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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 ...
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 ...
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 ...
New approach for modelling size selectivity in shrimp trawl fisheries
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-10)
In the deep sea trawl fishery targeting shrimp (Pandalus borealis) and other cold-water shrimp species, fishers often use a Nordmöre sorting grid ahead of a small mesh codend to avoid bycatch. However, small fish can pass through the grid and are subsequently retained in the codend. This makes shrimp size selection complex and the size-dependent curve for both the shrimp and the bycatch species often ...
Size selectivity and length-dependent escape behaviour of haddock in a sorting device combining a grid and a square mesh panel
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-04)
Size selectivity of a new sorting section combining a sorting grid and a square mesh panel was tested for haddock (Melanogrammus aeglefinus) in the Barents Sea demersal trawl fishery. Sampling data for a wide size range enabled investigating the selection process for this species in detail, both for the grid and the square mesh panel. Contrary to earlier studies modelling size selectivity for grids ...
Size selection of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) in the Northeast Atlantic bottom trawl fishery with a newly developed double steel grid system
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-06)
In recent years, Norwegian fishermen have reported problems with fish accumulation in front of the mandatory sorting grids (Sort-X, Sort-V, and Flexigrid). These problems are associated with high fish entry rates and low water flow through the grid sections. In this study, we replaced the lifting panel in the original design of a sorting grid section (Sort-V) by another steel grid (“lower grid”) in ...
Could green artificial light reduce bycatch during Barents Sea Deep-water shrimp trawling?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-31)
The Nordmøre grid is widely used in shrimp trawls to reduce the bycatch of fish species. However, small-sized fish species and juveniles still pass through the grid and enter the codend, along with the targeted shrimp. This bycatch of small fish has a negative impact on the ecosystem due to increased fish mortality, and leads to additional sorting work onboard. Some small-sized fish that enter the ...
Performance of the Nordmøre grid in shrimp trawling and potential effects of guiding funnel length and light stimulation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-31)
The introduction of the Nordmøre grid to shrimp trawls has reduced the issue of bycatch to that of small-sized species and juveniles that are able to pass through the grid and enter the small-meshed cod end together with the targeted shrimp. This study estimated the size- and species-selective performance of the Nordmøre grid in the configuration most often applied by fishermen and made a preliminary ...