I’m sorry. I had to go there. You didn’t really expect me not to, did you?
The reason, of course, is that today we got our first settled and metamorphosed Pisaster stars! We were doing our normal Monday water change when I noticed a teensy orange speck on the bottom of one of the jars. I used my beat-up old paintbrush to remove the tiny dot to a dish, put it under the dissecting scope, and saw this:
From this picture it’s a little hard to see what’s going on. The entire body has contracted a lot, from a 2.5-mm larva to about 1/4 of the original size as a 600-µm juvenile, and become much more opaque. There are tube feet and spines as well as some remnants of larval body (the soft bits at the bottom of the animal) at this in-between larvenile stage.
Here’s a picture of a fully metamorphosed little star:
I expect we’ll be seeing more tiny orange dots on the bottoms and sides of the jars in the next several weeks. At some point we will have to figure out what they eat and provide it for them. But at least we know we’re able to get them through the larval phase.
Just for kicks, here are some pictures of where we grow the larvae and how we do the twice-weekly water changes.
An update on other matters:
Today is the six-month birthday of my baby urchins! Six months ago to the day these little guys were zygotes, and six-months-plus-one-day ago their parents were roaming the intertidal. They grow up so fast!
And lastly, that little shmoo-type thing that I found in the plankton yesterday has revealed itself to be. . . an anemone!
One of the things I like best about cnidarians is the beautiful transparency of their bodies. I love how you can see fluid circulating through the tentacles. Gorgeous, isn’t it?