Urchin corrals


I have installed the first of what will likely be several different contraptions to contain urchins. It’s an urchin corral! You can see it here in the kiddie pool tanks at MaST aquarium:

Photograph of urchin corral out of the waterClose up of urchin corral

It’s kind of like a little urchin boxing ring!

If you’re wondering why on Earth I’m doing this, you might check out this previous post.  These urchins will eventually be used in a field experiment to test how their feeding affects the subtidal communities on artificial rocky substrates.  In order for the field experiment to work, I need to be able to keep the urchins from wondering off experimental plots.Photo of urchin pressing against edge of corral

Enter little urchin boxing rings… this is likely the first of several iterations of the urchin corral/boxing ring idea.  Over the next week I’ll be trying to figure out whether urchins are escaping and how exactly their doing it.  If I can develop a design that contains urchins effectively, the next Photo of urchin corral in kiddie poolstep will be to put something like this into the field and evaluate whether it seriously alters flow, traps algae, excludes other important critters, or changes some other aspect of the physical environment on seawalls.

In its current form, the boxing ring/urchin corral is constructed from bolts protected by pieces of artificial sponge (thanks to Rus Higley at MaST aquarium for this fantastic idea) and monofilament line (this idea compliments of my advisor, Ken Sebens). I’ll let you know what happens!