Article
 

Echo strength and density structure of Hawaiian mesopelagic boundary community patches

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/articles/1r66j260m

Descriptions

Attribute NameValues
Creator
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 surface echosounder surveys permitted comparison of density estimates from two techniques. Echo strength values suggest nearshore boundary community animals are primarily myctophid fishes, which was confirmed by preliminary photographic evidence. Echo strength varied significantly as a function of distance from the shoreline and time. These measures of echo strength are important for estimating density from a surface echosounder. Density estimates from these revised echo strengths compare well with those made with echo highlight counting, which is independent of echo strength. These density measures suggest that previous density estimates were too low but do not change the conclusions of these studies. Vertical microstructure in density was apparent but animal size and compositional structure was not evident within a patch. Patch edges were abrupt, with no differences in the density or echo strength from patch interiors. These edges were generally straight, with a sharp drop in density to the background density of zero. Estimates of animal size as a function of time provide information about the diel migration patterns of these mesopelagic animals.
  • Keywords: bioacoustics, echo, sonar detection, underwater acoustic propagation, structural acoustics, acoustic measurement, acoustic wave scattering
Resource Type
DOI
Date Available
Date Issued
Citation
  • J. Acoust. Soc. Am. 114 (4), 1888-1897 October 2003, DOI: 10.1121/1.1612484
Journal Title
Journal Volume
  • 114
Journal Issue/Number
  • 4
Rights Statement
Funding Statement (additional comments about funding)
  • This work was supported in part by Office of Naval Research Grant No. N00014-98-1-068, Dr. Robert Gisiner, Program Manager. This work was also funded by a grant from the National Oceanic and Atmospheric Administration, Project No. R/FM-7, which is sponsored by the University of Hawaii Sea Grant College Program, SOEST, under Institutional Grant No. NA86RG0041 from NOAA Office of Sea Grant, Department of Commerce.
Publisher
Language
Replaces
ISSN
  • 0001-4966

Relationships

Parents:

This work has no parents.

Items

Thumbnail Title Date Uploaded Visibility Actions
file details JAcoustSociety2003EchoStrength.pdf 2017-07-24 Public Download