Escape response of juvenile fish in a shaking codend determined from tank experiments

Kim, Yonghae

doi:10.1016/j.fishres.2014.08.012

Cited by 5 publications

(12 citation statements)

References 25 publications

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“…In addition, the mean shaking period of 14 s was longer than the period of the model cod end in the field towing experiments of Kim shaking cod end of the shrimp beam trawl was reduced by -30% compared to the steady cod end, and the shaking cod end achieved a 25% decrease in total bycatch and 24% decrease in discarded garbage. These reductions in the shaking cod end attached to the shrimp beam trawl were similar to those observed in the model shaking cod end in a tank by Kim (2015). However, the retained number of juvenile fish in a shrimp trawl in the northeastern United States was similar between a rope grid BRD and traditional cod end (He and Balzano, 2013).…”

Section: Resultssupporting

confidence: 68%

Effects on bycatch reduction in a shaking cod end generated by canvas in a shrimp beam trawl

Kim¹,

Whang²

2014

Journal of the Korean society of Fisheries Technology

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An active stimulating device, such as a fluttering net or canvas attached to the end of a cod end generating a shaking motion, could help to encourage the escape of juvenile fish positioned passively near the net. Field fishing trials using a shrimp beam trawl were carried out to examine the effect on the reduction of juvenile fish or other discard catch by generating a shaking movement of the cod end using an unbiased cap-like round canvas. The mean period of the shaking motion with the round canvas was -14 s, and the mean amplitude was 0.4 m as measured by peak event analysis and the global wavelet method. The bycatch of juvenile fish in 14 trials decreased by -30% and by -25% using a steady cod end for the total bycatch using a shaking cod end in the shrimp beam trawl, while the marketing catch was similar between steady and shaking cod ends. There was no difference in the body size of the shrimp or fish and species composition between the steady and shaking cod ends. Above results demonstrate a new method for bycatch reduction using an active stimulating device, although more detailed studies are needed.

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Section: Resultssupporting

confidence: 68%

Effects on bycatch reduction in a shaking cod end generated by canvas in a shrimp beam trawl

Kim¹,

Whang²

2014

Journal of the Korean society of Fisheries Technology

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“…Kim [ 19 , 20 ] stated that a “shaking” ratio of 0.5 encouraged fish to move and approach codend nettings. Amplitude ratios in the reported study stayed below 0.5, though preliminary results of size selectivity suggest that escapes could have been increased; no video observations were made to determine if these escapes were derived from behavioural, mechanical, or both selectivity mechanisms.…”

Section: Discussionmentioning

confidence: 99%

“…The logger was attached to the middle of the side panel, right before the front edge of the canvas. The change in depth allowed each codend to be characterized by amplitude ratio and period [ 19 , 20 ]. The amplitude ratio was defined by the peak-to-peak amplitude divided by the length of the side panel.…”

Section: Methodsmentioning

confidence: 99%

“…Additionally, Grimaldo et al [ 15 ] showed that mechanical stimulation can trigger escape behaviors for haddock in the Barents Sea demersal trawl fishery. Kim [ 19 , 20 ] used a circular piece of canvas at the posterior of the codend to form a cap which generates lifting force with respect to drag, inducing a “shaking” movement of the codend. This movement was shown to lead to an increased escape rate for small fish through the codend meshes.…”

Section: Introductionmentioning

confidence: 99%

“…This movement was shown to lead to an increased escape rate for small fish through the codend meshes. Escape rates of juvenile fish were observed to increase by 22–30% when compared with a codend without the canvas [ 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

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Developing a full-scale shaking codend to reduce the capture of small fish

et al. 2023

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To reduce the retention of undersized fish in the redfish (Sebastes spp.) trawl fishery in the Gulf of St. Lawrence, Canada, we developed a full-scale shaking codend. The shaking codend uses a mechanical stimulating device, an elliptical-shaped piece of polyvinyl chloride canvas, attached to the posterior of a T90 codend that generates a lifting force with respect to drag, causing a ‘shaking motion’. A shaking codend could stimulate fish movement and increase contact probability, both of which could increase the escape of small redfish out of a codend, especially when combined with a codend that maintains mesh openings. The movement and fishing characteristics of a shaking codend (T90 codend with canvas) relative to a T90 codend (without canvas) were tested in a flume tank and field experiment. In the flume tank test, the shaking codend had a peak-to-peak amplitude (i.e. the distance the codend moves from the lowest to highest depth) > 24 cm higher than the T90 codend for each velocity tested (1.0–1.8 kt), higher amplitude ratio, and a higher period (1 revolution) that gradually decreased with increasing velocity. The total acceleration (m s-2) and drag forces (kgf) estimated for the shaking codend were significantly higher than the T90 codend across all flow velocities. The results from the field experiment, considered preliminary due to a small sample size, showed that the shaking codend significantly reduced the capture of small redfish (< 21 cm) and the best fit model did not need to consider contact probability which was necessary for the non-shaking T90 codend. Overall, the dynamics of the movement of the codend was described and could be potentially used as an effective technique to reduce the catch of small redfish, and perhaps in other trawl fisheries to reduce the catch of small fish.

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Characteristics of catch losses in stow nets with finless porpoise excluder devices and a strategy to reduce them

Lee

Song

Kim

2022

Regional Studies in Marine Science

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Escape response of juvenile fish in a shaking codend determined from tank experiments

Cited by 5 publications

References 25 publications

Effects on bycatch reduction in a shaking cod end generated by canvas in a shrimp beam trawl

Effects on bycatch reduction in a shaking cod end generated by canvas in a shrimp beam trawl

Developing a full-scale shaking codend to reduce the capture of small fish

Characteristics of catch losses in stow nets with finless porpoise excluder devices and a strategy to reduce them

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