Abstract

Surveys have been conducted since 2005 on a multi-species grouper spawning aggregation at Mona Island, Puerto Rico. Over two years, red hind (Epinephelus guttatus) and yellowfin grouper (Mycteroperca venenosa) were found aggregated and exhibiting signs of spawning activity (distended abdomens, unusual coloration, and peculiar behavior). Diver surveys with GPS tracking were used to pinpoint the location of highest densities within the site as well as determine how these vary around the full moon and among the winter spawning months. The focal areas used by the two species were separate (~100m) and remained constant over two years. Epinephelus guttatus aggregated at 20 m on low relief colonized hardbottom while M. venenosa were found at 25-30 m on the high relief shelf eldge. The density of E. guttatus peaked in January and M. venenosa 2 days after full moon in March. A third species, tiger grouper (M. tigris), has also been observed aggregating at this site but has not been surveyed quantitatively. Maintaining these aggregations may be critical. The Mona Channel is a semi-permeable geographic boundary, and the Mona fish fauna is most probably dependent upon self recruitment, but may also serve as an important stepping stone for ecological connectivity between Puerto Rico and Hispaniola. This baseline information is a first step in monitoring these spawning populations, advancing our knowledge of their reproductive behavior, and assessing the success of management actions

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