Comparing the size selectivity of a novel T90 mesh codend to two conventional codends in the northern shrimp (Pandalus borealis) trawl fishery

Einarsson, Haraldur Arnar; Cheng, Zhaohai; Bayse, Shannon M.; Herrmann, Bent; Winger, Paul D.

doi:10.1016/j.aaf.2020.09.005

Cited by 14 publications

(14 citation statements)

References 27 publications

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“…In addition to the estimation of size selectivity, it is essential to quantify how the tested codends with different mesh sizes perform under the same fishing population of the target shrimp, a specific scenario of population, nPop l , was generated by pooling length data from both cover and coded over all hauls ( Melli et al, 2019 ; Einarsson et al, 2021 ; Yang et al, 2021 ). In total, four different fishing population scenarios of the target shrimp species were generated.…”

Section: Methodsmentioning

confidence: 99%

Comparing size selectivity and exploitation pattern of diamond-mesh codends for Southern velvet shrimp (Metapenaeopsis palmensis) in shrimp trawl fishery of the South China Sea

Yang

Herrmann

Liang

et al. 2021

PeerJ

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In this study, size selectivity and exploitation pattern of six diamond-mesh codends with different mesh sizes, ranging from 25 to 54 mm, for Southern velvet shrimp (Metapenaeopsis palmensis) were tested and compared in a shrimp trawl fishery of the South China Sea (SCS). We used a codend with a mesh size of 25 mm (D25) as a starting point, which is the minimum mesh size (MMS) currently regulated in the studied area. Four different fishing population scenarios were applied to quantify and compare how mesh sizes of codends used would impact the size selectivity and exploitation pattern for the target shrimp species. The results demonstrated that the D25 codend was not proper for protecting juvenile shrimp at the studied area. By applying this legal codend, L50 (50% retention length) of the target shrimp species was below its minimum conservation reference size (MCRS, 7.0 cm total length), the retention probability of shrimp with a length of MCRS was above 95% CI [91–99] and more than 43% of undersized shrimp was retained. To mitigate the bycatch issue of undersized shrimp, increasing the mesh size in the diamond mesh codend is a simple and effective option. However, the loss of catch efficiency for marketable shrimp is a major concern while increasing the mesh size. A good compromise between releasing undersized shrimp and maintaining the legal individuals is manifested by using the codend with 35 mm mesh size (D35). Our study will be beneficial for the management of shrimp trawl fisheries in the SCS.

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Section: Methodsmentioning

confidence: 99%

Comparing size selectivity and exploitation pattern of diamond-mesh codends for Southern velvet shrimp (Metapenaeopsis palmensis) in shrimp trawl fishery of the South China Sea

Yang

Herrmann

Liang

et al. 2021

PeerJ

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“…In order to test and compare how these codends with different mesh sizes perform under the same fishery population of white croaker, a specific scenario of population, nPop l , was generated by pooling cover and codend data over all hauls conducted with all codends [21,22]. We assumed that fishing population (nPop l ) was the same for all codends.…”

Section: Estimation Of Exploitation Pattern Indicatorsmentioning

confidence: 99%

Effects of six codend meshes on the size selection of juvenile white croaker (Pennahia argentata) in demersal trawl fishery of the South China Sea

et al. 2021

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White croaker (Pennahia argentata) is a commercially important but overexploited species that is often caught in trawl fishery of the South China Sea (SCS). The codend size selectivity for this species in the local commercial trawl fishery is of concern when considering the established minimum landing size (MLS). This study investigated the size selectivity of white croaker for six different diamond-mesh codends with mesh size from 25 to 54 mm. We paid special attention to two codends, made with meshes of 25 and 40 mm in size, which are currently used according to the regulations established in the SCS. The results demonstrated that the legal codends do not perform satisfactorily in the fishing grounds where juvenile white croaker is relatively abundant. This is because at a length similar to the minimum landing size of the species (MLS = 15.0 cm), all white croaker were retained, and the estimated discard ratio was >97% in both cases of legal codends. Our study showed that by increasing the mesh size, the size selection of tested codends could be improved for white croaker, and the retention rates for juvenile fish would decrease. However, none codend was proved efficient to release undersized white croaker suggesting that other gear design changes may be necessary.

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“…To quantify and compare how these codends with different mesh sizes perform under the 176 same fishery population of banded scad, a specific scenario of population, nPopl, was 177 generated by pooling data from both codend and cover for all tests over all hauls (Melli et al,178 2019; Einarsson et al, 2021). Applying the size selection predicted in section 2.3, four 179 exploitation pattern indicators, nP-, nP+, nRatio, and dnRatio (Eq.…”

Section: Estimation Of Exploitation Pattern Indicators 175mentioning

confidence: 99%

“…Both nRatio and 189 dnRatio should be as low as possible. The double bootstrapping approach was applied to 190 estimate the Efron percentile 95% CIs for the indicator values, taking both within-and 191 between-haul variation into consideration (Herrmann et al, 2012;Herrmann et al, 2018;192 Melli et al, 2019;Einarsson., 2021). 193…”

Section: Estimation Of Exploitation Pattern Indicators 175mentioning

confidence: 99%

“…Estimation of exploitation pattern indicators can enable to assess whether the fishing gear is 74 well suited for a certain fishery. This approach has been widely used in selectivity studies 75 (Wienbeck et al, 2014;Brinkhof et al, 2020;Cheng et al, 2021;Herrmann et al, 2021). For 76 the demersal trawl targeting banded scad, however, there is no study address the exploitation 77 pattern.…”

Section: Introduction 34mentioning

confidence: 99%

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Size selection and exploitation pattern of diamond mesh codends with different mesh sizes in demersal trawl fishery for banded scad (Caranx (Atule) kalla) in the South China Sea

Yang

Herrmann

Liang

et al. 2021

Regional Studies in Marine Science

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Comparing the size selectivity of a novel T90 mesh codend to two conventional codends in the northern shrimp (Pandalus borealis) trawl fishery

Cited by 14 publications

References 27 publications

Comparing size selectivity and exploitation pattern of diamond-mesh codends for Southern velvet shrimp (Metapenaeopsis palmensis) in shrimp trawl fishery of the South China Sea

Comparing size selectivity and exploitation pattern of diamond-mesh codends for Southern velvet shrimp (Metapenaeopsis palmensis) in shrimp trawl fishery of the South China Sea

Effects of six codend meshes on the size selection of juvenile white croaker (Pennahia argentata) in demersal trawl fishery of the South China Sea

Size selection and exploitation pattern of diamond mesh codends with different mesh sizes in demersal trawl fishery for banded scad (Caranx (Atule) kalla) in the South China Sea

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