Whaylen, L., Pattengill-Semmens, C.V.,
Semmens, B.X., Bush, P.G. and M.R. Boardman. 2002. Observations of a
Nassau Grouper (Epinephelus striatus) Spawning Aggregation Site In
Little Cayman, Including Multi-Species Spawning Information. Gulf and
Caribbean Fisheries Institute Meeting. November 2002, Mexico.
precipitous decline in mass spawning aggregations of Caribbean grouper and
snapper species has been well documented.
to one-half of the known Caribbean aggregation sites are now inactive due
to the ease with which aggregating species are caught. Historically,
five spawning locations have been documented in the Cayman Islands.
Today, three of these sites are dormant or commercially extinct.
2002, an expedition was led by the Reef Environmental Education Foundation
(REEF) to Little Cayman Island to document a recently discovered spawning
aggregation of Nassau grouper (Epinephelus striatus) on the
islandís west end.
A team of divers conducted visual and video surveys on the
aggregation site and on nearby reefs for ten days surrounding the full
Size and abundance estimates, color phase, and courtship and
spawning behavior were documented.
The Nassau grouper at the aggregation site shifted from mostly
white belly phase early in the aggregation cycle to predominately dark
phase in the middle of the cycle to mostly bicolor phase at the end.
Toward the middle of the aggregation cycle the number of animals
reached a maximum of approximately 5,200 fish.
Courtship behaviors were documented each night and spawning was
witnessed on 4 nights beginning 5 days after the full moon.
Courtship coloration and behavior were documented in ten additional
Five of these species were seen spawning.
Hook and line fishing occurred daily on the aggregation.
The Cayman Islands Department of the Environment reported a total
catch of 1,934
Nassau grouper during the 10-day project, with an average landed
size of 61.9 cm and a female to male sex ratio of 1:1.6 for all landed
fish (39% females).