Echo integration using non-vertical sonar beams: The bias caused by non-uniform distribution of fish within the echo beam

Vatnehol, Sindre; Handegard, Nils Olav

doi:10.1121/1.5057120

Cited by 2 publications

(1 citation statement)

References 29 publications

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“…Hydroacoustic techniques are often used to observe fish behavior in water. [1][2][3][4][5] Fishes can be detected using acoustic signals even in turbid water or low light conditions, where visual inspection and underwater video recording are ineffective. To detect schools of fish from onboard a ship, fish finders, sonar, quantitative echo sounders, etc.…”

Section: Introductionmentioning

confidence: 99%

Detection of fish passing through a narrow path using reflected and transmitted ultrasonic waves

Miyamoto

Doi

Mizutani

et al. 2023

Jpn. J. Appl. Phys.

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The properties of echoes and transmitted waves from a fish body, in megahertz bands, were investigated to construct a fish detection method in a narrow path by a simple measurement structure using a pair of transducers. Experiments were performed in a water tank using dead Japanese jack mackerel (Trachurus japonicus). From the echoes, the outlines of fish could be observed. High amplitudes of echoes from the swim bladder and fins were observed, while relatively low amplitudes of echoes were observed from other body parts, e.g., the head, body surface, and vertebral columns. From the transmitted waves, decreased amplitudes and times-of-flight in waves transmitted from the fish body were observed. The fish could be detected using ultrasound, in megahertz bands, and the combined use of the echo and transmitted waves could increase the information obtained about fish compared with the use of echoes only.

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Section: Introductionmentioning

confidence: 99%

Detection of fish passing through a narrow path using reflected and transmitted ultrasonic waves

Miyamoto

Doi

Mizutani

et al. 2023

Jpn. J. Appl. Phys.

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Estimating individual fish school biomass using digital omnidirectional sonars, applied to mackerel and herring

Peña

Macaulay

Ona

et al. 2021

ICES Journal of Marine Science

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Economic profitability and responsible fisheries are objectives of fishermen and fisheries managers. In purse seine fisheries, an accurate biomass estimate of the targeted school is crucial to accomplish this. For this study, omnidirectional fisheries sonar was used to estimate individual school biomass of Norwegian spring spawning herring (Clupea harengus) and Atlantic mackerel (Scomber scombrus). A sonar sampling design based on professional skipper’s experience provided detailed information on school dimensions and acoustic backscattering. Using calibrated digital sonar data, school volume and fish densities were obtained, and school biomass computed. A positive linear relation was found between the estimated sonar school biomass and purse seine catches for both species (r2 = 0.92; residual standard error, RSE = 4.7 t). Large variability in volume backscattering coefficient and uncertainty in side-aspect target strength (TS) are the main sources of discrepancy between the estimates and the catch. Using a 4 dB (39%) weaker mean TS for mean side-aspect TS than the normal mean dorsal aspect TS was needed for optimizing the 1:1 relationship between sonar biomass estimate and catch. Accurate estimation of single school biomass can reduce the catch of unexpectedly large schools, leading to improvements in economic efficiency and reduced release of dead or dying fish.

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Echo integration using non-vertical sonar beams: The bias caused by non-uniform distribution of fish within the echo beam

Cited by 2 publications

References 29 publications

Detection of fish passing through a narrow path using reflected and transmitted ultrasonic waves

Detection of fish passing through a narrow path using reflected and transmitted ultrasonic waves

Estimating individual fish school biomass using digital omnidirectional sonars, applied to mackerel and herring

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