1A: Did you recognize the first critter? Here he is, in a more co-operative mood:

Sitka Coastal Shrimp

He's now about full adult size, just over an inch long. The two smaller ones are starting to catch up.

And 2A: It's a line-up of anemones reflected in the underside of the water surface. Most of them live up there, for some reason. There's a quite large one that wanders around, mostly on the front of the tank, where the current is milder. It has grown to a couple of inches long and across the tentacles. These are all under 1/2 an inch.

In the photo, they are closed down tight. I don't know why they do that; they all open up at once and start looking for food, then they all shut down together. Bedtime.

The other animal is a small scale worm, cuddled up to the base of the largest anemone. (And reflected on the water surface, too.)

3: The trophon (below): a vicious, insatiable, efficient predator. Willing to take on prey three or four times her size. Serves as hunter for the whole community; when she's stuffed herself for the moment, the hermits and crabs and nassa snails move in and polish off the carcass.

She and her two cousins eat all but the smallest barnacles and mussels. I've caught her killing two large clams; she attaches herself to the outside of the shell and spends a couple of days just drilling through. When she's done with it, the clam is dead and opens up, and the shell has a neat hole in it, as perfectly round as I would make with a power drill and a good bit.

A couple of times, I saw her attached to the shell of a hermit crab. I took her off, but she got right back on. I worried a bit, then realized how silly that was; the minute she drilled through the shell and touched the backside of the hermit, he would move out. He's not tied down, like a clam. All that work for nothing! (And maybe that's why I've been seeing hermits walking around nude, looking for a new suit, instead of finding the new outfit first and then changing.)

But she's beautiful.

4: The big male shore crab.

I noticed, when the light is just right, it shines right through the upper shell, so that I can see the innards, and even the pincers moving on the far side. It seems that the carapace is a transparent sheet with spots of pigment scattered on it. Places where this is really apparent is in the center, around those two dimples. I tried to get a photo that showed this, but with no luck this time. In this photo, you can see just a hint of the base of the eyestalks beyond the carapace. I'll be trying again, and again. One of these days, I'll get a good one to show you.

Anti-procrastination: Rock Flipping Day, 2010

Saturday. The day before the official Rock Flipping Day. (The list of flippers is posted here.) I was worried about the weather, and whether I would even have time on Sunday; so I jumped the gun. I flipped a few rocks, just in case.

(As it turned out, I had time to flip even more on Sunday, so I'm in the clear.)

We were on Centennial Beach, at Boundary Bay; a quick walk before the tide forced us back. Boundary Bay is not the place to go looking for rocks.

Mud, sand, eelgrass. The raised lumps are worm poop mounds. Sand. Not a rock in sight.

But up against the last house before the park, the wall had been reinforced with riprap, against high water.

Too big to manage.

Smaller rocks on the park side.

I found one I could lift, and carefully flipped it over. Earwigs scattered in all directions. By the time I'd trained my camera on the space, they were gone. All but one; she wasn't planning to move.

Hole in the center, earwig, and something white.

Standing her ground, ready to defend her eggs.

A male, on his way to hide under a neighbouring rock.

This is the giant seaside earwig, Anisolabis maritima. We saw some on Vancouver Island this summer. The female has straight pincers (forceps) at the tail; the male's are curved inwards.

A few steps up the slope, sea rocket grew over the sand at the base of the rocks. A few rocks had rolled down onto it; I flipped a medium-sized one.

Sea rocket. Cakile maritima, I think, from the deeply indented leaves.

Dead sea rocket under the rock. Note the sharp stay-at-home seed pods. A smoother section has floated or rolled away.

Brown sowbug that scuttled away to hide under a plank.

I took a few steps the opposite direction, down the beach. A few rocks had ended up on the gravel at high tide level: had they been there long enough to attract critters? At least one had.

Purple shore crab trying to make himself invisible under the stones.

Getting worried. I replaced his rock, gently.

Twenty steps, three different habitats.

Do they bite?

"I found a crab!" Three little boys, about 5 to 10 years old, were digging among the rocks on Centennial Beach the other day. "I found a crab!" the littlest one shouted again.

"Does it bite?" his brother asked.

No.  And it probably won't pinch. Not hard, anyhow. But the boys crouched there, poking gingerly at it with sticks. Such excitement! Such danger!

I remember. I was a kid, teasing crabs with a twig, long ago. And I still feel a bit of that excitement when I turn over a stone and a green shore crab dares me to "Come on!"

Looking for more crabs. Well armed.

Most of the crabs we see on the beaches are either dead or the cast-off molts. Live ones usually scuttle off under a rock or a knot of weed. We don't get much of a chance to count the "teeth" or compare the shapes of pincers.

But I still bring crab shells, and sometimes whole dead crabs, sun-dried, home. I have bowls and trays and shelves full of them. So I decided to count their teeth, for practice.

The crabs most accessible to us in the upper intertidal zone of the Lower Mainland are the shore crabs, green and purple. They show up just below the high tide line, mostly hiding underneath stones in rocky areas.

Two very small green shore crabs. The large one measures 1/4 inch.

The green shore crab, Hemigrapsus oregonensis, has a rectangular carapace and tiny hairs on the walking legs. (On these two, I could see them with the hand microscope.) It grows to about 2 inches across the carapace. Juveniles can be any colour from deep red to green, to white.

Another green.

And a purple shore crab carapace, with the broken pincer. And polka dots!

The purple shore crabs look like the greens; they may be green, too. But the legs are never hairy, and the pincers have red dots. (Unless the crab is green; then it's only the hair that separates them, and you may not see that on the beach.) Two other characteristics I don't find in the books, but see on the crabs, all colours, are the three teeth along each side of the front, and the smiley face in centre back, looking at them from the rear.

Dungeness crabs may be green, too, although the books say "reddish brown to purplish".

Reddish brown Dungeness, Cancer magister, with purplish tints.

The Dungeness is a large crab, growing to about 11 inches across the fan-shaped carapace. This one measured 6 inches; that's usually about the size of the big shells we find, mostly on the White Rock or Boundary Bay beaches. They like wide, sandy beaches, with few rocks.

We see the live ones only at low tide. Even then, they're difficult to see, since they bury themselves almost completely in the sand. I have looked at one for up to a minute without seeing it, then suddenly the shapes resolve themselves and I notice the eyes, watching me intently.

Here's where we count the teeth. The Dungeness has ten "teeth" on either side of the eye, ending at the wide point of the carapace.

"Teeth". Only the little white bumps on each paddle count as teeth; tooth, bump, bump, bump, and a valley.

The pincers are long and strong; be careful handling a live one! Pick it up from the top of the back, not the hindquarters; they can reach you there with the pincers.

Pincer. More "teeth". Sort of looks like locking pliers (vise grips). The tips are white or whitish.

Live Dungeness, underwater, on Centennial Beach at lowest tide. This one's more green than red. The pincers are white-tipped.

The red rock crab, Cancer productus, is similar to the Dungeness, and almost as large, up to 8 inches across the shell. They can be found on many types of beaches, from sand to gravel to rock, in quiet waters or strong waves, shoreline to deep underwater. I find it strange that I have only seen one, a tiny one, on the beach in Campbell River. I do have a pincer that I picked up on the White Rock beach, though:

These pincers are thick and strong, with black tips.

On websites with crab recipes, I find repeated warnings about these crabs; they are likely to attack, and their claw can cut through strong work gloves.

The red rock is the same general fan shape as the Dungeness, and more or less a similar colour. The distinguishing feature, again, is the teeth along the edge of the carapace. Instead of 10, as in the Dungeness, they have 9. (Try counting them while the crab hides under the seaweed and snatches at your toes!) In between the eyes, the shell makes 5 peaks. So does the Dungeness, sometimes; I have one with only 4.

It will be easier, when I see my first big live one, to check the rim of the carapace. It is fluted, like the wavy pie crusts I used to make.

One other shell I have, one that I can't remember where I found it, is from a kelp crab;

Small shell, about 2 inches long, sun-bleached.

This is a long-legged crab that lives in kelp beds. Kozloff lists it among the most common crabs in this area, but it's most likely to be found underwater at extreme low tide, in the eelgrass. It will be a dark olive green. Another critter to look for.