The ecology of tidepool fishes has been extensively investigated worldwide over the past 40 years. As in many other ecological fields, studies in temperate zones outnumber studies carried out in tropical areas. Here, we document the short-term spatio-temporal variation of a tidepool fish assemblage from the Tropical Eastern Pacific (Gorgona Island, Colombia), compare our data with previous surveys made in 1993 and provide the first latitudinal comparison of tidepool fish assemblages in the Eastern Pacific coast (43°N to 36°S). During April-July 2006, monthly samplings were carried in 18 tidepools located at three sites this Island. A relatively species-rich tidepool fish assemblage (53 species) was found at Gorgona Island. Labrisomidae, Gobiidae and Gobiesocidae were the dominant resident components of this assemblage, whereas Pomacentridae, Muraenidae and Labridae constituted the transient component. Although the same dominant species were observed in surveys from 1993 and 2006, suggesting a high persistence of this assemblage over time, clear differences in the relative abundance of some species were also detected. These differences were partly the result of using different sampling methodologies (rotenone vs clove oil). Comparisons with other studies performed in tropical and temperate areas of the Eastern Pacific coast indicate a clear latitudinal pattern in the composition of these assemblages that correspond to well-documented biogeographic subdivisions of the marine fauna in this region. Further investigation of the ecological role that tidepool fishes play in rocky intertidal and subtidal areas of Gorgona Island and the whole Tropical Eastern Pacific region will benefit our understanding of the functioning of these important coastal ecosystems. Rev. Biol. Trop. 62 (Suppl. 1): 373-390. Epub 2014 February 01.

Keywords: tidepool icthyofauna, community structure, zoogeography, Colombia, Eastern Pacific Ocean