Numerical evaluation of the possibilities of remote laser sensing of fish schools

Krekova, M. M.; Krekov, G. M.; Samokhvalov, I. V.; Shamanaev, Vitalii S.

doi:10.1364/ao.33.005715

Cited by 20 publications

(12 citation statements)

References 1 publication

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“…One straightforward technique is Monte Carlo, in which a large number of individual photons are tracked through random paths based on the statistical properties of the medium. [30][31][32] Starting at the surface and continuing at each scattering event, random numbers determine the distance and direction to the next event. For the distance, l, a random number is selected from the probability-density function.…”

Section: Basic Characteristicsmentioning

confidence: 99%

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Review of profiling oceanographic lidar

Churnside

2013

Opt. Eng

149

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This paper provides a review of the development of profiling oceanographic lidars. These can provide quantitative profiles of the optical properties of the water column to depths of 20 to 30 m in productive coastal waters and to depths of 100 m for a blue lidar in the open ocean. The properties that can be measured include beam attenuation, diffuse attenuation, absorption, volume scattering at the scattering angle of 180 deg, and total backscattering. Lidar can be used to infer the relative vertical distributions of fish, plankton, bubbles, and other scattering particles. Using scattering as a tracer, lidar can provide information on the dynamics of the upper ocean, including mixed-layer depth, internal waves, and turbulence. Information in the polarization of the lidar return has been critical to the success of many of these investigations. Future progress in the field is likely through a better understanding of the variability of the lidar ratio and the application of high-spectral-resolution lidar to the ocean. Somewhat farther into the future, capabilities are likely to include lidar profiling of temperature in the ocean and an oceanographic lidar in space.

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Section: Basic Characteristicsmentioning

confidence: 99%

“…58 This early work demonstrated that lidar could be useful for fisheries applications, and this has been confirmed by several subsequent analyses. 32,59,60 The easiest case is when large fish are widely separated, so individuals can be seen in the return and counted. As an example, Fig.…”

Section: Fisheriesmentioning

confidence: 99%

Review of profiling oceanographic lidar

Churnside

2013

Opt. Eng

149

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“…Blue-green light propagates to depths up to 100 m (Squire and Krumboltz, 1981) and green lasers have been applied in the form of lidar (light detection and ranging), where photon backscatter is collected from light reflecting off biological targets in the water column. Although numerical algorithms for lidar detection of fish were established more than 20 years ago (Murphree et al, 1974), modelling of signal-to-noise ratio, estimation of fish abundance, and statistical treatment of lidar data is a continuing area of research (Krekova et al, 1994;Mitra and Churnside, 1999;Lo et al, 2000). Target strength is a function of green-light reflectivity and has been measured on frozen samples of several fish species (Churnside and McGillivary, 1991), and live sardines in a tank experiment (Churnside et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Remote sensing of capelin and other biological features in the North Pacific using lidar and video technology

Brown

2002

ICES Journal of Marine Science

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We evaluated airborne remote sensing, using lidar and colour digital video, in the North Pacific in 2000. Specific objectives were (1) to determine lidar depth-penetration range, (2) to develop ocean colour indices as a proxy for depth penetration and Chl a, (3) to compare lidar with acoustic and net-sampling data, (4) to define diurnal variability over large areas, and (5) to evaluate strengths and weaknesses. Depth penetration ranged from 18 to 50 m in non-silty water, with lowest values observed inshore by day and highest values on the continental shelf at night. A green index, derived from the three-band video data, was significantly related to depth penetration and was in general agreement with SeaWiFS satellite Chl a values. Significant correlations with acoustics data were obtained in an area with a high concentration of capelin, Mallotus villosus (Mü ller). The day and night distributions of two capelin locations are shown. At a number of zooplankton sampling stations, there was general agreement between densities derived from lidar and vertical net tows. We discuss the spatial patchiness of capelin and zooplankton, ramifications of those distributions on survey design and sampling, strengths, weaknesses, and future research direction for aerial remote sensing.

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“…The reflection that lidar obtains from a school of fish must be processed to obtain quantities proportional to the number of fish within the depth resolution. This issue has been considered before (Krekova et al, 1994, Churnside and Hunter, 1996, Churnside et al, 1997, although conversion into biomass requires species identification and experimental knowledge of fish reflectivity and size.…”

Section: Discussionmentioning

confidence: 99%

“…As it can be operated from a small aircraft, it is an accessible tool to survey shallow coastal waters. Processing the lidar signal to obtain quantities proportional to the number of fish within the operational depth range has been demonstrated, although conversion into biomass requires species identification and experimental knowledge of fish reflectivity and size (Churnside and McGillivray, 1991;Krekova et al, 1994;Churnside and Hunter, 1996;Churnside et al, 1997). In this context, to improve estimation of recruitment at age 0 of the pelagic resources in the Atlantic waters of the Iberian Peninsula and the Bay of Biscay, a research project named ''Experimental Surveys for the Assessment of Juveniles'' (JUVESU-FAIR CT97-3374) was developed.…”

Section: Introductionmentioning

confidence: 99%

Comparison of airborne lidar with echosounders: a case study in the coastal Atlantic waters of southern Europe

Carrera

Churnside

Boyra³

et al. 2006

ICES Journal of Marine Science

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The feasibility of using airborne lidar (Light Detection and Ranging) was studied to assess the early juvenile fractions of the main pelagic fish species of the coastal Atlantic waters of southern Europe (anchovy, sardine, mackerel, and horse mackerel). Field comparisons with more established echosounder methods were undertaken in the summers of 1998 and 1999 during the recruitment period of sardine and anchovy in the selected areas, in the presence of a variety of oceanographic and environmental conditions. Backscattered energies as well as the types of target recorded by both devices were compared. The distributions of energies and the shape of the targets were generally similar for both techniques, with moderate numerical correlation between sensors, demonstrating the potential of lidar for assessment of anchovy, sardine, and juvenile mackerel. However, differences in received backscattering energy were found, especially in the presence of certain plankton assemblages (to which lidar is more sensitive) and isolated schools with large vertical dimensions (for which shadowing is more significant for light than sound). Experimental ad hoc optical reflectivity measurements of fish and plankton are proposed to discriminate these two types of targets. In addition, an improvement on lidar implementation and data processing is suggested to achieve fish abundance estimates.

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Numerical evaluation of the possibilities of remote laser sensing of fish schools

Cited by 20 publications

References 1 publication

Review of profiling oceanographic lidar

Review of profiling oceanographic lidar

Remote sensing of capelin and other biological features in the North Pacific using lidar and video technology

Comparison of airborne lidar with echosounders: a case study in the coastal Atlantic waters of southern Europe

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