scholarly journals Ex situ target-strength measurements of Japanese anchovy (Engraulis japonicus) in the coastal Northwest Pacific

2009 ◽  
Vol 66 (6) ◽  
pp. 1219-1224 ◽  
Author(s):  
Donhyug Kang ◽  
Sungho Cho ◽  
Changwon Lee ◽  
Jung-Goo Myoung ◽  
Jungyul Na
Keyword(s):  
Video Camera ◽  
Ex Situ ◽  
Target Strength ◽  
Northwest Pacific ◽  
Japanese Anchovy ◽  
Least Squares Regression ◽  
Important Species ◽  
Engraulis Japonicus ◽  
Wet Weight ◽  
Underwater Video Camera

Abstract Kang, D., Cho, S., Lee, C., Myoung, J-G. and Na, J. 2009. Ex situ target-strength measurements of Japanese anchovy (Engraulis japonicus) in the coastal Northwest Pacific. – ICES Journal of Marine Science, 66: 1219–1224. The Japanese anchovy (Engraulis japonicus) is an important species in regard to the fisheries and ecology of the coastal Northwest Pacific. Measurements of ex situ target strength (TS; dB re 1 m2) were made on live anchovy using 38, 120, and 200 kHz split-beam echosounders. The fish were tethered using small hooks attached to their mouths. During the acoustic measurements, an underwater video camera was used to continuously monitor fish behaviour and tilt-angle (θ). Data for 35 individual anchovy ranging from immature to adult sizes (total lengths LT = 4.8–12.2 cm) were analysed. Least-squares regression fits of TS vs. log(LT) were: TS38 kHz = 20 log(LT) − 65.8 (r2 = 0.82), TS120 kHz = 20 log(LT) − 68.4 (r2 = 0.84), and TS200 kHz = 20 log(LT) − 69.1 (r2 = 0.71). The LT vs. wet weight (W; g) relationship for these fish was W = 0.0036 LT3.204. The mean θ for anchovy swimming freely in a large seawater tank was 9.1° (s.d. = 13.1°). These ex situ measurements of TS, LT, W, and θ can be applied to improve acoustic estimates of Japanese anchovy biomass.

scholarly journals Estimates of acoustic target strength for giant jellyfish Nemopilema nomurai Kishinouye in the coastal Northwest Pacific

2013 ◽  
Vol 71 (3) ◽  
pp. 597-603 ◽  
Author(s):  
Donhyug Kang ◽  
Jusam Park ◽  
Seom-Kyu Jung ◽  
Sungho Cho
Keyword(s):  
Acoustic Scattering ◽  
Ex Situ ◽  
Target Strength ◽  
Northwest Pacific ◽  
Bell Diameter ◽  
Least Squares Regression ◽  
Acoustic Measurements ◽  
Nemopilema Nomurai ◽  
Acoustic Target ◽  
Giant Jellyfish

Abstract Acoustic target strength (TS) measurements were made of ex situ giant jellyfish Nemopilema nomurai Kishinouye at 38 and 120 kHz. These TS data may be useful for developing acoustic scattering models, and surveying giant jellyfish distributions and biomasses. Each jellyfish was tethered in seawater using a monofilament line that vertically penetrated its bell's centre. During the acoustic measurements, an underwater video camera was used to continuously monitor the jellyfish's behaviour. Acoustic measurements were made using split-beam transducers. TS measurements were made of 27 individual jellyfish, but data were analysed for 23 specimens (bell diameter in air, Dair = 21–65 cm) at 38 kHz, and 19 specimens (Dair = 21–46 cm) at 120 kHz, respectively. Least-squares regression fits of TS vs. log(Dair) were TS38kHz = 20•log10Dair–82.7 (r = 0.76) and TS120kHz = 20•log10Dair–86.7 (r = 0.79). The mean TS values at 38 and 120 kHz, using the average Dair = 40.3 cm and 35.5 cm, respectively, were −50.6 and −55.7 dB. The reduced TS, a function of the ratio of Dair to wavelength (λ), was RTS(Dair/λ) = −6.1•log10(Dair/λ) –36.1 (r = 0.51). These RTS values decreased with increasing Dair/λ. Symbiotic medusa shrimp (Latreutes anoplonyx Kemp) contributed negligible bias to our TS measurements of giant jellyfish. These ex situ TS measurements may be used in acoustic surveys to estimate the distributions and biomasses of N. nomurai.

scholarly journals Target-strength, length, and tilt-angle measurements of Pacific saury (Cololabis saira) and Japanese anchovy (Engraulis japonicus) using an acoustic-optical system

2009 ◽  
Vol 66 (6) ◽  
pp. 1212-1218 ◽  
Author(s):  
Kouichi Sawada ◽  
Hideyuki Takahashi ◽  
Koki Abe ◽  
Taro Ichii ◽  
Kazutoshi Watanabe ◽  
...  
Keyword(s):  
Optical System ◽  
Tilt Angle ◽  
Video Camera ◽  
Target Strength ◽  
Japanese Anchovy ◽  
Pacific Saury ◽  
Engraulis Japonicus ◽  
Cololabis Saira ◽  
Angle Measurements ◽  
Stereo Video

Abstract Sawada, K., Takahashi, H., Abe, K., Ichii, T., Watanabe, K., and Takao, Y. 2009. Target-strength, length, and tilt-angle measurements of Pacific saury (Cololabis saira) and Japanese anchovy (Engraulis japonicus) using an acoustic-optical system. – ICES Journal of Marine Science, 66: 1212–1218. Pacific saury and Japanese anchovy generally congregate in dense groups or schools. An acoustic-optical system (the Japanese Quantitative Echosounder and Stereo-video Camera System or J-QUEST) has been developed to measure accurately the target strength (TS) of fish in a dense school. J-QUEST comprises a quantitative, 70 kHz, split-beam echosounder and a stereo-video camera. It was deployed from a research vessel to collect concomitant measures of TS and stereo images of in situ Pacific saury and Japanese anchovy. The stereo-video camera provides estimates of the fish lengths (L) and tilt-angles corrected for J-QUEST motion. In this way, empirical models of TS vs. log(L) were derived for Pacific saury and Japanese anchovy and compared with theory.

scholarly journals Swimming angle and target strength of larval Japanese anchovy (Engraulis japonicus)

2011 ◽  
Vol 77 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Yusuke Ito ◽  
Hiroki Yasuma ◽  
Reiji Masuda ◽  
Kenji Minami ◽  
Ryuichi Matsukura ◽  
...  
Keyword(s):  
Target Strength ◽  
Japanese Anchovy ◽  
Engraulis Japonicus

scholarly journals Ex situ target strength of rockfish (Sebastes schlegeli) and red sea bream (Pagrus major) in the Northwest Pacific

2003 ◽  
Vol 60 (3) ◽  
pp. 538-543 ◽  
Author(s):  
Donhyug Kang ◽  
Doojin Hwang
Keyword(s):  
Red Sea ◽  
Ex Situ ◽  
Sea Bream ◽  
Target Strength ◽  
Northwest Pacific ◽  
Fish Length ◽  
Sebastes Schlegeli ◽  
Red Sea Bream ◽  
Pagrus Major ◽  
Dual Beam

Abstract This study determined the ex situ target strength (TS) of rockfish (Sebastes schlegeli) and red sea bream (Pagrus major) in an artificial seawater tank as a means of helping to estimate fishery resources in coastal areas. TS experiments were conducted at frequencies of 38 kHz (split beam), 120 kHz (split beam), and 200 kHz (dual beam). The species were examined under two conditions: first, live fish confined to a small, net cage; and, second, as free-swimming fish inside a large tank. The study examined 21 rockfish and 20 red sea bream. The data were used to obtain expressions for TS against length and weight for the two species. The relationships between TS and fish length were as follows: for rockfish, TS38 kHz = 20 log10(L) − 67.7 (r = 0.80), TS120 kHz = 20 log10(L) − 74.3 (r = 0.61), TS200 kHz = 20 log10(L) − 72.8 (r = 0.41); and for red sea bream, TS38 kHz = 20 log10(L) − 66.8 (r = 0.86), TS120 kHz = 20 log10(L) − 74.0 (r = 0.65), TS200 kHz = 20 log10(L) − 74.1 (r = 0.83). The TS equations for rockfish and red sea bream as a function of fish weight at 38 kHz were TS38 kHz = 6.75 log10(W) − 56.0 (r = 0.78) and TS38 kHz = 4.08 log10(W) − 49.9 (r = 0.89), respectively. For comparison, calculations using the Helmholtz–Kirchhoff ray-approximation model based on swimbladder morphology were compared with the measured TS. When the tilt angle of the fish is zero, the mean TS from the model is 3–10 dB higher than the experimental results, although the maximum TS values were only 3–4 dB different.

scholarly journals Acoustic Target Strength Measurements for Biomass Estimation of Aquaculture Fish, Redlip Mullet (Chelon haematocheilus)

2018 ◽  
Vol 8 (9) ◽  
pp. 1536 ◽  
Author(s):  
Hansoo Kim ◽  
Donhyug Kang ◽  
Sungho Cho ◽  
Mira Kim ◽  
Jisung Park ◽  
...  
Keyword(s):  
Coastal Waters ◽  
Regression Line ◽  
Constant Term ◽  
Ex Situ ◽  
Target Strength ◽  
Biomass Estimation ◽  
Fish Length ◽  
Least Squares Regression ◽  
Wide Range ◽  
Acoustic Target

Redlip mullet (Chelon haematocheilus) is distributed in coastal waters of the North-Western Pacific Ocean and is a cultured fish in Korea. A hydroacoustic technique constitutes a useful method to assess the biomass and spatial distribution of mullet in sea cages or in coastal waters, and acoustic target strength (TS) information of the target fish is an essential parameter in using this method. In this study, ex situ TS measurements of 16 live mullets were made in an aquaculture sea cage in Korea. The split-beam scientific echo-sounder used for measurements was comprised of 38, 120, 200, and 420 kHz frequencies. An underwater video camera was simultaneously used to observe the mullets’ behavior during the TS measurements. The mullet TS data was analyzed from a wide range of total fish length (FL: 14.3–40.3 cm). As results for all frequencies, the frequency dependence of the mean TS values were relatively low, and the difference in mean TS was within 2.5 dB. When the slope of the least-squares regression line was forced to 20 into the TS equation, the resulting value for the constant term (b20) at each frequency was −67.0 dB, −68.3 dB, −66.3 dB, and −68.5 dB, respectively. The data tended to be frequency dependent. Additionally, the maximum TS appeared between tilt angles of 0° and 10°. These results indicate that TS measurements can be applied to estimate the biomass of the mullet in sea cages or in coastal waters.

scholarly journals Swimbladder Shape and Relationship Between Target Strength and Body Length of Japanese Anchovy (Engraulis japonicus)

2010 ◽  
Vol 37 (1) ◽  
pp. 46-59 ◽  
Author(s):  
Kazuo AMAKASU ◽  
Kazuhiro SADAYASU ◽  
Koki ABE ◽  
Yoshimi TAKAO ◽  
Kouichi SAWADA ◽  
...  
Keyword(s):  
Body Length ◽  
Target Strength ◽  
Japanese Anchovy ◽  
Engraulis Japonicus

scholarly journals Comparison of Target Strength of Pacific Herring (Clupea pallasii Valenciennes, 1847) from Ex-Situ Measurements and a Theoretical Model

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3009
Author(s):  
Euna Yoon ◽  
Woo-Seok Oh ◽  
Hyungbeen Lee ◽  
Kangseok Hwang ◽  
Doo-Nam Kim ◽  
...  
Keyword(s):  
Least Squares ◽  
Coastal Waters ◽  
Ex Situ ◽  
Target Strength ◽  
Pacific Herring ◽  
Important Species ◽  
Clupea Pallasii ◽  
The North ◽  
Commercially Important ◽  
The North Pacific

Pacific herring (Clupea pallasii Valenciennes, 1847) is a commercially important species that inhabits the coastal waters of the North Pacific from Korea to California, USA. This study analyzed the target strength (TS; dB re 1 m2) of Pacific herring individuals (n = 14, total length (LT) = 21.3–32.3 cm) at 38 and 120 kHz using ex-situ measurements and the Kirchhoff-ray mode (KRM) model. The least-squares regressions of the TS–LT relationship for the ex-situ measurements were TS38kHz = 20 log10(LT) − 70.10 (r = 0.17) and TS120kHz = 20 log10(LT) − 70.59 (r = 0.10). The least-squares regressions for the KRM model were TS38kHz = 20 log10(LT) − 68.39 (r = 0.40) and TS120kHz = 20 log10(LT) − 69.74 (r = 0.49). The b20 value of the KRM model was 1.71 dB higher than that of the ex-situ measurement at 38 kHz but similar at 120 kHz. These results provide basic data to evaluate the distribution and abundance of Pacific herring using fisheries’ acoustic technology.

Sign in / Sign up

Export Citation Format

Share Document