caa a22 4500 397551053 CHVBK 20180308164750.0 cr unu---uuuuu 161202e199604 xx s 000 0 eng 10.1006/jmsc.1996.0037 doi (NATIONALLICENCE)oxford-10.1006/jmsc.1996.0037 Acoustic scattering characteristics of several zooplankton groups [Elektronische Daten] [Timothy K. Stanton, Dezhang Chu, Peter H. Wiebe] The acoustic echo levels from zooplankton are strongly dependent upon the acoustic frequency and size, shape, orientation, and material properties of the animals. Because of the great number of species of zooplankton, it is practical to study the acoustic properties of species grouped by their gross anatomical similarity. Zooplankton from several major groups are discussed: fluid-like (decapod shrimp, euphausiid, salp), hard elastic shelled (gastropod), and gas-bearing (siphonophore). The results from laboratory tests show that the plots of (single ping) target strength versus acoustic frequency have a distinct pattern for each animal type. For example, the plot for euphausiids when ensonified at broadside incidence contained a series of broadly spaced deep nulls; the plot for gastropods either had more tightly spaced nulls or a flat spectrum; the plot for siphonophores either had a less consistent pattern of nulls or a flat spectrum. The nulls from the euphausiid data were sometimes as deep as 30 dB below surrounding levels. The patterns are linked to the physics of the scattering process and modeled mathematically. In addition, key results on these animals from Stanton et al. (1994a, ICES J. Mar. Sci., 51: 505-512) are summarized to further illustrate the variability in scattering characteristics of the animal groups (for example, data from 2-mm-long gastropods show that they produce a level of echo energy per unit biomass approximately 19 000 (i.e., 43 dB) times greater than that of 30-mm-long salps). The impact of these observations on design and interpretation of acoustic surveys is discussed. Very importantly, drawing a simple relationship between echo energy and biomass for regions containing a complex assemblage of zooplankton would be greatly flawed. © 1996 International Council for the Exploration of the Sea Regular Articles nationallicence acoustics nationallicence biomass nationallicence scattering nationallicence zooplankton nationallicence Stanton Timothy K. Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution 98 Water Street, Woods Hole, Massachusetts 02543-1053, USA aut Chu Dezhang Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution 98 Water Street, Woods Hole, Massachusetts 02543-1053, USA aut Wiebe Peter H. Department of Biology, Woods Hole Oceanographic Institution Woods Hole, Massachusetts 02543, USA aut ICES Journal of Marine Science Oxford University Press 53/2(1996-04), 289-295 1054-3139 53:2<289 1996 53 icesjms https://doi.org/10.1006/jmsc.1996.0037 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1006/jmsc.1996.0037 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Stanton Timothy K. Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution 98 Water Street, Woods Hole, Massachusetts 02543-1053, USA aut NATIONALLICENCE 700 1- Chu Dezhang Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution 98 Water Street, Woods Hole, Massachusetts 02543-1053, USA aut NATIONALLICENCE 700 1- Wiebe Peter H. Department of Biology, Woods Hole Oceanographic Institution Woods Hole, Massachusetts 02543, USA aut NATIONALLICENCE 773 0- ICES Journal of Marine Science Oxford University Press 53/2(1996-04), 289-295 1054-3139 53:2<289 1996 53 icesjms Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford