Fish by-catch in shrimp beam trawls in the northern South China Sea

Yang, Bingzhong; Lan, Yang; Zhang, P.; Tan, Y.-G.; Liang, Yan; Chen, Shuai

doi:10.1111/jai.12777

Cited by 10 publications

(8 citation statements)

References 7 publications

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“…Falling nets are a type of fishing gear that appeared and developed rapidly in the northern South China Sea in the early 1990s [9]. Falling-net fishing mainly aims to catch cephalopods and phototactic fishes.…”

Section: Introductionmentioning

confidence: 99%

Analysis of catch rates of LED lamps using on the falling-net fishing vessels in South China Sea

Wang,

Chen,

Xiong

et al. 2024

PLoS ONE

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Falling nets are a type of fishing gear that appeared and developed rapidly in the northern of South China Sea in the early 1990s. We have developed Light-emitting diode (LED) fishing lamps to replace metal halide (MH) lamps that reduce fuel consumption without reducing the catches. We conducted marine light-fishing experiments in the northern South China Sea during September 20 to 26, 2019 and August 29 to 31, 2021. The results in the first fishing experiment show that there is no significant change in catch of the falling-net fishing vessel when the white LED lamps (with a total power of 36 kW) were used instead of MH lamps (with a total power of 120 kW). Coleoidea catches of the falling-net fishing vessel increased significantly when white LED lamps (with a total power of 36 kW) and cyan LED lamps (with a total power of 6.0 kW) were used. The results in the second fishing experiment show that the total weight of catches of the cyan LED fishing lamps is more than that of the white LED fishing lamps, and the cyan LED light can attract Penaeus merguiensis, Thryssa dussumieri and Sardinella zunasi more effectively than the white LED light.

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Section: Introductionmentioning

confidence: 99%

Analysis of catch rates of LED lamps using on the falling-net fishing vessels in South China Sea

Wang,

Chen,

Xiong

et al. 2024

PLoS ONE

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“…It contributes to the highest proportion of total fishing production. But like most trawl fisheries around the world, trawl fishery in the South China Sea is also characterized by high by-catch problems due to its poor selective properties [2][3][4][5]. The Beibu Gulf has long held its esteemed status as one of the South China Sea's pivotal fishing grounds, boasting an abundance of groundfish and even setting records for the highest catch rates in bottom trawling operations.…”

Section: Introductionmentioning

confidence: 99%

“…However, over the past decade, a concerning shift has unfolded, revealing a tale of overexploitation and the rampant depletion of fishery resources within the Beibu Gulf. The once-harmonious balance has been disrupted as fishing intensity among fishermen has surged beyond optimal thresholds, triggering an alarming decline in the region's marine biodiversity [1,[3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Size Selectivity of a Diamond-Mesh Codend of Demersal Trawl for Largehead Hairtail (Trichiurus lepturus Linnaeus, 1758) in the Beibu Gulf, in the South China Sea

Liang

Yang

Peng

et al. 2023

JMSE

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Experiments were conducted to assess the selectivity of diamond mesh codends in capturing largehead hairtail (Trichiurus lepturus) in the demersal trawl fishery of the Beibu Gulf, located in the South China Sea. The selectivity experiments involved four codends with different mesh sizes (30, 35, 40, and 45 mm), and the covered codend method was employed. Catch data were analyzed using the maximum likelihood method, with both Logistic and Richards curves fitted to the data, and the abundance–biomass comparison (ABC) curve method was used to analyze the impact of codend on fishery resources. Model deviance was compared with the degree of freedom to choose the best fit curve. The Logistic curves gave a better fit for the codends with 30 and 40 mm mesh sizes, while the Richards curves had a better fit for the codends with 35 and 45 mm mesh sizes, respectively. The 50% retention lengths (L50) and selection ranges (SR) were determined for 30 mm (L50: 11.40 cm; SR: 3.81 cm), 35 mm (L50: 11.65 cm; SR: 3.98 cm), 40 mm (L50: 12.92 cm; SR: 5.30 cm), and 45 mm (L50: 13.28 cm; SR: 4.14 cm) mesh codends. The results indicated that the present minimum mesh size, 40 mm diamond mesh, did not match with minimum landing size of largerhead hairtail, 190 mm anal. length. Based on the observed linear relationship between L50 and mesh opening, it was determined that the diamond mesh codend should be adjusted to a larger mesh opening of approximately 72.47 mm in order to achieve an L50 value of 190 mm. The ABC curve characteristics indicate that the fish community structure in the Beibu Gulf in the South China Sea is in a severely disturbed state. This study suggests that the square mesh codend and T90 codend (diamond mesh netting turned by 90 degrees) should be tested and compared with the diamond mesh codend, to obtain the optimal configuration and mesh size of the codend for demersal trawl fishery in the Beibu Gulf in the South China Sea.

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“…Due to small mesh sizes used, a serious bycatch problem was induced in shrimp trawl fisheries of the SCS ( Yang et al, 2015 ; Yang et al, 2017 ). It was reported that undersized fish and juvenile shrimp constituted the majority of the bycatch species.…”

Section: Introductionmentioning

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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Fish by-catch in shrimp beam trawls in the northern South China Sea

Cited by 10 publications

References 7 publications

Analysis of catch rates of LED lamps using on the falling-net fishing vessels in South China Sea

Analysis of catch rates of LED lamps using on the falling-net fishing vessels in South China Sea

Size Selectivity of a Diamond-Mesh Codend of Demersal Trawl for Largehead Hairtail (Trichiurus lepturus Linnaeus, 1758) in the Beibu Gulf, in 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

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