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Effect of a quality-improving codend on size selectivity and catch patterns of cod in bottom trawl fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-26)
A new codend concept developed and tested exhibited significantly improved quality of caught cod (<i>Gadus morhua</i>) compared to that of the conventional codend used in the Barents Sea bottom trawl fishery. However, the design of the new quality-improving codend raised concerns about its size selectivity and the possibility that higher retention probability could negatively impact the catch pattern ...
Effect of mechanical properties of monofilament twines on the catch efficiency of biodegradable gillnets
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-24)
Gillnets made of the biodegradable resin polybutylene succinate co-adipate-co-terephthalate were tested under commercial fishing conditions to compare their fishing performance with that of conventional nylon polyamide (PA) gillnets. Both types of gillnets were made of 0.55 mm Ø monofilaments. However, since the biodegradable nets are weaker than nylon PA nets when using the same monofilament diameter, ...
Comparing the size selectivity of a novel T90 mesh codend to two conventional codends in the northern shrimp (Pandalus borealis) trawl fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-28)
The size selectivity and usability of three codends were quantified and compared for the first time in the inshore Northern shrimp (<i>Pandalus borealis</i>) trawl fishery of Iceland using the covered codend method: a conventional diamond-mesh codend (T0), conventional square-mesh codend (T45), and a 90° turned mesh codend (T90) constructed of four panels and with shortened lastridge ropes. Fishers, ...
Catch pattern and size selectivity for a gear designed to prevent fish injuries during the capture process in a North-East Atlantic demersal trawl fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-04)
In the North-East Atlantic demersal trawl fishery targeting cod and haddock, the interest on fishing gear designs that preserve fish quality and welfare has grown. However, the gear configurations tested so far imply practical challenges, therefore, more user-friendly designs are still sought by the industry. For a new design to be considered, it needs to have size selective properties that are at ...
Quantifying the performance of selective devices by combining analysis of catch data and fish behaviour observations: methodology and case study on a flatfish excluder
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-06)
This article describes a method for the quantitative analysis of fish behaviour relative to selection devices in trawl gears. Based on video observations, the method estimates probabilities for a given event to happen and establishes behavioural tree diagrams representing and quantifying behavioural patterns in relation to the selection device under assessment. Double bootstrapping is used to account ...
Comparing size selectivity and exploitation pattern of diamond-mesh codends for Southern velvet shrimp (Metapenaeopsis palmensis) in shrimp trawl fishery of the South China Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-02)
In this study, size selectivity and exploitation pattern of six diamond-mesh codends with different mesh sizes, ranging from 25 to 54 mm, for Southern velvet shrimp (Metapenaeopsis palmensis) were tested and compared in a shrimp trawl fishery of the South China Sea (SCS). We used a codend with a mesh size of 25 mm (D25) as a starting point, which is the minimum mesh size (MMS) currently regulated ...
Does the efficiency of a counter-herding device depend on seabed contact?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-06)
To prevent unwanted fish bycatch from entering the trawl, we modified a counter-herding device, FLEXSELECT, developed for a Northeast Atlantic <i>Nephrops</i> (<i>Nephrops norvegicus</i>) trawl fishery. FLEXSELECT, which was designed to direct fish away from the trawl by means of sweeping ropes in the herding area, has been shown to be highly effective on both roundfish and flatfish species. However, ...
A netting-based alternative to rigid sorting grids in the small-meshed Norway pout (Trisopterus esmarkii) trawl fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-28)
A new bycatch reduction device, termed “Excluder”, is presented as an alternative to a traditional rigid sorting grid, mandatory in the small-meshed Norway Pout (<i>Trisopterus esmarkii</i>) trawl fishery in the North Sea. The fishery is a high-volume fishery with large vessels, large demersal trawls and catches up to 100 tons per haul of this small forage fish. The Excluder is a 30 m long netting-based ...
Effects of six codend meshes on the size selection of juvenile white croaker (Pennahia argentata) in demersal trawl fishery of the South China Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-16)
White croaker (Pennahia argentata) is a commercially important but overexploited species that is often caught in trawl fishery of the South China Sea (SCS). The codend size selectivity for this species in the local commercial trawl fishery is of concern when considering the established minimum landing size (MLS). This study investigated the size selectivity of white croaker for six different ...
Dredge selectivity in a Mediterranean striped venus clam (Chamelea gallina) fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-15)
The striped venus clam Chamelea gallina is the target of a large fleet of hydraulic dredgers, which represent an important fishing sector in terms of income and landings in the Mediterranean Sea. Although there is information on the catch rates, impact and discards related to this fishery, the size selection process carried out by the dredge during trawl under commercial conditions is practically ...