CS35 Trophic Dynamics
Date: Friday, June 14, 2002
Time: 11:00:00 AM
Location: Carson A
 
GannonDP, Duke University Marine Laboratory, Beaufort, USA, dpg3@duke.edu
Waples, D, M, Duke University Marine Laboratory, Beaufort, USA, dwaples@duke.edu
Read, A, J, Duke University Marine Laboratory, Beaufort, USA, aread@duke.edu
 
HABITAT SELECTION IN BOTTLENOSE DOLPHINS: LINKING FISHERIES SCIENCE, ANIMAL BEHAVIOR, AND BIOACOUSTICS
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We used stomach contents analyses, transect surveys, behavioral sampling, trawl surveys, and acoustic monitoring to study habitat selection of bottlenose dolphins (Tursiops truncatus) in the Neuse River estuary, North Carolina. Dolphins preferred shallow waters (<3.5 m) of the lower estuary and exhibited behaviors consistent with feeding more often in this area. Croaker (48%) and spot (27%) were the primary prey. Spot, croaker, pinfish, and bay anchovies dominated trawl catches. Dolphins preferentially selected large prey. Densities of demersal fish were highest near shore and average fish lengths increased downstream. Fish calling rates were highest in the nearshore waters of the lower estuary. We conclude that (1) bottlenose dolphins are size-selective foragers specializing on soniferous demersal fish; (2) dolphins selected habitats where densities and calling rates of large croaker were highest; (3) eavesdropping on fish sounds may provide information on the location and density of fish schools, on species identity, and on the size of individual fish; and (4) passive acoustics may be used to evaluate quality of foraging habitat for coastal bottlenose dolphins.