Ichthyoplankton abundance along a recruitment corridor from offshore spawning to estuarine nursery ground

Abstract

Two temporally separate larval fish assemblages were identified from ichthyoplankton samples collected between November 1987 and January 1990 along a transect from offshore to Oyster Bayou tidal pass into Fourleague Bay, Louisiana. The warm water species (e.g. bay anchovy, naked goby, Microgobius sp., spotted seatrout and skilletfish) dominated in water temperatures >23 °C and the cooler water species (e.g. gulf menhaden and Atlantic croaker) dominated in water temperatures <23 °C. These assemblages were characterized by different life-history strategies, distributions, and seasonal abundances suggesting that they utilize resources in different locations and times. Analysis of Oyster Bayou tidal pass data indicated that larvae from all species were more abundant on flood than ebb tides and larval fish densities were often statistically greater near bottom, suggesting tidal transport and/or retention. In addition, larger larval bay anchovy and gulf menhaden were taken in the middle of the tidal pass during flood tides. During ebb tides, however, larger bay anchovy larvae were taken along the pass edges, suggesting behaviourally mediated transport into and/or retention within the estuary.