CORAL SPAWNING CRUISES

Every year, 7-10 days after the full moon in August, the reef-building corals of the Flower Garden Banks National Marine Sanctuary put on a fantastic spawning display. In ways that we still don't understand, each coral species times its gamete release for maximum benefit by avoiding the simultaneous spawning of other species. And, each year, sanctuary scientists and researchers from other facilities are there to observe this phenomenon in an effort to decipher even more pieces of the puzzle.

2007 SPAWNING CRUISE

A Christmas tree worm in the midst of a spawning colony of star coral in the Flower Garden Banks NMS on September 6, 2008. Photo: FGBNMS Volunteer

The 2007 Spawning Cruise was actually divided into two trips this year. Due to a full moon late in July, it was suspected that some of the corals might spawn in early August, so researchers were present in the sanctuary from August 6-8. Indeed, there was some spawning, but not a lot. Recreational Scuba divers visiting the sanctuary later in the week also reported some spawning activity during their night dives.

The second spawning cruise took place September 3-7, when the major spawning event was expected. The mass coral spawning event occurred as predicted for the most part, although not as heavy a spawn as seen in previous years. In addition, some species observations were a little off typical predictions. For example, Colpophyllia natans spawned on both the 9th night as well as the predicted 10th night after the full moon.  Other spawning predictions for brittle stars, christmas tree worms and sponges were not observed in numbers as expected.  Predictions were made based on a full moon on August 28, 2007 at 1035 GMT (Greenwich Mean Time).

A snowstorm of coral spawn on September 5, 2008. Photo: FGBNMS Volunteer

Two lighter spawning events are not necessarily unusual when the full moons occur late in July and August, as they did this year.

ADDITIONAL RESEARCH EFFORTS

While coral spawning is a major focus of this late summer cruise each year, it's not the only item of interest. After all, most of the spawning activity takes place at night, which leaves a whole lot of daytime to accomplish other tasks. This year's cruise included research efforts from the following individuals:

Dr. Craig Burnside (Bainbridge College) - tag and survey queen conch

Emma Hickerson (FGBNMS) - retrieve and maintain acoustic receivers at all three banks

Dr. Misha Matz & John Williams (University of Texas) - observe flouresence of oceanic bioflora and collect permitted samples

Martha Robbart & Jeremy Marshall (PBS&J) - rephotograph West Flower Garden Bank photostations

Kevin Strychar (Texas A&M University at Corpus Christi) - collect permitted sponge samples

Dr. Peter Vize, Sarah Davies & Dan Hilton (University of Calgary) - observe coral spawning activities and collect permitted samples

2007 SPAWNING OBSERVATIONS

Water temperature at observation depth :  86F
Salinity at observation depth:  35.5PPT
Depth of observations:  approximately 75' to 80'

A brain coral spawning in September 2008. Photo: FGBNMS Volunteer

September 3, 2007 (7th night after the full moon)
2115 Montastraea faveolata 1 colony
2120-2135 Diploria strigosa 2 colonies
2120-2130 Montastraea cavernosa 2 male colonies
2135 Montastraea cavernosa 1 female colony
2115-2135 Montastraea franksi 13 colonies

September 4, 2007 (8th night after the full moon)
2000 gametes on surface
2115-2210 Montastraea franksi 73 colonies
2118-2128 Montastraea cavernosa male 2 colonies
2115-2220 Diploria strigosa 58 colonies
2210-2045 Stephanocoenia intersepta 12 male colonies
2210-2045 Stephanocoenia intersepta 3 female colonies
2252-2310 Montastraea faveolata 7 colonies
2333 Montastraea annularis 1 colony

Other species:
2209 Spirobranchus giganticus christmas tree worms 4 male individuals
2209 Spirobranchus giganticus christmas tree worms 1 female individual

A close up view of a female Montastraea cavernosa colony spawning in September 2008. Photo: FGBNMS Volunteer

September 5, 2007 (9th night after the full moon)
2020-2130 Montastraea cavernosa 23 male colonies
2045-2132 Montastraea cavernosa 9 female colonies
2020-2200 Diploria strigosa 57 colonies
2120-2200 Montastraea franksi 16 colonies
2020-2115 Colpophyllia natans 7 colonies
2201-2240 Stephanocoenia intersepta 19 male colonies
2215-2240 Stephanocoenia intersepta 16 female colonies

Other species:
2020-2100 Ophioderma squamosissimum 2 female brittlestars

September 6, 2007 (10th night after the full moon)
2026-2105 Colpophylla natans 23 colonies

Other species:
2015-2105 Ophioderma squamosissimum 6 male brittlestars
2020-2100 Ophioderma squamosissimum 6 female brittlestars

For a summary and report of the 2006 spawning season, please visit our 2006 Coral Spawning Highlights page.