How does Baykeeper deal with what I assume would be an on-going need to control urchins? Have these sites seen an increase in urchin predators like lobster and sheephead? That is one of the saving graces for the kelp off Catalina... we still have reasonably good lobster and sheephead populations to keep those pesky echinoderms under control.
Bill,
You are right on, this is the type of question that keeps us up at night! There is not an easy answer to this.
We achieve urchin control through a few different means. When we clear the restoration sites out (each site is 16m x 30m), we leave approximately 1 urchin per square meter, as this is roughly the density seen in healthy kelp forests. We also try to clear a buffer zone around the sites because the restorastion area is often in a larger urchin barren, so urchins can move back into the restoration site. At Escondido, they were able to clear the whole reef. The purple and red urchins are not very mobile on sand, so this acts as a natural barrier. At Long Point right now there is still an urchin army in the shallows that I'm sure can smell the soup cookin and are migrating deeper. This is tough to clear out the urchins shallower than 20 ft, because usually the surge is too much to get work done.
There are a few factors on our side here. Urchin babies cannot eat adult giant kelp very easily. It's too big and tough for the little mouths of the babies to eat it. So once the kelp starts coming back, that limits the urchin population some. Sessile Invertrebrates that settle on the bottom in a recovering forest can take up reef space and that also keeps the urchins from dominating. There is a nice sand border on the deeper portion of that site that keeps them out coming from the deep, so that's nice too.
As for the urchin predators, we are not restoring in a reserve so they are far and few in between. Occasionally we'll see them, but not often enough to stop worrying. Right now there are even commercial lobster pots right in the Long Point restoration site! It seems that once the canopy was restored, the fisherman saw it as a likely target for lobster.
Having said all that, Escondido has been restored for a few years now and there is no sign of any urchin population growth in or around the sites. We have 9 sites there.
So, I hope that answers the question some. We are definitely supporters of the upcoming MPA process in a couple years, because we also believe that overfishing is going on here on the mainland. Our project shows that once you remove the urchins, the kelp forest comes back. We need more urchin control and habitat protection. The little urchins aren't malicious, they just reproduce like they're still in a healthy kelp forest, predators and all.
Brian
