Larval Fish Assemblage Structure at Coastal Fronts and the Influence of Environmental Variability

Within the coastal zone, oceanographic features, such as fronts, can have major effects on abundance and distribution of larval fish. We investigated fronts fish assemblages by jointly collecting physical (ADCP CTD) biological (larvae) data in nearshore waters south coast South Africa, four separate neap-tide occasions. Accumulation larvae at predominantly internal wave-associated was observed, with higher densities inshore within front than farther offshore. On each occasion, species pelagic eggs (Mugillidae Sparidae) were numerically dominant itself, while front, benthic (Gobiesocidae Gobiidae) more abundant. Offshore catches mainly comprised Engraulidae (pelagic eggs) larvae, which generally restricted to bottom, where current velocities onshore occasion. occasion when fast (>100 cm/s) currents prevailed, however, accumulation occurred offshore mixed throughout water column. Thus, occurrence these frontal systems strongly affected degree mixing currents, most occasions resulted retention. The results underline importance determining distributions particularly retaining region. environmental variability observed has potential implications for connectivity populations.