• Catch Efficiency of Groundgears in a Bottom Trawl Fishery: A Case Study of the Barents Sea Haddock 

      Larsen, Roger B.; Herrmann, Bent; Brinkhof, Jesse; Grimaldo, Eduardo; Sistiaga, Manu Berrondo; Tatone, Ivan (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 

      Sistiaga, Manu Berrondo; Herrmann, Bent; Grimaldo, Eduardo; Larsen, Roger B.; Olsen, Leonore; Brinkhof, Jesse; Tatone, Ivan (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 ...
    • Comparison of fishing efficiency between biodegradable PBSAT gillnets and conventional nylon (PA) gillnets 

      Grimaldo, Eduardo; Herrmann, Bent; Su, Biao; Føre, Heidi Moe; Vollstad, Jørgen; Olsen, Leonore; Larsen, Roger B.; Tatone, Ivan (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 ...
    • Could green artificial light reduce bycatch during Barents Sea Deep-water shrimp trawling? 

      Larsen, Roger B.; Herrmann, Bent; Sistiaga, Manu Berrondo; Brčić, Jure; Brinkhof, Jesse; Tatone, Ivan (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 

      Sistiaga, Manu Berrondo; Herrmann, Bent; Rindahl, Lasse; Tatone, Ivan (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 ...
    • Effect of lifting the sweeps on bottom trawling catch efficiency on the Northeast arctic cod trawl fishery 

      Sistiaga, Manu Berrondo; Grimaldo, Eduardo; Herrmann, Bent; Larsen, Roger B.; Tatone, Ivan (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 ...
    • The effect of Nordmøre grid length and angle on codend entry of bycatch fish species and shrimp catches 

      Larsen, Roger B.; Sistiaga, Manu Berrondo; Herrmann, Bent; Brinkhof, Jesse; Tatone, Ivan; Santos, Juan (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 ...
    • Fishing efficiency of biodegradable PBSAT gillnets and conventional nylon gillnets used in Norwegian cod (Gadus morhua) and saithe (Pollachius virens) fisheries 

      Grimaldo, Eduardo; Herrmann, Bent; Vollstad, Jørgen; Su, Biao; Føre, Heidi Moe; Larsen, Roger B.; Tatone, Ivan (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 ...
    • MultiSEPT - Full scale tests of the semicircular spreading gear (SCSG) 

      Grimaldo, Eduardo; Sistiaga, Manu Berrondo; Larsen, Roger B.; Tatone, Ivan; Olsen, fredrik (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 ...
    • New approach for modelling size selectivity in shrimp trawl fisheries 

      Larsen, Roger B.; Herrmann, Bent; Sistiaga, Manu Berrondo; Brinkhof, Jesse; Tatone, Ivan; Langård, Lise (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 ...
    • Performance of the Nordmøre grid in shrimp trawling and potential effects of guiding funnel length and light stimulation 

      Larsen, Roger B.; Herrmann, Bent; Sistiaga, Manu Berrondo; Brinkhof, Jesse; Tatone, Ivan; Langård, Lise (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 ...
    • 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 

      Larsen, Roger B.; Herrmann, Bent; Sistiaga, Manu Berrondo; Grimaldo, Eduardo; Tatone, Ivan; Brinkhof, Jesse (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 ...
    • Size selection of Greenland halibut (Reinhardtius hippoglossoides) in the Norwegian bottom trawl fishery with a newly developed double grid system 

      Larsen, Roger B.; Herrmann, Bent; Sistiaga, Manu Berrondo; Grimaldo, Eduardo; Brinkhof, Jesse; Tatone, Ivan (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 ...
    • Size selectivity and length-dependent escape behaviour of haddock in a sorting device combining a grid and a square mesh panel 

      Herrmann, Bent; Sistiaga, Manu Berrondo; Grimaldo, Eduardo; Larsen, Roger B.; Olsen, Leonore; Brinkhof, Jesse; Tatone, Ivan (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 ...
    • Use of semi-pelagic trawling for reducing bycatch in shrimp trawls. Trials onboard R/V Johan Ruud 02-06 February 2015 

      Sistiaga, Manu Berrondo; Grimaldo, Eduardo; Larsen, Roger B.; Tatone, Ivan; Vollstad, Jørgen; Herrmann, Bent (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 ...