Hitchikers and their kin.

My little home aquarium is a self-sustaining habitat. (Well, with a lot of work on my part, but that's just maintenance, making up for the lack of the tides which keep their home clean on the shore.) It's always full of life. Because over the years critters keep appearing, sometimes coming in on seaweed brought in, groceries for the current residents, sometimes sandwiched between barnacles I bring home to keep the snails happy. And sometimes they just sort of appear, whether brought in as eggs or floating in the clean water I collected at the shore. I'm cleaning the tank, scraping off brown algae, getting rid of leftover crumbs, and I see a tiny shape, sometimes just a hint of movement, a crab-like walk, or a waving tentacle. Something new living in the tank.

And I have to keep up the maintenance because I can't abandon my tiny friends, not without carrying every single one down to the proper level of the intertidal zone and releasing it safely. 

Green isopods arrive clinging so tightly to rockweed that I don't see them, even while I'm rinsing it off before I anchor it in the tank.

Rockweed isopod, Idotea wosnesenskii. Showing up on a piece of red alga. About 4 cm. long.

A fourteen-legger. Notice the hooks at the tip of each leg. They cling tightly to the algae, so that even with strong wave action (or me harvesting it) they are not dislodged.

And growing up in the tank is a large community of tiny isopods.

Isopods on an oyster shell. The largest are about 5 mm long. 

A large one, captured on its own.

Whenever I take a shell out of the tank, I find it covered in these critters, all running about, always in a hurry. I don't know what species they are.

A mussel shell, holding two isopods, and a couple of amphipods (the curly ones). The isopods always lay flat.

And this: I first noticed it a month or so ago. It was stuck to the glass below the sand level, only the size of one of the isopods, and looked like a baby limpet from that point of view. But the shape was wrong; it looked oval, not circular. Even with a lens, that was all I could see, but I thought it might be a chiton.

Two weeks ago, it turned up, now recognizable, on an oyster shell. And today it was on a small rock, which I took out, still keeping it underwater, to get a photo.

Woody chiton, Mopalia lignosa. With two orange-striped green anemones.

As far as I can tell, he's a woody chiton. If so, he will grow up to 8 cm. long. Today, he 1.7 cm.

He was not pleased with the trip. As soon as I replaced him in the tank, he hurried back to the oyster shell. These are shy beasties, hiding on the underside of rocks and shells. There, he barely moves from one day to the next, just peacefully eating algae and diatoms; he especially likes green sea lettuce, Ulva spp.. Tomorrow is a low-tide day; if the weather holds, I'll go find a handful of the lettuce for "Woody". And some eel-grass for the hermits, kelp for the crabs, barnacles for the carnivore snails, and ...

And no telling what else will hitchhike in.

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Mi acuario casero es un habitat que se sostiene vivo solo. (Bueno, aparte de mucho trabajo de mi parte, pero eso es mantenimiento solamente, debido a la falta de la marea, que en el mar les mantiene su casa limpia.)  Siempre sigue llena de vida. Porque año tras año siguen apareciendo criaturas nuevas. A veces llegan escondidos entre las algas que traigo a casa para la comida de los residentes ya presentes; a veces se cuelan entre los bálanos que mantienen felices a los caracoles marinos. Y muchas veces aparecen como por magia, tal vez habiendo llegado como huevos o como el plancton que flota en el agua que traje desde el muelle.Estoy limpiando el tanque, raspando algas invasivas, aspirando restos de comida, y veo algo que se mueve, apenas el movimiento ya que el animal es tan pequeño; el movimiento lateral típico de un cangrejo, o el ondeo de un tentáculo miniaturo. Algo nuevo que ahora vive en el acuario.

Y tengo que seguir con el mantenimiento, pues no puedo abandonar a mis amiguitos, no sin llevarlos uno por uno al sitio adecuado de su zona intramareal.

Isópodos verdes llegan cogidos tan fuertemente al alga parda, Fucus spp., tan apegados que no los veo, ni cuando estoy enjuagando las algas antes de instalarlas en el tanque.

Foto: # 1, 2: Isópodo de Fucus, Idotea wosnesenskii. Visible sobre un alga roja. Nótense los ganchitos en cada una de las catorce patas; estos se agarran tan fuerte al alga que ni las olas ni yo al trasportarla logran despegar el animal.

Y han crecido en el acuario una generación de isópodos muy pequeños.

Fotos # 3, 4: Isópodos en una concha de ostión. Los más grandes miden aproximadamente 5 mm. de largo. Siempre que saco una concha cualquiera del tanque, la encuentro cubierta de un gran número de esto, todos corriendo de acá para allá, siempre con mucha prisa.

Foto # 5: en una concha de mejillón hay dos de estos isópodos miniaturos y dos amfípodos; estos son los que se doblan, haciendo medio círculo.

Y esto: lo vi por primera vez hace un mes o más, apegado al vidrio debajo del nivel de la arena. Desde ese punto de vista se parecía a una lapa chica, pero la forma era diferente. Con una lente de aumento lo examiné y pensé que tal vez sería un quitón juvenil.

Hace quince dias estaba, ya más grande, en una concha de ostión y si era un quitón. Y hoy lo encontré en una piedrita. Lo saqué del tanque, manteniéndolo siempre en el agua, y le saqué una foto.

Foto # 6: Un quitón "de madera", Mopalia lignosa, creo. Con dos anémonas.

Parece que si es un quitón de madera. Si es así, puede crecer hasta los 8 cm.; por ahora mide 1.7 cm.

No estaba contento con su viaje. En cuanto lo regresé al tanque se fue a esconder bajo la concha de ostión de nuevo. Estos son animales tímidos que se esconden en la parte inferior de las piedras y las conchas de mar. Allí, no se mueve mucho; se mantiene allí tranquilamente comiendo algas y diátomos. Le gusta la lechuga de mar, Ulva spp.; mañana, que va a ser un dia con marea muy baja, si el tiempo lo permite, voy a la playa a buscarle un poco de lechuga marina para "Woody", y algo de hierba Zostera para los ermitaños, kelp para los cangrejos, y unos bálanos para los caracoles carnívoros. Y ...

Y quien sabe que otra criatura se subirá de pilón.

Gardener's companions

While I'm waiting for it to stop raining long enough to transplant seedlings, a tray of alyssum sits on my kitchen windowsill. I keep it well watered, and the word has gone out: there's a constant stream of sowbugs coming and going, loving the moisture.

There's also a bowl of lichen that gets sprayed twice daily. The sow bugs like that, too.

Sow bug on one of those bamboo "paper towels".

You can tell he's a sow bug by the two tails. Pill bugs don't have the tails, and roll into a ball when they're disturbed. Sow bugs can't do that; they just run and run.

Both pill bugs and sow bugs have seven pairs of legs, like their cousins, the amphipods in my tank. In this bottom photo, the seventh pair is partly hidden by a bit of trash. Usually, if the legs are visible, the beastie is running too fast to count them, but here, he'd paused to rest after I chased him all over the counter with the camera. 60 photos; two turned out.

Sowbugs and pillbugs live in moist environments outdoors but occasionally end up in buildings. Although they sometimes enter in large numbers, they do not bite, sting, or transmit diseases, nor do they infest food, clothing or wood. (Entomology, U of K.)

But they do get lost and end up in my kitchen sink. I catch them and replace them in a damp flowerpot. When the weather warms up, I'll be tossing them out the window into the flower bed.

It bit me!

And that was a good thing.

A couple of years ago, around this time of year, we were walking at the edge of the incoming tide at Boundary Bay, watching small, darting fish. I noticed some other animals, smaller than the fish, and much more active. They were dashing about in every direction, never stopping, always within the first few inches of the tide line.

I took the top off my collecting pill bottle and laid it on its side in the water and, wonder of wonders, a few critters swam in! I've tried many times to catch fish that way; almost impossible; they know it's a trap and stay out. Tiny shrimp, amphipods, even roaming worms, are equally cautious. Not these guys! Nothing scares them.

At home, I put them in a shallow container (this was two years ago) and tried to take photos. Here's where it got difficult. They never, ever, stopped dashing about. All my photos, even a video, were of speeding blurs.

I found and caught some again the other day. And this catch was a repeat. Except that I thought a faster camera might help. It didn't.

But when I removed enough of the water to trap a speeder in a drop, he surprised me by pushing his way through the water surface, climbing over the lip of my tray, and setting off to explore on dry ground. And it's much slower going that way. He even tired himself out!

Here he is, in the lid again, and all tired out from hiking.

Photos taken, I turned my attention to other things. I was moving a shell to the tank, when something bit me on the wrist. One of my speed demons. So tiny, (that lid is barely an inch across) but he delivered a painful bite that hurt for hours.

And that was good, because it gave me the clue I needed to identify these critters. They're Water-line isopods*, and unlike all other isopods I know of, they are extremely aggressive. In fact, according to Dave Ingram at Island Nature,

... if you stand motionless as the water washes over your feet you may soon be covered with nasty red bites!

From WallaWalla.edu: Very few crustaceans will actually bite you but this nasty little creature is definitely one of them.  Barefoot waders in an area with Excirolana will find that the animals quickly swim toward and swarm over bare feet, biting them so hard that blood will be flowing within moments.  Since the animals are so small the bites are tiny but painful like a pin prick, and the animals are often present in swarms of thousands.  Rapidly shuffling the feet reduces but does not eliminate the number of bites.

Now they tell me! I'm glad my current wading shoes are closed. And I won't be getting anything less protective in the future.

These isopods are scavengers that help to keep our beaches clean by eating any dead matter they can find. Thousands will swarm over a dead fish at the water's edge, and reduce it quickly to a skeleton.  They don't mind live meat, either, apparently.

*Once known as Cirolana kinkaidi, then Excirolana kinkaidi, aka Excirolana chiltoni.

Story on Stories Beach

Another of the Campbell River series.

One of my favourite beaches along the Campbell River coastline is Stories Beach. (Variably spelled; I've seen Storey's Beach, Storie's Beach. It's at the foot of Storrie Road.)

The beach has everything we could want; at the north end, children splash on sandy flats, adults walk dogs or head out on paddleboards; towards the south, where we like to wander, there are flat sandstone fields, fenced (by Ma Nature) with rows of rocks, covered with sea lettuce and crawling with critters of all descriptions. This trip, because of Laurie's injured leg, our time on the beach was limited. We still managed to get some photos to share.

Looking south. Sandstone flats, with Bonaparte's gulls.

Another burrowing anemone, with its heart markings on the tentacles.

A tiny green sculpin, pretending to be a shred of sea lettuce.

Bull kelp, float and fronds.

This old wheel doesn't belong, but it's being absorbed. Meanwhile, it makes a handy tidepool.

Very small sandpiper.

Pair of sandpipers, poking around under the seaweed for lunch.

On the upper levels, the sandstone is sculpted by wind and waves.

Sandstone rock, mid-intertidal zone. Here, they're gritty, covered with barnacles and mussels, and perforated with critter tunnels. The white mark at the centre is the bottom shell of an oyster, cemented to the rock and left behind when the oyster died.

In a deepish tide pool, assorted brilliant seaweeds flourish. Yellow rockweed, green sea lettuce, red stringy stuff, unidentified.

I turned over a rock that was a bit too big for me. My feet slipped and I went down on my back in an inch of water and mud. I missed the community sheltered under the rock, though.

Wosensensky's isopods, a few stubbies, and a pink and cream anemone, possibly the pink-tipped anemone.

Stubby isopods, the large Wosnesensky's, and a good-sized flatworm.

No critters were harmed in taking these photos. Nor was I, really; just wet through, and muddy. I managed to put the rock back in place without squashing anything, too. Time to head home, stopping at a garage sale on the way. A bit of muddy water never hurt anyone.

Glittery sea down the Georgia Strait.

This was the beach where we found the fish skull. More on that, later.

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.

Hidden harems

Each visit to the beach turns up a new mix of critters and plants to investigate. This Wednesday, we arrived at the White Rock beach just after high tide, a low high; there was plenty of barnacle-covered stony beach to keep us busy.

Stubby isopods like to hang out where the salinity is low. On this beach, that means around the openings of the culverts bringing runoff from the steep south slope of the town. Usually there are a few there, crawling around the tiny barnacles and mussels on the bottom side of the rocks.

This time, they were everywhere, in great numbers. Every stone I turned over had a busy colony.

Stubby isopods, aka Oregon pillbug, Gnorimosphaeroma oregonense. Look closely; the eyes are visible, mostly on the pale brown ones.

These isopods are very similar to the woodbugs (aka pillbugs, woodlice, roly-polies, etc.) that feed in our gardens. They grow to about 1/2 inch long at maturity, although most of the ones we saw were the smaller harem females. Like the land-based pillbugs, they roll up in a tight little ball if they are disturbed. Just brushing them off a stone will do it; they land rolling.

Pillbug "pill" on the barnacles, lower right.

It's spring; party time, time to find mates and start the next generation. For the stubby isopods, that means sex changes and harems. The baby isopod hatches as a female. She becomes a member of a harem "owned" by one male, produces one brood, then begins a series of molts which transforms her into a male, ready to find his own harem of immature, smaller females. If the harem's male is removed, or dies, the dominant female in the group becomes a male to take his place.

(Most other crustaceans that switch sexes have a reverse pattern; the immatures are male, and they become female at maturity.)

The spring population explosion will not last; crabs and hermit crabs love a snack of unrolled isopod. Like the tides, life on the beach ebbs and flows.

More info: UAS.Alaska, Protogynous Sex Change in the Intertidal Isopod Gnorimosphaeroma oregonense, WSU Beach Watchers.

It's official!

Yesterday, March 20th, was the vernal equinox, the first official day of spring. We celebrated (since the sun actually shone all day) by going down to White Rock beach to see what kind of a tide the supermoon had gifted us with. It was low, but not down to the level where we start to see starfish and geoduck clams. But there were eagles and crabs and ... Here: look.

"Begin her"? (That's what it says. Click to read the sign.) 

"To the lonely sea and the sky"

Glittery

Miniature tide pool atop a rock. Barnacles, periwinkle snails, seaweed.

Big barnacle mouth

Warty rockweed

Green stone, with barnacle scars

Mussel lips

Checking out a tiny creeklet

I see a face. Do you?

A community of isopods, on the underside of a stone.

Stoney happy face.

And the eagles flew far overhead, dodging crows.

Fourteen leggers, all

The Christmas season seems to have started. Laurie's making Christmas cards; I'm making lists.  Food, gifts to make, buy and/or wrap, seating and eating arrangements, cleaning to do, guests ... my family will be here Christmas Eve, some 25 or more of them. We probably won't be getting out much for the next two weeks.

I'll be getting my critter fix from my files; good thing there are so many!

These sea slaters were on the rocks at Oyster Bay, on Vancouver Island this summer.

The antennae look like old lead pipes.

Ligia pallasi

These isopods live just above the high tide line, hiding in the cracks of the rocks in the daytime, coming out at night to scavenge for dead plants and animals or growing algae. They can be quite large, up to about 1 1/2 inches long. Most are uniformly grey; the ones we saw at Oyster Bay had a cream-coloured dotted line down the center of the armored plates.

They are in the same sub-order as our common woodbugs or pillbugs, and look very much like one, only larger and faster-moving.

Compare:

Armadillidium vulgare, our common pillbug

And here are some intertidal isopods, also for comparison:

Intertidal isopods, next beach up. About 1/3 the size of the sea slaters.

Local eelgrass isopod. About 1/2 inch long.