Environmental influences on fish assemblage in the Venice Lagoon, Italy

This study aimed to investigate the small fish assemblage in the Venice Lagoon shallow waters in relation to selected environmental variables, such as water-quality parameters, sediment grain-size variables, and habitat structure factors. Fish sampling was carried out in 68 stations, seasonally, by using a small beach seine net. The results highlighted the primary importance of habitat structure variables, such as seagrass and salt marsh coverages, with regard to fish distribution in the lagoon, in association with turbidity and salinity gradients. Two distinct fish assemblages were identified, corresponding to opposite species preferences in relation to salt marsh coverage-turbidity and seagrass coverage-salinity gradients. These results confirmed the importance of the biologically mediated influence of environmental parameters over physical parameters on small fish assemblages in dynamic systems such as the Venice Lagoon.