It's continued to be a cold spring through the last few months, which means that the animals are behind where they usually are at this point on the calendar. But the last week or so we had a rash of warmer weather, and I was hopeful that I would be able to collect fully incubated Crepidula eggs to set up the first of my summer's experiment with newly hatched larvae.
I went out on this morning's spring tide to a lower water level even than last time, previously the lowest I had ever seen the beach. This happens sometimes on windy days -- the wind pushes the water even farther away from the shore. And boy, was it windy. There were whitecaps on the water, which is not something I usually see in the summer, and it was so cold that I was bundled up just as much as when I go out in October (note the rubber gloves in the photo below).
An egg mass of a whelk. All but the last
compartment or two had already hatched, and I could see miniature snails ready
to come out of the last ones. I very much wanted to take them back to the lab
to watch them grow, but they are predatory and I don't want them eating my experiments
when they get bigger. Photo credit A. Cahill.
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My site this morning. If I share enough of these you
might start to get the feel for the tidal heights at this place too. See this
post for a comparison of
the jetty on a neap tide. Photo credit A. Cahill.
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Crepidula fornicata bed, normally subtidal at this part of the site. Pretty high densities for this area. Photo credit A. Cahill. |
And when I got back to the lab, I was thrilled to find this:
Crepidula fornicata egg masses and
larvae. The yellow ones on the left are recently laid eggs and embryos with
lots of yolk. The brownish-grey blobs on the right are ready-to-hatch egg
masses whose larvae have used up all of their yolk. The little dots that look
like snow are the larvae themselves. Photo credit A. Cahill.
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I spent the rest of my day setting up larval cultures for my experiments. Happy summer!
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