Displacement of diverse ichthyoplankton assemblages by a coastal upwelling event on the Sydney shelf

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 176:49-62 (1999) - doi:10.3354/meps176049 Displacement of diverse ichthyoplankton assemblages by a coastal upwelling event on the Sydney shelf Kimberley A. Smith*, Iain M. Suthers School of Biological Science, University of New South Wales, Sydney, New South Wales 2052, Australia *E-mail: marsci@unsw.edu.au ABSTRACT: The influences of upwelling-favourable winds and thermocline displacement on the distribution of temperate/tropical ichthyoplankton assemblages were determined from vertically stratified plankton hauls across the Sydney shelf, southeastern Australia. Five stations were sampled along a shore-normal transect off Sydney, Australia, on 3 or 4 consecutive nights during January and April 1994. High taxonomic diversity (111 ichthyoplankton families) was attributed to the convergence of temperate and tropical waters in this region. Total larval abundance was higher in January than in April, reflecting the spawning times of many coastal taxa. In both months, highest larval density and taxonomic diversity were associated with the interface between the mixed layer and the thermocline. In April, a period of upwelling-favourable winds resulted in the offshore displacement of the nearshore mixed layer, as well as numerous shelf-spawned larvae (e.g. Centroberyx affinis, Chromis hypsilepsis, Arripis trutta) from the nearshore region, and coincided with the injection of deeply distributed mesopelagic larvae into the nearshore zone (e.g. Scopelosaurus sp., Melamphaes sp.). Shelf-spawned larvae were displaced to the outer shelf, where they were still associated with the mixed layer/thermocline interface. Dynamic ichthyoplankton distributions are interpretable, at least at a scale of weeks, by considering larvae as tracers of the local hydrography. KEY WORDS: Ichthyoplankton assemblages · Hydrography · Upwelling · Thermocline Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 176. Publication date: January 18, 1999 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1999 Inter-Research.