Bane of barnacles

Walking on the rocks below the high tide level, I am aware that I'm stepping on hundreds, thousands of barnacles. Tiny critters, glued in place, unable to scuttle into shelter like the crabs do, they hunker down and endure my footsteps. And yet I don't leave behind a trail of flattened barnacle meat.

Because they're well armoured. Each barnacle lives in a castle made of 6 solid calcite plates, cemented to a base plate, and for a door, there are another 4 movable plates. Packed together, up to 70,000 per square metre, they make a hard cover on the rocks, almost as hard as the rocks themselves.

Two species of barnacles; the tiny acorn barnacles, and the large, ridged thatched acorn.

But if I'm not a danger to the barnacles, they still have their enemies. Mainly snails.

Wrinkled rocksnail, Nucella lamellosa

These snails are probably the most common in our intertidal zone; they're extremely variable in shape and colour, and grow up to about 5 inches long. And they eat barnacles, scraping holes through those castle walls with their file-like radulas.

Another wrinkled dogwinkle. This one has "frills", which may serve as a protection against crabs.

A dire whelk, lirabuccinum dirum. Wearing a family of limpets.

The dire whelk is a predator and scavenger. It eats any injured prey, and barnacles are high on its list of favourites, although they have to wait until they open; these snails don't drill through the walls.

And a leafy hornmout snail, Ceratostoma foliatum.

The leafy hornmouth has three "wings" the length of its thick shell, protecting it from hungry crabs. Another barnacle eater.

It drills through their protective shell with its radula. After drilling through the shell Ceratostoma foliatum injects digestive enzymes into the prey's body cavity and sucks out the dissolved tissue.(WallaWalla)

Top side of the leafy hornmouth.

Poor barnacles!

~~~~~~~~~~~~~~~~~~~~~~~~

Caminando en las piedras en la zona intramareal me doy cuenta que estoy pisando miles de bálanos. Tan chicos, fijados al substrato, sin la capacidad de correr a esconderse como lo hacen los cangrejos, lo único que hacen es encerrarse y aguantar mi peso. Y sin embargo, no dejo atrás un rastro de carne aplanada de bálano.

Pues tienen su protección. Cada animalito vive en un castillo formado de 6 placas sólidas de calcita (carbonato de calcio), bien cimentados sobre su base, y con un portón hecho de otras 4 placas. Viviendo juntos, estrechamente apretados, llegando a alcanzar hasta 70,000 por metro cuadrado, forman una capa dura en la roca, casi tan dura como la roca misma.

Primera foto: dos especies de bálanos; Balanus glandula y el más grande Semibalanus cariosus.

Pero si yo, con todo y patas pesadas, no soy gran peligro para los bálanos, siguen teniendo enemigos, entre ellos, los caracoles marinos.

Segunda y tercera fotos: Nucella lamellosa, un buccino común en estas playas. Vienen en una gran variedad de formas y colores, y crecen hasta unos 12,5 cm. de largo. Y comen bálanos, taladrando la concha con su rádula hasta penetrar a la carne en el interior.

Cuarta foto; un buccino "terrible", Lirabuccinum dirum, decorado con una familia de lapas.

Este caracol es carnívoro, comiendo presa viva, dañada o muerta. Le gustan los bálanos, aunque tiene que esperar a que se abran, porque no usa la rádula para romperse camino.

Quinta foto: Ceratostoma foliatum, el caracol de "boca cornuda, con hojas". Este caracol trae tres "alas" pesadas a lo largo de la concha, lo que le protege de ataques de cangrejos. Y come bálanos.

"Taladra sus conchas protegedoras con la rádula. Después de taladrar la concha, Ceratostoma foliatum inyecta enzimas digestivas en la cavidad del cuerpo de la presa y luego succiona el tejido disuelto." (WallaWalla U)

¡Los pobres balanitos!

Leafy hornmouth and friends

Each critter that arrives in my aquarium, whether I brought it in on purpose, or it hitchhiked on seaweed or on a barnacle rock, or even if it was born in the tank, brings with it a responsibility. They each have their own specific diet to be provided, their own habitat needs; hiding spaces, climbing structures, sand or rocks, water currents and temperatures, company of their own sort. And providing those needs brings in more critters: the predators need prey, the gregarious ones need friends.

I don't know how the leafy hornmouth snail came to the tank. Maybe he arrived in a clump of mussels, brought in to feed the whelks. Or in a handful of seaweed. But he's here, and growing, (6.5 cm long now) and hungry. He eats barnacles and mussels, which means that I have to go shopping for barnacled rocks.

In between meals, he wanders around the glass walls.

Leafy hornmouth snail, Ceratostoma foliatum

Limpets travel on his back, and a family of orange-striped green anemones take advantage of the ever-changing currents; there's good eating in that water!

Foot and passengers

Spring is here. I guess I should be looking for a mate for him (or is it her? They know; I can't tell.)

One of the limpets. The yellowish blobs are limpet poop.

Empty snail shell with another orange-striped green anemone.

Next: leaving the tank behind and heading out into the forests again.

~~~~~~~~~~~

Cada animal que llega a mi acuario, sea como sea que llegue, trae una responsabilidad. Cada uno tiene su dieta preferida, sus requistos para el habitat: necesitan lugares para esconderse, estructuras donde pueden trepar, arena o piedras, corrientes de agua rápidos o suaves, temperaturas específicas. Los animales de rapiña necesitan su presa natural; las criaturas gregarias necesitan compañeros.

Y al traer lo que piden los habitantes del tanque, vienen otros animales, con sus propias necesidades.

No sé como llegó el caracol "leafy hornmouth" al tanque. Tal vez se escondió entre un grupo de bálanos; tal vez vino en una bolsa de algas de mar, traídas para comida de los cangrejos y ermitaños. Pero aquí está, creciendo rápidamente; ya mide 6.5 centímetros de largo. Y tiene hambre.

Come bálanos, mejillones y almejas, lo que me obliga a traer piedras cubiertas de bálanos y de mejillones de la playa para mantenerlo sano.

Cuando termina de comer, anda dando vueltas en las paredes.

Las fotos: el caracol, con las anémonas que se aprovechan de una base móvil; así les toca mejor comida. Una lapa. Otras están pegadas a la parte trasera del caracol; este está comiendo algas en el vidrio. Las bolitas amarillentas son caca de lapa.

Y finalmente, una concha vacía con otra anémona (anémona verde con rayas anaranjadas: Diadumene lineata.)

(Y ya es primavera; quiere decir que el caracol estaría más contento (contenta? Yo no sé distinguir, pero ellos sí saben.) si le traigo una compañera. Otra visita a la playa cuando la marea está baja.)

Mañana; dejo el tanque y me voy otra vez al bosque.

Stack of hungry beasties

And in the tank this week:

Crab, snails, snail food.

The big shell is a large leafy hornmouth, Ceratostoma foliatum, old and battered. I don't know what made me bring him home when I found him tossed up well above the tide line, instead of walking him back down to the water. Now I'm busy bringing him large barnacles to keep him fed. He won't eat the little ones; only steak dinners for him!  Here, he's on an old clam shell that still has a half-dozen surviving barnacles.

A couple of black patches are smaller snails, eating algae on the hornmouth's shell. And a channelled nassa, Nassarius fossatus, is thinking of boring through into the juicy hornmouth meat. (He gave up by the next morning; now he's wandering about looking for something not quite so thick.)

On top of the stack, the largest of my green shore crabs, a male close to the maximum size for his species. Always, always, hungry.

Side by side

Here's one of the new pink-tipped anemones, feeding and growing, standing tall.

Anthopleura elegantissima

And, right next to it, one of the Leafy Hornmouth snails:

Ceratostoma foliatum, with the Warty tunicate behind it.

I love the contrasting textures, the rough, craggy shell of the snail, and the creamy greens, pinks, reds, and yellows of the soft tissues.

On the hunt

A Leafy Hornmouth snail searching for food climbed the tank wall to the water surface, skating on his collected bubbles.

Ceratostoma foliatum, and bubbles.

They're out of barnacles. And they're hungry. They're checking every corner, every old shell or rock, even the glass walls. And they're not finding anything.

My bad. I'd better go "barnacle shopping" on the beach asap.

Climbing the walls

The leafy hornmouth snail collects sand grains around the edges of his shell, and carries them up the wall to help with his scratch making*. This time, he has another attachment, as well.

Can you find the barnacle molt?

*I am ever so careful with the outside of the glass, to keep it clear for taking photos, but the critters inside constantly frustrate my efforts.

Busy, busy!

More test shots; back to the aquarium and live critters again.

This first photo is as taken; despeckled, resized, and sharpened only. I left the "dust" in place; it's part of the action.

In the upper levels of the tank, like it would be on the intertidal flats, everything is in constant motion. Here, the red algae sways in the water, and a small family of blue anemones glued to a fragile blade waves its tentacles, hoping to catch some of the swimmers that muddy up the current. Behind, bubbles dance; large ones going down, from the pump; small ones heading back up to the surface, carrying goodies collected en route. Released at the top, the goodies float back down; more specks in the water.

This red algae gathers "dust". I pour clean water over it, or take it out and swish it around in fresh water, and it looks beautifully clean. A few minutes back in the tank, and it's covered in these little specks. Some may be sand, some is detritus, leftovers from critter meals or floating fragments of rotting eelgrass, and the rest is made up of small animals, copepods and amphipods eating detritus, and tiny worms eating copepods and amphipods.

And I hadn't even noticed the hermit until I looked at the photo. There's usually one or two hidden somewhere in this mess.

Everything going at once

On the other end of the tank, and up close to the wall, things are more peaceful.

Leafy hornmouth snail, Ceratostoma foliatum, sleeping.

The water is clearer away from the current; I removed only a handful of swimmers and a scratch on the glass. This snail eats barnacles; in between times, he wanders around the walls, then goes to sleep for a day or so.

His shell started out white and pink, but as he grows it gets craggier and darker. He's beginning to show the "leaves" that give him his name; for now, they're just sharp lengthwise ridges.

Setup for these photos: black poster board behind tank, white reflector above and on both sides, spotlight aimed at top reflector, flash ditto. This seems to work on the upper levels, but not down on the sand. More experimentation needed.