Feathery orange quill; the sea pen

For those of us humans restricted to dry land, or at least anywhere above the low-tide zone, there are creatures, close neighbours, that we rarely see except in aquariums. Like the orange sea pen; even though it likes relatively shallow water (down to 135 m.), it still remains stubbornly sub-tidal. "Try gently stroking one ..." suggests the Encyclopedia, but adds, "... on your next night dive".

I found an orange sea pen on the shore at high tide. Dead, of course; tossed up by winter storms, but still almost intact.

Orange sea pen, Ptilosarcus gurneyi. About 18 cm. long.

Back side. Restored to water, just in case it still clung to life.

"It", I say, but my pronouns are wrong; I should be saying, "they". It's not an animal; they're a whole community, or colony, of animals, each one joined to his or her neighbour (they come in both sexes) and performing his or her own function in the community. Some fish for planktonic food, some pump water in and out of the central stalk, some attend to respiration, some start the next generation. And one becomes the main support; it loses its tentacles and forms itself into a calcium carbonate stalk ending in a bulbous peduncle which serves as a root, anchoring the colony in the sea floor. The other members of the colony branch off the upper stalk.

They're Cnidarians, members of the phylum that includes sea anemones and corals; each animal is a polyp, a hollow column with eight tentacles, like a miniature sea anemone. They arrange themselves in rows with the tiny tentacles along the outer rims. (For more detail, WallaWalla.edu has photos. Scroll down.)

They can live up to 100 years. If a sea star doesn't eat them. Or a nudibranch; the opalescent nudibranch, Hermissenda crassicornis, common on our shores, is one of its main predators. Scientists estimated the age reading the growth rings in the stalk, like the growth rings on a tree, one ring assumed to represent one year. 

Oh, and stroking them? Like a cat purring, the sea pens glow green when they're petted. Gently, now!

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Para nosotros los humanos, los que estemos limitados a explorar en tierra firma, o por lo menos, si estamos cerca del mar, en la zona intramareal cuando la marea la deja expuesta, hay criaturas vecinas que raramente vemos si no están en el acuario. Entre ellas, la pluma de mar anaranjada; aunque vive en aguas cercanas a la costa (de 10 a 135m. de profundidad) se mantiene sumergida aun en las mareas más bajas. "Acaricie una suavemente," sugiere mi Enciclopedia, pero añade, "en su próximo buceo nocturno."

Encontré una pluma de mar anaranjada en la playa a marea alta. Muerta, claro está, arrancada de su sitio por las tempestades de invierno, pero casi entera.

Fotos: la pluma de mar anaranjada, Ptilosarcus gurneyi, primero fuera del agua, luego en agua, y volteado "boca abajo".

La pluma — pero mejor debo decir, las plumas, porque no es un individuo sino una comunidad, una colonia de animalitos, cada uno (o una; los hay en ambos sexos en la misma comunidad) con su tarea específica; unos (o unas) pescan entre el plancton para alimentar la colonia, unos llenan de agua el soporte, unos se encargan de la respiración, otros llevan a cabo la reproducción. Y uno forma la columna que sostiene erguida la colonia. Perdiendo sus tentáculos, se transforma en un tallo de carbonato de calcio, con el extremo inferior abultado para formar el pedúnculo, que se introduce al fondo marino. Todos los otros miembros de la colonia forman ramas de este tallo.

Son miembros del Filo Cnidaria, animales que incluyen las anémonas de mar y los corales; cada animalito es un pólipo, una columna hueca con ocho tentáculos. Se acomodan en hileras con los tentáculos en el borde exterior. (Para más detalle, vean las fotos de WallaWalla.edu.)

Pueden vivir hasta los 100 años, si no las come una estrella de mar. O un nudibranquio; el nudibranquio opalescente, Hermissenda crassicornis, que se encuentra comunmente en nuestras playas, es una de sus principales depredadores. La edad la estimaron los scientíficos leyendo los anillos de crecimiento en el tallo, parecidos a los anillos de crecimiento que se hallan en el tronco de los árboles, estimando que se forma un anillo cada año.

¿Y eso de acariciarlas? Como cuando lo acaricias, el gato ronronea, la pluma de mar produce un brillo verde, bioluminiscencia. 

Candy on a stick

"Tis the season. For laying eggs, hundreds and thousands and millions of eggs. And the bubble shells are enthusiastic egg-layers. Almost every blade of fuzzy eelgrass in the lower intertidal zone carries, somewhere, another blob of transparent jelly filled with yellow eggs.

But not all the eggs are theirs. I was surprised to see a large, pale pink decoration on one stalk in knee-deep water.

Pale pink eggs, without jelly, in messy eelgrass.

I looked for more, and found a few, some very pink, some almost white. The clumps were not like the usual jelly masses that snails leave, nor like the ribbons most nudibranchs create. These were short sausage-like tubes, glued to the eelgrass at the centre and loose at the ends; each one waved separately in the current.

But what laid these?

I found another mass in shallower water, glued to the inside of a clamshell. And with it, another of the opalescent nudibranchs, Hermissenda crassicornis. A clue!

Mother and babies?

At home, I Googled opalescent nudibranch eggs, and there they were; in most photos, the eggs were white, but some had a pinkish cast. And I found a photo of one laying her eggs, on Flickr.

I brought one of the pinker masses home to look at more closely.

Pink. Candy floss pink.

Zooming in. Hundreds of eggs in each "sausage".

I added the egg mass to my tank, but it didn't last. A few hours later, I found a hermit happily eating pink sausages. The next day, they were all gone.

Looks delicious!

Watch out for the coat!

On the underside of a rock at the end of the boat ramp at Boundary Bay - almost at the high tide line - I found a white and brown, squirmy, translucent bit of live jelly and wavy bits. It wouldn't sit still for its portrait, so I popped it in a bag with seaweed for protection, and brought it home.

He* wouldn't sit still in a bowl of clean water, either. I gave up and added him to the tank, where he promptly disappeared. He showed up two days later, and this time, he posed for me.

The opalescent nudibranch, Hermissenda crassicornis, hanging head down, belly outward. Isn't he beautiful?

Also known as the long-horned or thick-horned nudibranch, for the two long extensions in front. ("crassi ..." = L. "thick", "cornis" = L. "horn", as in unicorn, ".)

He's  about one inch long, usually, but sometimes stretches a good bit beyond. The "horns" are part of the foot. In this belly-forward photo, we can see the mouth and the two rhinopores. (More ancient languages, this time Greek: "rhinos" =  ῥινός, "nose", "phore" = φορος, "bearing".) All nudibranchs have these; they are scent or taste receptors. And on the right side, facing us, just above the head, that round, pearly button is the anus.

Along his back, he wears clumps of cerata, that function as gills; they wave about continuously in the current. In many of his cousins, the inner coloured area is orange; this guy only has tiny specks of orange.

Side view, showing the cerata and rhinophores.

He looks so soft and helpless; when my largest hermit came over to check him out, I cringed. Those huge pincers could have chopped him in two with no trouble, it seemed. But the hermit backed off and lost interest immediately. And "Herm" just kept on about his business, not in the least worried. He has his own hired bodyguards, in his coat.

This nudibranch eats anemones and hydroids. And digests everything but the stinging cells; those he stores in the tips of the soft cerata. And they still work, even in a foreign body, protecting the sea slug just as they protected the original anemones.

Browsing in the red algae; top of the head, with its distinctive markings.

He seems to have settled in happily to my aquarium; he wanders about, nibbling on whatever's growing on old stones and shells, and spending a lot of time in the red algae bushes.

 It eats hydroids, but the diet also includes small sea anemones, bryozoans, colonial ascidians (Aplidium solidum, botryllids), annelids, small crustacea, tiny clams, dead animals of any sort.  Will eat other Hermissenda. (From Wallawalla.edu.)

He shouldn't starve in the tank. Even though there's no other "Herm" for him to eat.

*These nudibranchs are hermaphroditic, with both male and female organs. Since this guy has no mate, he's not a mother, so "he" will do for him. For now.