Studies on Dorsal Aspect Target Strength of Ten Species of Fish Collected in the East China Sea.

Mukai, T.; Sano, Noritatsu; Iida, Kazuhiro; Sasaki, Seiji

doi:10.2331/suisan.59.1515

Cited by 18 publications

(9 citation statements)

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“…There are few studies on TS of S. japonicus: Miyanohana et al (1990) used four frequencies to measure TS of S. japonicus but they did not show the explicit values. Mukai et al (1993) measured the b 20 of individuals with a total length of 23.0-26.8 cm using the ex situ method, which was −64.1 dB at 25 kHz and −65.5 dB at 100 kHz. Gutieŕrez and Maclennan (1998) reported the b 20 of S. japonicus with a total length of 26-30 cm using the in situ method, which was −70.95 dB at 38 kHz and −70.8 dB at 120 kHz.…”

Section: Discussionmentioning

confidence: 99%

Impacts of Morphological Characteristics on Target Strength of Chub Mackerel (Scomber japonicus) in the Northwest Pacific Ocean

et al. 2022

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Chub mackerel (Scomber japonicus) is an important commercial fish in the Northwest Pacific Ocean. Accurate target strength (TS) underpins acoustic stock assessment but the TS of S. japonicus is still poorly understood. In this study, the Kirchhoff-ray mode (KRM) model was used to estimate the TS of S. japonicus and its relationship with sound wave frequency and fish morphology. The results revealed that TS values varied with pitch angle shifts, with the impact on fish scattering strength being greater at higher frequency. This is less important because 38 kHz has been used for the biomass assessment of these fish resources. At frequencies of 38 kHz, 70 kHz, 120 kHz and 200 kHz, TS was greatest at a pitch angle range of -10° to 0°, which was related to the angle of the swim bladder tilt. There were almost no differences between TS estimated using the measured pitch angle distributions and using the universal distribution. When the measured pitch angle was N[-3°,4°], the average TS of S. japonicus with body length of 12.04–22.17 cm at four frequencies was -48.88 dB, -49.14 dB, -49.75 dB and -48.55 dB, respectively. The regression intercept (b20) in TS–body length equation was -73.27 dB, -73.56 dB, -74.18 dB and -73.46 dB, respectively. Variation in TS range at 0–300 m depth was about 10 dB. The simulated broadband target strength spectrum shows the scattering characteristics of individuals with different swim bladder length between 0–250 kHz. These results could be used for identification of S. japonicus in echograms and provide reference for acoustic stock assessment of S. japonicus in the Northwest Pacific Ocean.

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Section: Discussionmentioning

confidence: 99%

Impacts of Morphological Characteristics on Target Strength of Chub Mackerel (Scomber japonicus) in the Northwest Pacific Ocean

et al. 2022

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“…where < S a ij > is the S a of a species i in group j, w i is the total weight of species i in a trawling catch, and < σ j > is the target strength of group j. The target strength ( σ ) within a group is assumed to be the same, because anchovy and round herring are physoclist fish, 11 and the target strength values of jack mackerel and chub mackerel are similar 12 . The σ values of physoclist fish and jack mackerel were calculated by the following formulas.…”

Section: Methodsmentioning

confidence: 99%

“…The target strength ( s ) within a group is assumed to be the same, because anchovy and round herring are physoclist fish, 11 and the target strength values of jack mackerel and chub mackerel are similar. 12 The s values of physoclist fish and jack mackerel were calculated by the following formulas. where BL is body length (cm).…”

Section: Methodsmentioning

confidence: 99%

Spatial distribution and biomass of pelagic fish in the East China Sea in summer, based on acoustic surveys from 1997 to 2001

Ohshimo

2004

Fisheries Sci

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Annual acoustic surveys were conducted using a quantitative echo sounder (frequency: 38 kHz) in the East China Sea from July to September of 1997-2001. Three groups of fish were identified from the echograms, based on school shape and swimming depth characteristics: (i) anchovy Engraulis japonicus and round herring Etrumeus teres ; (ii) jack mackerel Trachurus japonicus and chub mackerel Scomber japonicus ; and (iii) lantern fish Diaphus spp. and pearlside Maurolicus japonicus . The area backscattering strength ( S a) of each group was divided by the total weight of fish species caught in midwater trawls. Anchovy, round herring, jack mackerel, lantern fish and pearlside were the most abundant. The estimated biomass indices of anchovy and round herring were positively correlated with the commercial landings of these species, indicating the usefulness of acoustic surveys.

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“…Given the species' characteristics, chub mackerel TS experiments to date have mostly been conducted using dead specimens due to the difficulty of working with live individuals [19,20].…”

Section: Chub Mackerel Ts Sample Specimensmentioning

confidence: 99%

“…Most ex situ experiments on chub mackerel TS have been conducted using dead specimens [19,20]; however, it may result in inflated values compared to living specimens due to the expansion of body tissues or presence of gas bubbles [21]. Moreover, previous ex situ experiments have been limited to specimens with a total length of ≥ 23 cm [19]. Recently, chub mackerel TS has also been studied using the theoretical Kirchhoff-ray mode (KRM) model [7,22], but deriving an accurate and reliable TS-L relationship requires experiments to be conducted on living specimens of various sizes in a free swimming state.…”

Section: Introductionmentioning

confidence: 99%

Acoustic target strengths and swimbladder morphology of Chub mackerelScomber japonicusin the Northwest Pacific Ocean

Yoon,

Lee,

Lee

et al. 2024

Preprint

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The Northwest Pacific chub mackerel (Scomber japonicus) is one of the most productive, economically important fishery resources worldwide. Due to fluctuations in their abundance and distribution, there is a pressing need to accurately assess this species and to ensure total allowable catch limits are followed. Acoustic target strength (TS; dB) measurements of Scomber japonicus were conducted at 38, 70, and 120 kHz using a split-beam echosounder of individuals from nine size groups (mean fork length, 10.8~28.3 cm) swimming freely in a net cage within a seawater tank. An underwater camera was utilized to simultaneously measure the swimming angle. A least-squares regression analysis revealed that when the slope was constrained to 20, as per the generally applicable morphometric equation, the resulting values for the constant term (b20) were -67.7, -66.6, and -67.3 dB at 38, 70, and 120 kHz, respectively. The mean swimming angle of S. japonicus across the groups was -10.5~9.6 degrees (standard deviation (SD), 16.3~33.3 degrees). In addition, the ratio of swimbladder height to swimbladder length, swimbladder length to fork length, and tilt angle of the swimbladder (mean =/- SD) were 0.191 +/- 0.060, 0.245 +/- 0.055, and 9.6 +/- 3.0 degrees, respectively. These results can be used for the acoustic stock assessment of S. japonicus in the Northwest Pacific Ocean.

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Studies on Dorsal Aspect Target Strength of Ten Species of Fish Collected in the East China Sea.

Cited by 18 publications

References 0 publications

Impacts of Morphological Characteristics on Target Strength of Chub Mackerel (Scomber japonicus) in the Northwest Pacific Ocean

Impacts of Morphological Characteristics on Target Strength of Chub Mackerel (Scomber japonicus) in the Northwest Pacific Ocean

Spatial distribution and biomass of pelagic fish in the East China Sea in summer, based on acoustic surveys from 1997 to 2001

Acoustic target strengths and swimbladder morphology of Chub mackerelScomber japonicusin the Northwest Pacific Ocean

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