Title |
-
en
Density and sound-speed contrasts, and target strength of Japanese sandeel Ammodytes personatus
|
Creator |
|
Accessrights |
open access |
Rights |
-
ja
© 2009 公益社団法人日本水産学会
-
en
© 2009 The Japanese Society of Fisheries Science
-
en
The final publication is available at www.springerlink.com
|
Subject |
-
Other
en
Ammodytes personatus
-
Other
en
Density contrast
-
Other
en
Japanese sandeel
-
Other
en
Sound-speed contrast
-
Other
en
Target strength
-
Other
en
Theoretical scattering model
-
NDC
468
|
Description |
-
Abstract
en
Sound-speed and density contrasts (h and g, respectively), important acoustic material properties, of Japanese sandeel Ammodytes personatus were measured to estimate theoretical target strength (TS). The measured sound-speed contrast of adult fish varied between 1.016 and 1.023 (mean, 1.020), which showed temperature dependence. The measured density contrast differed significantly between juvenile and adult. The density contrast of juvenile varied between 1.017 and 1.024 (1.021), and that of adult varied between 1.026 and 1.038 (1.032). Using these results, TS at 38 and 120 kHz in the fishing season were estimated by an empirical sound scattering model. TS of an individual fish varied significantly with change of tilt angle. TS of near-dorsal aspect (TSmax) and tilt-averaged TS (TSave) differed up to 7 dB. At both frequencies, two different TSave-length relationships (TSave = a log L + b) were obtained for adult and juvenile. The coefficients of log L of adult were close to 20, suggesting that backscattering strength was proportional to the square of body length. These values were larger in juvenile (34.0 at 120 kHz, 56.5 at 38 kHz), suggesting that backscattering strength varied drastically with the cube or fifth power of body length.
|
Publisher |
en
Springer Japan
|
Date |
|
Language |
|
Resource Type |
journal article |
Version Type |
AM |
Identifier |
HDL
http://hdl.handle.net/2115/38598
|
Relation |
-
isVersionOf
DOI
https://doi.org/10.1007/s12562-009-0091-3
|
Journal |
-
-
en
Fisheries Science
-
Volume Number75
Issue Number3
Page Start545
Page End552
|
File |
|
Oaidate |
2023-07-26 |