[Coral-List] Coral Spawning Report

Alex Mustard atmu at soc.soton.ac.uk
Tue Sep 23 06:36:34 EDT 2003

Dear all,

Here are our observations from 3 days in Grand Cayman last week. This 
was the first time we had observed coral spawning on Grand Cayman's 
reefs, and are most grateful for guidance from coral list.

Alex Mustard with staff and guests at Oceanfrontiers Dive Centre, Grand Cayman.

SPAWNING REPORT: Playing Field Reef, East End, Grand Cayman
Location: 19š17.567N, 81š06.300W
Dates: 15-17/Sept/03
Species spawning: Acropora cervicornis, A. palmata, Montastraea 
annularis, M. faveolata, Diploria strigosa, + 2 species of sea rod 
gorgonians (have photos but no I.D.s!).
Images available at  http://www.soc.soton.ac.uk/GDD/hydro/atmu/coral/1.html
Depth: 5-14 m

Day 1 15/09/03
Sunset: 18:29
Tides H:14:03, L:17:30, H:21:12,
Sea state: waves 2ft, wind 5 mph
A. cervicornis bundle appearance: 20:35-21:12
A. cervicornis spawning: 20:12-21:35 (~20% of popn)
Spawning activity not correlated with colony size.

Day 2 16/09/03
Sunset: 18:28
Tides L:06:26, H:20:20,
Sea state: waves < 1ft, wind 0 mph
2 species of gorgonians spawning 20:45-21:15 (~10% of popn)
A. cervicornis bundle appearance: 20:35-21:12
A. cervicornis spawning: 20:12-21:35 (~10% of popn)
A. palmata spawning 21:45 (1 colony only, 1 observer only!)
Montastraea spp. bundle appearance: 21:40-22:15
Montastraea spp. spawning: 22:15-23:35 (~70% of popn - noticeably all 
large colonies)
Diploria strigosa spawning: 22:25 (~25% of popn)

Day 3 16/09/03
Sunset: 18:27
Tides L:07:22, H:20:05,
Sea state: waves 0 ft, wind 0 mph
1 species of gorgonians spawning 20:45-21:10 (~5% of popn)
Montastraea spp. bundle appearance: 21:35-22:05
Montastraea spp. spawning: 22:15-23:35 (~30% of popn)
Diploria strigosa spawning: 22:10-22:20 (~5% of popn)
Same species of gorgonian was spawning again at 22:35-22:50

Siderastrea sidereal, Colpophyllia natans and Montastraea cavernosa 
were common on the site but were not observed to spawn. Ophiuroids 
spawned at 22:30 on 16 & 17/09/03

State of local reefs: Study site was selected because it had good 
coral cover >30%, with all our "target" species present and covering 
a reasonable depth range. A. palmata ~5-7 m, A. cervicornis 7-12 m, 
Montastraea spp. 7-14 m. Occurrence of disease was low.

Comparison to previous years: we are not aware of any previous 
spawning observations on any of the Cayman Islands (sources: coral 
list, reefbase.org, peer-reviewed literature databases and talking to 
people on the Islands) but expect that there has been. I hope that 
this post will help us get in touch with other people who have 
observed spawning in the Caymans.


Dr Alexander Mustard                      T +44 (0)23 80 59 60 16
George Deacon Division                     F +44 (0)23 80 59 62 47
Southampton Oceanography Centre    M +44 (0)78 76 52 31 10
European Way, Southampton              E atmu at soc.soton.ac.uk
SO14 3ZH, UK

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