MEPS 345:167-184 (2007)  -  doi:10.3354/meps06916

Cross-shelf transport of pink shrimp larvae: interactions of tidal currents, larval vertical migrations and internal tides

Maria M. Criales1,*, Joan A. Browder2, Christopher N. K. Mooers1, Michael B. Robblee3, Hernando Cardenas1, Thomas L. Jackson2

1Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida 33149, USA
2NOAA Fisheries, Southeast Fisheries Science Center, 75 Virginia Beach Drive, Miami, Florida 33149, USA
3US Geological Survey, Center for Water and Restoration Studies, 3110 SW 9th Avenue, Ft Lauderdale, Florida 33315, USA

ABSTRACT: Transport and behavior of pink shrimp Farfantepenaeus duorarum larvae were investigated on the southwestern Florida (SWF) shelf of the Gulf of Mexico between the Dry Tortugas spawning grounds and Florida Bay nursery grounds. Stratified plankton samples and hydrographic data were collected at 2 h intervals at 3 stations located on a cross-shelf transect. At the Marquesas station, midway between Dry Tortugas and Florida Bay, internal tides were recognized by anomalously cool water, a shallow thermocline with strong density gradients, strong current shear, and a high concentration of pink shrimp larvae at the shallow thermocline. Low Richardson numbers occurred at the pycnocline depth, indicating vertical shear instability and possible turbulent transport from the lower to the upper layer where myses and postlarvae were concentrated. Analysis of vertically stratified plankton suggested that larvae perform vertical migrations and the specific behavior changes ontogenetically; protozoeae were found deeper than myses, and myses deeper than postlarvae. Relative concentrations of protozoea in the upper, middle and bottom layers were consistent with a diel vertical migration, whereas that of postlarvae and myses were consistent with the semidiurnal tides in phase with the flood tide. Postlarvae, the shallowest dwellers that migrate with a semidiurnal periodicity, experienced the largest net onshore flux and larval concentrations were highly correlated with the cross-shelf current. These results provide the first evidence of an onshore tidal transport (a type of selective tidal stream transport, STST), in decapod larvae migrating in continental shelf waters offshore, ca. 100 km from the coast and at a depth of 20 m, while approaching the coastal nursery grounds. Longer time series would be necessary to establish whether internal tides play any role in the larval onshore transport of this species and determine if the STST is the dominant onshore transport mechanism.


KEY WORDS: Selective tidal transport · Pink shrimp larval behavior · Internal tides · Farfantepenaeus duorarum


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Cite this article as: Criales MM, Browder JA, Mooers CNK, Robblee MB, Cardenas H, Jackson TL (2007) Cross-shelf transport of pink shrimp larvae: interactions of tidal currents, larval vertical migrations and internal tides. Mar Ecol Prog Ser 345:167-184

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