On the edge

When I visit a beach at a low tide, the first thing I do is walk out to the very edge of the water, and stand there for a couple of minutes, watching to see if the tide is coming or going, to calculate how much time I have to poke around. On a flat beach, an incoming tide can race, sometimes faster than I can walk safely; it doesn't do to get trapped.

Here, the tide was just about to turn; each tiny wavelet reached a level a hair's breadth lower than the previous one. Going out, but barely.

So: water's edge photos.

Intersection. Sand to my left, seaweed and stones to my right. A crow with something yummy.

Flat, but stony and slippery. Glacier scrapes. The area I left for next time, when the tide is still going out and I don't have to hurry.

Not the head of a giant seal.

Eelgrass being pushed towards the shore.

Last month, I was wondering how the eelgrass left on the sand by the outgoing tide ended up mainly pointing inshore. Now, with the water neither coming nor going, I watched several clumps of eelgrass still underwater. And they all floated with the roots towards the water, the tips towards shore. With each incoming wavelet, they lifted slightly, swished shorewards. As the waves retreated, they settled on the sand. So the outgoing water wasn't moving them, only the incoming waves.

That would explain the huge rows of piled seaweeds at high tide line after a storm, too. I've often wondered about that. Outgoing water pulls down towards the sand (or rocks), incoming waves lift and push.

Starfish looking for shelter beside the wrong rock.

Most of the starfish I passed had hidden themselves on the shady side of rocks with tidepools. A couple were just too far away and lay exposed on the sand, but still close enough to the water that the incoming tide would cover them in short order. They'd be ok. They're an intertidal species, adapted to survive several hours out of water.

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Cuando me encuentro en una playa con la marea baja, lo primero que hago es caminar hasta el mero borde del agua; allí me detengo unos minutos, observando para ver si sube o si baja el agua, con el fin de calcular cuanto tiempo me queda para explorar. En una playa poca inclinada, la marea, subiendo, puede correr, a veces más rapidamente de lo que yo puedo caminar con seguridad.

Este dia, la marea estaba casi a su punto más bajo; cada olita alcanzaba un nivel apenas milímetros más bajo que la ola previa. La marea salía, pero estaba al punto de volver.

1. Donde se encuentran dos tipos de playa; a la izquierda hay arena limpia; a la derecha, rocas y algas marinas. Un cuervo trata de abrir algo, un mejillón, tal vez, o un caracol marino.
2. Esta parte de la playa es resbalosa, llena de piedras movedizas; terreno formado por glaciares camino al mar. Un sitio que dejé para otro dia, cuando pueda seguir la marea mientras bajaba, para evitar apuros.
3. No es la cabeza de una foca gigante. Aunque así parece.
4. Hierba marina Zostera, empujada por las olas, apuntando hacia la tierra. 
   
   El mes pasado, me preguntaba como es que la hierba dejada en la arena por el agua que se aleja de la playa reposa apuntando hacia tierra firma. Ahora, cuando el agua ni venía ni se iba, observaba varios grupos de esta hierba que seguían bajo las últimas olitas. Y todos flotaban con las raices mar adentro, las puntas hacia tierra firma. Con cada ola, se levantaban las hojas un poquito, moviéndose hacia la playa. Y al regresar la ola, se asentaban sobre el sustrato. Así que el agua que se retiraba no las empujaba, sino solamente las olas que se rompían en la arena.
   
   Eso explicaría también los montones de algas marinas muertas que quedan a la linea de altamar después de una tempestad, algo que me ha intrigado muchas veces. El agua que se va arrastra la hierba hacia abajo, contra el sustrato; olas que vienen la levantan y la impulsan hacia la tierra.
   


5. Estrella de mar, buscando albergue al lado de una roca inadecuada.

La mayoría de las estrellas de mar que vi se habían escondido en las pozas mareales en la sombra de rocas grandes. Unos cuantos les había sorprendido la marea demasiado lejos de las piedras y se quedaban expuestas al aire y al sol. Pero estaban suficientemente cerca del agua para que la marea les cubriría en poco tiempo. Son una especie intermareal, y están adaptadas para sobrevivir varias horas fuera del agua.

Sorry about that.

I stepped on and broke several sand dollars yesterday. I'm sorry. I was in a hurry and not paying attention.

I was not planning on stopping at the beach, but on my way home I saw that the tide was 'way out, and the sand flats were empty and inviting. Couldn't resist.

The sand was clean, almost dry, and filled the bay. I walked out towards the water's edge; first stop, to see if the tide was coming or going. At first, the sand was smooth and bare. Everything living there, worms and clams and snails, was hiding underground, away from the deadly sunshine. Groups of eelgrass, mixed with a few seaweeds, lay flat on the sand.

But what was this? Most of the eelgrass lay with the tips pointing shorewards. But why? The last water they were in was rushing in the opposite direction. Shouldn't the plants have been swept seawards?

Explain this. I can't.

Half of the eelgrass here is laid down in the "proper" direction.

I stopped to look at a few more patches of eelgrass; most pointed shorewards. But I was wasting time; the tide might be coming in. I hurried, then, down towards the water's edge to see. And forgot to watch my feet until I felt the crunch of a broken, now dying sand dollar.

Look down!

How many sand dollars?

Live sand dollars hide at low tide just under the surface of the sand. They're fragile critters; step on one, and the test (shell) shatters.

Sand dollar community, detail. One sand dollar visible.

So I tiptoed out of the area, quite a large patch, and no matter how careful I was, I couldn't help smashing a few more animals. So sorry!

And then the tide was coming in, fast, and I had to hurry back to shore.

Old clamshell. Step on this without a pang. But check first, in case there's a crab hiding underneath.

Giant Pacific chiton, near the high-tide line. This one was dead already.

The tide rushed in. Before I got to the rocks of the breakwater, the sand was covered.

Good thing I hurried!

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Ayer pisé y machuqué varias galletas de mar (dólares de arena). Lo siento. Tenía prisa y no me fijaba donde caminaba.

No tenía planes de ir a la playa, pero camino a casa vi que la marea estaba muy baja, y la playa arenosa esperaba, ancha, vacía. No pude resistir.

La arena estaba limpia y casi seca, y llenaba toda la bahía. Me dirigí hacia la orilla del agua; el primer objectivo para ver si la marea iba o venía. Al principio, la arena estaba muy lisa, sin objetos. Todo lo que vive aquí se escondía bajo la arena, para escapar la luz solar, tan peligrosa. Grupos de la hierba de mar, Zostera marina, estaban aplastados sobre la arena.

Pero, ¿qué pasaba aquí? La mayoría de la hierba se había quedado con las puntas de la planta apuntando hacia la playa. ¿Pero, porqué? Lo último que habían visto del agua, esta corría en dirección opuesta. ¿No deberían haberse inclinados hacia el mar?

1. Hierba de mar, apuntando hacia la playa. Una flecha con dos cabezas: hacia la playa, y hacia el agua.
2. La mitad de esta hierba se inclina en la dirección que se supone sería inevitable.
3. Me detuve para examinar otros grupos de hierba; la mayoría apuntaba hacia la playa. Pero se me iba el tiempo y la marea podría estar avanzando ya. Me apuré, entonces, hacia la orilla para ver cuanto tiempo me quedaba. Y se me olvidó fijarme donde pisaba hasta que sentí que algo se quebraba bajo mi pie. Una galleta de mar, ahora una galleta de mar moribunda. ¡Fíjate donde pisas, mujer!
   
   ¿Cuántas galletas de mar hay aquí?
4. Las galletas de mar vivas se esconden apenas bajo la  superficie de la arena. Son frágiles; si pisas una, se fragmenta su esqueleto.
5. Comunidad de galletas de mar, detalle. Con una visible.
6. Concha vieja de almeja. Pisa esta sin problemas. Pero mejor, primero asegúrate que no esconde un cangrejo refugiándose del sol.
7. Quitón bota de goma, Cryptochiton stelleri, cerca de la playa. Muerta.
8. Y la marea subía rapidamente. Antes de que llegara a las rocas del rompeolas, ya estaba cubierta la arena.

Tied in knots

The tide was high, the wind brisk, the waves bouncy. The beach near Salmon Point was just a narrow strip of stones between the water and the rocks of the breakwater. I was there to look at eelgrass and kelp, torn from their roots and holdfasts, all tangled and tossed up by the waves.

Tangle of fresh bull kelp and eelgrass.

A knot like this is full of interest; teasing out separate strands, I find mostly eelgrass, rockweed, sea lettuce, and kelp, with occasional fragments of Turkish towel or washcloth, and maybe some spaghetti-like brown algae. Living on the blades of kelp are bryozoan colonies, sometimes, if I'm lucky and sharp-eyed enough, with their tiny cryptic nudibranchs. Any holdfasts that show up house miniature worms and immature snails, possibly a baby starfish.

The eelgrass carries snails and amphipods, sometimes a stray hermit crab. And in season, there are a variety of snail and nudibranch eggs, all doomed to be tossed onto the stones to die and be sundried. Some of the eelgrass crumbles and disappears; some remains as blackish heaps, leaping with sand hoppers. 

The kelp stipes hold their shape for a long time, bleaching to a greenish yellow. Crabs and hermits love to eat this when it ends up back in the water.

Eelgrass and sea lettuce. Green blobs in the waves themselves are sea lettuce washing in.

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La marea estaba a su máximo, la brisa algo fuerte, las olas caían en espuma sobre las piedras de la playa que ocupaban apenas unos metros entre el agua y el rompeolas de piedra. Yo estaba allí buscando hierba Zostera y quelpo, arrancados de sus raices y rizoides, hechos nudos y depositados por las olas sobre las piedras.

Primera foto: un nudo de quelpo Nereocystis luetkeana y de hierba Zostera en la playa cerca del Punto Salmón.

Un enredo como este tiene mucho de interés. Al separar cada hoja y estipe, encuentro en su mayor parte hierba Zostera, el quelpo, lechuga marina (Ulva sp.), sargaso vejigoso, con fragmentos de toalla turca, y otras algas pardas. En las hojas del quelpo viven colonias de briozoos, y a veces, si tengo suerte y los ojos no me fallan, con sus nudibranquios crípticos que comen los briozoos. Los rizoides que llegan al nudo protegen anélidos pequeñísimos y conchas marinas juveniles, y a veces una estrella de mar infantil.

La hierba Zostera marina lleva conchas marinas y anfípodos, y de vez en cuando un cangrejo ermitaño. En ciertas temporadas habrá huevos de varios nudibranquios y conchas marinas, todos destinados a morir sobre las piedras, tostarse en el sol, y o quedar como un montoncito de fibras negras donde saltan las pulgas de arena, o desmoronarse y desaparecer.

Los estipes del quelpo permanecen por largo tiempo, volviéndose suave y de un color amarillento. A los cangrejos y ermitaños les gusta comer esto, cuando por suerte cae otra vez en el agua.

Segunda foto: piedras, olas, y hierba Zostera. Las manchas oscuras dentro del agua son fragmentos de lechuga marina.

Rabbit-eared zebra

It was a grocery run. For the aquarium, that is. I had gone to the shore to collect eelgrass and kelp for my critters in the tank.

(I found the slime mold on my way back through the woods.)

The waves were noisy, the tide coming in. All along the edge were lines of eelgrass, all torn, mostly without roots. I was looking for roots; planted eelgrass lasts longer in the tank. On the return, I walked along the upper tide line; here the debris was older, drier, but less mangled. I found the kelp. And a big knot of eelgrass, with lots of roots. Dry and dying, but more or less complete. It went in my bag, with a freshly-molted crab shell.

At home, I washed the crab shell and added it to the tank. Hermits and crabs immediately organized a party.

The kelp was next; washed, it went into the tank.

Then I untangled and washed the eelgrass, removing foreign material, such as fragments of plastic. (They're everywhere, these days.) I didn't plant the eelgrass, not wanting to disturb the crab-meat banquet yet. It floated on top of everything for a while.

An hour or so later, a bright green spot showed up on a bit of dark seaweed, like a fragment of eelgrass gone a-wandering.

A zebra leafslug! About 1 cm. long. Phyllaplysia taylori.

The zebras are related to the nudibranchs, the sea slugs. They are also known as sea hares, probably referring to the two tentacles on the front of the head. They are more like flaps of skin, folded so that they look like rabbit ears. Green spotted rabbit ears.

The second two appendages are rhinophores (from rhino = nose, phore = carrier, Greek), sensory organs, "smellers." And just in front of the rhinopores, the eyes. Or at least, light-sensing organs.

Heading towards the green light.

I've found these leafslugs twice before, both times in the same situation, in Boundary Bay; eelgrass abandoned on the shore. They often hide in eelgrass, where they match the colour and stripes, resting between two blades at the base of the plant. They both survived for some time in the tank. I'm hoping this guy manages to find himself a safe corner.

Photo from 2014.

The "zebra" part of his name refers to the stripes. Imagine a green, underwater zebra.

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Iba en busca de comida para el acuario. Necesitaba hierba marina zoster, y algas "kelp" para alimentar a los animalitos en mi tanque.

(Es cuando encontré el moho mucilanigoso, en camino de regreso por el bosque.)

Las olas estaban altas y ruidosas; la marea subía. Al borde del agua había una fila de hierba marina, pero toda rota, sin raices. Buscaba raices, porque la hierba dura más tiempo en el tanque si la puedo sembrar. En la vuelta de regreso al largo de la playa, caminé en el nivel de la marea alta. Aquí, los desechos estaban algo secos, viejos, pero no tan rotos. Encontré el kelp, y luego un manojo de hierba, toda enredada, seca, pero con raices. La puse en mi bolsa, con los restos de un cangrejo recién mudado.

En casa, lavé la concha del cangrejo y la puse en el tanque. Los residentes, cangrejos y cangrejos ermitaños de inmediato organizaron una fiesta.

Siguió el kelp.

Luego lavé y desenredé la hierba con cuidado, quitándole objetos extraños, tales como fragmentos de plástico. (Estos, los encuentro dondequiera, en esto dias, desafortunadamente.) No sembré la hierba, pues no quería interrumpir la fiesta abajo. La dejé flotando bajo la superficie.

Una hora más tarde, un objeto verde brillante apareció en una de las algas rojizas. Parecía un pedacito de hierba ambulante.

Era una babosa de mar, "cebra", Phyllaplysia taylori, como de 1 cm. de largo. (Primera foto.)

Los "cebras" tienen parentesco con los nudibranquios. También se conocen como conejos de mar, por los dos tentáculos en la parte anterior de la cabeza. Son algo como prolongaciones de piel, dobladas hasta que parecen orejas de conejo. Orejas de conejo verdes, con lunares.

Los dos tentáculos atrás de las "orejas" son rinoporos, órganos sensorios, que perciben olores. Justo en frente de estos, se puede ver los dos ojos, que más bien son órganos que perciben la luz, pero no ven más.

He encontrado estos animalitos dos veces en años anteriores, en Boundary Bay, las dos veces en la misma situación; hierbas zoster abandonadas en la playa. Los dos sobrevivieron algún tiempo en el tanque. Espero que este también se encuentre un escondite seguro.

La tercera foto es del año 2014. Aquí se ven las rayas que le dieron el apodo de "cebra'.

Workout moves

In my aquarium, something, probably a crab, dug an eelgrass' roots out of the sand, leaving it floating upside-down, roots near the surface. Looks like fun, a little hermit crab said, and climbed up to practice his trapeze artist skills.

Head down

Feet up

Balancing on the bar

He's got a few holes in his shell. One is big enough to expose his backside.

The stripy section is the back of his cephalothorax, his head/thorax section. The abdomen is curled up in the bottom of the shell, as it lies here. There are a couple of holes there, too. Good fresh water circulation!

And then he climbed down again and went to pester the anemones.

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En mi acuario, alguien, probablemente un cangrejo, excavó las raices de una planta Zostera marina, dejándola flotando con las raices para arriba, cerca de la superficie del agua. Un cangrejito ermitaño, Pagurus hirsutiusculus, la vió y decidió ir a practicar sus habilidades de trapecista.

Tiene varios agujeros en la concha que lleva, uno bastante grande. Se le ve el cefalotórax en este. El abdomen queda en la parte inferior de la concha, como está dispuesta en la última foto, pero ahí también hay un par de agujeros. ¡Ventilación!

Y terminado el ejercicio, se regresó a la arena y fue a molestar a las anémonas.

Sticky eggs

Every spring I hope to see the herring spawn. So far, every year I've missed it. But I got down to the shore a few days later, and found a coating of roe everywhere.

A handful collected off the sand.

Herring roe on washed-up eelgrass.

The herring come in huge, dense schools—sometimes several kilometers long. Once they reach the spawning grounds, each female releases up to 40,000 clear, sticky eggs. The eggs stick to everything; they stick to the eel grass…they stick to the sea lettuce…they stick to the kelp…they stick to the rocks…they stick to the shells…they stick to the barnacles. In fact, there’s so many eggs that they don’t all get a chance to stick before the waves and the tide wash them up on the beaches—sometimes forming masses of eggs a foot or more deep. (Return of the Brants)

The eggs weren't a foot deep on the shore of Oyster Bay, just several inches deep all along the outer shore, and on everything tossed up by the tide.

MIllions and billions of eggs.

I was looking for kelp, to maybe cheer up my plumose anemone, but along the whole length of the Oyster Bay shore, inner and outer, I didn't find even one piece. Next time.

Pacific herring eggs are negatively buoyant. By depositing many layers of eggs on fronds of kelp, the spawn of herring has been known to sink entire kelp forests. Upon hatching and the release of tiny, swimming herring larvae, the forests rise again. (Raincoast.org)

I brought home a few handfuls of egg-laden eelgrass for my hermits and crabs. They usually like anything that grows on eelgrass. But not this time; a few of the crabs nibbled on eggs, but the hermits left them strictly alone.

It makes sense; the hermit crabs are scavengers; they don't take live food. The minute it dies, it's fair game.

I looked at the eelgrass under the microscope.

A blade of eelgrass with herring eggs.

More eggs. They are white, without a purple or green eelgrass backing.

A few days later. Each egg has a white blob inside. I don't see any movement there, but around the edges teeny copepods swim happily.

After a day in the tank, the eggs started to fall off the eelgrass, and coat the sand at the bottom, just as they did on the shore.

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Año tras año, en la primavera, los arenques llegan a nuestras playas para depositar su hueva. Y año tras año, yo llego tarde para verlos. Ni modo: por lo menos esta primavera, llegué a tiempo para ver los huevos que habían depositado.

Cada arenque desova hasta 40.000 huevos. La mayor parte no llegan a nacer; se los comen los pájaros, las focas, mamíferos como por ejemplo los mapaches, y hasta los osos. 

Los huevos son pegajosos, y se adhieren a todo lo que tocan; algas marinas, piedras, los percebes y caracoles, hierba Zostera, kelp, y hasta la arena de la playa, donde forman una capa que puede llegar a 30 cm. de hondo.

Recogí una bolsita llena de hierba con hueva para los cangrejos y ermitaños en mi acuario; siempre les gusta una poca de variedad en su dieta. Pero los ermitaños no la comieron; son carroñeros y no comen comida viva.

Después de unos dias, los huevos se depegaron y cubrieron el suelo de mi acuario, tal como lo habían hecho en la playa. Pero no tan hondo, claro.

No sé si alguno de los pecesitos vayan a nacer en mi tanque. Ya veremos.

Bubbles and bladders

Winter is almost over, and the occasional blade of eelgrass is turning up on the beaches again. I found a few plants with roots and brought them home. The hermit crabs are happy about that; they love to sit up high on a green blade and watch the world go by.

View of the tank with winter seaweeds; red algae and brown wireweed. And 3 eelgrass plants.

The tall, brown seaweed bearing little round float bladders is a Sargassum, possibly Sargassum muticum, an invasive from Japan. For most of the winter, the hermits and snails ignored it, not interested in searching it for food. In the last few weeks, perhaps tired of having nothing to climb, a few have been found swinging on the upper branches, but now that there's a bit of eelgrass, they've abandoned the Sargassum again.

Few organisms have been found living on Sargassum muticum in British Columbia, though a number have been reported in Washington, Oregon and California. A study in southern California estimated that a 5 m tall plant hosts an average of 3,000 animals, including foraminifers, hydroids, flatworms, polychaete worms, leeches, snails, ostracods, cumaceans, isopods, gammarid and caprellid amphipods, opossum shrimp, euphausid shrimp, crabs and bryozoans ... (Nicholson et al. 1981) (The Exotics Guide)

Why BC critters are pickier than the ones in the U.S, I have no idea.

"Bubbles", hanging out on the eelgrass.

Bare-bones flowers

Eelgrass is not a seaweed, but a perennial flowering plant, related to the land-based grasses. In spring and summer, the plants send out long, stiff stems, bearing clusters of flowers. "Relatively inconspicuous," Kozloff says; an outright understatement. 

You'd never seen them? Nor had I. I'd found the unripe seeds; rows of yellow-green buttons along the blades, but no flowers. Until now. The lonely eelgrass plant I found last week is loaded with them, tiny male and female flowers in separate rows, half hidden between the blades.

They don't exactly look like my preconceived idea of flowers, but the essentials are there.

Zostera marina; female flower styles, half covered by a sheath. A few developing seeds on a lower blade. And the yellowish, stiff stem at lower right. The blades of eelgrass are 4 mm. wide at this point.

The female flower is little more than a two-pronged tube (the style) with an ovary beneath. It captures floating pollen threads, and then bends down against the blade to produce its fruit. Each fruit contains one seed.

Another row of female flowers, one tangled in pollen.

The male flower grows on the same plant, but on different blades. It does look a bit more "flowery"; it is like a thick, cupped petal a few millimetres tall, and releases pollen at the tip.

Three blades of eelgrass, one with a style and pollen, and the rear one with the anther, which produced the pollen.

The male flowers depend on water currents to carry the pollen threads to the styles; no other pollinators are needed. The stems are light and float to the surface, which keeps all the flowers more or less at the same depth and exposed to sunlight. The seeds, once they mature, are heavy, and drop out of the sheath to the ground beneath. There they may take root, or be eaten by birds and fish, and carried, undigested, to new meadows.

I've noticed that the hermit crabs eat everything that grows on the eelgrass, except the flowers and seeds; these they leave strictly alone.

Dancing jester

Nothing is ever as simple as it seems. Especially underwater. Everything is layered; things grow on shells, on seaweed, on rocks; other plants and animals grow on those, and are home, again, to another community of something else. And everything eats. Hydroids eat plankton; nudibranchs and hermit crabs eat hydroids; crabs eat hermits when they can catch them; gulls eat crabs. So do we, if they're big enough.

On one of the blades of the skinny eelgrass I brought home the other day, I noticed a fuzzy barnacle. And the fuzz, looking at it with a hand lens, was not the expected diatoms or algae.

Side view of the blade of eelgrass. The barnacle is about 3 mm high.

These look like some type of hydroid; there's a stalk, a polyp surrounded by tentacles, these ones with knobs on the tips. But I can't find them in any of the books or web pages I've searched, probably because they are too small to attract attention.

Our common Obelia hydroids are branched.

Small Obelia, on another blade of the same plant. The eelgrass blade is 4 mm. wide.

But the new ones are clubs with at the most two polyps at the top. And they're noticeably orange, rather than semi-transparent like the Obelias.

But wait a minute! Looking at that first photo again, what is that thing that looks like a little man in a jester's hat? That's no hydroid!

I watched for a while, and the jester began to dance.

See him there, on the centre left side of the eelgrass?

It's a Caprellid, a skeleton shrimp. I never expected to see one so small. But nothing else dances like they do.

Standing upright again, waving antennae and big pincers (the jesters hat).

I found three more skeleton shrimp, all about the same size, along the blade of eelgrass. Standing upright, with the pincers raised, they mimic the hydroids, possibly as protection from predators that will avoid the stinging tentacles of a hydroid, and otherwise would find a caprellid quite tasty.

Most species are predators that sit and wait like a praying mantis, with their gnathopods ready to snatch any smaller invertebrates which come along. They accentuate their adaptive form and colouration by assuming an angular pose, resembling that of the fronds among which they live. They remain motionless for long periods of time while waiting to ambush their prey, often protozoa or small worms. (From Wikipedia, Caprellidae)

Wikipedia adds that they are eaten, in turn, by anemones, nudibranchs, and fish. I think I would add hermit crabs to the list. The colonies of hydroids and skeleton shrimp lasted only a night, with a dozen hermits busy cleaning the eelgrass. All that was left in the morning was the barnacle.

....

And there's more! Empty doughnuts tomorrow.

On staples and little boxes

Sea lettuce. Barnacles. And eelgrass. The staple foods for my aquarium critters. Barnacles for the leafy hornmouth snail, sea lettuce for the hermits, the crabs, and the bubble shells. And eelgrass, preferably decorated with hydroids, for the hermits and snails. Anything else is a special treat, but these three are essentials.

This week, the high tide brought in a truckload of fresh, bright green sea lettuce, which pleased the bubble shells; one ate so much of it that I could see the green in his stomach right through the shell and flesh.

But though I walked a long way, just at the edge of the incoming waves, I only found one small eelgrass plant. And it was a meagre, frayed one, mostly straggly stem and browning leaves. I would have left it there, except that it was the only one available. I and the hermits would have missed a treat.

Settling it into the tank, I noticed a small patch of bryozoans on one thin blade of grass, just below the water surface. A live patch, too; I could even see, with a lens, movement on its surface.

I rarely get to see these; out of the water, they shut down instantly. Underwater, the turbidity and the depth make them into a faint blur. Too much light, and they're asleep. And the individual animals are so very tiny; millimetre-high, transparent funnels.

Encrusting bryozoan colony, Membranipora membranacea, awake and feeding.

This is a small colony, about 8 to 10 animals from edge to edge. Each individual zooid lives inside a little box; seen from above, they look like walls, but there is a top, as well. The animal lies horizontally inside, and when the situation looks right, extends its feeding funnel up into the water. At the slightest disturbance, the funnels disappear and all that can be seen are the walls.

Hydroids and anemones have stinging tentacles, to subdue their prey; these bryozoans do not, but are filter feeders like the barnacles, relying on water currents to deliver their groceries. They will eat diatoms and bacteria, as well as other planktonic swimmers, like my newly-hatched crab zoea.

The little spines at the corners of their boxes (difficult to see here, but we really need a microscope for a better view, like this one) help to make the colony an uncomfortable base for a hungry Doridella nudibranch. I found several of these a few years back, on kelp, eating bryozoans, spines or no spines. There were none on this little eelgrass; not enough prey to keep them here.

...

That was the beginning. I kept finding more and more interesting things on that eelgrass. Unidentified "thingies", tomorrow. And a thingie mimic.

Sand in his teeth

Found on Crescent Beach:

"That's not my spinach!"

Eelgrass washed up on the west shore of Boundary Bay and around the corner at White Rock piles itself up in great, knotty heaps of rotting black bands, smelly and usually covered with flies. On Crescent Beach, on the east shore, it blows up above the tide line onto the gravel, and dries into these short brown ribbons. No flies, no noticeable odor.

It is probably the effect of the wind, which is much stronger and more constant on Crescent Beach.

Tidewrack

With the tide at its maximum on Boundary Bay, I poked around in rolls of tangled eelgrass and under stones, and found nothing alive but a pair of barnacles broken off their rock. But the eelgrass had brought in many recently molted crab remains, their legs tied up in dripping green ribbons.

The waves and tide rip up tall eelgrass and create astonishingly complex knots with it.

"... the longer a string got, the greater the odds of knot formation became." From a study of the physics of knotted string, reported on Wired.

This little molt had been tossed up above the waves and was still intact.

Young molted crab, with sea lettuce. You can see, at the base of his carapace, where it separated to allow him to back out of his hard "skin".

I liked the rock he was on, too.

What makes that yucky-looking yellow foam? I'll explain tomorrow.

Rabbit ears on a green zebra

Ten minutes on the beach; that's all I needed. The weather was miserable, and I wasn't dressed for it; Laurie's feet hurt and I was trying to ignore a migraine. But I had to go to the beach because my critters were getting bored with their store-bought diet. They wanted green stuff, green and soft and salty.

Luckily, the tide was just off the peak and the water was choppy; all along the shore were piles of ripped-up eelgrass, still wet, still fresh. I collected a bagful in my ten minutes. Long blades of eelgrass, sheets of sea lettuce, the durable red Turkish towel, rockweed, delicate red lacy fronds, sugar-wrack kelp, a tall, leafy, bladder-bearing weed, and handfuls of blackish hair; everything newly deposited in a convenient pile for me.

My critters are happy again.

Most of the animals that have the bad luck to be riding uprooted seaweeds at high tide end up dying when the water recedes. I checked my gleanings over carefully, as usual, turning up a few feeble amphipods and a couple of snails.

One of the blades of eelgrass had a brighter green spot on it, barely noticed as I planted the roots in the aquarium. A few minutes later, I saw it again, swimming, and fished it out.

Zebra leafslug, 1 cm. long, on sea lettuce. (I had to fade out the background, almost the same shade as the slug. Good camouflage.)

I had never seen one of these before, but it was easy to find in my Encyclopedia, near the nudibranch section. But it's a sea hare, not a nudi.

The sea hares are related to the nudibranch, the bubble shells, and the aglaja that I've found before, all Gastropods among the Heterobranchia. The bubble shells are like snails that carry their shells mostly inside the body. Nudibranchs have no shells. And sea hares may or may not have shells, which like the bubble shells, they wear under the skin. In the zebra leafslug (aka Taylor's sea hare, or Phyllaplysia taylori) the shell is probably just a small plate, invisible inside the body.

Another difference: the nudibranchs' gills are outside the body cavity, (therefore nudi = nude, branchia = gills). The sea hare's gills are inside. On the photo above, towards the back on the right, there is a projection, like a flap. Sea water enters through a hole on the head end of this flap, and exits on the other.

While I checked him out and looked up info, the leaf slug rested on the sea lettuce in a bowl. He barely moved; I wondered if he was dying after his stressful afternoon, in the waves and in my car. But then I learned that he lives on eelgrass, eating the diatoms and algae that grow there. I put him on a knot of eelgrass in the aquarium and he woke up and started to wander.

"The Zeeb", on eelgrass in the aquarium.

Sea hares got their name long ago, from the two tentacles on the front of the head. They are more like flaps of skin, folded so that they look like rabbit ears. A little back from these are the rhinophores (from rhino = nose, phore = carrier, Greek), those tall white tubes. Zeeb smells with these.

The eyes are at the base of the rhinophores, but probably don't see more than the difference between day and night.

 Zeeb is a youngster, about half his adult size. He's a hermaphrodite, with both male and female organs, capable of fertilizing another leafslug and then laying millions of his/her own eggs. On the eelgrass, of course.

. . . sea hares often forming mating chains of 3 or more animals where the ones in the middle are acting as males and females simultaneously. (http://www.seaslugforum.net/message/17079)

Zeeb's been prowling around the eelgrass and the glass, cleaning up the algae for a day now. I hope the aquarium suits him. I'll have to keep him well supplied with fresh eelgrass. More reasons to go to the beach!

Wading in liquid glass

On Boundary Bay, the tide starts its descent in low gear. The beach slopes a bit here, and the bay has widened; the water drains from a circle over a mile across. Further out, the beach is almost flat, the area much less, and the current speeds up until it runs like a river.

We caught the noonday tide last Sunday at the top of its run and waded out with it. At low tide, on calm days, the water starting inward is fairly clear, but it's already carrying bits of weed from further out, and it scours the beach as it races in; by the time it reaches shore, it can be a thick soup of blackened eelgrass fragments and other muck. But then it sits for a few minutes, the gunk settles, and, if the wind hasn't whipped up the waves, the freshly cleaned water eases on out, as transparent as melted glass.

On a day like this, you can see the individual grains of sand under ankle-deep water.

Wormholes, a snail, and dwarf eelgrass (Zostera japonica) blades.

A snail trail, undisturbed by the flowing water.

And this dwarf eelgrass stands up around our legs, instead of lying down in a mat, as we usually see it.

A thick bed of eelgrass, under about 8 inches of water. Like an old-fashioned window, settled over many decades, the water distorts the view in spots.

A worm volcano, with its poop cap.

Clamshell and wave marks from our feet.

Hurry, hurry!

We caught up to this medium-sized crab on a bare patch that would be a sandbar a bit later on. He was heading leisurely out to shelter in the larger eelgrass beds, where the sand is softer and never dries out. Quite a ways to go, but there was time enough.

Laurie was trying to keep up with him and take his photo, but he kept moving away, so I got downstream of him, and stretched out a foot to slow him down. "Aha!" he thought; "Shelter from that horrible man!" and scuttled under my foot.

I could feel him, through my shoe sole, snuggle in cozily, relaxing, then suddenly realize his mistake. He jerked back, pushing upwards against the foot (just in case I might decide to stomp him into the sand), backed out, and raised his pincers in self defence, or possibly challenge.

Assessing his options. Flight or fight? Fight first!

And when my foot stayed put, and didn't attack, he lowered his pincers and ran out to sea.