A mobile horizontal hydroacoustic fisheries survey of the River Thames, United Kingdom

Hughes, Simon

doi:10.1016/s0165-7836(98)00063-0

Cited by 21 publications

(16 citation statements)

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“…Thus, to sample the upper layers of the water column, horizontal beaming has been employed in freshwater lakes and reservoirs (Hughes 1998;Kubecka and Wittingerova 1998;Yule 2000;Drastik and Kubecka 2005). Other studies have used only vertical beaming (Brandt et al 1991;Nyberg et al 2001;Cyterski et al 2003;Schimdt et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Hydroacoustic fish biomass assessment in man-made lakes in Tunisia: horizontal beaming importance and diel effect

Djemali

Toujani

Guillard³

2008

Aquat Ecol

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We used a Simrad EK60 echosounder equipped with two split-beam transducers to develop a sampling strategy for assessing fish resources in Tunisian man-made lakes. Day and night surveys, using vertical and horizontal beaming, were carried out between December 2006 and February 2007, a period when fish catchability is high. Four reservoirs with differing surface areas and bathymetries were selected. Echogram analysis revealed that fish communities were mainly composed of individual targets. A few schools were detected near the surface during daylight, but these schools dispersed slightly at night. In these multispecies reservoirs, considerable day and night differences in density existed, but with no clear trend. Target strength (TS) distribution mode values detected at night were always lower or equal to daytime values. Biomass estimates were significantly higher during daytime in three reservoirs, corresponding with higher TS modal values. In the other reservoir, the biomass estimate was significantly higher during nighttime corresponding with higher mean density during this period. Using only a vertically aimed transducer in our study reservoirs would have led to an underestimate of density and biomass by 5-100% and 20-100%, respectively, depending on the man-made lake. We conclude that acoustic sampling in our reservoirs must be done during day and night and that both vertical and horizontal beaming must be used to obtain the best possible picture of the fish stocks.

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Section: Introductionmentioning

confidence: 99%

Hydroacoustic fish biomass assessment in man-made lakes in Tunisia: horizontal beaming importance and diel effect

Djemali

Toujani

Guillard³

2008

Aquat Ecol

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“…Nevertheless, hydroacoustic assessments have been used extensively for fish monitoring, especially in lakes where sampling strategies have been developed (e.g., Guillard & Vergès, 2007), with target strengths related to species-specific attributes to increase knowledge on community composition (Frouzova, Kubecka, Balk, & Frouz, 2005). In lowland rivers, such as the River Thames and River Trent in England, mobile hydroacoustic techniques have been applied to monitor the spatial and temporal distributions of fish communities (Hughes, 1998;Lyons, 1998). The method has also been applied to assessing the status of endangered fishes (Zhang et al, 2009).…”

Section: Non-capture Monitoring Techniquesmentioning

confidence: 99%

Effective monitoring of freshwater fish

et al. 2019

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Freshwater ecosystems constitute only a small fraction of the planet's water resources, yet support much of its diversity, with freshwater fish accounting for more species than birds, mammals, amphibians or reptiles. Fresh waters are, however, particularly vulnerable to anthropogenic impacts, including habitat loss, climate and land use change, pollution and biological invasions. This environmental degradation, combined with unprecedented rates of biodiversity change, highlights the importance of robust and replicable programmes to monitor freshwater fish. Such monitoring programmes can have diverse aims, including confirming the presence of a single species (e.g., early detection of alien species), tracking changes in the abundance of threatened species, or documenting long‐term temporal changes in entire communities. Irrespective of their motivation, monitoring programmes are only fit for purpose if they have clearly articulated aims and collect data that can meet those aims. This review, therefore, highlights the importance of identifying the key aims in monitoring programmes and outlines the different methods of sampling freshwater fish that can be used to meet these aims. We emphasize that investigators must address issues around sampling design, statistical power, species’ detectability, taxonomy and ethics in their monitoring programmes. Additionally, programmes must ensure that high‐quality monitoring data are properly curated and deposited in repositories that will endure. Through fostering improved practice in freshwater fish monitoring, this review aims to help programmes improve understanding of the processes that shape the Earth's freshwater ecosystems and help protect these systems in face of rapid environmental change.

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“…Echo sounders can survey horizontally or vertically at typical fish locations such as migration routes, and spawning and feeding grounds, to survey diurnal or seasonal activity in rivers (Hughes, 1998;Johnson & Moursund, 2000;Steig & Iverson, 1998), lakes (Knudsen & Saegrov, 2002), reservoirs (Kubecka & Wittingerova, 1998;Tušer, Kubecka, Frouzova, & Jarolim, 2009), and estuaries (Boswell, Miller, & Wilson, 2007). The two Simrad EK60 spilt beam echo sounders at the 120 kHz frequency, had been used horizontally and vertically simultaneously, to address the spatiotemporal niche changes of freshwater fishes in an offshore-inshore system successfully (Muška et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Measuring fish length and assessing behaviour in a high-biodiversity reach of the Upper Yangtze River using an acoustic camera and echo sounder

et al. 2016

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Summary In the past decade improved acoustic hard‐ and software have enabled estimations of abundance and distribution patterns of aquatic organism, including non‐intrusive monitoring of fish migrations and behaviour. In this study, a high frequency acoustic camera (DIDSON‐LR, 1.2 MHz, 0.7 MHz) and a portable split‐beam scientific echo sounder (Simrad EY60, 200 kHz) collected acoustic data on 192 and 157 individuals within 24 hr (19–20 April 2011) in the Mituo reach of the Yangtze River, China. Mean fish length estimated from the acoustic camera data was 18.7 ± 5.6 cm, with an average swimming speed of 0.19 ± 0.13 m s−1. The mean fish target strength (TS) produced by the echo sounder was −43.8 ± 4.4 dB, which corresponded to 5.7–119.9 cm fish length when converted by three different TS‐length equations. Average swimming speed was 0.11 ± 0.06 m s−1 from the echo sounder. Compared with the actual fish catch by the three layers of drift gill net in the survey area, the target length indicated by DIDSON was more accurate than the EY60 results, which were highly affected by the choice of TS length equations. It was determined that the two devices used synchronously could estimate fish length effectively to investigate their behaviour and distribution.

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A mobile horizontal hydroacoustic fisheries survey of the River Thames, United Kingdom

Cited by 21 publications

References 1 publication

Hydroacoustic fish biomass assessment in man-made lakes in Tunisia: horizontal beaming importance and diel effect

Hydroacoustic fish biomass assessment in man-made lakes in Tunisia: horizontal beaming importance and diel effect

Effective monitoring of freshwater fish

Measuring fish length and assessing behaviour in a high-biodiversity reach of the Upper Yangtze River using an acoustic camera and echo sounder

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