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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 ...
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 ...
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 ...
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 ...
Comparison of fishing efficiency between biodegradable PBSAT gillnets and conventional nylon (PA) gillnets
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-19)
Gillnets made of a new biodegradable resin (polybutylene succinate co-adipate-co-terephthalate (PBSAT) were tested under commercial fishing conditions to compare their fishing performance with that of conventional nylon (PA) nets. The relative catch efficiency between the two gillnet 15 types was evaluated over the entire winter fishing season for cod (<i>Gadus morhua</i>) in northern Norway. The ...
Fishing efficiency of biodegradable PBSAT gillnets and conventional nylon gillnets used in Norwegian cod (Gadus morhua) and saithe (Pollachius virens) fisheries
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-10)
Fishing trials were carried out to compare the relative fishing efficiency of gillnets made of a new biodegradable resin (polybutylene succinate co-adipate-co-terephthalate, PBSAT) with conventional (nylon) nets. The fishing trials covered two consecutive fishing seasons (2016 and 2017) for cod (<i>Gadus morhua</i>) and saithe (<i>Pollachius virens</i>) in northern Norway. Results generally showed ...
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, ...
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 ...