Freshwater fish diversity of a tropical eastern pacific island: PNN Isla Gorgona, Colombia

Given its biogeographical importance a study was performed on the diversity of fish in the streams of the Colombian Pacific Gorgona National Natural Park. This place is characterized by having the largest insular creeks system of the Colombian Pacific with 25 permanent streams and an estimated 75 temporary. The island was divided into east and west zones and the sampling was carried out in sites of nine streams, starting from the mouth upstream. The sampling sites were separated by paths of 50 meters with a total of seven points per stream. At each site, diversity data were taken through visual censuses modulated by time and additionally some physicochemical parameters were recorded. Nine species were registered, of which eight are of amphidrome origin and one primary freshwater. Differences were found in the species composition between some streams and between the zones. Flow rate and total dissolved solids were the variables that most contributed to the distribution of species, in this case diversity increased at points with lower flow levels and low values of dissolved solids.