[Coral-List] Montastraea cavernosa spawning problems

Mike Matz matz at whitney.ufl.edu
Fri Aug 22 13:28:22 EDT 2003

Hello listers,

I would greatly appreciate your opinion about the following.

This Monday and Tuesday (August 18 and 19) we've been trying to catch some Montastraea cavernosa eggs during the spawning event. We sat on the bottom at 15 feet during the spawning time (from sunset to about 2 hours after) constantly monitoring selected colonies, as well as used catch-tents of Alina Szmant's design (these were installed over 5 colonies at each of the two different depths, 15 and 50 feet, and checked the next morning if they caught anything). I would say that on each of the nights at least 15 colonies were monitored in this way. Curiously, we seen numerous male colonies spawning (on both nights of 18 and 19, there was already nothing on the night of 20), but not a single one that would resemble a female spawning. Instead, there were many colonies that did not spawn at all. We were expecting to see pink egg bundles floating up, but out of desperation ended up collecting anything weird that appeared near the polyps. This stuff turned out to be mostly strings of mucus with some sediment stuck into it. Likewise, none of our 10 tents caught a single coral egg (we looked very cartefully).

The question: is it indeed possible that males spawn and females do not? Or our failure is attributable to some fundamental fault in our procedure? such as using dive lights too much, for example? (this one would not apply to tents, though) 



Mike Matz, Ph.D.
Assistant Scientist
Whitney Lab, University of Florida
904 461 4025

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