FISH COMMUNITY STRUCTURE OF STREAMS AND CANALS AT BABCOCK RANCH, CHARLOTTE AND LEE COUNTIES, FLORIDA

Fish communities were surveyed three times each year at 6 lotic habitats (small streams and manmade drainage ditches and canals) at Babcock Ranch, Charlotte and Lee Counties, Florida. Sampling methods were adopted from the baseline assessment of the Picayune Strand Restoration Project. Breder traps were deployed for one hour at each site for each sampling event. Active fish sampling with D-frame dip nets was also conducted for one hour at each location while traps were set. Data from passive and active sampling methods were combined for statistical analyses. A total of 26 fish species, representing 14 families were collected, including seven non-native fish species from four families. The most abundant fishes were native Gambusia holbrooki and non-native Hemichromis letourneuxi, respectively. Fish assemblages in canals were significantly different than in natural streams. Native sunfishes of the genus Lepomis were more abundant in streams than canals. Canals served as thermal refugia for non-native cichlids during severe cold weather events in 2009 and 2010. The removal of anthropogenic drainage canals and ditches, that serve as thermal refugia and pathways for dispersal for H. letourneuxi should benefit native fish species over time.