Predicting size selection of cod ( Gadus morhua ) in square mesh codends for demersal seining: A simulation-based approach

Herrmann, Bent; Larsen, Roger B.; Sistiaga, Manu Berrondo; Madsen, Nina; Aarsæther, Karl Gunnar; Grimaldo, Eduardo; Ingólfsson, Ólafur Arnar

doi:10.1016/j.fishres.2015.07.015

Cited by 18 publications

(12 citation statements)

References 19 publications

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“…Using FISHSELECT, we demonstrated that the experimentally obtained double logistic size selection curves can only be explained if we assume that part of the fish are able to escape through slack and wide-open cod end meshes. This finding is in line with Herrmann et al (2016), which investigated the Herrmann et al (2016) further speculated that the slack mesh size selection might occur at the last stages of the fishing process when the cod end is at the surface. Based on this, we could reason that a similar situation occurs in the case of Danish seining with a diamond-mesh cod end.…”

Section: Discussionsupporting

confidence: 83%

“…Applying FISHSELECT in this way requires (1) a morphological model describing the cross sections of importance for size selection of the species and (2) a model describing how and to what extent the fish cross sections can be squeezed when trying to pass through a mesh. The methodology has previously been used to investigate size selectivity for numerous species and fisheries (Frandsen et al 2010;Herrmann et al 2012Herrmann et al , 2013bHerrmann et al , 2016Krag et al 2011, SIZE SELECTION IN DIAMOND-MESH COD ENDS 281 2014; Sistiaga et al 2011;Tokac et al 2016). The FISHSELECT models necessary to study Atlantic Cod and Haddock size selectivity in diamond-mesh cod ends were already available through the studies by Herrmann et al (2009) and Krag et al (2011) and were adapted to the present study.…”

Section: Methodsmentioning

confidence: 99%

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Understanding and Predicting Size Selection in Diamond‐Mesh Cod Ends for Danish Seining: A Study Based on Sea Trials and Computer Simulations

et al. 2016

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Danish seining is an important fishing method used to harvest demersal species. Knowledge about the size selectivity of different demersal species with this type of fishing gear is therefore of importance for managing the exploitation of marine resources. However, there are only limited data on size selection in cod ends in this fishery. Sea trials were therefore carried out to collect size selectivity data for Atlantic Cod Gadus morhua, Haddock Melanogrammus aeglefinus, and Witch Flounder Glyptocephalus cynoglossus for a diamond‐mesh cod end. For all three species, the data were best described by a double logistic selection curve, implying that two different size selection processes occur in the cod end. The double selection process could be explained by an additional selection process occurring through slack meshes. The results imply that the escapement of 46% and 34% of the larger Atlantic Cod and Haddock (those above 48 cm), respectively, would be through wide‐open or slack meshes. Since these mesh states are only likely to be present in the latest stage of the fishing process (e.g., when the cod end is near the surface), a large fraction of the bigger fish probably escaped near the surface, which might influence their likelihood of survival. Furthermore, based on the models established for explaining the experimental size selection, we were able to predict the effect of changing the mesh size on cod end size selection in the Danish seine fishery. Received December 9, 2015; accepted February 18, 2016

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Section: Discussionsupporting

confidence: 83%

Section: Methodsmentioning

confidence: 99%

Understanding and Predicting Size Selection in Diamond‐Mesh Cod Ends for Danish Seining: A Study Based on Sea Trials and Computer Simulations

et al. 2016

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“…The length of each sample fish was measured and tested in a vertical direction under the influence of gravity to determine whether it would fall through the meshes or not (see Herrmann et al (2009) for further information about this methodology). Besides, the mesh opening angle varies during fishing according to the state of the mesh (stiff or slack), which affects the size selective potential of codend meshes (Herrmann et al, 2016). Therefore, we carried out fallthrough experiments for four different codend mesh scenarios.…”

Section: Fall-throughmentioning

confidence: 99%

“…According to the AIC values, H0 could be rejected because the AIC value was higher than that for the logit and the Clogit model. Using the method described by Herrmann et al (2016), the relative likelihood between H0 and the logit model indicated that there was an 8.96 × -7 % probability of H0 being extremely unlikely.…”

Section: Tablementioning

confidence: 99%

Escape rate for cod (Gadus morhua) from the codend during buffer towing

Brinkhof

Herrmann²,

Larsen

et al. 2017

ICES Journal of Marine Science

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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 fully processed, the trawl is lifted off the seabed and towed at a given depth at low speed. This is called buffer towing. Cod that escape from the codend when the trawl is shallower than the initial fishing depth are exposed to an increased likelihood of barotrauma-related injuries, increased disease susceptibility, and predation, which could be lethal, or affect growth and reproduction capability. Therefore, this study quantified the escape rate and size selectivity during buffer towing of cod. A new analytical method was applied that allows using the same trawl configuration as applied during commercial fishing and avoids potential bias in the assessment of buffer towing size selection. Our results demonstrated a significant size selection for cod during buffer towing where cod measuring up to at least 42 cm in length were proven to escape. In particular, at least 60% of cod measuring 20 cm were estimated to escape during buffer towing. For cod measuring 30 and 40 cm, at least 53 and 45% were estimated to escape during buffer towing, respectively.

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“…Due to this limitation, we used a different approach, where a predictive model for creel selectivity was obtained based on laboratory experiments using dead Nephrops. Our approach has some conceptual similarities with the method for investigating blue crab size selectivity described in Guillory (1998), but it was mostly inspired by a method previously applied for trawls (Herrmann et al 2009;Frandsen et al 2010;Krag et al 2011;Herrmann et al 2013;Tokaç et al 2016) and demersal seine selectivity (Herrmann et al 2016a;Herrmann et al 2016b).…”

Section: Introductionmentioning

confidence: 99%

CREELSELECT—A method for determining the optimal creel mesh: Case study on Norway lobster (Nephrops norvegicus) fishery in the Mediterranean Sea

et al. 2018

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In the laboratory, we investigated which sizes of Nephrops (Nephrops norvegicus) could pass through the meshes of different size and shape to establish a predictive model for the creels size selectivity. Predictions agreed well with the results from experimental fishing, demonstrating the reliability of this simple method. Nephrops minimum target size is 20 mm carapace length in the Mediterranean creel fishery, with some areas having restrictions on the mesh size, minimum being 36 or 40 mm. The model predicts that Nephrops below 28 and 32 mm carapace length would escape from creels with respectively 36 and 40 mm mesh size, implying a suboptimal exploitation pattern. Our method provides easy and quick identification of optimal mesh size and shape without the exhaustive sea trials with various creel designs. It was predicted that a square mesh of 30 mm would better match the desired exploitation pattern. The method could easily be adopted to other species and different creel fisheries, helping to determine optimal mesh matching a prescribed exploitation pattern. *Manuscript including abstract Click here to view linked References Mean (SD) 41.04 (0.72) 82.47 (4.35) 0.9679

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Predicting size selection of cod ( Gadus morhua ) in square mesh codends for demersal seining: A simulation-based approach

Cited by 18 publications

References 19 publications

Understanding and Predicting Size Selection in Diamond‐Mesh Cod Ends for Danish Seining: A Study Based on Sea Trials and Computer Simulations

Understanding and Predicting Size Selection in Diamond‐Mesh Cod Ends for Danish Seining: A Study Based on Sea Trials and Computer Simulations

Escape rate for cod (Gadus morhua) from the codend during buffer towing

CREELSELECT—A method for determining the optimal creel mesh: Case study on Norway lobster (Nephrops norvegicus) fishery in the Mediterranean Sea

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