Following the tide

Exploring a beach at low tide, I head straight out to the very edge of the water, and then follow it as it retreats and later advances. Above this line, I will be seeing animals and algae in lockdown, hiding from the air and the sunshine. And most will not be visible at all; they've buried themselves in the mud or sand, or crawled under rocks. Seaweeds lie flat, drying, bleaching. Some animals will be dying, not having gone into hiding soon enough.

In the water, it's another world. Anemones wave their tentacles; out of the water, they've contracted to soggy blobs. Algae lift their blades and bladders, swaying in the current. Sea lettuce floats. Tiny crabs lift menacing claws as I pass, not seeming to be aware of the difference in size. Schools of small fish dart away, seeing or feeling my approach from a good distance. Kelp crabs follow the retreating water, avoiding being caught in the dry; they hurry when my shadow falls near them, but they were already in motion before then.

Starfish underwater are fuzzy. Barnacles feed until the last possible moment. Tubeworms blossom at the  end of their coils. Jellies pulse.

Then the water drops another bit and everything closes down.

These beasties were all in the water when I found them.

Kelp crab and sea lettuce.

Two painted anemones, Urticina crassicornis, hiding under an overhanging rock.

Red trumpet calcareous tubeworm, Serpula sp.. A small crown, but always brilliant.

Fuzzy starfish.

The skin on the top of a starfish (the top as we see it on a starfish lying on the sand; feeding on the underside of a rock, it would be the bottom; a better word would be "aboral", ab = opposite, oral = the mouth, because the mouth is on the far side). Start again: the skin on the aboral surface of a starfish is rough and spiny (the calcium carbonate "spines" are small, hard, white bumps); it feels hard and stiff to our fingers.

Unseen out of the water are the tiny skin gills, or papulae. Exposed to air, they are retracted into the surface of the star's body; underwater, they expand.

... the extended papulae or coelomic pouches, used for respiration and waste excretion, ... are often extended when seastars such as P. ochraceus are underwater.  The papulae give the seastar's surface a soft, fuzzy appearance. (Wallawalla)

Several sea stars with their patterns scrambled by incoming waves.

Three small grainy-hand hermits.

This area of the beach is a snail desert. In the upper intertidal zone, there are many periwinkle snails, but as you go down the zone, they peter out. And where I would expect to find whelks, I saw none; there were three discarded whelk shells, one occupied by a hermit. And that was it.

So the local hermit crabs are wearing really old, broken shells, sometimes fragments of shells. Shells where they can barely manage to insert their shell-grabber legs. Shells that leave their tender abdomens exposed, pieces of shells with hardly a curve for the coiled abdomen. Look at the one at the top in the above photo; this is the tip of an old whelk shell, heavy, with jagged edges.

Another grainy-hand with his abdomen open to view.

And two more.

What happened to the snails?

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Cuando visito una playa en un dia con marea baja, siempre me dirijo directamente al borde del agua, y de allí sigo la marea mientras baja y sube. En la parte expuesta de la playa, veré animales y algas en cierre de emergencia, escondiéndose del aire y de la luz del sol. Y la mayoría estarán invisibles; se habrán enterrados en el lodo o bajo la arena, o se habrán ocultado bajo las rocas. Las algas se adhieren a la area, secándose, blanqueándose. Algunos de los animales se estarán muriendo por no haber encontrado albergue oportunamente.

En el agua, es todo un mundo distinto. Las anémonas agitan sus tentáculos; fuera del agua, se contraen y se vuelven masas amorfas. Las algas levantan hojas y vesículas, bailando en las corrientes. La lechuga de mar flota libre. Cangrejitos (¡Tan valientes!) alzan pinzas amenazantes, sin importarles la diferencia entre nuestros tamaños. Bancos de peces pequeños se distancian aprisa; me ven o sienten mi presencia desde lejos. Los cangrejos del kelp siguen el agua mientras se aleja, evitando ser atrapados en el aire; aceleran su movimiento cuando mi sombra les toca, pero ya corrían antes.

Las estrellas de mar, bajo el agua, parecen ser hechos de peluche. Los bálanos siguen pescando hasta el último momento. Los gusando tubícolos abren sus "flores" brillantes. Las medusas palpitan.

Luego baja la marea un poco más y todo se encierra.

Estos animalitos todos estaban bajo la superficie del agua.

1. Un cangrejo de kelp, Pugettia producta y lechuga de mar, Ulva sp.
2. Dos anémonas pintadas, Urticina crassicornis, escondidas bajo una roca.
3. Un gusano tubícolo "trompeta roja", Serpula sp. Tiene una corona muy chica, pero siempre brillante.
4. Una estrella de mar "de peluche". 
   
   La piel en la superficie superior de la estrella de mar (mejor llamada la superficie aboral; ab = opuesto, oral = la boca, puesto que la boca está en la superficie opuesta); esta piel es rugosa y espinosa, con "espinas" que más bien son botones de carbonato de calcio. En nuestras manos se percibe como sólida y tiesa. 
   
   Lo que no vemos fuera del agua son las pequeñas branquias, o papulas. Cuando están expuestas al aire, se retraen bajo la superficie de la piel; en agua se abren.
   
   

   ... las papulae o sacos de la celoma, usados para la respiración y la excreción de desechos, ... frecuentemente se extienden cuando las estrellas de mar tales como P. ochraceus están en el agua. Las papulae dan a la superficie de la estrella de mar una apariencia suave, como de peluche. (Wallawalla)

5. Tres ermitaños de mano granosa pequeñas.
   
   Este sector de la playa no tiene caracoles. En la zona superior intermareal, hay muchos caracoles Littorina sp., pero bajando hacia la zona inferior, desaparecen. Y donde espero encontrar bocinas, no hay ninguna; vi tres conchas de bocinas vacías; una con su ermitaño. Y eso fue todo.
   
   
   Así que los ermitaños del rumbo llevan conchas bien viejas, rotas; a veces solamente fragmentos de conchas. Conchas donde apenas pueden insertar sus patas traseras, conchas que dejan expuestos sus abdómenes tiernos, pedazos de conchas que no permiten doblar el abdomen. Mira el ermitaño en la parte superior de esta foto; la concha es el extremo de una concha de bocina, muy pesada, y con bordes afilados.
6. Otro ermitaño Pagurus granosimanus con el abdomen expuesto.
7. Y otros dos.

¿Qué les habrá pasado a los caracoles?

When in doubt, hide.

Recently, every time I've been on the shore, the tide has been high. Until a couple of days ago; I missed the lowest ebb and the water was rising quickly, but a good bit of sand was still exposed. Sand and black sand dollars, mostly half buried in the sand, vibrating their tiny spines to dig themselves in deeper.  There were barnacles on stones with crabs hiding underneath, clam holes (where they spit out water when they feel vibration, such as my footsteps) and the squishy depressions where little green anemones wait for the water to come back. 

And I passed this lonely hermit crab. It looked as if something had dug it up; it lay open side up beside a small pit in the sand. (Maybe flipped over by a running dog? Or a gull looking for clams?)

Grainy hand hermit, Pagurus granosimanus.

I watched it for a while, then picked it up and held it for a bit longer. It never moved, never attempted to run away. I finally turned it mouth down and left it at water's edge. Where it waited, without moving, until I left.

Most hermits in our upper intertidal zone are either Hairies (Pagurus hirsutiusculus) or  Grainy Hands (P. granosimanus). And they can be identified even at a distance by their behaviour. Hairies, found in difficult or threatening circumstances, instantly run away. They're speedy little critters, and usually choose a shell that looks slightly too small for them, not too heavy, not too difficult to manouver. Built for speed. 

Grainy Hand hermits, instead, hide. They choose shells big enough for them to retreat completely into the spiral. And there they stay, blocking the entry way with the biggest pincer, until things look safe.

As first seen, on the sand.

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Por un tiempo hasta ahora, cada vez que voy a la playa, encuentro la marea alta. Por fin, el otro dia, parte de la zona intramareal estaba descubierta. La marea ya venía subiendo, pero un buen tramo de arena seguía expuesto. Arena y sus habitantes: vi las galletas de mar, negras y medio cubiertas de arena, vibrando sus espinitas para seguir enterrándose; bálanos adheridos a piedras con cangrejos escondidos debajo; los hoyos que dejan las almejas al escupir agua cuando sienten movimiento; y las depresiones esponjosas circulares donde anémonas verdes esperan a que regrese el agua. 

Y encontré este cangrejo ermitaño solitario. Parecía que algo le había movido; esperaba con la boca de su concha mirando al cielo; a un lado había una pequeña depresión en la arena. (Tal vez un perro le había desenterrado al pasar corriendo. ¿O sería una gaviota buscando almejas?)

1. Cangrejo ermitaño "mano granosa", Pagurus granosimanus.
2. Como lo encontré en la arena.

Me quedé observándolo por un tiempecito, luego lo alcé y lo detuve en la mano por otro rato. No se movió, no trató de escapar. Por fin, lo deposité cerca del agua, boca abajo, como normalmente se encuentra. Allí esperó sin moverse hasta que me fui.

La mayoría de los ermitaños que viven en nuestra zona intramareal superior son o "Peludos" (Pagurus hirsutiusculus) o "Manos Granosas" (P. granosimanus). Se pueden identificar, aun a alguna distancia por su comportamiento. Los "Peludos" al encontrarse en circunstancias difíciles o amenazantes, se echan a correr al instante. Son animalitos veloces, y escogen una concha que, a nuestra vista, parece demasiado pequeño; una concha que no pesa demasiado, que no sea difícil de maniobrar; una concha que les permite correr rapidamente. 

Los ermitaños granosimanus, en cambio, se esconden. Escogen conchas grandes, de suficiente tamaño para que el animalito pueda retirarse completamente dentro del espiral de la concha. Y allí se quedan, cerrando la entrada con su quelípedo grande, hasta que se sienten seguros de que el peligro haya pasado.

A grainy hand and 3 hairies

Interlude. Between outings to forest and shore, I come home to a dozen busy hermit crabs wanting dinner. Sometimes they even pose for photos.

A grainy-hand hermit, Pagurus granosimanus.

Eating dried kelp.

There are 5 medium-sized hermits, both grainies and hairies. The grainy-hand hermits grow up to 2 cm. long, counting the shell they've chosen; hairy hermits are just a bit smaller.

They're picky about the shells they use. I bought a package of these imported white shells; nice, clean shells with a wide opening, not too heavy. The grainy-hand hermits like them but the hairies won't touch them; they prefer whelk or periwinkle shells, or even the invasive mud-flat snail shells.

I'm not really sure how many baby hairy hermits there are; I count a half-dozen any day, but some of these, at least, grew up in the tank, and I have seen some so small I only knew they were hermits by the way the shell moved. Snails inch themselves along; hermits scuttle.

One of the larger of the tinies, a hairy hermit about 5 mm. long, shell and all.

They all love dried kelp. I cut off chunks for them about 2 cm. long.

About as small as the camera can capture. Another hairy hermit, Pagurus hirsutiusculus.

This one was perched on a small barnacle which had attached itself to a mussel. The white strands are the mussel's byssal threads, by which it has glued itself to the wall of the aquarium. Each thread is about the diameter of a human hair. Off to the right side, there's a copepod female carrying her egg sac. The red dot is her one eye.

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Intermedio. Entre vueltas por los bosques y las playas, regreso a casa donde me esperan mis cangrejos ermitaños, queriendo cenar. A veces hasta se detienen para que les saque una foto.

Fotos:

#1. Un ermitaño de mano granosa, Pagurus granosimanus.

#2. Comiendo quelpo resecado. (Y mojado ahora, claro.)

Hay 5 ermitaños de tamaño mediano,  P. granosimanus y P. hirsutiusculus, los peludos. Los granosimanus crecen hasta unos 2 cm. de largo, con todo y concha; los peludos son un poquito más chicos.

Son algo quisquillosos en lo que respeta a las conchas que deciden ocupar. Les compré un paquete de estas conchas importadas, limpias y blancas, con boca amplia, no muy pesadas. Los ermitaños de mano granosa las usan, pero los peludos ni los tocan; prefieren conchas de bocina o bígaro e inclusive del caracol invasivo Batillaria attramentaria.

No sé por cierto cuantos de los ermitaños peludos juveniles viven en el acuario; puedo contar, cualquier dia, una media docena, pero algunos de ellos crecieron aquí en el acuario, y he visto algunos tan miniaturos que solamente los reconocí por su manera de moverse. Los caracoles se arrastran paso por paso: los ermitaños corretean.

#3. Un ermitaño peludo juvenil. Mide aproximadamente 5 mm con todo y concha.

#4. Les gusta el quelpo seco. Les corto pedacitos de como 2 cm. de largo.

#5. Este es a lo más pequeño que mi cámara puede captar. Otro ermitaño peludo. Se había subido a un balanito, el cual a su vez se había fijado a un mejillón. Los hilos blancos son los bisos del mejillón, con los cuales se ha adherido a la pared del acuario. Cada biso tiene el diámetro de un pelo humano. Al lado derecho se puede ver un copépodo hembra llevando su saco de huevos. El puntito rojo es su único ojo.

Shy hermit

 A hermit in hand is worth a dozen under a stone.

Grainy hand hermit, Pagurus granosimanus

There are two main larger (but still small, up to around an inch long) hermit crab species on our shores. The hairy hermit is an active, brave little beastie. When I pick one up, he retracts into the shell for a few seconds, then pushes his way into the open again and takes off running. He likes to use smaller shells that don't get in his way.

The grainy hand hermit, the one in the photo, is shy and timid. He chooses shells big enough for him to retreat until he is invisible. And picked up, he stays inside until he's absolutely sure it's safe to show himself.

I waited for this one to realize I wasn't going to eat him. I waited. And waited; eventually he showed me his blue-grainy hands, (as if I needed those to identify him!) but that was as far as he was willing to go. And then he waited me out. I put him down beside his stone finally, still hidden inside his shell.

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Ermitaño en mano vale por dos debajo de la piedra.

Hay dos especies principales de ermitaños de tamaño regular (pero todavía menos de 2 cm.) en nuestras playas. El ermitaño peludo, Pagurus hirsutiusculus, es una criatura activa y valiente. Cuando recojo uno, se esconde por unos segundos dentro de su concha, y luego sale al aire, extiende las patas y se echa a correr. Le gustan las conchas chicas, que apenas le quedan, porque no le impiden el movimiento.

El ermitaño de manos granosas, Pagurus granosimanus, el de la foto, es tímido y asustadizo. Escoge conchas sufiecientemente grandes como para meterse tan adentro que resulta invisible. Y cuando lo levanto, se queda escondido hasta que se siente completamente seguro.

A este, le esperé a que se convenciera que yo no le iba a comer. Esperé. Y esperé. Por fin, me enseñó las manos con sus granitos azules, (aunque no necesitaba verlas para poderle identificar; su comportamiento ya me había puesto al corriente) pero ese fue su límite. Así se detuvo mientras yo esperaba. Por fin, le puse de nuevo al lado de su piedra; todavía estaba bien dentro de la concha.

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.

Colourful

In a party mood:

Grainy hand hermit, Pagurus granosimanus

The local hermit crabs, from here in our northern shores, look a bit grungy, clad in camouflage greys and greens, under our normal muted daylight, especially underwater. But under a bright light, it turns out that they're as brightly coloured as any of the tropical critters.

This was taken with double flash, the overhead tank light, plus two bright LED lights a couple of inches away. The hermit didn't seem to mind at all.

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Los cangrejos ermitaños de nuestras costas norteñas están vestidos en colores de lodo, en camuflaje gris y verde grisaceo, vistos bajo la luz del dia, nunca muy fuerte aquí en la isla y aún más tenue dentro del agua. Pero con una luz más fuerte, resulta que tienen colores tan brillantes como cualquiera de las criaturas tropicales.

Para esta foto, usé el flash con un esclavo auxiliar (dos), la luz normal del tanque, y además dos luces LED, a unas dos pulgadas de distancia. No parecía que la luz molestaba al ermitaño en absoluto.

Spare parts

Hermit crab enjoying his lunch.

Shrimp pellets; Yum!

Hermit crabs, besides the chelipeds (pincers) that they use to grab and carry things, have three pairs of mouthparts, which they use to hold and manipulate their food. Here, two are plainly visible as the hermit holds onto his fresh shrimp pellet.

He seems to have lost at least one of his chelipeds, probably after an argument with a crab, or even another hermit. He'll do fine, though; hermits can use the legs to grab their food, too. They're not as efficient, but they'll do. And with the next molt, he'll have a new cheliped. The blue appendage on the left is the growing replacement; hermit blood is blue, and the skin on the new pincer is still thin.

Going places

When the tide is low, and the sand is just right, not too wet, not too dry, not too packed down, not too loose, when the wind dies down and the sun hides behind clouds, you just might find hermit crab tracks.

Hermit crab trails, Willow Point beach

The hermit runs forward, instead of sideways like his cousins, the crabs. He leads with his big left pincer, then follows with the small right pincer and two larg(ish) legs on either side. Depending on the shell he's chosen, he either drags it behind, leaving a deep valley down the centre of his track, or carries it above ground level, so that his several rows of footprints aren't erased.

In the photo above, the smaller hermit, who left his trail top to bottom more or less down the centre line, was carrying a draggy shell, probably one of the long, pointy Asian mud snail shells. A larger hermit carrying his shell high, barely touching the sand, crossed right to left, corner to corner.

More trails. These hermits mostly travel in straight lines, not like the mud snails that wander all around, often crossing their own path several times. The hermits know where they're going; probably looking for shelter, now that the tide has abandoned them.

Meanwhile, back in the tank ...

The new hermit with the blue pincer is settling in nicely.

Big Blue, in hiding deep in the tank, in the semi-dark. He likes it there.

So far, he's selected three girlfriends, holding onto each one for several days, then abandoning her, probably after he's mated with her. I'll be watching them for growing eggs.

Deep in the tank, the blue pincer fades to green. When he comes up front, to the light, it glows as brightly blue as the day I saw him first, on the shore.

Thoughts on a rocky shore

I love a rocky beach.

Polished rocks, a sprinkling of barnacles

The current runs strong along the eastern shore of the Georgia Strait, and the tides pound in and drain out quickly. Many of the rocky areas are like this; water-polished rocks, with very little life visible. Turning over stones at low tide, I find more smooth stones. No crabs, no hermits, no worms. They must be there, but have retreated to deeper, safer hideouts.

Sometimes there are barnacles, in flatter areas thickly covering the stones, in other spots clustered on the sheltered sides and bottoms of the rocks. There are spots where none are to be seen, where the rocks shine as if they were waxed and buffed.

Down near the lowest tide line, seaweeds cover the rocks. It's dangerous walking; the weeds are slippery, and the rocks move underfoot. No matter how carefully I step, I'm always a twisted ankle away from a spill. But here, the crabs and other critters find a refuge. From the waves, from hungry gulls, and also from me, as I usually gingerly skirt the greenest areas, keeping an eye on the water's edge, ready to hurry towards land when the tide turns; I don't want to be caught in seaweed over stones as the water races in. Too risky.

A flatter spot, in the lower intertidal zone, with small erratics and tide pools. More barnacles here.

Coming towards a tide pool, I see ripples and splashes at the surface. By the time I get there (and sometimes I sneak up from the far side of the rock) there is nothing. The pool looks empty, just more clean stones with clear water. Even the tiny fish have hidden underneath the stones.

But there are always snails. Tiny, and tinier snails, dotting the rocks, basking in the warmth or resting in a tide pool. Most are pinhead size, some as "big" as a grain of rice. They hold on tight, or don't provide enough resistance to the waves to be washed away. Maybe their shape helps; smooth and rounded, with a sharp tip.

Under an inch of water in a tide pool, rice-grain snails and a few limpets choose the warmest rock.

Everywhere else, where I find tiny snails, a good half of the shells house miniature hermit crabs. Not here. I think I saw one leg poking out of a shell; otherwise, every snail shell is full of snail. Hermits can easily be bowled over by a wave and swept away.

The tiniest snails are a worry for me. In some spots, every decent-sized stone is covered with them, like sprinkles on a donut. I can't put my foot down without stepping on some. I try to brush them aside, but risk tripping myself up as the stone shifts. I am glad my shoes have deep ridging; at least some of my footprint is safe for tiny critters.

Sand is safer, for the snails, and for me.