I wanted to give the class an update on the status of my crab eggs, Pachygrapsus crassipes. I am nothing short of amazed having watched these guys develop from yolky embryos to full-fledged zoeal larvae.
Pipetting the individual eggs and larva and releasing them into a new dish with clean (2 micron filtered) sea water, rather than changing the sea water with the larvae within, is the way to go. In this batch of eggs I am witnessing life both at its finest and most vulnerable. Some zoea are struggling to free themselves from the strands that attach them to the eggs, while others are testing out how to move their setae to swim about in the dish. Others were less fortunate, as the eggs simply did not continue to develop or were attacked by bacteria prematurely. If I take away one thing from the eggs and adults of P. crassipes, it is that these are some resilient organisms! Due to the thick membrane that encases the eggs, they can go weeks after being separated from the mother's abdomen and still manage to survive.
Beneath I am also posting a picture of the larva from our mystery egg mass from Moss Landing. They are quite small, which makes them unideal for a close-up, in-focus picture on this camera/microscope. Regardless, it's interesting to note how fast these eggs developed and hatched into trochophores. Now they have graduated to veliger stage, with shell formation and all. I am really looking forward to watching how these guys continue to develop throughout the week.
best,
Chris
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