scholarly journals Effect of three different codend designs on the size selectivity of juvenile cod in the Barents Sea shrimp trawl fishery

2019 ◽  
Vol 219 ◽  
pp. 105337
Author(s):  
Bent Herrmann ◽  
Manu Sistiaga ◽  
Roger B. Larsen ◽  
Jesse Brinkhof
Keyword(s):  
Barents Sea ◽  
Size Selectivity ◽  
Trawl Fishery ◽  
The Barents Sea ◽  
Shrimp Trawl

scholarly journals Bycatch reduction in the deep-water shrimp (Pandalus borealis) trawl fishery by increasing codend mesh openness

2021 ◽  
Author(s):  
Nadine Jacques ◽  
Hermann Pettersen ◽  
Kristine Cerbule ◽  
Bent Herrmann ◽  
Ólafur A. Ingólfsson ◽  
...  
Keyword(s):  
Deep Water ◽  
Barents Sea ◽  
Juvenile Fish ◽  
Size Selectivity ◽  
Pandalus Borealis ◽  
Trawl Fishery ◽  
Bycatch Reduction ◽  
Drag Forces ◽  
The Barents Sea ◽  
Trawl Fisheries

In most trawl fisheries, drag forces tend to close the meshes in large areas of diamond mesh codends, negatively affecting their selective potential. In the Barents Sea deep-water shrimp (Pandalus borealis) trawl fishery, selectivity is based on a sorting grid followed by a diamond mesh codend. However, the retention of juvenile fish as well as undersized shrimp is still a problem. In this study, we estimated the effect of applying different codend modifications, each aimed at affecting codend mesh openness and thereby selectivity. Changing from a 4-panel to a 2-panel construction of the codend did not affect size selectivity. Shortening the lastridge ropes of a 4-panel codend by 20% resulted in minor reductions for juvenile fish bycatch, but a 45% reduction of undersized shrimp was observed. Target-size catches of shrimp were nearly unaffected. When the codend mesh circumference was reduced while simultaneously shortening the lastridge ropes, the effect on catch efficiency for shrimp or juvenile fish bycatch was marginal compared to a 4-panel codend design with shortened lastridge ropes.

scholarly journals Effect of a quality-improving cod end on size selectivity and catch patterns of cod in bottom trawl fishery

2019 ◽  
Vol 76 (11) ◽  
pp. 2110-2120 ◽  
Author(s):  
Jesse Brinkhof ◽  
Bent Herrmann ◽  
Roger B. Larsen ◽  
Tiago Veiga-Malta
Keyword(s):  
Gadus Morhua ◽  
Barents Sea ◽  
Relative Size ◽  
Bottom Trawl ◽  
Size Selectivity ◽  
Total Size ◽  
Trawl Fishery ◽  
The Barents Sea ◽  
Sea Bottom ◽  
Significant Difference

A new cod-end concept developed and tested exhibited significantly improved quality of caught cod (Gadus morhua) compared with that of the conventional cod end used in the Barents Sea bottom trawl fishery. However, the design of the new quality-improving cod end raised concerns about its size selectivity and the possibility that higher retention probability could negatively impact the catch pattern by increasing the proportion of undersized cod. Therefore, the goal of this study was to quantify and compare the size selectivity and catch pattern for cod when deploying, respectively, the conventional and new quality-improving cod end in the Barents Sea bottom trawl fishery. The new quality-improving cod end had significantly lower relative size selectivity than the conventional cod end, but no significant difference in the catch patterns was detected in the trawl. Further, estimation of the total size selectivity in the trawl revealed that the increased retention of small cod when using the quality-improving cod end was minor. Hence, despite the reduced selectivity, the quality-improving cod end can be used with low risk of retaining small cod.

Understanding limits to cod and haddock separation using size selectivity in a multispecies trawl fishery: an application of FISHSELECT

2011 ◽  
Vol 68 (5) ◽  
pp. 927 ◽  
Author(s):  
Manu Sistiaga ◽  
Bent Herrmann ◽  
Kåre N. Nielsen ◽  
Roger B. Larsen
Keyword(s):  
Gadus Morhua ◽  
Barents Sea ◽  
Atlantic Cod ◽  
Morphological Characteristics ◽  
Melanogrammus Aeglefinus ◽  
Size Selectivity ◽  
Sea Trial ◽  
Trawl Fishery ◽  
The Barents Sea ◽  
Morphological Differences

This investigation demonstrates how a multidisciplinary approach based on the FISHSELECT framework, sea trial data, underwater recordings, and laboratory investigations of netting can be applied to size selectivity studies and related management issues. We studied the morphological characteristics of Atlantic cod ( Gadus morhua ) and haddock ( Melanogrammus aeglefinus ) in the Barents Sea bottom trawl fishery. The differences between the L50 values (i.e., the size at which a fish has a 50% chance of being retained) that were recorded for the two species during sea trials can to a large extent be explained by the morphological differences between them. Because of these morphological differences, L50 is always larger for cod than for haddock with the grid and codend setup commonly used in the area. While catch separation of cod and haddock is a management objective in the Barents Sea, we demonstrate that the morphological differences between the species and the grid and codend setup in force today limit achievable differences in L50 to 5.5 cm. Furthermore, we show that for this fishery, the scope for increasing L50 differences between these species by changing the mesh shape configuration of the codend is minimal.

scholarly journals New approach for modelling size selectivity in shrimp trawl fisheries

2017 ◽  
Vol 75 (1) ◽  
pp. 351-360 ◽  
Author(s):  
Roger B Larsen ◽  
Bent Herrmann ◽  
Manu Sistiaga ◽  
Jesse Brinkhof ◽  
Ivan Tatone ◽  
...  
Keyword(s):  
Barents Sea ◽  
Cold Water ◽  
Small Fish ◽  
Size Selectivity ◽  
Size Selection ◽  
Trawl Fishery ◽  
Size Dependent ◽  
Shrimp Trawl ◽  
Pass Through ◽  
The Individual

Abstract 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 exhibits a bell-shaped signature. In this study we developed a new model and method to estimate size selection in this fishery, conducted fishing trials in the Northeast Barents Sea, and applied the new method to quantify the individual and combined size selection of the Nordmöre grid and codend for deep water shrimp and two bycatch species. The size selectivity for both bycatch species showed the expected bell-shaped signature with low retention probability of very small and larger fish. The Nordmöre grid had high passage probability for all sizes, although it decreased slightly for the largest shrimps. The smallest shrimps were released by the codend.

scholarly journals Potential for codends with shortened lastridge ropes to replace mandated selection devices in demersal trawl fisheries

2021 ◽  
Author(s):  
Manu Sistiaga ◽  
Jesse Brinkhof ◽  
Bent Herrmann ◽  
Roger B. Larsen ◽  
Eduardo Grimaldo ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Barents Sea ◽  
Size Selectivity ◽  
The Barents Sea ◽  
Alternative Solutions ◽  
Trawl Fisheries

In many trawl fisheries, codend size selectivity is supplemented by adding selection devices to the gear. In the Barents Sea gadoid fishery, combining diamond mesh codends with sorting grids is compulsory. However, the use of grids increases the costs and complexity of the gear, causing discontent among fishermen and prompting researchers to seek alternative solutions. Lastridge ropes are ropes attached to the selvedges of the codend. In this study, we tested the effect of shortening the lastridge ropes of two diamond mesh codends with different mesh sizes on the size selectivity of cod (Gadus morhua), haddock (Melanogramus aeglefinnus), and redfish (Sebastes spp.). Shortening the lastridge ropes by 15% increased the mesh opening during the fishing process, which significantly improved the size-selective properties of the codends. Further, the L50 values were always higher for the codends in the short lastridge configuration. Therefore, codends with shortened lastridge ropes may be a simpler alternative to sorting grids in this fishery, and they may be applicable to many other fisheries in which additional selection devices are used.

scholarly journals Effect of gear design on catch damage on cod (Gadus morhua) in the Barents Sea demersal trawl fishery

Food Control ◽  
2021 ◽  
Vol 120 ◽  
pp. 107562 ◽  
Author(s):  
Jesse Brinkhof ◽  
Bent Herrmann ◽  
Manu Sistiaga ◽  
Roger B. Larsen ◽  
Nadine Jacques ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Barents Sea ◽  
Trawl Fishery ◽  
Gear Design ◽  
The Barents Sea

scholarly journals Fisheries change spawning ground distribution of northeast Arctic cod

2009 ◽  
Vol 6 (2) ◽  
pp. 261-264 ◽  
Author(s):  
Anders Frugård Opdal
Keyword(s):  
Barents Sea ◽  
Size Structure ◽  
Sudden Increase ◽  
Spawning Grounds ◽  
Norwegian Coast ◽  
Trawl Fishery ◽  
Climatic Variations ◽  
The Barents Sea ◽  
Spawning Stock

Prior to the 1920s, the northeast Arctic (NA) cod were caught at spawning grounds ranging from the southernmost to the northernmost parts of the Norwegian coast, but have for the last 50 yr mainly been caught around the Lofoten archipelago and northwards. The NA cod have their feeding and nursery grounds in the Barents Sea, and migrate south towards the Norwegian coast in the winter to spawn. This study uses commercial fisheries' data from landing ports along the entire Norwegian coast during the period 1866–1969 as evidence of long-term truncation and northerly shift of spawning grounds. Nearly all spawning grounds south of Lofoten have been abandoned, while an increasing proportion of the spawning stock only uses the northernmost areas of the Norwegian coast, Troms and Finnmark. The truncation can hardly be attributed to long-term climatic variations, but may result from an intensive size-selective trawl fishery in the Barents Sea causing a sudden increase in fishing mortality, probably altering the size structure and migratory capacity of the stock.

scholarly journals Escape mortality of cod, saithe, and haddock in a Barents Sea trawl fishery

2007 ◽  
Vol 64 (9) ◽  
pp. 1836-1844 ◽  
Author(s):  
Ólafur Arnar Ingólfsson ◽  
Aud Vold Soldal ◽  
Irene Huse ◽  
Mike Breen
Keyword(s):  
Barents Sea ◽  
Fish Length ◽  
Commercial Fishing ◽  
Experimental Conditions ◽  
Closely Related Species ◽  
Large Variability ◽  
Trawl Fishery ◽  
The Barents Sea ◽  
Methodological Problems ◽  
Low Levels

Abstract Ingólfsson, Ó. A., Soldal, A. V., Huse, I., and Breen, M. 2007. Escape mortality of cod, saithe, and haddock in a Barents Sea trawl fishery. – ICES Journal of Marine Science, 64: 000–000. We investigated the survival of gadoid fish in the Barents Sea escaping from a demersal trawl during commercial fishing conditions, with and without a sorting grid, at high and low levels of fishing intensity. The mortality of cod and saithe was negligible and unrelated to experimental conditions. Haddock mortality was generally greater than observed in earlier experiments and inversely related to fish length. Any possible effects of experimental conditions were hidden by large variability in the observed rates of mortality. We conclude that the observed mortality of haddock is confounded by methodological problems, particularly the instability of the observation cages, and does not reflect the true escape mortality. Cod and saithe are capable of surviving the stress of passage through, and escape from, the trawl, whereas haddock are more vulnerable, despite being a closely related species.

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