After class on Thursday April 16th I drove down to Squalicum beach hoping that I would be able to observe some interesting wildlife. It was my first time visiting the park there. After sitting and watching for a while I noticed the multitude of arthropods that call the beach home.
The first thing I saw were the shore crabs (brachyura) scurrying around under the water. They darted from rock to rock in the blink of an eye, obviously trying to lessen their risk of predation while looking for food. Almost every time I picked up a rock there would be a crab underneath that would dart into the billowing sediment and be lost to sight. I managed to catch one in a small pool where it did not have anywhere to run to. I examined it and placed it where I could better observe it and take a few photos.
Above is an image I captured of the crab after it had partially buried itself in the pebble substrate.
Nearby I noticed this dead crab with a swarm of flies (diptera) around it. As I watched, the flies jumped around the carcass trying to access the nutrients within.
By far the most fascinating thing I saw was a species of tiny arthropods that had mysterious habits. They were running across the surface of rocks in the intertidal zone that were covered in algae. Every so often a dozen or more would gather into a ball and they would disperse again after less than a minute. One ball of them rolled off of the rock it was on and amazingly stayed together ofter impacting the sand below. My hypothesis is that it is some sort of mating behavior but I could be wrong. I attempted to photograph them but they were too tiny, they moved too fast, my camera ran low on battery life, and the sun started to set. It seems that the mystery will have to remain a mystery...
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