30 September 2009

Cultivating Coral

This morning and yesterday afternoon I went with the SFS interns to transplant coral onto the reef balls we had submerged a little while back (see Reef Balls). About a week ago they attempted to do so using the method I mentioned before: gluing them on with a special marine cement. As it turned out, that wasn't the way to go. The cement crumbled in the water and wasn't strong enough to hold the corals in place. Based on his previous experience transplanting corals, Will suggested a new method: zip-tying them in place using plastic cable ties.

Newly transplanted corals.

It's not the most aesthetically pleasing method, but so far it appears to be working really well. This morning we checked closely on the ones we attached yesterday, and the coral polyps were extended and feeding - a very good sign. And, I was told, the corals will eventually grow over the plastic, concealing it within the stony structure.

Healthy looking polyps on my piece of Pillar Coral.

Finding enough coral fragments to transplant is pretty easy. It's part of the coral lifecycle to break apart and grow new colonies. It's only a problem when there's a catastrophic event (like Hurricane Ike last year) or a dramatic change in the ecosystem (like those often caused by pollution, silting, and climate change) that kills off the entire colony. We simply snorkeled on the surface until we spotted a detached piece, then dove down and collected it. They're much less fragile than I expected too. When the polyps are retracted they are protected by the hard structure they've built around themselves (at least, this is the case for hard corals).

Fastening Zip-Ties

In the previous post about reef balls I said that I expected fish to colonize them on their own and almost immediately. I was wrong. Apparently fish are not attracted to plain concrete objects. I was really impressed, however, when I attached a piece of Dendrogyra cylindrus (Pillar Coral) and three fish swam right in and started nipping algae off the dead portions! I pulled the zip-ties tight, backed up, and literally within 10 seconds the fish were there. They recognized the balls as a nice place to live once there was some coral there.

Now we wait and watch. At regular intervals, Will will be taking photographs (with a ruler in the frame) to track their rate of growth.

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