Maximum Side-Aspect Target Strength of an Individual Fish

Love, Richard H.

doi:10.1121/1.1911756

Cited by 50 publications

(45 citation statements)

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“…We could differentiate age-0 and adult paddlefish because differences in mean TS were large. Use of acoustic TS to differentiate large adult freshwater fishes from age-0 fish of the same species or from smaller coexisting species should be possible because TS is generally proportional to fish size (Love 1969(Love , 1971(Love , 1977. Age-0 and adult fish have been differentiated via TS for a number of smaller species.…”

Section: Discussionmentioning

confidence: 99%

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Paddlefish as Potential Acoustic Targets for Abundance Estimates

Hale

Horne

Degan³

et al. 2003

Transactions of the American Fisheries Society

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Abstract.-Underwater acoustics is a noninvasive sampling technique that potentially reduces expense and injury to target species, but this method may be underutilized for sampling large freshwater fishes. We measured target strength (TS), developed anatomically based backscatter models, and conducted gill-net and acoustic surveys of paddlefish Polyodon spathula to explore the potential use of acoustic surveys for estimating the abundance of large freshwater fishes. Mean TS measured from two size-groups of paddlefish at 200 kHz was Ϫ37.14 decibels (dB; SD ϭ Ϫ2.36) for age-0 fish (353-406 mm) and Ϫ27.25 dB (SD ϭ Ϫ2.21) for adult fish (1,018-1,284 mm), indicating that TS could differentiate these size-groups. Backscatter models identified strong contributions of the swim bladder to TS and revealed the sensitivity of acoustic backscatter to paddlefish length, aspect, and acoustic carrier frequency. Model results were generally within one SD of measured means from individual fish of each size-group. Target strength results were used to count two populations of adult paddlefish in mobile surveys using an echo sounder with a 200-kHz, 6Њ split-beam transducer. One population was stocked in 1.6-ha Hebron Pond, where no large fish were previously present. The other population resided in 28-ha Horseshoe Lake, an Ohio River backwater. Twenty-one paddlefish stocked in Hebron Pond were accurately counted during the first of six side-looking surveys, but subsequent surveys only counted between two and seven fish. Depletion gillnetting results in Horseshoe Lake provided an estimated baseline of 130 Ϯ 55 paddlefish for comparison with abundance estimates from side-looking and down-looking acoustic surveys during day and night. Acoustic abundance estimates ranged from 187-313 fish (sidelooking) to 3,464-13,489 fish (down-looking) depending on survey time (day or night) and the approach to analysis. Ratio estimates and cluster estimates provided similar results, and the coefficient of variation of the mean (100·SE/mean) ranged from 20% to 50%. Acoustic estimates were either greater or more variable than those derived from depletion gillnetting, yet acoustic surveys required only 6 man-hours compared to 180 man-hours for the gillnetting estimate. Our study is the first to indicate that TS can be used to count adult paddlefish and that, upon refinement of survey techniques, TS can be used to estimate paddlefish abundance. The benefits of acoustic surveys may be realized sampling other large freshwater fishes when the target species can be differentiated with TS and considerations are made for transducer selection.

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Section: Discussionmentioning

confidence: 99%

“…Generalized equations to estimate fish lengths from TS have been developed for the side, dorsal, and any aspects (Love 1969(Love , 1971(Love , 1977. These equations are widely used, and have proven useful for a variety of species (Burczynski et al 1987;Brandt et al 1991;Yule 2000;Warner et al 2002).…”

mentioning

confidence: 99%

Paddlefish as Potential Acoustic Targets for Abundance Estimates

Hale

Horne

Degan³

et al. 2003

Transactions of the American Fisheries Society

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“…Studies include measurement of target strengths in situ and ex situ, with multiple and single targets. In situ measurements are conducted in the natural environment yet present the challenge of unknown target size, orientation and position relative to the acoustic beam; ex situ measurements, however, provide greater control over these factors (Foote, 1997) Ex situ measurements of tethered fish (similar to the method presented in Chapter 3 of this thesis) include those conducted by Jones and Pearce (1958), Haslett (1969Haslett ( , 1977, Diercks and Goldsberry (1970), Love (1969, 1970, 1971), and Nakken and Olson (1977. In spite of the fact that these measurements were performed at a limited number of angles of orientation (mostly dorsal), they were performed on a variety of species of different sizes and at a number…”

Section: Acoustic Measurements Of Fishmentioning

confidence: 99%

Acoustic scattering by axisymmetric finite-length bodies with application to fish : measurement and modeling

Reeder¹

2002

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This thesis investigates the complexities of acoustic scattering by finite bodies in general and by fish in particular through the development of an advanced acoustic scattering model and detailed laboratory acoustic measurements. A general acoustic scattering model is developed that is accurate and numerically effcient for a wide range of frequencies, angles of orientation, irregular axisymmetric shapes and boundary conditions. The model presented is an extension of a two-dimensional conformal mapping approach to scattering by irregular, finite-length bodies of revolution. An extensive series of broadband acoustic backscattering measurements has been conducted involving alewife fish (Alosa pseudoharengus), which are morphologically similar to the Atlantic herring (Clupea harengus). A greater-than-octave bandwidth (40-95 kHz), shaped, linearly swept, frequency modulated signal was used to insonify live, adult alewife that were tethered while being rotated in 1-degree increments over all angles of orientation in two planes of rotation (lateral and dorsal/ventral). Spectral analysis correlates frequency dependencies to morphology and orientation. Pulse compression processing temporally resolves multiple returns from each individual which show good correlation with size and orientation, and demonstrate that there exists more than one significant scattering feature in the animaL. Imaging technologies used to exactly measure the morphology of the scattering features of fish include very highresolution Phase Contrast X-rays (PCX) and Computerized Tomography (CT) scans, which are used for morphological evaluation and incorporation into the scattering modeL. Studies such as this one, which combine scattering models with high-resolution morphological information and high-quality laboratory data, are crucial to the quantitative use of acoustics in the ocean.

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“…The underwater acoustics literature contains a number of references dealing with the interactions between fish and low-amplitude, nondamaging pressure waves: e.g., HJersey and Backus (1-966), Weston (1967), Love (1969 and1971), Holliday (1972), Dang and Andrews (1971).…”

Section: 21mentioning

confidence: 99%

The Effects of Underwater Explosions on Swimbladder Fish

Christian¹

1973

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A new method is proposed for predicting the maximum ranges to which an underwater explosion will injure fish that have gas-filled swimbladders.In this study the swimbladder damage is ascribed to tension waves that are generated when the explosion shock wave is reflected back into the water from the surface. The locations at which the tension reaches damaging levels are assumed to be the samo as those where the surface-reflected waves cause bulk cavitation of the water. Cavitation theory is then used to predict probable damage zones for various weights and depths of explosive charge.The limited fish-kill data now in hand do not permit a true test of the new damage model.However, from comparisons with qualitative observations and the few available test results, the new predictions proposed here appear to give more realistic results than previous estimates.

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Maximum Side-Aspect Target Strength of an Individual Fish

Cited by 50 publications

References 0 publications

Paddlefish as Potential Acoustic Targets for Abundance Estimates

Paddlefish as Potential Acoustic Targets for Abundance Estimates

Acoustic scattering by axisymmetric finite-length bodies with application to fish : measurement and modeling

The Effects of Underwater Explosions on Swimbladder Fish

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