Index Catalog // ScholarsArchive@OSU

Creator:: Benoit-Bird, Kelly J. and Au, Whitlow W. L.
Abstract:: Sonar techniques were used to quantitatively observe foraging predators and their prey simultaneously in three dimensions. Spinner dolphins foraged at night in highly coordinated groups of 16–28 individuals using strict four-dimensional patterns to increase prey density by up to 200 times. Herding exploited the prey’s own avoidance behavior to achieve...
Resource Type:: Article

Creator:: Au, Whitlow W. L., Benoit-Bird, Kelly J., and Kastelein, Ronald A.
Abstract:: The target strength as a function of aspect angle were measured for four species of fish using dolphin-like and porpoise-like echolocation signals. The polar diagram of target strength values measured from an energy flux density perspective showed considerably less fluctuation with azimuth than would a pure tone pulse. Using detection...
Resource Type:: Article

Creator:: Benoit-Bird, Kelly J.
Abstract:: Land-associated, sound-scattering layers of mesopelagic micronekton surround the Hawaiian Islands. These animals undergo diel migrations during which they split into multiple, distinct layers that have differences in animal density, taxonomic composition, and size. A video-camera system capable of quantitatively estimating the biological constituency of the layers was combined with a...
Resource Type:: Article

Creator:: Benoit-Bird, Kelly J. and Au, Whitlow W. L.
Abstract:: A 200-kHz echosounder modified to digitize the envelope of the received echoes directly into a computer was used to measure the ex situ target strength (TS) of live animals from the Hawaiian mesopelagic boundary community as a function of animal size, tilt and roll angle, and biological classification. Dorsal aspect...
Resource Type:: Article

Creator:: Benoit-Bird, Kelly J. and Au, Whitlow W. L.
Abstract:: Acoustic backscattering strength is often used as an index of biomass; however, the relationship between these variables has not been directly validated. Relationships were investigated between acoustic cross section at 200 kHz, measured as part of a previous study, and measured values of length, biovolume, dry weight, ash-free dry weight,...
Resource Type:: Article

Creator:: Benoit-Bird, Kelly J. and Au, Whitlow W. L.
Abstract:: A broadband sonar system and digital camera with strobe lights were mounted on a vertically profiling frame with a depth sensor. The echo strengths and densities of animals within individual mesopelagic boundary community patches were investigated as a function of depth. Time and distance from shore were also investigated. Simultaneous...
Resource Type:: Article

Creator:: Au, Whitlow W. L. and Benoit-Bird, Kelly J.
Abstract:: The characteristics of acoustic echoes from six species of deep-dwelling (up to 400 m) Hawaiian Lujanid snappers were determined by backscatter measurements at the surface. A broadband linear frequency-modulated signal and a short dolphinlike sonar signal were used as the incident signals. The fish were anesthetized and attached to a...
Resource Type:: Article

Creator:: Benoit-Bird, Kelly J., Au, Whitlow W. L., and Kastelein, Ronald A.
Abstract:: The hypothesis that sounds produced by odontocetes can debilitate fish was examined. The effects of simulated odontocete pulsed signals on three species of fish commonly preyed on by odontocetes were examined, exposing three individuals of each species as well as groups of four fish to a high-frequency click of a...
Resource Type:: Article

Creator:: Benoit-Bird, Kelly J., Gilly, William F., and Au, Whitlow W. L.
Abstract:: This study presents the first target strength measurements of Dosidicus gigas, a large squid that is a key predator, a significant prey, and the target of an important fishery. Target strength of live, tethered squid was related to mantle length with values standardized to the length squared of −62.0, −67.4,...
Resource Type:: Article

Creator:: Au, Whitlow W. L. and Benoit-Bird, Kelly J.
Abstract:: Broadband simulated dolphin echolocation signals were used to measure the ex situ backscatter properties of mesopelagic boundary community MBC in order to gain a better understanding of the echolocation process of spinner dolphins foraging on the MBC. Subjects were captured by trawling with a 2-m-opening Isaacs-Kidd Midwater Trawl. Backscatter measurements...
Resource Type:: Article

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