Abstract

In order to understand the present status of Nassau Grouper at a remote island of western Puerto Rico, the past fishery exploitation and present distribution was investigated. Interviews with ten patriarch fishers provided information to describe the exploitation patterns of Nassau grouper at Mona Island since the 1950s. Most fishers targeted spawning aggregations at different sites around the island with traps, spearfishing, and hook and line during winter months (December to February). Nassau Grouper landings ranged from 500 to 1,500 lbs per 5-7 day trip (~167 lbs/day). and after the 1980s declined significantly when fishing trips to Mona Island were no longer feasible. Most fishers believed these spawning aggregations have ceased to exist, and much of the effort has been shifted to other species and sites. Underwater visual surveys were conducted by roving searches and belt transects throughout the insular platform of Mona from 2004 to 2007. The abundance of Nassau Grouper is extremely low, and its distribution is limited to specific depths and habitat types depending on size class. No spawning aggregations of Nassau grouper were observed, although other grouper species were found aggregated and reproductive coloration patterns were present on two individuals. In addition, early juveniles (< 10 cm TL) have been observed during more than one year, suggesting successful reproduction is occurring somewhere at or near Mona. The current population of Nassau Grouper at Mona Island may provide a refuge for this species.

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