Habitat partitioning of fishes in an urban,estuarine Bayou

The physiochemical variability inherent to estuaries makes it difficult to identify those variables of importance to habitat selection by fishes. We used factor analysis to investigate habitat partitioning of fishes in Contraband Bayou, an oligohaline creek within the City of Lake Charles, in southwestern Louisiana. This bayou receives runoff and organic wastes from the City of Lake Charles and adjacent farmland (adding levels of complexity to an analysis of fish habitat preferences). Fishes were sampled from locations within the Contraband drainage in winter and summer of 1983 and 1984. At each location, 14 environmental variables were measured. Distribution of each common species in a season relative to these variables was characterized by calculating means of individuals for each environmental variable. A species' mean for a variable (the state of the variable where individuals of the species are most likely to be found) was interpreted as the species' “preference” for the variable. Factor analysis was used to identify trends in habitat partitioning among species, based on their preferences for all environmental variables. In all seasons, habitat partitioning separated typically freshwater forms from estuarine fishes, and separated forms more tolerant of organic pollution from less tolerant species. Some species entered the bayou only in summer, and in this season, additional factors were related to the preference of some of these species for areas with little cover that were normally shunned by resident species.