Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 2227 - 2236 |
| Number of pages | 10 |
| Journal | Canadian Journal of Fisheries and Aquatic Sciences |
| Volume | 61 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - 2004 |
| MoE publication type | A1 Journal article-refereed |
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Simulation and experimental measurement of side-aspect target strength of Atlantic salmon (Salmo salar) at high frequency. / Lilja, Juha; Marjomäki, Timo J.; Jurvelius, Juha; Rossi, Tuomo; Heikkola, Erkki.
In: Canadian Journal of Fisheries and Aquatic Sciences, Vol. 61, No. 11, 2004, p. 2227 - 2236.Research output: Contribution to journal › Article › Scientific › peer-review
TY - JOUR
T1 - Simulation and experimental measurement of side-aspect target strength of Atlantic salmon (Salmo salar) at high frequency
AU - Lilja, Juha
AU - Marjomäki, Timo J.
AU - Jurvelius, Juha
AU - Rossi, Tuomo
AU - Heikkola, Erkki
PY - 2004
Y1 - 2004
N2 - Numerical simulations and empirical measurements of swimming Atlantic salmon (Salmo salar) were used to describe the effects of fish behavior on side-aspect target strength (TS). Simulation results were based on the numerical solution of the Helmholtz equation with the finite element method (FEM). A three-dimensional geometric model approximated the shape of the swimbladder of an Atlantic salmon. Numerical simulations were used to study the dependence of TS on the fish length, orientation, and swimming behavior. The results showed strong variation in TS, both when the side-aspect angle was changed and when the swimbladder was bent to the direction of the sonar beam. A total of 11 swimming adult Atlantic salmon 62–107 cm long were measured with a horizontally aimed echosounder (200 kHz) and video camera, and the experimental results were compared with the corresponding simulation results. The linear regression between mean TS and the logarithm of fish length (L, cm) was TS = 24.4log10(L) – 72.9 dB. The strong variability of TS owing to the orientation and bending of the fish and large L/λ ratios reduces the usefulness of TS alone for fish size estimation or species discrimination.
AB - Numerical simulations and empirical measurements of swimming Atlantic salmon (Salmo salar) were used to describe the effects of fish behavior on side-aspect target strength (TS). Simulation results were based on the numerical solution of the Helmholtz equation with the finite element method (FEM). A three-dimensional geometric model approximated the shape of the swimbladder of an Atlantic salmon. Numerical simulations were used to study the dependence of TS on the fish length, orientation, and swimming behavior. The results showed strong variation in TS, both when the side-aspect angle was changed and when the swimbladder was bent to the direction of the sonar beam. A total of 11 swimming adult Atlantic salmon 62–107 cm long were measured with a horizontally aimed echosounder (200 kHz) and video camera, and the experimental results were compared with the corresponding simulation results. The linear regression between mean TS and the logarithm of fish length (L, cm) was TS = 24.4log10(L) – 72.9 dB. The strong variability of TS owing to the orientation and bending of the fish and large L/λ ratios reduces the usefulness of TS alone for fish size estimation or species discrimination.
U2 - 10.1139/f04-166
DO - 10.1139/f04-166
M3 - Article
VL - 61
SP - 2227
EP - 2236
JO - Canadian Journal of Fisheries and Aquatic Sciences
JF - Canadian Journal of Fisheries and Aquatic Sciences
SN - 0706-652X
IS - 11
ER -