Human and conservation factors affect spatial variation of reef fish assemblages in Colombian Pacific reefs

Human populations and conservation efforts are recognized as influential factors that can impact marine communities, but their impacts are variable and occasionally contradictory. Using an empirical database of fish assemblages compiled from 393 underwater visual censuses along the Colombian Pacific Coast, we assessed spatial variation in these assemblages and investigated whether they are influenced by human and conservation factors which have either negative (i.e., number of fishers and market distance) or positive (i.e., conservation status and Marine Protect Area age) effects on fish communities. Our study reveals that remote locations have a higher fish density and biomass than those near the coast. Additionally, we found that grunts (Haemulidae) were the most species-rich family and contributed the most to fish density and biomass. Piscivores were the trophic group most affected by human factors, showing lower species richness, density, and biomass in coastal locations. In contrast, other trophic groups did not show a negative response to human factors across locations. We did not observe an effect of human and conservation factors on the total species richness of fish assemblages, regardless of whether Malpelo was included in the model or not. However, market distance negatively influenced the average fish density and biomass when all locations were included. Our results provide the first quantitative assessment of fish assemblages across the Colombian Pacific Coast, enabling future comparison and enhancing our understanding of the effects of human and conservation activities on the patterns of species richness, density, and biomass of reef fishes in the Eastern Tropical Pacific.