[Coral-List] Montastraea cavernosa gentlemen's club

[Mike Matz]

Hello all,

I did not get a single reply to my previous message about apparent "males-only" spawning of M. cavernosa on FL Keys (see below) - looks like nobody really knows what to say. In this case, please, relay vague rumors, express wild ideas and non-substantiated opinions. My feeling is that if our observation is true, it might be interesting from the evolutionary ecology point of view and worth further study.

Also - please tell me when and where would be our next chance to collect M. cavernosa eggs? Is spawning of this species expected somewhere/sometime during September-October? I would greatly appreciate receiving this information!..

best wishes

Mike

Mike Matz, Ph.D.
Assistant Scientist
Whitney Lab, University of Florida
904 461 4025
http://www.whitney.ufl.edu/research_programs/matz.htm


my previous message:
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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) 

cheers

Mike