Monday, September 03, 2012

Of anemones and hermits

Back to the Campbell River series ...

Remember the wounded anemone I rescued on "our" beach? I kept it on the table in the motel, changing its water twice daily, and it seemed to be recovering. When we came home, it came with us, securely double-packed and wedged into a bottle holder on the car door, arriving here unfazed by the experience.

I had brought a litre of its "home" water with me, and continued changing it as before. But that couldn't continue; my guest needed a proper environment.

So. I have set up the little aquarium again*, with a new pump and water from Boundary Bay, tested for a salinity match - dead on! - and some eelgrass, aquarium gravel and beach sand, which came loaded with tiny worms. I brought along some snails to keep the place clean, and a few small hermits.

As usual, half of the snails turned out to be hermits, and the eelgrass was carrying more, miniatures. So the aquarium is bursting with life again.

And here s/he is! In the aquarium, alone as yet.

I've identified it as a burrowing anemone, Anthopleura artemisia. The heart-shaped marks on the tentacles were the main clue, as the colour varies.** These are solitary animals, often reproducing by cloning; right now, it's in the business of reproducing its own body. The circle of tentacles is almost closed, but the mouth area is still only half healed.

Anemones are predators; they catch and kill small fish and crustaceans. So we have been surprised to see how casually the hermit crabs climb over this one, even nibbling at bits of detritus or slime they find on the tentacles. As if they weren't venomous! And the anemone doesn't even bother to close down. It sure does if I barely touch it with a wet paintbrush.

Oh, Google! "Anemones + hermit crabs + symbiosis".
One of the best known examples of symbiosis is that between the hermit crab and a sea anemone (e.g. , Adamsia). The anemone is often found attached to the shell in which the hermit crab lives. ... Often, a sea anemone attaches itself to the crab's shelter and it may envelop part of the crab's own shell as well. ... As the crab moves about in search of food the anemone is brought into contact with a greater supply of food and the crab is protected by the anemone's stinging cells. (From The Encyclopedia of Science)

Of course! Now I remember how one of my previous hermits carried a white plumose anemone on his shell.

Rex, the hairy hermit.

This just goes one step beyond.

In the aquarium now, I have three species of hermits; the Grainy hand hermit, Pagurus granosimanus, ...

At Stories Beach. Red antennae, blue spots on green legs and pincers. And he likes a big, enveloping shell.

A slow mover, maybe because of that heavy shell.

... Greenmark hermits, Pagurus caurinus, ...

Orange on legs, pale orange antennae, without white spots.  A small species, looking like a young hairy. 

He's in the broken tip of a larger shell. They're a speedy race, not burdened with too much armour. This guy was off the edge of my hand and lost among the rocks before the camera was ready for a second shot.

... and the common Hairy hermit, Pagurus hirsutiusculus***. Like Rex, above.

*Wish us luck!

** For convenience, I think I'll be calling him/her "Val" for "Valentine", because of the heart-y tentacles.

*** Hirsutiusculus translates as "hairy tail". Granosimanus is "grainy hand". Sometimes the Latin names actually make sense. But Caurinus (the Greenmark's name) means "North-west wind". So much for relevance. And I still can't find that green mark!


Once again, a reminder: Rock Flipping Day is next Sunday, September 9th. Instructions, history, etc.

Last year, several people wrote later, to say that they had intended to join in, but forgot until it was too late. So this year, I'm harping on the date. You can help by passing the word along. Thanks!

1 comment:

  1. Is this ever fun!
    What fun! We're visiting granddaughters today, after hubby finishes his Meals on Wheels deliveries. An hour drive to the city is well worth it!
    Cheers from Cottage Country!


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