Aquatic Sciences Meeting, Albuquerque 2001

SS07 Biomechanics: Turbulent Mass Transfer (Environmental Connections)

Date: Monday, February 12, 2001, Time: 2:30:00 PM

Location: San Miguel

Pilditch, C, A, Coastal Marine Group, Dept. Biological Sciences, Uni. Waikato, Private Bag 3105, Hamilton, New Zealand, c.pilditch@waikato.ac.nz

Black, K, P, Coastal Marine Group, Dept. Earth Sciences, Uni. Waiakto, Private Bag 3105, Hamiton, New Zealand, k.black@waikato.ac.nz

TRANSPORT OF BENTHIC INVERTEBRATE LARVAE IN A TIDALLY DOMINATED ESTUARY

Field and modelling studies were combined to investigate the influence of hydrodynamics on the dispersal of benthic larvae. Tauranga Harbour, New Zealand, is a large (218 km2), enclosed, shallow (mean depth=2.5m) estuary and during a tidal cycle 60-65 % of the water is flushed into the coastal region. A calibrated hydrodynamic model (3DD) was used to examine the effects of tide, wind and release site on the transport of passive particles within the harbour. The model differentiated spawning sites in the upper portions of the estuary that were likely to retain larvae for periods greater than development times from those closer to the entrance that exported larvae into coastal waters. A field study confirmed the presence of retention areas that were characterised by polychaete, bivalve and gastropod larvae and higher chlorophyll a concentrations. In regions predicted to export larvae, abundances were an order of magnitude lower and dominated by barnacle cyprids and nauplii. Results suggest that residual circulation patterns within estuaries can lead to internal sources of competent larvae that may play an important role in benthic recruitment dynamics.

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Aquatic Sciences Meeting, Albuquerque 2001

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