Abstract

Coastal fisheries in The Bahamas face a variety of threats from over-fishing, loss of near shore habitats, changing water quality and possibly invasive species. The lack of quantitative historical data and fisheries independent information makes change detection for individual species and fish assemblages difficult. This research documents reference conditions for fish assemblages based on island-to-island and habitat specific surveys. A synoptic survey method was used to: a) characterize fish fauna, b) evaluate reference conditions, and c) look at intra and inter-island and habitat-specific relationships to establish indicators to detect changes over time throughout the archipelago. Roving diver visual surveys were used to gather fish abundance data from four large islands (Andros, New Providence, Abaco and Great Exuma), and from specific sites and habitats around a small cay (Great Guana Cay, Abacos). Four characteristics were evaluated from these surveys: 1) the ecological similarity between islands and between habitats, 2) rank-order abundance for the top 65 species, 3) rank-order abundance of indicator species, and 4) the proportion of species in trophic guilds in specific habitats. The results showed significant inter-island differences when sufficient observations were available; thus island group comparisons must be analysed independently for change detection. Small scale, intra-island habitat analyses allowed for reference characterization of the area, which can be critical for detecting localized community changes over time. As threats to coastal fisheries continue to increase, identifying reference conditions and island patterns is critical for better management and to detect changes over time or space

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