Modelling the size selectivities of a trawl codend and an associated square mesh panel

Zuur, Grietje

doi:10.1006/jmsc.2001.1049

Cited by 48 publications

(46 citation statements)

References 14 publications

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“…For the fish contacting the meshes, the probability that they subsequently escape by passing or squeezing themselves through a mesh is quantified by a logistic size selection curve. Examples for using this modelling approach for studying size selection of square mesh panels in trawls include Zuur et al (2001), O'Neill et al (2006), and Alzorriz et al (2016). A limitation of this modelling approach is that it assumes the contact probability to be the same for all sizes of fish that would be able to pass or squeeze themselves through the meshes.…”

Section: Collection Of Release Efficiency Data and Underwater Recordingsmentioning

confidence: 99%

Improving release efficiency of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) in the Barents Sea demersal trawl fishery by stimulating escape behaviour

Grimaldo

Sistiaga

Herrmann

et al. 2018

Can. J. Fish. Aquat. Sci.

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Abstract:We tested the ability of stimulators to improve the release efficiency of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) through the meshes of a square mesh section installed in a trawl. The section was tested in three different configurations: without any stimulation device, with a mechanical stimulation device, and with LED light stimulation devices. We analysed and compared the behaviour of cod and haddock in all three configurations based on release results and underwater recordings. Parallel to the fishing trials, we carried out fall-through tests to determine the upper physical size limits for cod and haddock to be able to escape through the square meshes in the section. This enabled us to infer whether lack of release efficiency was due to fish behaviour or release potential of the square meshes in the section. The results showed that the escape behaviour of haddock can be triggered by mechanical stimulation. In contrast, cod did not react significantly to the presence of mechanical stimulators. LED light stimulation had some effect on the behaviour of haddock, but not on cod.Résumé : Nous avons vérifié la capacité de stimulateurs d'améliorer l'efficacité de la libération de morues (Gadus morhua) et d'aiglefins (Melanogrammus aeglefinus) par les mailles d'une section de mailles carrées installée dans un chalut. La section a été mise à l'essai selon trois configurations différentes, soit sans aucun instrument de stimulation, avec un instrument de stimulation mécanique et avec des instruments de stimulation à lumière DEL. Nous avons analysé et comparé le comportement des morues et des aiglefins dans les trois configurations à la lumière des résultats de libération et d'enregistrements sous l'eau. Parallèlement aux essais de pêche, nous avons mené des essais de passage par gravité afin de déterminer les limites supérieures des tailles auxquelles les morues et aiglefins peuvent s'évader par les mailles carrées dans la section. Cela nous a permis d'établir si l'absence d'une libération efficace était due au comportement des poissons ou au potentiel de libération des mailles carrées dans la section. Les résultats montrent que le comportement d'évasion des aiglefins peut être déclenché par une stimulation mécanique. Les morues, au contraire, n'ont pas présenté de réaction significative à la présence de stimulateurs mécaniques. La stimulation à la lumière DEL a eu un certain effet sur le comportement des aiglefins, mais pas sur celui des morues. [Traduit par la Rédaction]

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Section: Collection Of Release Efficiency Data and Underwater Recordingsmentioning

confidence: 99%

Improving release efficiency of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) in the Barents Sea demersal trawl fishery by stimulating escape behaviour

Grimaldo

Sistiaga

Herrmann

et al. 2018

Can. J. Fish. Aquat. Sci.

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“…For example, Zuur, G., et al (2001) describe an experiment to estimate the size selection of a cod-end and a square-mesh panel using covers over both the cod-end and the panel. Selection on each haul was modelled using five parameters that were then combined over hauls.…”

Section: Parametric Curvesmentioning

confidence: 99%

“…Millar and Fryer 1999;Zuur, G., et al 2001), because some dab could pass into the upper cod-end without contacting the grid by always swimming in the upper part of the trawl.…”

Section: Illustration: Grid Selectionmentioning

confidence: 99%

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Using mixed models to combine smooth size-selection and catch-comparison curves over hauls

Fryer¹,

Zuur²,

Graham³

2003

Can. J. Fish. Aquat. Sci.

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Parametric size-selection curves are often combined over hauls to estimate a mean selection curve using a mixed model in which between-haul variation in selection is treated as a random effect. This paper shows how the mixed model can be extended to estimate a mean selection curve when smooth nonparametric size-selection curves are used. The method also estimates the between-haul variation in selection at each length and can model fixed effects in the form of the different levels of a categorical variable. Data obtained to estimate the size-selection of dab by a Nordmøre grid are used for illustration. The method can also be used to provide a length-based analysis of catchcomparison data, either to compare a test net with a standard net or to calibrate two research survey vessels. Haddock data from an intercalibration exercise are used for illustration.Résumé : Les courbes paramétriques de sélection de la taille sont souvent combinées dans toutes les récoltes pour obtenir une courbe de sélection moyenne qui utilise un modèle mixte dans lequel la variation de la sélection entre les récoltes est considérée comme un effet aléatoire. Notre étude démontre comment le modèle mixte peut être étendu de façon à estimer une courbe de sélection moyenne en utilisant des courbes lisses de sélection non paramétriques. La méthode estime aussi la variation de la sélection entre les récoltes pour chacune des longueurs et elle peut modéliser des effets fixes sous forme de niveaux différents d'une variable catégorique. Un exemple utilise des données obtenues pour estimer la sélection de taille chez la limande par une grille de Nordmøre. La méthode peut aussi servir à analyser des données de comparaisons de récoltes d'après la longueur, soit pour comparer un filet expérimental avec un filet standard ou pour calibrer deux navires d'inventaire de recherche. Un exemple utilise des données sur l'aiglefin provenant d'un exercice d'intercalibration.[Traduit par la Rédaction] Fryer et al. 459

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“…Quantitative assessment methods have been employed to analyze the separation effectiveness of the BRD, including the contact probability model developed by Tokai et al [9], Tokai [10], and Zuur et al [11]. The combination of contact selection and contact probability was termed the available selection model by Millar and Fryer [12].…”

Section: Introductionmentioning

confidence: 99%

Modeling of available size selectivity of the SURF-BRD for shrimp beam trawl

Kajikawa

Tokai

2013

Fish Sci

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The System of Unwants Ramp-way FilteredBycatch Reduction Device (SURF-BRD) was developed to reduce shrimp bycatch in a shrimp beam trawl. It consists of a pair of rectangular net panels, namely, the front panel (FP) and rear panel (RP), and two fish escape vents. In this study, numerical models for expressing available selection by the SURF-BRD were proposed and assessed in several fishing experiments conducted using two types of the BRD: a prototype and an improved type with the BRD attached at a higher point on the side-nets . Contact probability and selectivity parameters of the FP and the RP for four major species were estimated for each BRD type. The improved type with the higher BRD showed a larger contact probability for the FP. Size selectivity of the FP and RP for two species (cinnamon flounder and spotted swimming crab) was almost equivalent to the mesh selectivity of the net panel, but that for lizard fish seemed to depend not on mesh size of the FP but on the swimming behavior of the fish. These results suggest that the smaller mesh size of the RP would be helpful for releasing more fish of smaller size and to exclude more spotted swimming crab, which hinder ondeck sorting by fishermen.

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Modelling the size selectivities of a trawl codend and an associated square mesh panel

Cited by 48 publications

References 14 publications

Improving release efficiency of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) in the Barents Sea demersal trawl fishery by stimulating escape behaviour

Improving release efficiency of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) in the Barents Sea demersal trawl fishery by stimulating escape behaviour

Using mixed models to combine smooth size-selection and catch-comparison curves over hauls

Modeling of available size selectivity of the SURF-BRD for shrimp beam trawl

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