Seastar Wrap Up

This summer for my research, I was seeing the effects of changes in maternal investment in seastars. I was looking at what the effects of cutting the egg size in half would have on the size of the juvenile seastar after metamorphosis and the time it took the larva to develop into a juvenile. We started the summer looking at multiple species of seastars, but in the end we were only able to collects data from Pisaster, a species found on the west coast. Pisaster have small, planktotrophic developing eggs, but their eggs are on the larger side of the planktotrophic marine invertebrates.

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Juvenile Seastars

Even though I am now home from Friday Harbor, I need to tell you all about my last weeks at the labs and all of my research.  The last time I updated you on my research I was trying to spawn and raise Pteraster embryos to hatch. Unfortunately, not enough Pteraster hatched to run any experiments, but we did have 4 embryos reach metamorphosis and become juveniles. This was extremely exciting, even though there were only 4 because I had never worked with Pteraster before, and it is extremely encouraging for future experiments that I am able to rear the embryos to metamorphosis once they hatch.

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Slimey Seastars

Hi again! The last time I left you I mentioned a new experiment I would be starting on the seastar, Pteraster tesselatus.  Pteraster are commonly called the slime star because when agitated they produce massive amounts of a clear slime. Unlike the Pisaster and Evasterias, Pteraster do not have a feeding larval stage. Instead, Pteraster embryos hatch into larvae that do not feed before they settle and undergo metamorphosis to become a juvenile. There is not a large history of Pteraster research, especially in egg size manipulations, and I have never worked on this species before. Since it can be very difficult to work with this species, before we could do any true experiment to manipulate egg size, we had to make sure we would be able to spawn and fertilize the eggs.

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Seastars, Lasers, and Blue Stains

Hello! Last time I posted I was just finishing my first few trials of blastomere separations on the seastar, Evasterias. While the seastars were extremely reproductive (one female, ‘Big Mama’ gave us over 50 million eggs!), we weren’t able to perform full blastomere separations as the eggs did not develop and we lost a trial due to a seatable flooding. Female seastars are only able to spawn once in a season, so with all of the failed trials, we ran out of female Evasterias to spawn. Luckily, there is another seastar here, Pisaster ochraceous, which we could use instead of the Evasterias. Pisaster egg sizes are comparable with Evasterias eggs, and the two species have a similar development, allowing us to use Pisaster for our comparative study.

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