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Effect of lifting the sweeps on bottom trawling catch efficiency on the Northeast arctic cod trawl fishery
(Research report; Forskningsrapport, 2014)
Fuel consumption and environmental concerns have led bottom trawlers fishing for cod (Gadus morhua) in the Barents Sea to use semi-pelagic doors. However, this change may affect fish herding and consequently the catch efficiency of the gear. In this study we compared the catch efficiency of two different setups where the sweep length with bottom contact was different. This setup also enabled us to ...
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 ...
MultiSEPT - Full scale tests of the semicircular spreading gear (SCSG)
(Research report; Forskningsrapport, 2013-06-24)
This reportdescribes full scale tests at sea with the semi-circular spreading gear (SCSG). This activity is part of Work Package 3 (WP3: Development of new ground gear) of the MultiSEPT project. The spreading of the SCSG and rockhopper gear was measured by useof MARPORT distance sensors. Bottom contact was monitored by use of SCANMARtrawl sensors and by underwater cameras mounted in the headline ...
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 ...
Use of semi-pelagic trawling for reducing bycatch in shrimp trawls. Trials onboard R/V Johan Ruud 02-06 February 2015
(Research report; Forskningsrapport, 2015)
The present study evaluates whether lifting the trawl doors and sweeps from the seabed
can reduce bycatch in shrimp trawl fisheries. We carried out a catch comparison and catch
ratio analysis between two gear setups, one with the trawl doors and sweeps at the
seabed (the traditional way) and the other with the doors and sweeps lifted. The study was
carried out on American plaice. The results ...