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Catch Efficiency of Groundgears in a Bottom Trawl Fishery: A Case Study of the Barents Sea Haddock
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-10)
The catch efficiency of two types of groundgear—a conventional rockhopper and a new type of groundgear called the semicircular spreading gear (SCSG)—was investigated through experimental fishing for Haddock Melanogrammus aeglefinus conducted in the Barents Sea. A retainer bag was attached behind the footrope of the trawl, and the number of fish that were overrun by the trawl was compared with the ...
Understanding the Size Selectivity of Redfish (Sebastes spp.) in North Atlantic Trawl Codends
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
The majority of trawl selectivity studies for the three redfish species of particular commercial importance in North Atlantic fisheries: Sebastes marinus, Sebastes mentella and Sebastes fasciatus, are based on data collected from diamond mesh codends with mesh sizes ranging from 88 mm to 147 mm. We demonstrate how results from these studies can be understood by morphological characteristics of ...
Coincident mass occurrence of gelatinous zooplankton in Northern Norway
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-23)
In autumn 2015, several sources reported observations of large amounts of gelatinous material in a large north Norwegian fjord system, either caught when trawling for other organisms or fouling fishing gear. The responsible organism was identified as a physonect siphonophore, Nanomia cara, while a ctenophore, Beroe cucumis, and a hydromedusa, Modeeria rotunda, were also registered in high abundances ...
Sequential codend improves quality of trawlcaught cod
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-10)
Trawl-caught fish are frequently associated with deteriorated catch quality. This study presents a new dual sequential codend concept with the aim of improving the quality of trawl-caught fish by minimizing the frequency and severity of catch damage. During towing, the fish are retained in an anterior codend segment with the legislated mesh size. A quality improving codend segment, is attached to ...
Combination of a sorting grid and a square mesh panel to optimize size selection in the North-East Arctic cod (Gadus morhua) and redfish (Sebastes spp.) trawl fisheries
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-27)
Sorting grids and square mesh panels are the two most-applied technical devices to supplement codend size- and species-selection in demer-
sal trawls. In the Barents Sea gadoid fishery, the compulsory size-selectivity system comprises a mesh section with a sorting grid followed by a
diamond mesh codend. We tested the size-selective performance of a new sorting section that comprised a sorting grid ...
Size selection of Greenland halibut (Reinhardtius hippoglossoides) in the Norwegian bottom trawl fishery with a newly developed double grid system
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017)
Greenland halibut (<i>Reinhardtius hippoglossoides</i>) is a commercially important species in the northeast Atlantic trawl fishery. However, direct fishing for it is not allowed and it can only be harvested as bycatch. We investigated for the first time the size selection of Greenland halibut in a newly developed double steel grid system designed for the cod and haddock bottom trawl fishery. In ...
Escape rate for cod (Gadus morhua) from the codend during buffer towing
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-30)
The high abundances of Northeast Arctic cod (Gadus morhua) in the Barents Sea have led to the development of a new fishing tactic called buffer towing. On factory trawlers, the trawl is deployed immediately after taking the catch onboard, a tactic used to ensure a continuous supply of fish is being processed. If the desired amount of fish is caught before the catch from the previous haul has been ...
Size selectivity of redfish (Sebastes spp.) in the Northeast Atlantic using grid-based selection systems for trawls
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
Using experimental data and a model to predict size selection based on morphological data, we investigated
size selection of redfish (Sebastes spp.) in the grid-based selection systems used in Northeast Atlantic trawls. We
found that not all redfish make physical contact with the spacing between the bars in the sorting grids while they pass
in the direction of the codend, and therefore the ...
The effect of semi-pelagic trawling on american plaice (hippoglossoides platessoides) by-catch reduction in the northeast arctic shrimp fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017)
The present study reports results of a small-scale preliminary experiment to evaluate whether lifting trawl doors and sweeps from the seabed can lead to a reduction of by-catch in the Northeast Arctic shrimp trawl fishery. We carried out a catch comparison and catch ratio analysis between two gear configurations: one with trawl doors and sweeps on the seabed (traditional rigging) and the other with ...
The effect of Nordmøre grid length and angle on codend entry of bycatch fish species and shrimp catches
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-18)
The Nordmøre grid is regarded as an efficient bycatch reducing device and is used in various shrimp trawl fisheries globally. However, in some shrimp fisheries bycatch remains a problem that seriously impacts commercial trawl activities. This study tested and compared the performance of two versions of the Nordmøre grid in the Northeast Arctic Deepwater Shrimp (Pandalus borealis) fishery; a standard ...