An Automatic Method of Counting Fish Echoes

Mitson, R. B.; Wood, R. J.

doi:10.1093/icesjms/26.3.281

“…(2) shows that the regression slope is very variable for traces containing few echoes. This variation is likely to be caused by errors in the alongship angle.…”

Section: Expected Parameter Values For the Next Echo In A Tracementioning

confidence: 99%

“…Use of sonar and echo sounder to detect fish and map the distribution of fish populations started before the world war 2, [1]. Acoustic abundance estimation of fish followed and started by the echo counting method [2][3][4], but this was replaced early on by echo integration, a method that has developed further since then and became the standard method of acoustic abundance estimation. The most important reason for this is that the echo integration method has few restrictions on the within-beam fish density.…”

Section: Introductionmentioning

confidence: 99%

Estimating Fish Densities from Single Fish Echo Traces

Aksland¹

2009

TOOEJ

0

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Estimating mean fish density per unit area has been done by counting single fish echo traces with a split beam echo sounder system in the open sea. A data program has been written that scans the acoustic signals for echo peaks and classify these into echo traces. The program counts the number of echo traces from fish that cross the beam within given distances from the acoustic axis over a known sailing distance, and gives an absolute estimate of fish density. This is obtained by using the off acoustic axis angles of fish that generate resolved echoes to compute the athwartship distance from the vertical acoustic axis to the fish. The program is described and demonstrated on selected files of raw data recorded by the SIMRAD EK 60 split beam system. Estimated fish densities for these files are also obtained by the echo integration method, and the echo trace method gives estimates that agree well with these estimates under sufficiently "good conditions".

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“…In the 1950-60s, the concept of a species-and size-dependent directivity pattern of single fish was known, with these effects being highlighted through target strength measurements (Cushing, 1955;Jones & Pearce, 1958;Midttun & Hoff, 1962). Approaches using acoustics in fish stock assessment were also developed in the 1950-60s, first through counting of individual echoes (Tungate, 1958;Mitson & Wood, 1961), summing of the echo amplitudes (Richardson, 1959), and finally the echo-integration method based on the echo amplitude (Dragesund & Olsen, 1965). Integrating the echo intensity was later shown to be a more correct approach (Scherbino & Truskanov, 1966).…”

Section: Historical Surveymentioning

confidence: 99%

Practical calibration of ship-mounted omni-directional fisheries sonars

Macaulay

¹

,

Vatnehol

²

,

Gammelsaeter³

et al. 2016

Methods in Oceanography

5

0

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show abstract

“…In the 1950-60s, the concept of a species-and size-dependent directivity pattern of single fish was known, with these effects being highlighted through target strength measurements (Cushing, 1955;Jones & Pearce, 1958;Midttun & Hoff, 1962). Approaches using acoustics in fish stock assessment were also developed in the 1950-60s, first through counting of individual echoes (Tungate, 1958;Mitson & Wood, 1961), summing of the echo amplitudes (Richardson, 1959), and finally the echo-integration method based on the echo amplitude (Dragesund & Olsen, 1965). Integrating the echo intensity was later shown to be a more correct approach (Scherbino & Truskanov, 1966).…”

Section: Historical Surveymentioning

confidence: 99%