On June 18, there was a negative low tide very early in the morning, so we made a trip of it to check it out.
There is a small breakwater on the north end of Imperial Beach, which has a lot of marine organisms typical of what one would see in a tide pool environment.
Then the beach stretches north towards the Silver Strand, and there were sand bars and unusual "rivers" along the edge of the water, some spots capturing a lot of shells and other marine debris.
Here are some of the organisms of the rocky jetty area:
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| A small Bat Star (Patiria miniata) with a tiny wentletrap (probably Epitonium tinctum) just to its left, and another wentletrap on the right (I only saw these in the photo afterwards!). I also saw one Pisaster ochraceus (Ochre Sea Star), which looked healthy. A good sign during this time of mass die-offs of sea stars along the west coast. |
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| This is a bit of a mystery - but looks quite a bit like Aplidium sp. (a colonial tunicate). In Florida, this sort of thing washed up on the beaches is called "sea pork". There was quite a bit of this in the rocks of the small jetty, and more washed onto the sand. |
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| I believe that this is Acanthinucella punctulata, a small muricid. |
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| A fancy house for this hermit crab - Calliostoma canaliculatum, one of the prettier gastropods usually found off shore slightly. |
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| The Striped Shore Crab (Pachygrapsus crassipes) - ubiquitous where there are rocks along our coast. This was an immature one - lighter than more matures ones. |
Here are some organisms seen on the sandy beach north of the breakwater.
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| This was a new creature for me - a Spiny Mole Crab (Blepharipoda occidentalis). There were a few washed up along the sandy shore, and they were either dead or very lethargic (dying?). This one was one of the most healthy-seeming. I took lots of images at different angles. It was about 2.5 inches long. I have seen their carapaces on the sand, sometimes in very large numbers, in the past, but thought they were immature lobster carapaces. Now I know. |
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| Posterior view. |
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| Anterior view. |
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| Ventral view. |
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| A live Dendraster excentricus. A very common sand dollar species along these shores. |
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| In a kelp holdfast this caprellid amphipod was hiding, very well camouflaged. |
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| This is the "typical" mole crab that digs in the sand along the shore - Emerita analoga (the Pacific Mole Crab). |
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| A gravid female E. analoga. |
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| A live Olivella biplicata, burrowing in the sand. |
