On a beach at the south end of the Campbell River Rotary seawalk, there is a tidewater pool, which looks artificial; a square dredged out of the stony beach, with not much to say for itself as yet. We walked out to the far side of this at low tide. The scenery, looking out across the water to Quadra Island, was beautiful, as always. But the beach was mostly clean rocks, with nothing much living underneath, not even seaweed.
|Dry rocks and tiny barnacle shells|
|Periwinkle snails gather just above the water line.|
It was difficult walking on the loose stones, and Laurie's injured leg was bothering him by the time we got to the water's edge, so he sat on a rock and I entertained myself looking for interesting stones. At the edge of a small tide pool - grey rocks, grey stones, grey rocks - I noticed a half-dried, rotting kelp stipe, balanced on the stones. The tide was coming in, and as it reached the kelp, purple shore crabs began to crawl out from between the rocks to attack the kelp, which they began eating hungrily.
|Not much else to eat on this beach.|
As the water rose, more and more crabs appeared. The first arrivals fought off the newcomers, often knocking them back down into the water. Occasionally, three or more would be struggling together, legs and pincers intertwined.
I've seen crab fights before, usually over some choice bit of fish, but never over dry kelp.
|I count 14 in this photo, of a small section of the kelp.|
|The green crab at the right is also a purple shore crab.|
Green shore crabs (aka, Oregon shore crabs) may be many colours, usually green, white, or grey. The purples are usually purple, sometimes green. I have a white one in the aquarium. They are distinguishable, sometimes, by the polka-dotted pincers (see the one near the left on the photo above) and by their hairless legs; the green shore crabs are hairy. (Here's a green and white green shore crab; notice the hairy legs.)