Search
Now showing items 1-10 of 24
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 ...
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 ...
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 ...
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 ...
Effect of Bait Type and Bait Size on Catch Efficiency in the European Hake Merluccius merluccius Longline Fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-21)
We investigated the effect of bait type and bait size on the catch ef
fi
ciency of a demersal longline
fi
shery targeting
European Hake
Merluccius merluccius
in the North Sea. Automation of the labor-intensive processes onboard
fi
shing
vessels requires
fi
nding alternatives to the traditional bait used in the
fi
shery (i.e., whole European Pilchard
Sardina
pilchardus
). Of the six ...
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 ...
How many fish need to be measured to effectively evaluate trawl selectivity?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
The aim of this study was to provide practitioners working with trawl selectivity with general and easily understandable guidelines regarding the fish sampling effort necessary during sea trials. In particular, we focused on how many fish would need to be caught and length measured in a trawl haul in order to assess the selectivity parameters of the trawl at a designated uncertainty level. We also ...