Archipelago Los Roques: A potential baseline for reef fish assemblages in the southern Caribbean

Abstract

Abstract1. Despite increasing policies of protection, few localities in the Caribbean remain spared from human impacts. These lightly affected areas can better reflect the past composition of reef fish assemblages and provide baseline information about the natural factors driving fish distributions in the region.2. Reef fish assemblage structures were analysed in 21 Caribbean fished areas and marine protected areas (MPAs) along a gradient of distance to the nearest major market place. Assemblage structures by size and by trophic group were significantly related to the distance to market.3. Relationships of reef fish life‐history traits, families, and vulnerability indicators were examined with the seascape and the benthic composition at Los Roques Archipelago, the most isolated MPA in the analysis. Factors linked to seascape features were more important than benthic composition or human activities in explaining fish assemblage structure.4. Wave exposure was the most influential seascape metric. Exposed habitats were dominated by octocorals and sponges. More sheltered habitats were characterized by high coral cover, while leeward sites were characterized by steep slopes with close proximity to deeper water.5. Exposed habitats were mostly occupied by unspecialized fish species. Piscivore densities were high at south and south‐west sites, and were likely related to the large concentrations of planktivorous fishes found there. South and south‐west sites experience full oceanic conditions, and supported the highest species richness and densities within the archipelago.6. Los Roques National Park is one of the oldest and most remote Caribbean MPAs. Its fish assemblage structure is healthier than other fished or protected areas, with higher species richness, higher density of piscivores, and an abundance of large species. Predator–prey relationships provided additional evidence that Los Roques reef fish assemblage presented specific characteristics.7. The main patterns observed in this study represent a baseline for assessing reef fish assemblages elsewhere in the southern Caribbean.