Comparative study on the full-scale prediction performance of four trawl nets used in the coastal bottom trawl fishery by flume tank experimental investigation

Thierry, Nyatchouba Nsangue Bruno; Tang, Hao; Achile, Njomoue Pandong; Xu, Liuxiong; Hu, Fuxiang; You, Xinxing

doi:10.1016/j.apor.2019.102022

Cited by 19 publications

(13 citation statements)

References 22 publications

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“…As mentioned above, the codends with cutting ratio were designed to contain a small amount of twine compared to codends without a cutting ratio and those used in the midwater trawl fishery industry to demonstrate the effect of the cutting ratio on hydrodynamic force and net shape. In conclusion, according to the experimental results of Balash et al [33] and Thierry et al [3] on the effect of net cutting of the prawn trawl body and bottom trawl wing on the trawl performance, and the results of this study, the net cutting of some part of the trawl net allows it to change its shape, which automatically reduces its twine area and drag force while making it more efficient.…”

Section: Effect Of Cutting Ratio On the Net Shape And Drag Force Of Empty Codendssupporting

confidence: 61%

“…Midwater trawling involves pulling a fishing net horizontally through the water behind one or two vessels. This fishing equipment is normally designed according to the behavior of target species to achieve more selective netting, and to reduce the nets' drag to decrease the fuel consumption of fishing vessels, thus improving fishing efficiency and increasing economic benefits [3,4]. The shape of a midwater trawl is almost similar to an elliptical cone when dragged; the scientific conicity and outline make the midwater trawl smooth and stable, guiding the fish better and with uniform force [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…However, to ensure that all of the nets of the trawl are at the same inclined angle with a smooth contour, the cutting ratio generally increases from the wing to the codend, causing the trawl 2 of 15 contour line to form a convex curve inwardly when the nets are connected. Then, the curve becomes a straight line by water impact [3].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Cutting Ratio and Catch on Drag Characteristics and Fluttering Motions of Midwater Trawl Codend

Liu

Tang

You

et al. 2021

JMSE

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The codend of a trawl net is the rearmost and crucial part of the net for selective fish catch and juvenile escape. To ensure efficient and sustainable midwater trawl fisheries, it is essential to better understand the drag characteristics and fluttering motions of a midwater trawl codend. These are generally affected by catch, cutting ratio, mesh size, and twine diameter. In this study, six nylon codend models with different cutting ratios (no cutting, 6:1, 5:1, 4:1, 7:2, and 3:1) were designed and tested in a professional flume tank under two conditions (empty codends and codends with catch) and five current speeds to obtain the drag force, spatial geometry, and movement trend. As the cutting ratio of empty codends decreased, the drag force decreased, and the drag coefficient increased. The unfolding degree of codend netting and the height of empty codends were found to be directly proportional to the current speed and inversely proportional to the cutting ratio. The positional amplitude of codend with cutting ratio 4:1 was the smallest for catch. The drag force of codends with catch increased as the current speed increased, and first decreased and then increased as the cutting ratio decreased. To ensure the best stability and minimum drag force of the codend, it is recommended to use the 4:1 cutting ratio codend.

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Section: Effect Of Cutting Ratio On the Net Shape And Drag Force Of Empty Codendssupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

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Effect of Cutting Ratio and Catch on Drag Characteristics and Fluttering Motions of Midwater Trawl Codend

Liu

Tang

You

et al. 2021

JMSE

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“…Thereby, the scaling model was based on the modified Tauti's law developed by Hu et al (2001). Furthermore, the linear scale factor used is defined as the quantity in the full-scale trawl divided by the corresponding quantity in the model (Thierry et al, 2020b). The fundamental…”

Section: Experimental Process In the Flume Tankmentioning

confidence: 99%

Flume Tank Evaluation on the Effect of Liners on the Physical Performance of the Antarctic Krill Trawl

et al. 2022

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The Antarctic krill (Euphausia superba) is one of the most abundant resources in the ocean, which provides food for several important species in the Antarctic Ocean, and is targeted commercially by humans for many decades. To sustainably manage and harvest the species, energy-efficient, catch-efficient, and selective fishing gears should be developed for the Antarctic krill trawl fishery. This study investigates the effect of twine area and the liner length on the engineering performance of trawl through flume tank testing of trawl model to predict the performance of the full-scale midwater trawl used in the Antarctic krill fishery. Four 1/35th scale trawl model nets with varying lengths of the liner, based on the traditional trawl used in the Antarctic krill fishery, were designed using modified Tauti’s law and were tested in a flume tank at different towing speed, door spread, heavy bob weight, and the ratio of buoyancy to the fishing line (F/G). The results showed that the reduction in liner length by 25 and 50% from the traditional trawl net led to the decrease in twine area by 11.01 and 19.31% and, consequently, resulted in reductions in the lower bridle tension by 12.44 and 19.78%, and increases in energy efficiency by 17.98 and 25.73%, respectively. In addition, the reduction in liner length by 25 and 50% were found to increase the net mouth opening by 2.63 and 5.38% and the swept area by 6.52 and 8.38%, respectively, both of which are proportional to catch rates. Although the trawl net with 50% liner length is more energy-efficient and large mouth opening than those of the trawl net with the liner length over 75% of the trawl body, the large mesh section without a liner can result in the escape of the krill from the trawl, reducing overall catch efficiency. We, therefore, recommend the trawl with 75% of liner length as a suitable design for Antarctic krill considering energy efficiency and catch efficiency.

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“…Over the past few decades, different methods have been explored, such as the optimization of hull geometry and propulsion systems (Gabiña et al, 2016;Lin et al, 2018;Schau et al, 2009) and fouling control on vessels' hulls to diminish ship resistance (Notti et al, 2019). Trawl gear performance and modifications have also been investigated (Thierry et al, 2020a;Wileman, 1984;Wileman & Hansen, 1988). Different trawl designs, larger meshes, or alternative netting materials (Thierry et al, 2020b;Parente et al, 2008;Sala et al, 2008;Verhulst & Jochems, 1993) have been shown to be effective in reducing fuel consumption while maintaining a gear's ability to catch target species.…”

Section: Introductionmentioning

confidence: 99%

Fishing the waves: comparing GAMs and random forest to evaluate the effect of changing marine conditions on the energy performance of vessels

et al. 2022

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The optimization of consumption and the reduction of gas emissions in fisheries rely on a thorough examination of all factors affecting the energy balance of fishing vessels. Engines, propellers, or the hydrodynamic characteristics of vessels and gears are unquestionably the primary factors affecting this balance, and an improvement in energy efficiency based on these factors is typically attained through technical modifications to existing technologies. Behavioral modifications, such as a reduction in operational speeds or the selection of closer fishing grounds, are another option. There may still be room for improvement in behavioral responses, for instance by adapting fishing strategies in response to changing weather and sea conditions. As far as the authors are aware, the influence of varying sea state and wind conditions on the energy expenditure of fishing vessels has not yet been investigated and is the focus of this research. In this study, wind and wave actions were associated with the observed activity of three fishing vessels operating in the northern Adriatic Sea: an OTB, a PTM, and a TBB trawler. The analysis made use of a comparison between two different approaches, generalized additive models (GAMs) and random forest, in order to quantify the significance of each variable on the response and generate consumption forecasts. In our analysis, the observed influence of predictors was significant albeit occasionally ambiguous. Wave height had the most obvious impact on energy expenditure, with the towing and gear handling phases being the most affected by wave action. Conversely, navigation seemed to be mostly unaffected by significant wave heights up to 1.5 meters, with unclear effects on consumption estimated above this threshold. The relationship between winds and fuel consumption was found to be nonlinear and ambiguous; hence, its significance should be investigated further.

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Comparative study on the full-scale prediction performance of four trawl nets used in the coastal bottom trawl fishery by flume tank experimental investigation

Cited by 19 publications

References 22 publications

Effect of Cutting Ratio and Catch on Drag Characteristics and Fluttering Motions of Midwater Trawl Codend

Effect of Cutting Ratio and Catch on Drag Characteristics and Fluttering Motions of Midwater Trawl Codend

Flume Tank Evaluation on the Effect of Liners on the Physical Performance of the Antarctic Krill Trawl

Fishing the waves: comparing GAMs and random forest to evaluate the effect of changing marine conditions on the energy performance of vessels

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