Crunchies

The sandstone shore around the glacial erratic I visited last week, exposed at mid-tide, is densely populated by large barnacles. Millions of them; billions, maybe.

Thatched acorn barnacles*; one small patch.

I felt guilty, walking across this beach: crunch, crunch: at every step I could hear breaking shells. I tried to find spots with no barnacles to put my feet down, but there were few.

At one point, I turned and examined the barnacle I had just stepped on. There it stood, undisturbed, solid as ever. How strong are those shells? I think, possibly, the crunches I heard were dead, empty shells; they seem easy to break, from the right angle. More experiments are needed.

Stone formation, with barnacles, oysters, gull and more.

Farther down the beach, below the erratic, a few slabs of stone stood like a fence against the waves. Here, I found more barnacles, and a scattering of oysters, each one firmly cemented to the rock. The dark green stuff is rockweed.

More than meets the eye.

All across this plain, and crammed into every niche in the rocks, tiny critters go about their business, dwarfed by the barnacles. Looking closely, I found hundreds of pinhead snails. (But when I brought a handful home, most of them contained miniature orange-legged hermit crabs.) In the photo above, only one hermit crab is identifiable, but most of the blue-black snails are probably hermits, too. In the lower third, left of centre, a yellow patch is made up of whelk egg cases. And here and there, limpets try to blend into the rock.

Empty barnacle shell and black rock algae.

I brought home a few barnacles to clean my tank and feed my barnacle-loving snails. Checking them over before I added them to the aquarium, I found several healthy flatworms. No matter how strong a barnacle shell may be, these worms can slither through the cracks between plates, kill and eat the barnacle inside. Some flatworms may even eat the oysters.

*Barnacles may be hard to identify, but the thatched acorn has a black feeding foot. The barnacles that came home with me all have black cirri.

Eggs in urns

The whelks are laying eggs.

A small collection of egg cases. Each one holds about 20 to 100 eggs. Of these, only a dozen or two will mature into baby snails.

These egg cases are new; as the eggs develop, they show up as slowly moving dots inside the translucent casings. One has already been broached by a predator, probably a crab looking for an omelet.

The same eggs, with their blurry mother, a whelk. (Species not identified.)

The clear dot at the top of each egg case is a "cork" of gelatinous material. Over the incubation period, this gelatin dissolves, finally leaving an open passage for the baby snails' escape to the big world out here. (See A Snail's Odyssey; Whelks and relatives, for more info.)

Mystery # 1

This is an trio of pink-tipped green anemones. They're a dime a dozen in the intertidal zone. But look again.

Anthopleura elegantissima, with whelks and Wosnesenski's isopod.

First, what has it been eating? It looks like a black snail shell, and, separate from that, two pieces of very white flesh. Is the anemone in the act of expelling the snail shell and simultaneously swallowing the meat?

Second, and this really leaves me wondering; look closely at the right bottom of the anemone. Look through the translucent flesh. See the circle of what looks like snail eggs inside?

Zooming in.

How did they get there? Did a snail crawl in, avoid being digested, exit the stomach, and lay her eggs? How is that possible?

Or are these part of the usual anemone anatomy that I have never seen, and can't find in any cross-section diagram?

Or did the anemone just crawl along the rock and station itself on top of eggs?

And no, they can't be seen from the opposite side; I'm not looking through the entire animal.

What do you think?

Baby pics!

I've been checking those Leafy Hornmouth egg cases in the aquarium every few hours this week, and finally this afternoon, I saw a dark speck on top. Very tiny; it looked more like a speck of dust, and I left it there. This evening, there were three specks. I fished them out with a paintbrush and looked at them under the microscope, because they were too small to see clearly with only the hand lens.

They are baby snails, still carrying what looks like a bit of yolk, but ready to go out into the wide world.

The egg case is 1 cm. long; the baby snail is about 2.5 mm.

Stretching to turn itself over. I had just returned it to the tank, upside-down.

Two of the babies, out of the tank.

Now, three hours later, another four have emerged, and there are several in the "birth canals", the pointed top ends of the egg cases. More are waiting inside.

The first three have gone on their ways. I don't see them anywhere;it's a big, busy tank, with many hiding places. And many dangers. I hope they have found safe havens.

And meanwhile, Ma and Pa are down on the bottom of the tank, pigging out on a rock full of barnacles that I brought them this Monday.

December dig

Well, that was a short winter. Or maybe not; maybe it's just a practice run and the next edition will be the real thing.

A week ago, I was still seeing moths on the wall by our door, sometimes half a dozen at a time. The weather was mild, and garden plants were putting out spring buds. My lobelia and bacopa were still flowering cheerfully; there was even one pallid nasturtium in the few inches of garden where the sun still hits occasionally.

The first of December, the average temperature on the beach at White Rock was 9.3 degrees Celsius, almost 50 Fahrenheit, with a high of 11.2 in the afternoon. A week later, it was -4, dropping to -8; over 19 degrees difference. (Or a drop of about 34 degrees Fahrenheit.) And with the windstorm, the wind chill brought it down to -15 on the beach, -20 inland (like where we live.)

Our southern BC gardens aren't prepared for that kind of a shock. The rhododendrons curled up their leaves into tight tacos, the winter-hardy hellebores drooped and shrivelled, the evergreen bergenia gave up and lies dying, even though I covered it against the cold. Even the sausage vine up against the wall, well wrapped up in six layers of heavy paper, became instead a taco vine. And there are no more moths.

And today, it was over. Monday, it snowed, just a fine dusting, but the temperature climbed to zero. This afternoon, it was raining. Back to normal. I watered the hellebores with warm water to thaw their soil, and they rewarded me by poking a new shoot an inch into the air. The old leaves won't recover, but the plants still live.

I started to wonder how the residents of my soil handled the sudden drop. This afternoon, I brought in three full flowerpots. I couldn't get any garden soil; it was still frozen too hard, too deep, to break off even a chunk.

In the first two pots, all I found alive was a tiny, tightly coiled cyanide millipede. As soon as I removed it from the pot, it unwound itself and started to explore.

Just under an inch long. Doesn't really mind the cold.

And that was it. There were no snails, no slugs, no woodbugs, no beetles, no worms. Not even their frozen dead bodies. No tiny mites, no springtails, no spiders to prey on them. Nothing alive.

Except. All through the soil frozen yellow balls were scattered. Dozens of them, maybe hundreds, in sizes varying from a pinhead to a small pea, the colour of grapefruits. A solid yellow while still cold, they quickly became translucent when I exposed them to room temperature air.

They rolled into the channel around the rim of my tray.

I accidentally squashed a few; they were liquid inside. I found a few empty ones. These had a yellow skin on the outside, and a chalky coating inside.

I don't know if they're slug eggs or snail eggs. All the slug eggs I've seen around here have been colourless and transparent. I'm keeping a couple of dozen inside, in potting soil, to see what emerges, thinking it's spring.

The third pot has a bulb in it, and was protected on a base of leaves inside a bucket, and under one of those paper garden bags half full of leaves, and stashed in a corner of the wall. This soil was frozen, too, but the bucket held two tiny running critters, one lively small wasp, and one springtail. A handful of old moss harboured one aphid. Still no mites or spiders or woodbugs, dead or alive.

I wonder where they went? Did they know in advance that the weather would turn? Are they smarter about the weather than us? (Probably.)

A bubble in the hand . . .

is worth any number in the eelgrass.

It's interesting, how once you've gotten familiar with the shape and movements of a critter, that you see them in places where you looked before, without finding any. Like the bubble shell snails; I've waded knee-deep in the eelgrass beds at low tide in Boundary Bay many times, and all I saw were crabs and isopods. This last time, I recognized the bubble shells, dozens of them.

They're easy to catch; they hang out on the eelgrass blades, and when they're disturbed, they just let go and float down to the next blade. And they're just as content to land on my hand.

I got this one still on his eelgrass. He's upside-down, twisting up to get a look at me.

Setting out to explore. Isn't he a cutie?

"Hi, there!"

These snails are incredibly fragile; their shells are paper-thin, and as brittle as eggshell porcelain. Other snails have thick, sturdy shells, essential for survival in crab country. Even so, I find many empty shells, peeled back by crabs to get at the tasty meat inside. How do the bubble shells, without that protection, manage to live?

Watching them on the eelgrass, it all became clear. As long as the eelgrass in underwater, it stands upright, swaying in the current. The crabs scuttle along underneath, but only the smallest climb the eelgrass; it won't support the weight of the larger ones. Up at the top of the bed, there are no hard edges, no stones, no crabs, nothing to squeeze or bang those fragile shells.

When a bubble shell drops to the sand, he buries himself immediately. I've been watching in my tank, as they just ooze down between the sand grains and disappear, in seconds. The next time I see them, they're climbing an eelgrass stalk, up to safety.

Bubble shell egg ribbon, on eelgrass

I have seen these egg ribbons many times, but didn't know which snails they belonged to. Now I do: I've watched the bubble shells laying them, gluing them to the eelgrass blades near the top of my tank.

There must be thousands of eggs in one ribbon, and a bubble shell will lay several ribbons over the course of a few days. Few of them survive, or we'd be wading through a mass of bubble shells. Hermit crabs love them; fish eat them, so do nudibranchs. Even in the gentle eelgrass beds, life is precarious.

Hermie gets a makeover

When they eat, they scatter the crumbs. They don't clean their plate; they don't tidy away leftovers. That's SEP*. They abandon their houses, walking off with nary a backward glance. Occasionally, they strip off their old clothes and drop them on the ground. Then they climb to high places and sit there, all undressed.

No wonder they get into trouble!

Another of my hermit crabs molted this afternoon. I found his discarded body armour floating in the current, and looked for the ex-owner.

Sure enough; he's resting on the top of a clump of sea lettuce.

He's one of the hairy hermits. The hair isn't usually so apparent. Now, it's new and just stretching out. And he has no jacket on.

While he's walking around in the altogether, we get a chance to count legs. A hermit has 5 pairs of legs, including the pair that serves as pincers. Two more legs on each side are used for walking. The fourth pair, easily seen in this photo, is used to move in and out of the shell he borrows. The fifth pair is smaller, barely visible here. It is used to clean the gills and to remove wastes.

Visitor.

At the very tip of the abdomen, a pair of curvy uropods works as an anchor inside the shell.

As long as the hermit stays aloft, in my tank, he's fine. If there were any fish, he wouldn't be; he'd be a fine lunch. Here, once he goes down to search for a new shell, any crab that he meets will eat his soft abdomen. I kept an eye on him; when he climbed down, I chased out my one crab and put him in a bowl to keep him out of mischief. (I gave him a piece of fish as compensation.)

Hermie took his time choosing his new shell; so many styles and patterns!

He was slow; the crab had to stay in solitary for three hours. While I was watching, I noticed something else in the tank:

Six pearly eggs!

Spring is definitely on it's way, and the snails are ready for it. One of them laid these eggs. I don't know which; there are four species of snail in this tank; the invasive mud snails, a bunch of pretty little Nassas, several periwinkles, and some really tiny, pointy snails that I haven't been able to identify yet. These last are smaller than the eggs, so they're not the parents. Any one of the others could be.

Bonus; the teeniest of all the hermits, like a half grain of rice, even with the shell on.

And Hermie finally decided on that fat white whelk shell.

*Somebody Else's Problem. See Douglas Adams.