[Coral-List] Coral mass spawning in Puerto Rico

Hernandez Edwin coral_giac at yahoo.com
Mon Aug 29 16:04:41 EDT 2005

Dear coral-listers:

Hola! Below, a summary of last week's mass spawning
event in Culebra Island, Puerto Rico.

Best regards,


Edwin A. Hernandez-Delgado, PhD
Affiliate Researcher

University of Puerto Rico
Department of Biology
Coral Reef Research Group
PO Box 23360
San Juan, PR 00931-3360
Tel. 787-764-0000, x-4855
Fax 787-764-2610
e-mail: coral_giac at yahoo.com


Coral mass spawning report for Puerto Rico

Friday – August 26, 2005
Punta Soldado, Culebra Island, Puerto Rico
Lat 18 16.772N
Lon 65 17.244W

Weather conditions:

A major thunderstorm preceded mass spawning in Culebra
Island at about 20:00; lightning, heavy rain and
massive runoff. However, the diving site was not
impacted by stormwater runoff. After that, clear
skies, calm wind, very calm seas and slack tide.

Peak mass spawning occurred during the evening of
August 26, 2005, exactly at the 7th evening following
August full moon. The following coral species spawned:

Montastraea annularis (22:15 – 22:30)
Montastraea faveolata (22:15 – 22:45)
Montastraea franksi (22:30 – only a single colony was

Diploria clivosa gametes were also observed floating
in the surface.

A massive pink-peach colored spawn slick was washed
ashore at about 23:30 while we surfaced. It was
composed of very small-sized gamete bundles that
resembled Acropora cervicornis gametes. No colonies
were observed spawning indeed. This is the first time
during the last 10 years that we have observed such a
massive spawn slick of Acroporid-like gametes to occur
after the 4th evening following full moon.

No other species were documented to spawn.

Some interesting facts.

1.  Peak spawning for Montastraea annularis species
complex occurred in Culebra exactly as we predicted,
during the 7th night following the August full moon,
at about 22:15. This is exactly coincident with our
observations during 2002, 2003 and 2004.

2.  Polyp distension was documented at approximately
21:45-22:00 (about 15-30 minutes before spawning).

3.  The exact spawning time was correctly predicted in
situ exactly 2 minutes before based on the behavior of
brittle stars. Somehow, brittle stars are capable of
detecting some kind of chemical clue and become very
active simultaneously climbing to coral surfaces.
Again, this was an unequivocal signal that spawning is
about to occur.

4.  No spawning was documented in colonies that
appeared partially bleached or stressed out by
sediment smothering.

5.  The Punta Soldado local population of Acropora
cervicornis is largely composed by dispersed colony
fragments that rarely exceed 1 m in diameter. The
observed spawn slick was at least 50 x 7 m. If these
gametes were actually from cervicornis this might
suggest that very small-sized colonies were capable of
producing significant gamete production. But this was
never confirmed during our limited diving time. No
observations were conducted on A. cervicornis becaused
we expected this species to spawn during the 3rd or
4th evening following full moon and not during a 7th

6.  There were large and widely dispersed slicks of
gametes (including acroporid-like gametes) during the
early morning of the following day when seas were
still calm. Slicks were documented to occur around
east, south and west of Culebra, and also around the
vicinity of Los Corchos Reef and Culebrita Island, to
the east of Culebra.

Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 

More information about the Coral-List mailing list