Monday, September 15, 2014

Dem dry stones



Cougar Creek drains from the clay soils near our house, seeps under a couple of malls, meanders over to Cougar Creek Park with its lagoons and beaver dams, and plunges into a steep canyon. At the bottom end, it tunnels under the road into Sunshine Hills, and out into the Burns Bog flats.

We started our rock flipping excursion from that road, heading upstream, at first, into the canyon.

Reflections of the trees at the top of the Canyon. This year, the creek is shallow and slow.

Dying alder leaves and shadows of horsetails on the stones along the river bank.

We turned over many stones, both on the banks, and in the dry areas of the creek bed. Under a few, we found pillbugs, and one earthworm. Nothing more; the ground was dry, the creek bed scoured clean, and barely damp.

Where the creek was slightly deeper, held back by sticks and leaves caught on a few rocks, I turned over a rock, saw something flashing in the current, and caught it. I spread it out on the next rock to examine it.

A gruesome find. A red dragonfly, minus most of the head and abdomen, probably eaten by fish. The wings are intact. Nothing there to interest a hungry trout.

We crossed the road into Burns Bog. This part of the bog was once extensively mined for peat, and is criss-crossed by walls and railway tracks. A large part of it was paved over, but the pavement is cracked and mossy, buckling as the ground has heaved under it. Alders and maples grow in the gaps.

Moss breaking pavement, making soil for larger plants.

Cracked pavement. I looked in the cracks; nothing was moving.

It's been a dry summer; even in the shade, the moss was dry and scratchy. The ground underneath was no damper. We turned over many rocks and chunks of broken concrete, finding mostly dry soil, baked hard.

Under one slab of concrete, a few reddish ants had dug tunnels. They have something damp and bluish in the upper centre here; some sort of dead critter.

The underside of a paving stone. Ant trails, hot and crispy. No ants in sight.

Pillbugs

And a small, sleeping slug. I have never seen one before with a spotted white face; I didn't know there were such critters.

And this I will never understand: Burns Bog is supposed to be an ecological preserve, even this once-mined area. Access is mostly on foot, and the trails are long. Why, then, do people haul garbage deep into the woods here? On foot, carrying heavy trash, when we have door-to-door pickup or easily available bins?

Every time, we find something. Bottles and buckets, bicycle parts, grocery store trolleys, old cabinet TVs, rotting mattresses, shoes . . . This time, it was electronics. Underneath the chunks of concrete.

TV? Or what?

And what is this? It's plastic, backed with cardboard.

This I do understand. There's a graffiti'd wall just beyond.


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Sunday, September 14, 2014

Neon waters

A good place to hunt rocks:

Cougar Creek, in September colours.


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Saturday, September 13, 2014

It's tomorrow!

International Rock Flipping Day, that is.

Here's a handy badge for your blog. (Copy, save, and paste.)

We're looking forward to a good turnout this year; I hope you'll be joining us.

A quick reminder: if you've flipped rocks before, you know the drill. If not, here's what we'll be doing, from our host this year, Heather at "At the Edge of the Ordinary".

  • Find a rock. Sometime around September 14, flip it over and record what you discover. You can flip more than one rock.
  • You can record your findings in whatever way you prefer, whether that is through photos, videos, sketches, prose, or poetry.
  • Share your findings in a blog post (and use the badge at the beginning of this post, if you like), or upload your photos to this Flickr group.
  • ... I will collect all of your IRFD links and post them here for everyone to explore. You can then share them on your blog or social media (the hashtag on Twitter is #rockflip).

I (that's me, Susannah) will be monitoring the Flickr group, and will pass on the links to Heather.

Sunday is the Day itself, but it's ok to jump the gun if Sunday is impossible for you. I, for one, will be home expecting company all day Sunday, so we're heading to Cougar Canyon this afternoon to find some good rocks.

A likely-looking rock, at Boundary Bay.

And remember: be safe*, be respectful**, and have fun!

*One thing I (Dave Bonta) forgot to do in the initial post is to caution people about flipping rocks in poisonous snake or scorpion habitat. In that case, I’d suggest wearing gloves and/or using a pry bar — or simply finding somewhere else to do your flipping. Please do not disturb any known rattlesnake shelters if you don’t plan on replacing the rocks exactly as you found them. Timber rattlesnakes, like many other adult herps, are very site-loyal, and can die if their homes are destroyed. Also, don’t play with spiders. If you disturb an adjacent hornet nest (hey, it’s possible), run like hell. But be sure to have someone standing by to get it all on film!
**The animals we find under rocks are at home; they rest there, sleep there, raise their families there. Then we come along and take off the roof, so please remember to replace it carefully. Try not to squish the residents; move them aside if they're big enough; they'll run back as soon as their rock is back in place.



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Friday, September 12, 2014

A never-ending supply

Val, the big burrowing anemone eats snails. Eats them and spits out the shells for the hermit crabs to wear. Or glues them to her column.

But it's not just any snail that she likes; she prefers the upper intertidal periwinkles that climb to the top of the tank and occasionally drop straight into her mouth. One gulp, and they're gone.

She'll reject the Asian mud snails, as if the longer, sharper shell gets stuck in her throat. Or maybe she just doesn't like the taste.

And I've never seen her eat a little Nassa, but somehow there's always a supply of new empty shells; she must nibble on them at night, when I'm not watching.  And somehow, although I don't bring Nassas home with me, when I clean out the tank, I find dozens of these snails plowing through the sand. They're breeding here.

The Japanese Nassa, Nassarius fraterculus.

I've watched them mating often; one snail chases down another. When he catches up, there's a quick writhing and twisting interaction, and then they both hurry away. I've never seen their eggs; they lay them in the sand, in small capsules containing two or three eggs each, and the juveniles are as small as the sand grains. (Here's a video of mating Nassas, the eggs, and emerging juveniles.)

The recent pump disaster didn't seem to worry them at all; they're as active and numerous as ever.

This may be Nassarius fostatus. Or maybe not.



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Thursday, September 11, 2014

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.

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Wednesday, September 10, 2014

Babies, babies!

The snails are hatching! Three are out and exploring their new home, already!

I'll have photos asap.

Couldn't wait to crow!

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Wings and sails

Boundary Bay, Monday.

Heading out for the afternoon

Heading North for the winter end of summer.*

It's that time of year again. Three or four V's of geese flew overhead, all going North, in the short time we were on the beach.

Update: From Cornell:
Even members of "resident" populations, which do not migrate southward in winter, will move north in late summer to molt.

Back to the tank inventory tomorrow; more prolific snails.

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Tuesday, September 09, 2014

Reconsidering

A couple of years ago, faced with snail egg capsules and an infant snail found with them, I tentatively identified them (with help from commenters here) as one of the rock snails, aka murex snails or Muricidae. I thought they were probably Trophonopsis orpheus, or another of the trophons. These prey on barnacles or mussels and other bivalves, and seemed to match some barnacle-eaters I'd had previously in the aquarium.

The hatchling, only a few millimetres long.

There were problems with the id; some references called it a subtidal snail, living at depths up to 180 feet. But I had found these in the upper intertidal zone. In Marine Life of the Pacific Northwest, it was the only rock snail that matched the snails I found, but again, it was supposed to be subtidal.

So every time I find another of these, or mention them, I spend some time reviewing the websites and books, looking for a closer match, a snail that fits everything I'm seeing in my tank.

And now, having the egg cases at hand, and confirming that these snails do, in fact, lay these eggs, I think I've been mistaken; that they are no trophons, after all.

Look at these egg cases. (Copyrighted, so you'll have to go there to see them. Here's the page; scroll to the second species.)

Now look at these, from my tank.

Tillie's eggs. A good match.

These are from the Leafy Hornmouth, Ceratostoma foliatum. This is another Muricid (rock or murex snail) that lives in the intertidal zone, but almost all the photos I find are of the full-grown adults; in these, the ribs are prominent, "leafy". The younger ones are like those in my tank.

This is fairly common to find intertidally.  The juveniles exhibit crosshatch sculpturing.  The axial ribs grow to large flares as it matures.  The adults may be plain white to purplish and may be striped.  At the base of the aperture there is a projecting tooth.  It lays a distinctive egg case. (From PNWSC.)

The Wallawalla.edu page adds more details: the siphonal tube of the Leafy Hornmouth is closed along its length, opening again at the tip. And the foot is a mottled cream colour.

(The siphonal canal of Trophonopsis is open.)

This is the youngest one in my tank, still quite small. The siphonal canal is completely fused along its length. The tooth is only visible from this angle as a slightly whiter spot. The shell is white with purplish stripes.

Here's the tooth, looking from the side.

Tillie, laying her eggs. The siphonal canal is closed, the tooth is near the entrance to the canal, and the flesh is a mottled creamy colour.

Down at the beach this afternoon, just below the high tide line, I was turning over rocks, looking at flatworms and a variety of eggs and egg cases. On one stone, I found several clumps of freshly-laid egg cases to match the ones at home. And there were the snails; some laying eggs, some eating barnacles. I turned each one over. Every one had the closed siphonal canal and the tooth.

Snail on rock, stony section of upper intertidal zone, Boundary Bay.

One snail in my tank looks like these, (but cleaner) but is much smaller. And its siphonal canal is open. It has no tooth. It's the oddball. Or it's too young to have developed yet. We'll see.

But. There's always a but.

On the Wallawalla.edu page, I see this:
Depth Range:  Low intertidal zone and subtidal to 60 m.
Habitat:  Found on rocky faces near barnacles and bivalves.  Avoids sand and mud. Most common in areas of strong surf ...
So I'm still not totally convinced; maybe other snails have the same egg cases, the same tooth, and the closed canal. I want to see if Mike and Tillie and their companion develop those big leafy wings as they grow larger. I'll keep on studying the reference sites and books until then.

What do you think?



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Monday, September 08, 2014

Green curtains

Hermit in sea lettuce:

Hi!

I'm still working on snails. Everything always takes twice as long as I thought it would.

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Sunday, September 07, 2014

Snail on snail

More aquarium snails; the oddballs

Unidentified snail on young trophon snail, probably Boreotrophon orpheus*.

*More on this species, and why I call it the oddball, tomorrow.

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Saturday, September 06, 2014

Maternity ward, underwater

Mike and Tillie, the large snails in my aquarium, have been together for 6 months now, and may be on the verge of becoming parents. They've been trying for a long time, at least in snail years.

Tillie has been here since last summer, and I brought Mike home in April of this year. By the end of April, Tillie had laid her first batch of eggs. Nothing came of them, though. Sometime around June, I scraped them off the wall, hardened and broken, dead.

She laid two more batches, on and behind the pump at the top of the tank, where I could monitor them closely. Nothing happened; they sat there until they shrunk and died. No snails showed up. (The ones I'd found on the beach two years before had one tiny infant snail on them, so I know these should be visible when they hatch.)

The pair kept trying. They like the pump site, and have glued down three more groups of eggs there. Numbers 4 and 5 were duds, too; buttery yellow vases with nothing happening inside.

But the eggs in batch number 6 are alive, growing and moving about inside their little "jugs", and almost out of room. Any time now . . .

Laying the second batch of eggs on the pump, in July.

A few eggs are visible, but they never developed beyond that stage.

Batch number 6, three days ago. One case is smooth and beautiful, but empty. In the others, eggs and darker snails are visible.

When I watch these, I can see movement, but it is so slow that I wonder if it was just my imagination, or my eyes getting tired. But I go away and come back half an hour later, and the babies are in different positions.

Day before yesterday. Compare the positions of the snails and remaining yellow eggs (or yolks?).

Yesterday. There are more dark snails, and they've moved about quite a bit.

And I continue to check on them every hour or so. At the last check, one of the lower cases had a crack in the pointed tip.

While we wait, here are the propective parents:

Mike, on sea lettuce in a bowl.

Tillie, stretching the surface of the water.

Now there's a third snail, the same species, in the tank; slightly smaller, very clean. A youngster. He/she has shown great interest in the egg laying activity, hanging around an inch away, but never attempting to take part. Nor does s/he attempt to mate with either of the other two. It makes me wonder; are these snails monogamous?

So many questions!


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Friday, September 05, 2014

It's next week!



Just a reminder: Rock Flipping Day is coming up next weekend, September 14th*. Have you picked out your rock yet?

Small rock in my tank. Lots of life on top; I wonder what's underneath?

I'm still chasing baby snails, and trying to be there when some of the eggs hatch. Wish me luck!

*More Rock Flipping Day instructions and history, here.




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Thursday, September 04, 2014

Supporting cast

I'm busy chasing amorous snails and spinny young 'uns. Meanwhile, here are a few more co-operative tank residents:

The only crab in the aquarium at the moment. She doesn't seem to mind.

Val, the big burrowing anemone. The other anemones, the little haliplanella lineatas, clone themselves constantly; she doesn't. She's a loner.

A few tiny acorn barnacles. The snails have eaten all their larger relatives.

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Wednesday, September 03, 2014

Happy hermits

The stars in my aquarium (or maybe the clowns) are always the hermit crabs. They're social animals, and never happier than when they're climbing over each other, or playing a rousing game of "King of the Castle". They love a crowd.

Before the mishap with the pump, there were thirty hermits in the tank, Hairies, Grainy hands, and a bunch of tiny ones, possibly Greenmarks. I took them all out and counted them tonight; twenty-five survived. They look healthy; bright-eyed, curious and lively.

And a fair number are in berry, carrying developing eggs.

In berry. She's carrying reddish eggs on the side of her cephalothorax. The eggs are new; the mass is still small.

After the new pump was installed several of the hermits molted the same day. This would be the moment when they were able to mate; once their new exoskeleton has hardened, it is again impossible.

Very tiny pale blue and green hermit. Probably recently molted, as the colour darkens later on.

Another female, a Hairy hermit, in berry.

A small hermit. I love the graceful "flags" they are always waving. The one on the left (our left) is probably folded back at the moment.

When the eggs mature and are released, the hatchlings will be planktonic swimmers called zoeas. Once again, they will probably be too small to survive in a tank with a pump and filter.

Some critters do breed well in the tank; I'll talk about them tomorrow.

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Tuesday, September 02, 2014

Busy bubbles

A family of bubble shell snails came home on the last batch of eelgrass; 2 adults and 4 tiny ones, still just wriggly brown balls. Two of those got lost, eaten, or crushed, but the other two are now full-size.

And they're all working on re-populating the tank. I keep seeing couples twisted together; later, almost every day, there's a new batch of eggs, some on the remaining eelgrass, but mostly on the glass wall.

Bubble shell underside, on glass wall. Cream and grey, with egg-yolk internal shell.

The largest of the bubble shells. This one has dots of orange on his back, and a dark rear end.

One of the egg masses, a transparent jelly with almost white eggs arranged in a rough spiral.

Smaller bubble shell, with new egg mass. It looks like his inner shell was cracked at some time, although he has recovered. The shells are paper-thin, and brittle.

The egg masses gradually disintegrate over a week or so. Looking at a mass a few days old through the microscope, I can see each individual egg; a solid centre surrounded by its own transparent container. Most of these will be spinning around, slowly the first few days, but more rapidly as they develop.

I haven't seen any new babies crawling about, though. It is possible that they get dragged into the filter and destroyed.

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