Beast of burden

It's all about location; find a perfect site and settle in, and you can thrive. Hide off in a corner, and life's a struggle. The pink-tipped anemones in my aquarium know this, so they're always moving about, searching for the ideal spot, where the food is plenty and the diet varied.

This one seems to have the right idea. But the poor snail!

Heavy load

The snail, here browsing among the algae halfway up the wall, is one of the mud snails, Batillaria attramentaria, about half an inch long. And he's been completely encased in the base of the anemone, twice his size. And to add to his burden, the anemone has brought along its pet rock, and couple of pieces of clamshell; together the anemone's decor must weigh more than the snail.

And yet, the snail goes about his business, tranquilly scraping up the algae, moving on to the next patch; what doesn't kill you makes you stronger, he says, flexing his weight-lifting muscles.

(I've cleaned the algae off the glass in the photo, for visibility. It's still there, where the snail and his burdens are: those yellow-brown patches between the rock and the glass, for example.)

Gate-post snail

"Well, I'm back." (As Samwise Hamfast said, with more reason, having actually been gone and returned.) Ready to start blogging again, anyhow.

I feel sort of like this gate-post snail:

"Is it safe to come out yet?"

The crab, in a fit of landscaping enthusiasm, hammered the snail point down into the sand like a gate-post in the crab's front yard. A poor choice of construction materials: once work had stopped for the day, the gatepost woke up, peered around, then stretched and twisted until he could grab the shell next to him, uprooted himself, and slid away.

Snail road maps

Satellite view:

Sand Hills National Park, trails and campsite circles.

Highway with rest area

End of the road. The Pit. Or, more pleasantly, Ye Old Watering Hole.

We got down to the beach yesterday for the first time in it seems like forever. Fresh air, empty water, blue sky: it's turned me a bit silly.

I blinked first

A major part of the cleanup crew in my aquarium is made up of mudflat snails, Batillaria attramentaria, those invasive snails that crunch under our feet on the beaches of Boundary Bay. They probably would be invasive here, too, were it not that the big burrowing anemone eats all she can catch.

Most of them spend their time under the sand; when they venture out, usually to climb the walls scrubbing off the algae, all that can be seen of them are the shells and a hint of dark flesh at the lip. Rarely, one decides to look me in the eye (or camera lens). One of those curious ones was cleaning off a shell right beside the wall the other day.

Striped face, striped tentacles. And a staring eye.

These eyes can see some shapes, but they don't have a focussing lens, so things are blurred. And it seems that they don't see colours. Still, they can detect light and dark, day and night. For the rest, they don't have to chase the algae, nor could they dodge predators if they saw them; the eyes are good enough.

And they don't blink.

The three curves in the shade under the body almost look like crawly-type feet, but that effect is either from the pattern or the folding of the one fleshy foot.

Full-face view. The eyes are at the base of the tentacles, and bulge outward. The one on the right is barely visible from here.

A couple of years ago, another snail consented to be photographed. I blogged about it here.

Big foot, patterned in green and grey, folded.

And doesn't this critter, if you ignore the shell, look like a cuttlefish? Well, except that the cuttlefish eyes are on the forehead. And the nose is really a mass of tentacles. And it changes colour. And ... Well, you'll see what I mean if you look at this Common cuttle, from the Monterrey Bay Aquarium. (It's copyrighted, so I can only provide you with the link.)

Homebodies

It may be a mistake to think of a given beach as "the beach", at least as far as its small residents are concerned. They don't live there, in the way we live in the Lower Fraser Valley, but are free to travel or move house to any part of the world, with little inconvenience. (Always excepting Antarctica or the sea bottom, of course.) The intertidal critters live in small communities, sometimes never leaving their underside of a rock, or the line where stones give way to mud, for example.

Barnacles and periwinkles, and probably a crab or two.

Mud snails are relatively mobile. We have watched them as the tide retreats, just above the water line, hurrying down in pursuit of the disappearing shelter of the waves. They're not fast enough, and after a futile chase of a few minutes, they bury themselves in the sand to wait for conditions to improve. I sometimes follow their trails from exit hole to new retreat; they manage to cover about 10 of my paces, but rarely in a straight line, so they're not too far from home when they stop.

Hermit crabs scuttle about, sometimes covering quite a distance, compared to their size. And I have seen them, caught in the current, rolling, rolling, out with the tide, until they find some strand of eelgrass to grab onto before they get nabbed by a passing fish.

The other day, walking on the bare sand, I picked up every snail shell I saw, and examined it. Every one, every single one, without exception, held a hermit crab. If a hermit borrows the shell from a snail that died and was eaten, then the hermits and snails should be found in the same general location, I reasoned. But I saw no snails where there were hermits.

Maybe the snails had dug themselves into the sand when the tide went out. So when I picked up a hermit in a snail shell, I dug in that area, scooping out the sand and water wrist deep. Each time, I found clams, clams, clams, clams. No snails. Not one.

So the hermits, at least, have travelled some distance from their supply of homes.

All this is well and good; a barnacle or a mussel on a rock is basically set for life; a starfish in a crevice at the mid-tidal zone will still be there next week or month, a snail circles around the bits of beach that feel comfortable.

Double holdfast

But what of the poor critters that settle down in a perfect spot, sheltered, climate-controlled, well supplied with food and company, only to find their home uprooted and tossed on some inhospitable shore, exposed to air and light and flies? What of the subtidal residents of bull kelp holdfasts, or the eelgrass root dwellers?

Ma Nature is so unfair!

Now that's a proper live beach!

The tide was high when we arrived at Crescent Beach on New Year's Day, so we walked along the shore watching the birds: gulls, an eagle, a flock of chattering yellowlegs, and further out, rafts of ducks, pintails, we think. The birds close to shore were feasting; we caught one yellowlegs on camera running along with something floppy and red dangling from his beak, and another bird in hot pursuit. And in our few photos (too far, too bright to take very many), I counted 10 gulls with a beak full of clam or snail.

By the shape of it, this looks like a snail.

We walked almost to the point. By then, the water had gone down enough to expose the upper intertidal zone, so I went down to the edge to flip rocks. Every stone and rock I turned exposed a mob scene, crabs and hermits, snails, isopods, amphipods, all piled higgledy-piggledy.

A pretty orange clam, burying himself as quickly as possible.

Crabs upon crabs. There are a half-dozen crabs visible in this photo. Can you see them?

At least half of the snail shells here are occupied by hermit crabs, mostly greenmarks, the tiny ones with orange marks on their legs and pincers. (I haven't seen any green marks on them yet.) But there is a larger hairy hermit near the centre, mostly hidden. The snails and snail shells are Asian mud snails (the long, striped one) and Sitka periwinkles (round, fat coils); these last always live close to the high water mark. A couple of snail shells are from Nassas. In the upper left, you can see a large rockweed isopod.

Hermits upon hermits

The large one in the center is a hairy hermit, identifiable by the black and white striped antennae. On the upper left is one of the Eastern mud snails so common lower down on this beach, and there's a pretty green Nassa at the bottom.

Isopods upon isopods

On the underside of the rocks, the animals weren't quite as crowded as on the ground underneath. These isopods are distinguishable from the eelgrass isopod, about the same size, up to 2 inches, by the rounded tail end. The eelgrass 'pod's has a concave bite cut out of it.

Splotchy isopod

The isopods come in various shades, including this mottled green, black and grey pattern. The brown, bubbly snail on its left is an oriental cecina. It likes the extreme high tide level.

Isopod, greenmark hermit, and several limpets.

The limpets belong to two different species; the larger, ridged, black and grey patterned ones, and a small orange speckled limpet, with two spiral tube worms attached. There were quite a few of these; this was the largest I saw.

The crab photo again, cropped to center on the hiding hairy hermit. The shell and eyes are well buried under other animals.

Greenmark hermit in a checkered periwinkle shell. I think the shell just above it is a wrinkled amphissa.

Not all the snail shells contain hermits; these still house the original owners.

A small starfish, about 2 inches across, has cleared an area on a stone, either by eating everything, or by scaring it away.

Blob

I don't know what this is. There is a shell similar to this in the hermit photo (scroll up three photos), but this doesn't look like a shell. It showed up in three photos from different angles; in each, it just looked like a blob. No snails in the Encyclopedia match it. Help wanted!

I made a list of the different animals found in a few minutes:

• One whelk, one polychaete worm, one sand dollar, not shown,
• small acorn barnacles, assorted amphipods, red encrusting sponge, shown but not mentioned,
• orange limpets, black ridged limpets, green shore crabs, greenmark and hairy hermits, rockweed isopods, mud snails (Batillaria), Sitka and checkered periwinkles, amphissa snail, Nassa snails, Oriental cecinas, Eastern mud snails, clams, spiral tubeworms, a starfish, and the "Blob".

I was looking for flatworms, but didn't see any. I'm sure they were there, too.

A multi-species community

These are a few of the larger intertidal critters from the aquarium, photographed in the course of a tank census:

Three different shells; from right to left, Nassa snail, Asian mud snail, and barnacle.

Barnacles usually live attached to rocks or other solid materials. When they break off, the base gets left behind and the barnacle dies. Occasionally, one detaches from the rock without breaking. This one has most of the base intact, so it is still alive and feeding. Look closely to see the pale tentacles at the mouth.

The Nassa shell, on the right, has several round holes drilled through it, the work of a carnivorous snail, such as a whelk. Once the hole penetrates the flesh, the whelk injects paralyzing and digestive enzymes, which dissolve the snail inside. Often, once the shell is vacant, I discover the tentacles of worms waving from these holes.

Rockweed isopod, about an inch long. The flash makes the red seaweed glow in neon reds. Under normal lights, it is a bit paler than the burgundy Turkish towel that the isopod is feeding on.

The second isopod. Look closely; on the back, it is carrying a small shelled animal, probably a limpet.

Head of a polychaete worm, out looking for a meal. They rarely leave the sand completely, and retract almost instantaneously at any disturbance..

One of the round algae-eating periwinkles, with an amphipod taking a short break.

At least four species of snails live in my tank: Nassas, mud snails, periwinkles, and the tiny lacunas; these last may be so small that even with a lens, I am hard put to determine whether they are snails or sand grains until they move. Their eggs often come home with me on blades of eelgrass.

Underside, through the glass, of a very small anemone. 

This anemone sat for weeks on a stone, and then went wandering about. It has now hidden itself. I have never seen that "petal" effect on the base before.

The youngest crab, raised in the tank from babyhood. 

And my new mascot, found in a thrift store. $0.50; I couldn't resist.

Look me straight in the eye and say that!

The Asian mudflat snail is an invasive pest. A million or so of them make a beach crunchy; they wipe out native snails and discourage birds. It's easy to learn to grumble at them, easy to miss their beauty. To appreciate that, you have to get down, eye to eye with them, one at a time.

Mudflat snail, in a matching coat and shell, with barnacle scar cap.

Shimmering grey-green and black coat, an observant eye.

Of course, it helps if they're in a clean tank, out of all that mud.