Monday, February 1, 2010

After the Storm

I paid another visit to Abalone Cove last week when we were having some nice late afternoon negative tides. What a change has taken place there since last October! I think they must have imported truck-loads of rocks to maintain the beach and protect the cliffs from further erosion. Either that or the storms we had washed away all the sand exposing the rocks. I know that Palos Verdes Dr. South had to be closed for awhile due to mudslides the week before when the rains were so heavy. Whatever the reason for the rocks, it made getting to the best of the tidepools more difficult even with a tide as low as -1.6. But the weather was gorgeous and the hills were green again. It was a beautiful day!

My prize for the day was my first nudibranch. I think it is a Monterey Dorid, Archidoris montereyensis. Nudibranches can be very colorful, iridescent even, which is actually a warning to other creatures that they are poisonous. They are carnivorous and sometimes feed on jellyfish and sea anemones retaining the "sting" of these animals which repels their predators. I wasn't sure what this was when I first saw it, but it moved when I nudged it gently. The left end is the head. It was all tucked up because it was out of water and trying to wedge itself into the crack in the rock where it was moist.

I found two Giant Keyhole Limpets, Megathura crenulata, very close to each other. One was mottled gray and the other was totally black. The soft body of this impressive animal envelopes the shell.

I realized that in my previous posts about tidepooling, I had never shown a picture of the Aggregating Anenome even though there are hundreds of them at every pool I have been to. They are easy to take for granted (and to step on if you are not careful!) Most of the time, I see them all closed up and covered with bits of rocks and shells to retain their moisture until the tide rolls in again. They like to clump together and can make interesting patterns on the rocks.
Although they live side by side, clonemates from different groups are enemies. Warrior anemones with knoblike swellings packed with large stinging cells border each group. If a warrior comes in contact with an enemy warrior, they exchange a barrage of poison darts, causing injury to both. The warriors withdraw, leaving behind a “demilitarized zone.”

Happily, the interesting and beautiful stepping-stone rock ledges were still there. I have taken many pictures of these rocks in different lighting and still find them fascinating.

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