SS1.09 Fisheries Population Linkage Spatial and Temporal Variation in Zooplankton
Date: Wednesday, June 12, 2002
Time: 4:45:00 PM
Location: Carson C
 
SindlingerLS, Texas A&M University, Dept. of Oceanography, College Station, USA, laurie@ocean.tamu.edu
Biggs , D, C, Texas A&M University, Dept. of Oceanography, College Station, USA, dbiggs@ocean.tamu.edu
DiMarco, S, F, Texas A&M University, Dept. of Oceanography, College Station, USA, dimarco@aquaman.tamu.edu
Mullin, K, D, National Marine Fisheries Service, Pascagoula, USA, Keith.D.Mullin@noaa.gov
 
ACOUSTIC BACKSCATTER INTENSITY AS A PROXY FOR PLANKTON AND MICRONEKTON BIOMASS IN SPERM WHALE HABITATS IN THE NE GULF OF MEXICO
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In the Gulf of Mexico, acoustic backscatter intensity (ABI) from an acoustic Doppler current profiler (ADCP) is a proxy for zooplankton and micronekton biomass, and regions of sperm whale abundance are correlated with regions having locally high ABI. We extend previous analysis of ABI in sperm whale habitats, to determine how ABI varies temporally and spatially. During NOAA's Sperm Whale and Acoustic Montioring Program (SWAMP) and follow on ichthyoplankton survey (SEAMAP), a hull-mounted 300kHz ADCP collected ABI data July to September 2001, in 4m vertical bins with the deepest usable bin centered 76m below surface. ABI averages were higher at night than during day, because of diel vertical migration of zooplankton and micronekton. Analysis indicates a cyclonic region present along the continental margin of the NE Gulf had higher average ABI, while a region containing a warm filament had lowest average ABI. The ADCP was run continuously during SEAMAP gaining across-margin ABI data which are being analyzed, and the wet displacement volume of 9 deepwater Bongo net tows are being used to compute linear regression between ABI and plankton biomass.