The veligers are on their way!

Today a lot of my Dendronotus eggs had hatched on their own, swimming through the water as bona fide veliger larvae.  Nudibranch larval culture has officially started!

These bad boys are much more spherical now--whew!-- which makes me think that pointy-shell thing I saw last week was an artifact of their premature hatching.  Now they look like little swimming bubbles.  Interestingly, their shells are mostly empty.  My invertebrate larval culture guide says that planktotrophic larvae (those that feed while in the plankton) such as these hatch with relatively tiny bodies that grow as the larvae feed. We'll see if that holds for these guys.

I captured some video of the little veligers zooming around.  Here they are at 10X magnification:

Here's another short video clip of some veligers that were conveniently squished under the coverslip.  This kept them from swimming away and I was able to film them at higher magnification.  You can see the little velum whirling away and then being retracted.  See also how most of the shell space is empty?

So, now that these guys have hatched and have all that empty space inside their shells to fill up, they need to eat.  What do I feed them, you ask?  Well, because I was in a hurry to get them something, anything, to eat this morning, I fed them a bit of Isochrysis galbana, which is a haptophyte.  Algal taxonomy is not well established yet, and there are many ways of classifying both micro- and macroalgae.  I hesitate to wade into those murky waters, so suffice it to say that Isochrysis is a unicellular alga, golden-brown in color but neither a diatom nor a dinoflagellate.

This is what Isochrysis galbana looks like in culture.  We grow it in 1000-mL flasks of sterilized seawater and nutrients.

Isochrysis galbana in culture

According to the literature, veligers of Dendronotus frondosus can be raised on a mixture of Isochrysis galbana and a red alga called Rhodomonas salina.  And it just so happens that we also have R. salina in culture, so starting tomorrow the veligers will get a mixture of algae for their breakfast.

3 thoughts on “The veligers are on their way!

  1. Chris

    I believe Rhodomonas is a cryptophyte, not a rhodophyte. I seem to recall that there is some kinship there on the tree of life, but I am rusty with my (urg!) algal systematics. Very cool movie!

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  2. algong

    You're right, Rhodomonas is a cryptophyte. I called it a red alga because it is indeed red in color, but did not intend to imply that is a rhodophyte. Dang limitations of common names and the English language!

    Reply

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