[Coral-List] Montastraea cavernosa gentlemen's club

[Yusef F. Fadlalla]

Mike, 

Let us assume that what you observed was not an aberration. We might
then want to consider that Montastrea cavernosa employs more than one
mechanism to effect and maximize fertilization.  In addition to
participation in female-male synchronized spawning, the female colonies
of Montastrea cavernosa may hedge by capturing (how about all that
mucus?) sperm released into the water column by neighboring
"opportunisitic" male colonies.    

Sperm capture by corals may not be common, but is not unknown.  The
brooding females of the solitary coral Balanophyllia elegans capture
sperm released into the water column by neighboring males.  I have seen
male Porites cf. lutea colonies spawn in mid-day.  I believe some
workers may have reported similar observations.  

Yusef Fadlallah 


-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Mike Matz
Sent: Monday, August 25, 2003 9:19 PM
To: coral-list
Subject: [Coral-List] Montastraea cavernosa gentlemen's club


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:
--------------------------------------
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

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