Wednesday, February 03, 2021

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'.

4 comments:

  1. Do your critters eat the eelgrass directly? Or do they just graze off the bits attached to the eelgrass? Also, for new organisms that you bring in (such as the leafslug), do you keep them in the tank for further study, or do you return them to the ocean?

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  2. The hermits and snails browse the eelgrass, eating anything that grows there. Eventually, the eelgrass turns black and dies. They and the crabs all eat the kelp directly. Smaller critters, amphi- and cope- and isopods hang out on the rose seaweed and the eelgrass. I don't know what they're eating.
    When something arrives unexpectedly, I accomodate it in the tank. Returning it to where I found it (high and dry on the beach, or in a mass of rotting seaweeds) would be to condemn it to death. If I could return it to its original home, it would be a different story.
    Some things live quite well in the tank; others last a few days. But they are days they wouldn't have drying out on the beach or pounded against the sand.

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  3. How neat! It wouldn't have occurred to me that a nudibranch could be alive on the beach, even a little one. I think of them in the ocean only.

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    Replies
    1. I don't think he was on the beach by choice. The recent storms have torn up a lot of the intertidal and subtidal vegetation and tossed it ashore, critters and all.

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