Two methods to improve the accuracy of target-strength estimates for horizontal beaming

Rakowitz, Georg; Herold, Wolfgang; Fesl, Christian; Keckeis, Hubert; Kubečka, Jan; Balk, Helge

doi:10.1016/j.fishres.2008.06.005

Cited by 9 publications

(11 citation statements)

References 39 publications

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“…Hence, these outliers had to be removed manually from the fish tracks in order not to oversize the fishes. Consequently, there is a need to improve autotracking algorithms especially for horizontal beaming, which would remarkably increase quality and efficiency of hydroacoustic post‐processing (Rakowitz & Kubečka, 2006; Rakowitz et al , 2008 b ).…”

Section: Discussionmentioning

confidence: 99%

“…bottom or fish reverberations appeared in the fish tracks, which were not identified as outliers by auto‐tracking. These outliers had to be removed manually from the fish tracks in order not to oversize the fish (Rakowitz & Kubečka, 2006; Rakowitz et al , 2008 b ).…”

Section: Methodsmentioning

confidence: 99%

“…This was in accordance with 92% of migrants as well as 91% of all captured fishes between 41 and 51 cm; this size range was therefore used as a reference to discriminate this species from all others in the hydroacoustic recordings. The L T calculation of hydroacoustically detected fishes was based on the 95th TS percentile of tracked fishes according to Rakowitz et al . (2008 b ).…”

Section: Methodsmentioning

confidence: 99%

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Intercalibration of hydroacoustic and mark–recapture methods for assessing the spawning population size of a threatened fish species

Rakowitz

Kubečka

Fesl

et al. 2009

Journal of Fish Biology

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Hydroacoustic counting and a three-year mark-recapture study with passive integrated transponders (PIT tags) were used to estimate the size of a spawning population of nase Chondrostoma nasus, a threatened potamodromous cyprinid that undertakes annual spawning migrations into a tributary of the Danube River. In 2005, the estimates of the size of the spawning population from the hydroacoustic counts (N = 2234, 95% CL 1929-2538) and from the Jolly-Seber model (N = 1198, 95% CL 461-5842) corresponded well. Estimates from the jackknife-estimator based on the hydroacoustic counts yielded slightly higher values (N = 2783, 95% CL 2529-3037), but were still in the same order of magnitude as those from the hydroacoustic and mark-recapture approach. At low run-size, hydroacoustic counting was more time consuming and technically demanding than mark-recapture studies. At the same time, it was non-invasive, provided real-time data on a fine temporal scale, and estimates showed less variability than the Jolly-Seber model. Mark-recapture of fish in spawning streams involved substantial disturbance at a sensitive stage of the life cycle. Hence, hydroacoustics is highly suited for population estimates of threatened potamodromous fishes, where interference needs to be minimized.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Intercalibration of hydroacoustic and mark–recapture methods for assessing the spawning population size of a threatened fish species

Rakowitz

Kubečka

Fesl

et al. 2009

Journal of Fish Biology

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“…Sonar imaging based on split beam methods has been used to monitor the movement behaviour of individual fish, and it can determine their 3D positions (Handegard & Tjøstheim ; Rakowitz et al . ; Tao et al . ).…”

Section: Feeding Control Methods Based On Acoustic Technologymentioning

confidence: 99%

“…According to some studies, the quantity of fish is related to the acoustic intensity (Conti et al 2006). Sonar imaging based on split beam methods has been used to monitor the movement behaviour of individual fish, and it can determine their 3D positions (Handegard & Tjøstheim 2005;Rakowitz et al 2008;Tao et al 2010). Dual-frequency identification sonar, which can produce results similar to those from optical images, shows great potential for detecting fish behaviour (Rose et al 2005;Handegard & Williams 2008;Xie et al 2008).…”

Section: Sonar Imagingmentioning

confidence: 99%

Intelligent feeding control methods in aquaculture with an emphasis on fish: a review

Zhou

Kai

et al. 2017

Reviews in Aquaculture

130

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In aquaculture, feeding is the primary factor determining efficiency and cost, so it is important to know when to stop feeding to maximize efficiency. Until now, fish feeding has been mostly based on artificial discrimination, which is usually time‐consuming and laborious. In recent years, intelligent feeding control according to changes in behaviour and growth status has gained increasing attention. This approach involves many methods as well as monitoring and feedback equipment and can automatically determine the feeding demands of fish. This review summarizes the development of intelligent feeding control methods, such as mathematical models, acoustic methods and computer vision, in aquaculture over the past three decades. All methods have unique application scenarios and models for the culture to which they are most suitable, and the advantages and disadvantages of each method in the laboratory as well as in pond, cage and recirculating aquaculture systems are analysed. Studies show that improvements in sensor accuracy and hardware and software processing speed have promoted the development of new technologies and methods, providing effective or potential support for intelligent feeding control. However, its accuracy and intelligent are still need to be improved to meet the needs of actual feeding scenarios. Through close collaborations between engineers and fish behaviourists, the feeding machine and system will be more elaborate and precise on the basis of the above methods, and the level of intelligence will be further improved.

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Deep pools of the Danube River: ecological function or turbulent sink?

et al. 2013

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Two methods to improve the accuracy of target-strength estimates for horizontal beaming

Cited by 9 publications

References 39 publications

Intercalibration of hydroacoustic and mark–recapture methods for assessing the spawning population size of a threatened fish species

Intercalibration of hydroacoustic and mark–recapture methods for assessing the spawning population size of a threatened fish species

Intelligent feeding control methods in aquaculture with an emphasis on fish: a review

Deep pools of the Danube River: ecological function or turbulent sink?

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