P. vigil caught near the mangroves in the back of the pond.
This weekend we did a series of seines in the fishpond to catch more Thalamita crabs and glass shrimp ('opae). Usually a few seines at one site can turn up 10 crabs, but this weekend, not so. Why? We kept catching these in our nets. Meet mo'ala, or Podophthalmus vigil, the long-eyed swimming crab. The name "vigil" means "watchful," and probably refers their long eye-stalks. We found tens of these in our seines across the pond, and even a few gravid ones holding eggs. I'm not sure why they were so abundant this month. We also spotted an endemic Hawaiian species, the blood-spotted swimming crab (Portunus sanguinolentus). Surveys by Bob Hiatt in Hawaiian fishponds in the 1940's turned up these same species, which are both eaten by ulua, one of the main predators in the pond.
There is some variation in claw color in P. vigil. Notice the eyes peeking out from behind the chelipeds.
Gravid Rainbow. The panel that holds the eggs next to the body is called the apron, and is wider and rounder in females. It can hold millions of eggs at a time. This crab was caught near the seawall.
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