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9篇 您的检索式:作者名="Wenjiang Guan"
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1Application of a Bayesian method to data-poor stock assessment by using Indian Ocean albacore (Thunnus alalunga) stock assessment as an example显示文摘It is widely recognized that assessments of the status of data-poor fish stocks are challenging and that Bayesian analysis is one of the methods which can be used to improve the reliability of stock assessments in data-poor situations through borrowing strength from prior information deduced from species with good-quality data or other known information. Because there is considerable uncertainty remaining in the stock assessment of albacore tuna(Thunnus alalunga) in the Indian Ocean due to the limited and low-quality data, we investigate the advantages of a Bayesian method in data-poor stock assessment by using Indian Ocean albacore stock assessment as an example. Eight Bayesian biomass dynamics models with different prior assumptions and catch data series were developed to assess the stock. The results show(1) the rationality of choice of catch data series and assumption of parameters could be enhanced by analyzing the posterior distribution of the parameters;(2) the reliability of the stock assessment could be improved by using demographic methods to construct a prior for the intrinsic rate of increase(r). Because we can make use of more information to improve the rationality of parameter estimation and the reliability of the stock assessment compared with traditional statistical methods by incorporating any available knowledge into the informative priors and analyzing the posterior distribution based on Bayesian framework in data-poor situations, we suggest that the Bayesian method should be an alternative method to be applied in data-poor species stock assessment, such as Indian Ocean albacore.GUAN Wenjiang TANG Lin ZHU Jiangfeng TIAN Siquan XU Liuxiong 2016Acta Oceanologica Sinica2016,35,2:13
2A New model to forecast fishing ground of Scomber japonicus in the Yellow Sea and East China Sea显示文摘The pelagic species is closely related to the marine environmental factors, and establishment of forecasting model of fishing ground with high accuracy is an important content for pelagic fishery. The chub mackerel(Scomber japonicus) in the Yellow Sea and East China Sea is an important fishing target for Chinese lighting purse seine fishery. Based on the fishery data from China's mainland large-type lighting purse seine fishery for chub mackerel during the period of 2003 to 2010 and the environmental data including sea surface temperature(SST), gradient of the sea surface temperature(GSST), sea surface height(SSH) and geostrophic velocity(GV), we attempt to establish one new forecasting model of fishing ground based on boosted regression trees. In this study, the fishing areas with fishing effort is considered as one fishing ground, and the areas with no fishing ground are randomly selected from a background field, in which the fishing areas have no records in the logbooks. The performance of the forecasting model of fishing ground is evaluated with the testing data from the actual fishing data in 2011. The results show that the forecasting model of fishing ground has a high prediction performance, and the area under receiver operating curve(AUC) attains 0.897. The predicted fishing grounds are coincided with the actual fishing locations in 2011, and the movement route is also the same as the shift of fishing vessels, which indicates that this forecasting model based on the boosted regression trees can be used to effectively forecast the fishing ground of chub mackerel in the Yellow Sea and East China Sea.GAO Feng CHEN Xinjun GUAN Wenjiang LI Gang 2016Acta Oceanologica Sinica2016,35,4:5
3Linkages between the biomass of Scomber japonicus and net primary production in the southern East China Sea显示文摘Fish biomass is a critical component of fishery stock assessment and management and it is often estimated from ocean primary production(OPP). However, the relationship between the biomass of a fish stock and OPP is always complicated due to a variety of trophic controls in the ecosystem. In this paper, we examine the quantitative relationship between the biomass of chub mackerel(Scomber japonicus) and net primary production(NPP) in the southern East China Sea(SECS), using catch and effort data from the Chinese mainland large light-purse seine fishery logbook and NPP derived from remote sensing. We further discuss the mechanisms of trophic control in regulating this relationship. The results show a significant non-linear relationship exists between standardized CPUE(Catch-Per-Unit-Effort) and NPP(P<0.05). This relationship can be described by a convex parabolic curve, where the biomass of chub mackerel increases with NPP to a maximum and then decreases when the NPP exceeds this point. The results imply that the ecosystem in the SECS is subject to complex trophic controls. We speculate that the change in abundance of key species at intermediate trophic levels and/or interspecific competition might contribute to this complex relationship.GUAN Wenjiang CHEN Xinjun GAO Feng LI Gang 2014Acta Oceanologica Sinica2014,33,10:2
4Using Bayesian Bio-economic model to evaluate the management strategies of Ommastrephes bartramii in the Northwest Pacific Ocean显示文摘The neon flying squid(Ommastrephes bartramii)in the Northwest Pacific Ocean is one economically important cephalopod,largely exploited by squid jigging fleets from Chinese Mainland,Japan,and Chinese Taibei.In this study,a Bayesian Bio-economic model was developed using fishery data from Chinese Mainland,Japan,and Chinese Taibei,and relevant fishery economic data from Chinese Mainland.The stock assessment and risk analysis of alternative management strategies for O.bartramii were carried out.Three prior distributions(i.e.,uniform,normal and logarithmic normal)for model parameters were assumed in different scenarios.The results showed that the estimated model parameters and reference points such as maximum sustainable yield(MSY),maximum economic yield(MEY),bio-economic balance point(BE)and fishing mortality were similar in the scenarios of normal and logarithmic normal prior assumptions.However,the estimates were larger in the scenario of uniform prior assumption.The fishing mortalities and annual catches from 1996 to 2008 were lower than the reference points F_(0.1) and MSY in all the three scenarios,indicating that O.bartramii stock is at sustainable exploited level.The results of decision analysis indicated that under the same harvest rate,the catch and biomass in 2023 from the uniform assumption were the highest.However,the highest probability of the collapse was found for squid resources after 2023.Our findings suggested that the harvest rate of 0.4 appeared to be the best management regulation under the uniform assumption,and the MSY would be 200 thousand tons.In addition,the harvest rate of 0.5 would be the best management regulation under the other two assumptions,and the MSY would be 180 thousand tons,which balanced the desire for high yields and the healthy population.The results of this study could be used to provide management suggestions for neon flying squid in the Northwest Pacific Ocean.Jinli Liu Wei Yu Luoliang Xu Xinjun Chen Wenjiang Guan Gang Li 2021Aquaculture and Fisheries2021,6,2:1
5Evaluation of the performance of alternative assessment configurations to account for the spatial heterogeneity in age-structure: a simulation study based on Indian Ocean albacore tuna显示文摘Various population structures or spatial heterogeneities in population distribution have been an important source of model misspecification and have had an impact on estimation performance in fisheries stock assessment.In this study,we simulated the Indian Ocean albacore spatial heterogeneity in age-structure using Stock Synthesis according to the stage-dependent migration rate and region-dependent fishing mortality rate and generated the stock assessment data.Based on these data,we investigated the performances of different spatial configurations,selectivity curves and selections of CPUE(catch per unit effort)indices of the assessment models which were used to account for spatial heterogeneity.The results showed:(1)although the spatially explicit configurations,which exactly matched the operating model,provided unbiased and accurate estimates of relative spawning biomass,relative fishing mortality rate and maximum sustainable yield in all simulation scenarios,their performance may be very poor if there were mismatches between them and the operating model due to gaps in knowledge and data;(2)for spatially explicit assessment configuration,the correct boundary was required,but for non-spatially explicit assessment configuration,it seemed more important for analysts to partition the area to properly reflect the transition in field data and to effectively account for the impacts of ignoring the spatial structure by using the additional spatially referenced parameters;(3)although the areas-as-fleets methods and flexible time-varying selectivity curves could be used as better alternative approaches to account for spatial structure,these configurations could not completely eliminate the impacts of model misspecification and the quality of estimates of different quantities from the same assessment model may be inconsistent or the performance of the same assessment configuration may fluctuate significantly between simulation scenarios;(4)although the worst estimates could generally be avoided by using multiple CPUE indices,there were no best solutions to select or regenerate the CPUE indices to account for the impacts of the ignored spatial structure to obviously improve the quality of stock assessment.Compared with the results of assessment model configurations which are used to account for the spatial structure by different modelers,the performances of the configurations are always casespecific except for spatially explicit configurations which exactly match the operating model.In this sense,our study will not only provide some insights into the current Indian Ocean albacore stock assessment but also enrich existing knowledge regarding the performance of assessment configurations to account for spatial structure.Wenjiang Guan Jiawen Wu Siquan Tian 2019Acta Oceanologica Sinica2019,38,10:1
6An individual-based probabilistic model for simulating fisheries population dynamics显示文摘The purpose of stock assessment is to support managers to provide intelligent decisions regarding removal from fish populations.Errors in assessment models may have devastating impacts on the population fitness and negative impacts on the economy of the resource users.Thus,accuracte estimations of population size,growth rates are critical for success.Evaluating and testing the behavior and performance of stock assessment models and assessing the consequences of model mis-specification and the impact of management strategies requires an operating model that accurately describe the dynamics of the target species,and can resolve spatial and seasonal changes.In addition,the most thorough evaluations of assessment models use an operating model that takes a different form than the assessment model.This paper presents an individual-based probabilistic model used to simulate the complex dynamics of populations and their associated fisheries.Various components of population dynamics are expressed as random Bernoulli trials in the model and detailed life and fishery histories of each individual are tracked over their life span.The simulation model is designed to be flexible so it can be used for different species and fisheries.It can simulate mixing among multiple stocks and link stock-recruit relationships to environmental factors.Furthermore,the model allows for flexibility in sub-models(e.g.,growth and recruitment)and model assumptions(e.g.,age-or size-dependent selectivity).This model enables the user to conduct various simulation studies,including testing the performance of assessment models under different assumptions,assessing the impacts of model mis-specification and evaluating management strategies.Jie Cao Wenjiang Guan Samuel Truesdell Yong Chen Siquan Tian 2016Aquaculture and Fisheries2016,1,1:1
7Effects of RE on the microstructure and mechanical properties of Mg - 8Zn - 4Al magnesium alloy显示文摘Yingxin Wang Shaokang Guan Xiaoqin Zeng Wenjiang Ding 2006Materials Science and Engineering A2006,416,:1
8Simulation of the distribution,growth,and survival rate of chub mackerel larvae and juveniles in the East China Sea显示文摘In the East China Sea(ECS),chub mackerel Scomber japonicus constitutes an important coastal-pelagic fishery resource that is mainly exploited by Chinese,Japanese,and Korean light-purse seine fisheries.Because the early life history of chub mackerel plays a significant role in its recruitment,we developed an individual-based model to study the distribution,growth,and survival rate of chub mackerel larvae and juveniles in the ECS to improve our understanding of the chub mackerel population structure and recruitment.Our results show that as body length rapidly increases,the swimming capacity of chub mackerel larvae and juveniles improves quickly,and their spatial distribution depends more on their habitat conditions than the ocean currents.Correspondingly,the juveniles from the central and southern ECS spawning ground are scarcely recruited into the Japan/East Sea(JES)or the western Pacific Ocean,but a significant proportion of juveniles from the northern ECS spawning ground still enter the JES and there are exchanges between the stocks in the ECS and JES.Thus,it seems more reasonable to assess and manage the chub mackerels in the ECS and JES as a stock.The water temperature and ocean primary production in the ECS are two important factors influencing the chub mackerel habitat conditions and their spatial and temporal distribution are significantly different as the spawning time changes.Therefore,the spawning time and location play an important role in the growth and survival rate of the larvae and juveniles.Generally,when chub mackerel spawns at the southern ECS spawning ground in March,the larva and juvenile growth and survival rate is relatively high;as spawning time moves forward,higher growth and survival rates would be expected for the chub mackerel spawned coastward or northward.For specific spawning sites,early or delayed spawning will reduce the survival rate.Wenjiang GUAN Xuelian MA Weiwei HE Ruixing CAO 2023Journal of Oceanology and Limnology2023,41,4:0
9Simulation Study on the Interannual Variation of the Transport and Distribution of Chub Mackerel (Scomber japonicus) Larvae and Juveniles Using Individual-Based Model显示文摘An individual-based model of Scomber japonicus in the East China Sea(ECS)was developed to simulate the effects of physical environment on the transport and distribution of eggs,larvae and juveniles of S.japonicus from 1978 to 2013.The results showed that there were interannual differences in the transport and distribution of eggs,larvae and juveniles of S.japonicus in the ECS due to different physical environments from 1978 to 2013,and this difference was extremely obvious in some specific years.The current in the drift path of eggs and juveniles controlled and affected the transport process and distribution characteristics.In April,the distribution of eggs and larvae was mainly controlled by the Taiwan Warm Current(TWC).The number of eggs and larvae transported into the northeastern waters of the ECS was positively correlated with the intensity of TWC.In May,it was mainly regu-lated by the TWC and the Tsushima Strait Warm Current(TSWC).In June,the number of larvae and juveniles entering the Tsushima Strait and the Pacific Ocean was determined by the TSWC.In general,in the years with high number of larvae and juveniles into the Tsushima Strait,the catch of 0-year-old S.japonicus was also higher.In addition,the number of larvae and juveniles entering the Tsushima Strait in El Niño years was less than that in La Niña years.In July,the transport was mainly controlled by the Kuroshio Current(KC),and the eddy within the KC strongly affected its distribution.YU Wei FENG Zhiping PAN Lingzhi GUAN Wenjiang ZHANG Yu LI Yuesong 2022Journal of Ocean University of China2022,21,5:0
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