Abstract

In order to determine the spatial distribution and abundance patterns of the rainbow wrasse (Thalassoma lucasanum) across a coral reef of the eastern tropical pacific, visual censuses of fish were carried out along 10 transects in a fringing coral reef at Gorgona Island off Colombia. The abundance of initial-phase males and females (IP) and terminal-phase (TP) males at each main reef zone (Channel, Flat and Outer Slope) was computed and their quantitative distribution across the reef is described. Both phases were observed across the coral reef. The IP was significantly more abundant in the channel (57.0 ±1.95 ind 1000 m-2; P ? 0.05), than at the flat or outer slope. The highest relative abundance of TP occurred in the outer slope (4.0 ± 0.43 ind 1000 m-2); however, no significant differences were observed in the distribution of density across the reef for this phase (P ? 0.05). The spatial pattern observed for T. lucasanum was not related to living coral cover or relative reef complexity. It is suggested that abundance and distribution of this species at Eastern Tropical Pacific (ETP) reef is determined by other factors like food availability or social system.