Response of larval fish assemblages to a riverine plume in coastal waters of the central Great Barrier Reef lagoon

Abstract

Ichthyoplankton assemblages were compared among stations in the vicinity of a riverine plume in coastal waters of the central Great Barrier Reef lagoon, Australia, during January 1991. Although the plume dramatically influenced both community structure and abundance of larval fish, effects were temporally dynamic and taxon‐specific. Mullids were the only family to show significantly higher densities at the plume front than either inside or outside the plume. Samples from the plume front and coastal waters outside the plume showed similar taxonomic affinities. These affinities appeared to be driven by the offshore movement of the plume translocating coastal larvae offshore, which also led to accumulation of these larvae at the plume front. Given the large area that the plume covered and the high zooplankton biomass and secondary production in these waters, we suggest that the plume may have affected larval fish survival and recruitment more than the associated plume front.