Effects of Habitat Complexity on Reef Fish Assemblages Associated with Northwest Gulf of Mexico Banks

The naturally occurring reefs and banks in the northwest Gulf of Mexico provide important habitat for a variety of commercially and recreationally important reef fish species. Exploratory studies of the banks have recorded distinct zonation of benthic habitat characteristics and the associated fish communities. This study provides new information about the influence of benthic habitat complexity on defining reef fish assemblages associated with natural hard-bottom banks in the northwestern Gulf of Mexico. Video footage was collected via high definition stereo camera arrays at a variety of habitats on three prominent banks and one artificial reef. Videos were analyzed for fish species composition and abundance, as well as a variety of habitat characteristics. We found that habitat characteristics were similar within a given habitat zone, and significantly different between zones (F=11.5, p=0.001). Similarly, the habitat zone within which a survey was conducted played a significant role in defining the fish species and relative abundances observed (F=2.49, p=0.02). Distance-based linear modeling showed that quantitative complexity characteristics explained a significant proportion of the variance in observed fish assemblages. These results suggest distinct structuring of fish communities at relatively small scales, dependent on benthic habitat zonation and the underlying environmental and habitat characteristics.