Mass Spawning - NW Gulf Mex.

Gittings, S. sgittings at
Tue Sep 12 18:07:18 EDT 1995

Observations of coral reef spawning at the Flower Garden Banks, NW Gulf of 
Mexico, August 14 - August 22, 1995. 

Compiled by Steve Gittings and Ken Deslarzes 

Flower Garden Banks NMS 
1716 Briarcrest Dr., Suite 603 
Bryan, TX 77802 
Phone: (409) 847-9296 
Email: sgittings at 

The following provides details of spawning observations reported by scientists 
and recreational divers who participated on cruises between August 14 and 25, 
1995 in the Flower Garden Banks National Marine Sanctuary.  Quotation marks 
indicate dive descriptions of their observations. 

Be on the lookout for a possible September 16 coral spawning event following 
the September 8 (2338 hrs) full moon. 

August 14, 1995 
Night time observation: possible spawning by Mussa angulosa  a red material 
was seen streaming from a polyp.  It was uncertain whether it was from the 
coral or from something between the polyps.  Photographs were taken by a 
recreational diver and hopefully, will be forwarded to the Sanctuary. 

August 15, 1995 - no diving operations were conducted. 

August 16, 1995 (East Flower Garden Bank)  
1930 hrs: Spawning by one male Montastrea cavernosa. 
2120 hrs: Spawning by female Montastrea cavernosa colonies.  One Christmas 
Tree Worm (Spirobranchus giganteus) was seen spawning ("spiral of smoke"), 
probably a male, based on diver description. 
2130-2230 hrs: Montastraea franksi spawned in abundance, but less than in 
2130-2230 hrs: Coral gamete bundles were observed at the sea surface. 
2245 hrs: A Rough Fileclam (Lima scabra) released a "cloud".  The fileclam 
shot the material out during one pulse.  The cloud dissipated in about 10-15 

August 17, 1995 (East Flower Garden Bank) 
0011-0020 hrs: A few coral gamete bundles were spotted on the surface at 0011 
hrs.  The coral spawning pulse reached a peak at 0020 hrs, but subsided to nil 
before 0030 hrs. 
1630 hrs: Two Bar Jacks (Caranx ruber) were seen spawning. 
2050-2128 hrs: Numerous male Montastrea cavernosa  colonies spawned. 
2103 hrs: Several Diploria strigosa colonies spawned. 
2110 hrs: Call from the M/V Fling at the West Flower Garden Bank reporting 
coral spawning had begun. 
2112 hrs: Egg release by Montastrea cavernosa . 
2115 hrs: Diploria strigosa and two Christmas Tree Worms were seen spawning. 
2130 hrs: One huge female Montastrea cavernosa  colony was seen spawning. 
2130-2230 hrs: M. franksi spawned in abundance, also one small Diploria 
strigosa colony spawned.  Ruby Brittle Stars (Ophioderma rubicundum) were out 
on the coral heads but none were seen spawning as has been witnessed in the 
2300-0030 hrs: Spawning by numerous Montastraea faveolata.  
Samples of Montastrea and Diploria were collected and processed for 
fertilization experiments. 

August 18, 1995 (East Flower Garden Bank) 
1630-1930 hrs: Bluehead Wrasse (Thalassoma bifasciatum) were seen spawning.  
Eight to eleven female Bluehead Wrasse, large in size, full adults, were seen 
swimming very closely together within a 1 m2 area, 30 cm above the reef.  One 
supermale Bluehead Wrasse swimming in the periphery of the 1 m2 area, was seen 
going into the school of females to then rush 30-40 cm above the school along 
side a female.  A brief (no more than a few seconds) and spontaneous release 
of male and female gametes was seen. 
1900 hrs: A "plump " Montastrea cavernosa  colony was observed and another 
with gametes present and visible in body cavity. 
2145 hrs: Diploria strigosa was seen spawning. 
2200-2220 hrs: M. franksi  spawned in relatively low numbers. 
2225-2305 hrs: Surface coral gamete slick observed. 
2250 hrs and 2330 hrs : M. faveolata spawning. 
August 19, 1995 (East Flower Garden Bank) 
0100 hrs: No spawning activity was observed. 
2045-2115 hrs: Active Colpophyllia natans spawning, dense surface gamete 
2130-2300 hrs: One female Ruby Brittle Star was seen spawning. 

August 20, 1995 (West Flower Garden Bank) 
Daytime observation: Bluehead Wrasse were seen releasing gametes. 
1900-2015 hrs: Christmas Tree Worms spawned.  Both sperm and eggs release 

August 21, 1995 (East Flower Garden Bank) 
2130 hrs: A Diploria strigosa colony was seen spawning ("a seven to eight 
minute release of pinkish eggs"). 

August 22, 1995 (West Flower Garden Bank) 
1755 hrs: Montastrea cavernosa  was seen spawning. 
2115 hrs: Coral gamete bundles seen at the sea surface (not a dense slick). 
2130-2230 hrs: No spawning activity seen on the bottom. 

August 22, 1995 (East Flower Garden Bank) 
2000 hrs: Creole Wrasse (Clepticus parrae) spawning rushes observed 



Mussa angulosa (?)  Aug 16	 
Caranx ruber  Aug 17	 
Ophioderma rubicundum  Aug 19 
M. cavernosa  Aug 16, 17, 22	 
Thalassoma bifasciatum  Aug 16, 20	 
Spirobranchus giganteus  Aug 16, 17, 20 
M. franksi  Aug 16, 17, 18	 
Clepticus parrae  Aug 22	 
M. faveolata  Aug 17, 18		 
D. strigosa  Aug 17, 18, 21		 
C. natans  Aug 19		 

DATE	        TIME 
Aug 16-17	1930-0020 
Aug 17-18	2050-0030 
Aug 18	   2145-2330 
Aug 19	   2045-2115 
Aug 21	   2130 
Aug 22	   2115 

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