Horizontal beaming as a crucial component of acoustic fish stock assessment in freshwater reservoirs

Kubečka, Jan; Wittingerova, Monika

doi:10.1016/s0165-7836(98)00064-2

Cited by 89 publications

(85 citation statements)

References 14 publications

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“…We included the acoustic techniques in an effort to assess the feasibility of comparing biomass indices across multiple gear types and to acquire highresolution information on the size and biomass of the fish associated with estuarine habitats. We adopted a stationary sampling design because previous work in shallow environments had suggested that there were strong biases in mobile acoustic surveys stemming from avoidance (Kubecka and Wittingerova 1998;Knudsen and Saegrov 2002;Krumme and Saint-Paul 2003).…”

Section: Discussionmentioning

confidence: 99%

Seasonal Estimates of Fish Biomass and Length Distributions Using Acoustics and Traditional Nets to Identify Estuarine Habitat Preferences in Barataria Bay, Louisiana

Boswell

Wilson²,

Macrae

et al. 2010

Mar Coast Fish

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We conducted hydroacoustic, gill‐net, and push trawl surveys to quantify changes in habitat‐specific fish size and biomass in shallow (<2‐m) estuarine waters of Barataria Bay, Louisiana, in order to evaluate essential fish habitat. Surveys were conducted monthly between June 2003 and May 2004 among regions located along a north—south salinity gradient. The fish length distributions derived from the gill‐net and push trawl catches showed moderate concordance with the measured target strength distributions, indicating that our integrated approach more effectively characterized the fish community than using only a single gear type would have. Acoustic estimates showed that biomass was highest during fall (mean ± SE; 2.30 ± 0.27 g/m3) and next highest in spring (1.49 ± 0.20 g/m3), with relatively low biomass during summer (0.70 ± 0.14 g/m3) and winter (0.86 ± 0.14 g/m3); pelagic fish biomass from nets was low during winter (53.9 ± 14.9 grams per unit effort [gpue]) but relatively high in fall (846.1 ± 207.2 gpue), spring (774.3 ± 175.5 gpue), and summer (620.3 ± 140.7 gpue). Oyster habitat supported a greater biomass of pelagic fish (acoustic survey: 1.54 ± 0.15 g/m3; gill‐net survey: 467.3 ± 81.0 gpue) than soft‐bottom habitat (acoustic: 0.94 ± 0.11 g/m3; gill‐net: 315.2 ± 54.8 gpue). Among regions, the greatest biomass of pelagic fish was observed at polyhaline stations (acoustic: 1.78 ± 0.19 g/m3; gill‐net: 654.3 ± 136.5 gpue), followed by mesohaline (acoustic: 1.18 ± 0.15 g/m3; gill‐net: 378.5 ± 79.1 gpue) and oligohaline stations (acoustic: 0.82 ± 0.12 g/m3; gill‐net: 228.3 ± 50.2 gpue). Gill‐net biomass was linearly related to the acoustic biomass estimates of small pelagic fish. The complementary, multigear approach proved to be useful in evaluating habitat use and may be particularly helpful in identifying and monitoring ecosystem reference points to evaluate change and in standardizing ecosystem‐based assessment approaches.

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Section: Discussionmentioning

confidence: 99%

Seasonal Estimates of Fish Biomass and Length Distributions Using Acoustics and Traditional Nets to Identify Estuarine Habitat Preferences in Barataria Bay, Louisiana

Boswell

Wilson²,

Macrae

et al. 2010

Mar Coast Fish

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“…Fish species in manmade reservoirs have rarely been observed below the thermocline during summer thermal stratification (Kubečka and Wittingerová 1998;Matthews et al 2004;Vašek et al 2004;Järvalt et al 2005), except for larval and juvenile perch (Čech et al 2005). Diel vertical migration was not observed at the studied reservoirs, most likely because strict temperature and oxygen stratification of the water column prevent fish from swimming to deeper layers.…”

Section: Discussionmentioning

confidence: 99%

Hydroacoustic estimates of fish stocks in temperate reservoirs: day or night surveys?

Draštík

Kubečka

Čech

et al. 2009

Aquat. Living Resour.

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-Day and night acoustic surveys were used to compare fish stock estimates at eight European reservoirs and one flooded mining pit. During both photoperiods of summer, higher fish biomass was observed in the uppermost 4 m of the water column by horizontal beaming than in deeper water by vertical beaming. Comparisons of volume backscattering coefficient (s v ), fish biomass (kg ha −1 ), abundance (ind. ha −1 ) and average fish weight (g) did not show a common pattern among the reservoirs but were found to vary significantly across photoperiods. At most reservoirs, the night surveys had higher estimates than day surveys. However, at several reservoirs the opposite pattern was observed. These patterns could not be explained by the species composition of the fish stocks. Fish size distributions were found to be different between day and night. A higher proportion of 1+ and older fish were found during the night at two of three studied waterbodies. In general, it was not possible to decide whether day or night acoustic surveys gave more reliable fish stock assessments. We advise performing both day and night transects on a given water body before deciding when to conduct the full survey. For a complete fish assessment it is very desirable to combine acoustic mobile surveys with active sampling gear.Key words: Hydroacoustics / Fish biomass / Diel migration / Man-made lake Résumé -Evaluation hydro-acoustique de stocks de poissons en lacs artificiels de la zone tempérée : de nuit ou de jour ? Des campagnes acoustiques nocturnes et durant le jour ont été effectuées pour comparer les estimations de stock de poissons de 8 lacs artificiels et un puits de mine inondée d'Europe centrale. Durant l'été, de jour comme de nuit, des biomasses plus élevées de poissons ont été observées dans la partie haute (jusqu'à 4 m de profondeur) de la colonne d'eau, par sondage acoustique horizontal que dans la partie plus profonde par sondage vertical. Des comparaisons du coefficient de rétro-(réverbération) en fonction du volume d'eau (s v ), de la biomasse de poissons (kg ha −1 ), de leur abondance (ind. ha −1 ) et du poids moyen des poissons (g) ne montrent pas de schémas communs entre ces réservoirs mais varient significativement en fonction de la période du jour ou de la nuit. Pour la plupart des réservoirs, les campagnes nocturnes présentent des estimations plus importantes que celles effectuées de jour. Cependant, le contraire est aussi observé pour certains réservoirs. Ces différences ne peuvent s'expliquer par la composition en espèces des stocks de poissons. La répartition en tailles des poissons est différente entre la nuit et le jour. Une plus grande proportion de plus gros poissons (1+) est trouvée durant la nuit pour deux des trois lacs réservoirs et du lac minier. En général, il n'est pas possible de décider si des campagnes de jour ou de nuit fournissent des estimations plus fiables des stocks de poissons. Nous conseillons d'effectuer des transects de nuit et de jour avant de décider de la période d'évaluation. Pour un...

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“…A possible solution to these vertical approach difficulties, like the sampling of coastal regions and surface layers of the water column, can be the use of horizontal hydroacoustic, in which the transducer is positioned horizontally in the water column. Several authors have used this technique successfully in acoustic survey at shallow areas (Kubecka and Wittingerova, 1998;Knudsen and Saegrov, 2002;Monteoliva and Schneider, 2005), however the horizontal hydroacoustic serve only for echo-counting and not for echo-integration.…”

Section: Fish Density and Body Length Estimatesmentioning

confidence: 99%

Implementation of hydroacoustic for a rapid assessment of fish spatial distribution at a Brazilian Lake - Lagoa Santa, MG

2013

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Aim: To study the distribution, structure, size and density of fish in the karst lake: Lagoa Central (Lagoa Santa, MG -surface area: 1.7 km 2 ; mean depth: 4.0 m; and maximum depth: 7.3 m). Methods: The hydroacoustic method with vertical beaming was applied, using the echosounder Biosonics DT-X with a split-beam transducer of 200 kHz. The analysis of the acoustic data was performed with the software Visual Analyzer (Biosonics Inc.). Thematic maps of density echoes associated with fish, estimated by the technique of echo-integration, were made using the kriging interpolation. The density and vertical distribution of insonified fish were estimated using the technique of echo-counting. Results: The lake had a mean density of 0.89 echoes associated with fish per m 2 , showing large spatial variations in the density of fish. The size estimated for the echoes associated with fish range from 2.7 to 15.9 cm (mean = 5.3 cm). Conclusions: The use of hydroacoustic to obtain rapid and realistic estimates of fish abundance and vertical distribution of the fish stock was successful.Keywords: ichthyofauna, density, fisheries, Lagoa Santa.Resumo: Objetivos: Estudar a distribuição, densidade e estrutura de tamanho de peixes nas águas da Lagoa Central (Lagoa Santa, MG -área: 1,7 km 2 ; profundidade média: 4,0 m; e profundidade máxima: 7,3 m). Métodos: O estudo utilizou o método hidroacústico com orientação vertical. Uma sonda Biosonics DT-X, equipada com um transdutor split-beam de 200 kHz, foi utilizada. A análise dos dados acústicos foi feita com o programa Visual Analyser (Biosonics Inc.). Mapas temáticos de densidades dos ecos associados a peixes, estimadas através da técnica de eco-integração, foram confeccionados utilizando a interpolação kriging. Já o número e distribuição vertical dos peixes insonificados foram determinados utilizando a técnica de eco-contagem. Resultados: A Lagoa Central apresentou uma densidade média de 0,89 ecos associados a peixes por m 2 , indicando grandes variações na densidade dos peixes em áreas particulares do lago. A estimativa de tamanho dos ecos associados a peixes variou de 2,7 a 15,9 cm (média = 5,3 cm). Conclusões: O uso de hidroacústica para obter estimativas rápidas e realistas de abundância de peixes e distribuição vertical da população de peixes foi bem sucedida.Palavras-chave: ictiofauna, densidade, recurso pesqueiro, Lagoa Santa.

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Horizontal beaming as a crucial component of acoustic fish stock assessment in freshwater reservoirs

Cited by 89 publications

References 14 publications

Seasonal Estimates of Fish Biomass and Length Distributions Using Acoustics and Traditional Nets to Identify Estuarine Habitat Preferences in Barataria Bay, Louisiana

Seasonal Estimates of Fish Biomass and Length Distributions Using Acoustics and Traditional Nets to Identify Estuarine Habitat Preferences in Barataria Bay, Louisiana

Hydroacoustic estimates of fish stocks in temperate reservoirs: day or night surveys?

Implementation of hydroacoustic for a rapid assessment of fish spatial distribution at a Brazilian Lake - Lagoa Santa, MG

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