An assessment of nets with a square mesh panel as a whiting conservation tool in the Irish Sea Nephrops fishery

Briggs, R.P.

doi:10.1016/0165-7836(92)90023-m

Cited by 55 publications

(44 citation statements)

References 1 publication

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“…As a tool to improve the selectivity of trawls, the concept of the window is not a recent invention but was tested more than 90 years ago by Ridderstad (1915) in the Kattegat and the Baltic Sea. The window was tested in various fisheries in the beginning of the 1990s (Briggs 1992;Briggs and Robertson 1993;Hillis et al 1991;Thorsteinsson 1992;Polet and Redant 1994;Madsen and Moth-Poulsen 1994).…”

Section: Factors Affecting Selectivitymentioning

confidence: 99%

Selectivity of fishing gears used in the Baltic Sea cod fishery

Madsen

2007

Rev Fish Biol Fisheries

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The Baltic cod (Gadus morhua) plays a very significant role in the Baltic Sea ecosystem being the major fish top predator and the most important commercial species for the Baltic Sea fishing industry. Consequently the management and understanding of the exploitation pattern of the stock is of major importance. Technical regulations, improving the selectivity of cod, have been a major management strategy and the Baltic Sea is likely to be the area where most fishing gear selectivity studies, focussing on size selectivity, have been conducted over time. The methodology for conducting and analysing selectivity data has been significantly improved in recent years. The subject is reviewed since the choice of methodology can have a significant effect on the interpretation of the outcome of selectivity experiments. Factors affecting the selectivity of trawl and gill nets are considered. Alternative ways to improve the size and species selectivity of trawls using selective devices are reviewed. Selectivity parameters from available literature are listed and the correlations of selectivity parameters to the mesh size for different gears are estimated. The historical legislation on selectivity is reviewed and the expected selectivity for trawls is estimated. Management considerations concerning the mortality of escaping and discarded fish and wider management impacts have to be considered if improving selectivity. The review is ended by conclusions including reflections on needed research in the future.

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Section: Factors Affecting Selectivitymentioning

confidence: 99%

Selectivity of fishing gears used in the Baltic Sea cod fishery

Madsen

2007

Rev Fish Biol Fisheries

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“…Cod, for example, are known to enter the trawl close to the fishing line and mainly follow a path close to the lower netting panel in the trawl unless stimuli are used to raise their vertical position Sangster 1981, 1985;Ferro et al 2007;Krag et al 2009;Rosen et al 2012). Furthermore, unlike haddock (Tschernij and Suuronen 2002;Grimaldo et al 2007), cod appear to have a low activity level when inside trawls (Briggs 1992;Rosen et al 2012). …”

Section: Introductionmentioning

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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“…Other methods based on gear designs that include square meshes or escape windows in different parts of the net have been tried for various species (Ulmestrand and Larsson, 1991;Briggs, 1992;Campos et al, 1996;Broadhurst, 2000;Halliday and Cooper, 2000;Madsen et al, 2001;Massutí et al, 2002;Campos et al, 2003). The effect of towing speed and gear size on the selectivity of bottom trawl nets has also been tested (Dahm et al, 2002).…”

Section: Introductionmentioning

confidence: 99%