more coral spawning

Derek Hagman d.k.hagman at
Mon Sep 20 18:52:00 EDT 1999

I apologize for the delay.......

Recent observations of mass spawning by reef corals at the Flower Garden Banks
National Marine Sanctuary, northwest Gulf of Mexico.

Sept. 2, 1999 (7th evening after the full moon, Aug 26th.)

Unusually rough weather prevented scuba diving operations, however an ROV
was deployed and the following information gathered:
Beginning around 20:30 Central Daylight Time (CDT) male colonies of
Montastraea cavernosa were observed spawning and continued well past 21:30.
Adjacent female colonies were observed spawning within minutes of male
sperm release.  Shortly after 21:15 CDT a few colonies of M. franksi, and
later (21:50) Diploria strigosa, were videoed spawning.  Both shallow (17
m) and deeper colonies down to 42 m were observed spawning during this time
period.  By 23:00 CDT a substantial gamete slick (considering the rough
surface conditions/4-5 seas) existed.

Sept. 3, 1999 (8th evening after the full moon, Aug 26th.)

The ROV was again deployed early to look for spawning activity prior to the
planned scuba ops.  Several bundle plumes but no direct observations of
spawning were made between 19:55-21:30 CDT.  Several Diploria colonies were
however observed spawning thereafter until roughly 22:00 CDT.

Spawning observations by scuba divers began around 21:30 CDT, with colonies
of Diploria strigosa (predominantly) and Montastraea franksi spawning.
Shortly after 22:15 CDT male, then female colonies of Stephanocoenia
intersepta began spawning prolifically.  By 23:00 CDT late divers observed
several colonies of Montastraea faveolata spawning.  This was projected
to>be the most intense night of spawning activity, unfortunately it proved
be a disappointment in comparison to previous years.  Neither D. strigosa
or M. franksi spawned with any great intensity, and no significant surface
slick was detected.

As in 1998, it appears that most of the spawning took place on the 7th
evening, one night earlier than anticipated based on the previous
observations made between 1991-1997.

Sept. 4, 1999 (9th evening after the full moon, Aug 26th.)

Few colonies of D. strigosa, M. franksi and Colpophyllia natans observed
spawning between 21:00-22:00 CDT.  This was expected to be and turnout to
be an "off night".

Sept. 5, 1999 (10th evening after the full moon, Aug 26th.)

Colpophyllia natans spawned between 20:40-21:10 CDT in large numbers as

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