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Size-dependent escape risk of lumpfish (Cyclopterus lumpus) from salmonid farm nets
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-13)
In the last decade, the salmon aquaculture industry has considerably increased the use of lumpfish juveniles as cleaner fish. Potential escape of reared lumpfish into the wild may spread diseases or genetically contaminate wild stocks. The guidelines for minimum sizes of cleaner fish to use in aquaculture cages are currently based on simple mesh penetration tests. However, these guidelines do not ...
Catch Pattern for Antarctic krill (Euphausia superba) of Different Commercial Trawls in Similar Times and Overlapping Fishing Grounds
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-28)
Antarctic krill (Euphausia superba) is harvested using different design midwater trawls. Knowing the selective properties between trawls is crucial information for the management of the krill resources. This study compared the catch patterns between different commercial krill trawls at similar times and overlapping fishing grounds based on scientific data collected by scientific observers onboard ...
Square mesh codend improves size selectivity and catch pattern for Trichiurus lepturus in bottom trawl used along Northwest coast of India
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-15)
The size selectivity and catch pattern of Trichiurus lepturus in 40 mm diamond and square mesh codends were investigated in this study. A 34 m high opening trawl was used, which is a common design used by fishermen operating along the northwest coast of India, and the cover codend method was employed to determine codend selectivity. Along with the changes in the length at 50% retention rate for ...
Estimating selectivity of experimental diamond (T0) and turned mesh (T90) codends in multi-species Mediterranean bottom trawl
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-11)
This paper evaluates the effect of changing from a diamond mesh codend (T0) to a 90° turned mesh codend (T90) on the size selectivity of seven commercially important species in the Mediterranean bottom trawl fishery. In sea trials conducted in the north-western Adriatic, two experimental codends made of 54 mm nominal mesh size netting and differing only in mesh configuration were alternately mounted ...
Use of artificial illumination to reduce Pacific halibut bycatch in a U.S. West Coast groundfish Bottom trawl
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-05)
In the U.S. West Coast groundfish bottom trawl fishery, Pacific halibut (<i>Hippoglossus stenolepis</i>) bycatch can impact some fishers’ ability to fully utilize their quota shares of groundfishes. In this study, we compared the catch efficiency for Pacific halibut and four commercially important groundfish species between an illuminated and non-illuminated trawl. The illuminated trawl caught ...
Predicting optimal combinations of by‐catch reduction devices in trawl gears: A meta‐analytical approach
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-02)
Global efforts to reduce unwanted catches have led to the development of a vast array of by‐catch reduction devices (BRDs), in particular for mixed trawl fisheries. Some of these BRDs could likely benefit from being combined. However, the number of possible combinations would be prohibitive to be tested experimentally. Therefore, in this study we propose a meta‐analytical approach that combines the ...
Effect of a lateral square-mesh panel on the catch pattern and catch efficiency in a Mediterranean bottom trawl fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-31)
The current legal codends used in Mediterranean bottom trawl fisheries are at high risk of retaining undersized individuals of several commercial fish species. This entails that codends alone are unable to provide the desired exploitation pattern. A simple technological measure that potentially can provide higher release efficiency of undersized fish are Square-Mesh Panels (SMPs). SMPs are often ...
Prediction of size-dependent risk of salmon smolt (Salmo salar) escape through fish farm nets
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-08)
The escape of small smolt through farm cage netting is a major challenge faced by the Norwegian salmon farming industry. Escape can occur when the smolt placed in the cages are smaller than the size estimated by the farmers. Furthermore, one may assume wrong mesh-properties as the cage netting change shape and/or state from stiff (mesh bars with tension) to slack (mesh bars without tension) due to ...
Escape, discard, and landing probability in multispecies Mediterranean bottom-trawl fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-17)
Commercial bycatch species and their exploitation pattern in the Mediterranean trawl fishery are little studied. The present work examines the overall size-selection pattern, both regarding the trawl in the sea and the fisher onboard the vessel, for seven commercial bycatch species using different codends. The applied selection model predicted the escape, discard, and landing probability for each ...
Mesh sticking probability in fishing gear selectivity: Methodology and case study on Norway lobster (Nephrops norvegicus) and mantis shrimp (Squilla mantis) in the Mediterranean Sea creel fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-27)
Fish or crustaceans stuck in the fishing gear meshes can lead to operational problems in some fisheries and thereby affect the economic gain. However, mesh sticking probability has never been formally quantified as a part of the estimation of fishing gear size selectivity. Therefore, this study developed a size selection model and estimation procedure that, besides the size dependent retention and ...