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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 ...
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 ...
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 ...
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 ...
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 ...