Stock Status Estimating of 5 Shark Species in the Waters Around Taiwan Using a Length-Based Bayesian Biomass Estimation (LBB) Method

Ju, Peilong; Chen, Mingru; Tian, Yongjun; Zhao, Yu; Shen, Yang; Xiao, Jiamei

doi:10.3389/fmars.2020.00632

Cited by 12 publications

(10 citation statements)

References 33 publications

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“…Most coastal fish populations in China cannot be evaluated comprehensively because of a lack of data (Liang et al, 2020). However, the LBB method can effectively evaluate the population with limited LF data (Ju et al, 2020a;Liang et al, 2020;Zhang et al, 2020Zhang et al, , 2021. The stock status was given in the LBB model based on the parameter B/B MSY , which had been described in detail in previous studies (Froese et al, 2018;.…”

Section: Discussionmentioning

confidence: 99%

“…It was considered that the resources of 80% of the species assessed were overfished. According to Ju et al (2020a), 80% of the five shark stocks living around Taiwan, South China Sea, were overfished; Zhang et al (2020) evaluated 20 stock resources in Min River Estuary and found that 65% of the stock was overfished. The results of this study are consistent with these reports indicate most fish living in the South China Sea are facing overfishing pressures (Table 4).…”

Section: Discussionmentioning

confidence: 99%

“…If the parameter of the 95th percentile length to asymptotic length L 95th /L inf is close to one (>0.9), this suggests that there are at least some large fish in this region. The stock status was evaluated according to the estimated value of B/B MSY , showed in Table 2 (Froese et al, 2018;Palomares et al, 2018;Ju et al, 2020a;Liang et al, 2020;.…”

Section: General Description Of the Lbb Methodsmentioning

confidence: 99%

“…Recently, two methods have been applied to the assessment of fishery resources in China. One is the maximum sustainable yield (MSY) model, which uses a time series of catch and auxiliary data to estimate the MSY (Ju et al, 2020b;Liang et al, 2020;Zhai et al, 2020); The other is the length-based Bayesian biomass (LBB) model, which uses length frequency (LF) data to estimate asymptotic length, length at first capture, relative natural mortality and relative fishing mortality (Ju et al, 2020a;Kindong et al, 2020;Liang et al, 2020;Zhang et al, 2020Zhang et al, , 2021. Size measurement is the basic requirement for marine fishery resource surveys in China (Jin et al, 2012), and LF data are usually easier to obtain and cheaper than other data types (Liang et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Stock Assessment of 19 Perciformes in the Beibu Gulf, China, Using a Length-Based Bayesian Biomass Method

et al. 2021

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The Beibu Gulf in China is rich in fish resources. However, only a small number of commercially developed fish stocks have been specifically assessed owing to limited data and expertise. In this study, 19 perciform fish populations in the Beibu Gulf were assessed using a length-based Bayesian biomass (LBB) estimator method, which is a new approach to evaluate a fishery’s status using length frequency (LF) data. The results showed that only 21% of the evaluated stocks were healthy and 79% were overfished. In particular, 26 and 21% of the assessed species had collapsed and were grossly overfished, respectively. Only 11 and 21% of the assessed species were slightly overfished and overfished, respectively. The ratios between the mean and optimum length (Lmean/Lopt) and between the mean length at first capture and the mean length, which maximizes catch and biomass (Lc/Lc_opt), were below one in 14 out of the 19 stocks, suggesting a truncated length structure and fishing of undersized individuals. The ratio of the 95th percentile length to asymptotic length L95th/Linf was close to one (>0.9) in 10 of 19 stocks, suggesting that at least some large fish were still present. Our research confirmed that the fishery resources in the Beibu Gulf were seriously overfished and provided evidence that LBB was an efficient method to evaluate the fishery resources. Fishery managers need to take specific measures to restore fishery resources.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: General Description Of the Lbb Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Stock Assessment of 19 Perciformes in the Beibu Gulf, China, Using a Length-Based Bayesian Biomass Method

et al. 2021

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“…Pacific Spadenose Sharks' habit of occupying nearshore areas also render them more susceptible to other anthropogenic activities, such as habitat degradation and pollution. A recent study using a length-based Bayesian biomass estimation method showed that the Pacific Spadenose Shark stock in the southern Taiwan Strait is grossly overfished (Ju et al 2020). In addition, it is mainly caught by the small-scale fisheries and there are no catch data available, which generates the necessity of estimating life history parameters for the population assessment (Lam 2009).…”

mentioning

confidence: 99%

Reproductive Biology of the Pacific Spadenose Shark Scoliodon Macrorhynchos, a Heavily Exploited Species in the Southern Taiwan Strait

Zhao

Jiang

et al. 2022

Mar Coast Fish

Self Cite

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The reproductive biology of the heavily exploited Pacific Spadenose Shark Scoliodon macrorhynchos was studied by examining 246 males and 197 females, including 64 gestational individuals, caught by semi-industrial fisheries using demersal trawling in the southern Taiwan Strait. Total length (L T ) at 50% maturity (L 50 ) was estimated at 464 mm L T for males and 429 mm L T for females. The annual reproductive cycle was determined based on the percentage of pregnant mature females and the concurrent vitellogenesis with embryonic development. Mating occurred from August to December, as evidenced by the presence of females with fresh mating injuries on their body surface and spermatozoa in the cloaca and uteri. The monthly change of embryo size indicated that parturition occurred between June and August after 5-6 months of gestation, with an L T of 190-218 mm at birth. The litter size, which ranged from 1 to 20 pups with a mean AE SD of 9.4 AE 3.9 pups (n = 64), was positively correlated with the maternal L T . Altogether, these findings provide valuable information that is needed for the adequate management and conservation of Pacific Spadenose Sharks in the southern Taiwan Strait and adjacent waters.

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Performance of length-based assessment in predicting small-scale multispecies fishery sustainability

Medeiros‐Leal

Santos

Peixoto

et al. 2023

Rev Fish Biol Fisheries

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Small-scale fisheries play a critical role in food security and contribute to nearly half of reported global fish catches. However, the status of most small-scale fisheries stocks is still poor. In data-limited situations, length-based methods have been widely applied to estimate reference points and to understand stock status. This study applied three different length-based assessment methods (length-based indicators—LBI, length-based spawning potential ratio—LBSPR, and the length-based Bayesian biomass approach—LBB) to predict fisheries stock sustainability in the Azores. Overall, the three methods showed robustness for 15 out of 18 stocks assessed and agreed on their exploitation status. The results showed that 45% of the Azorean stocks were classified as sustainable stocks, 33% possible rebuilding/overfished and 22% overfishing/overfished stock status. Sensitivity analysis showed that biases on the source of initial life-history parameters, especially the asymptotic length (L∞) and the ratio of natural mortality and growth coefficient (M/k), have a stronger influence on the reference points of conservation of mature individuals (LBI), spawning potential ratio and fishing mortality (LBSPR) and the biomass relative to the maximum sustainable yield (LBB). Furthermore, sensitivity analysis indicated that, among the three methods, LBI is more robust. Our findings provide some management recommendations such as (1) catches and effort should be reduced; (2) minimum landing size should be increased; (3) minimum hook size should be increased, to be applied mainly for those stocks classified as possible rebuilding/overfished and overfishing/overfished stock status. Graphical abstract

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Stock Status Estimating of 5 Shark Species in the Waters Around Taiwan Using a Length-Based Bayesian Biomass Estimation (LBB) Method

Cited by 12 publications

References 33 publications

Stock Assessment of 19 Perciformes in the Beibu Gulf, China, Using a Length-Based Bayesian Biomass Method

Stock Assessment of 19 Perciformes in the Beibu Gulf, China, Using a Length-Based Bayesian Biomass Method

Reproductive Biology of the Pacific Spadenose Shark Scoliodon Macrorhynchos, a Heavily Exploited Species in the Southern Taiwan Strait

Performance of length-based assessment in predicting small-scale multispecies fishery sustainability

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