基于遗传算法的渔情预报HSI建模与智能优化

鱼类栖息地适宜性指数模型(HSI)基于鱼类分布与海洋环境之间存在的非线性关系而构建。然而,海洋环境因子之间存在着传统方法无法消除的相关性,导致获取的HSI参数较难准确表达环境因子与渔场之间的复杂关系。基于遗传算法(GA),自动消除海洋环境因子之间的相关性,构建了一种通用的鱼类HSI建模与智能优化框架(GeneHSI)。GeneHSI框架的核心是HSI建模空间向遗传算法空间的映射以及GA适应度函数的构建。该函数构建的思想是HSI预测的渔场概率与商业捕捞获取的渔场概率之间的累计误差值达到最小化。GeneHSI由待解问题构建、GA初始化和GA优化策略3部分组成。利用随机生成的标准化海洋环境数据与渔场概率数据,验证了GeneHSI模型框架的有效性。研究表明,GeneHSI能够有效优化HSI的建模并能自动获取HSI参数。不同限制条件下,遗传算法获取的HSI具有较大的差异,其中一般优化策略下获取的HSI参数最差;不等式、等式和上下界条件下,GeneHSI优化过程显著地更加合理,因此获取的HSI参数也更准确。此外,100、1000、5000和10000样本量下的优化建模表明,GeneHSI具有处理海量样本数据的能力。     

Standardizing fishery-dependent catch and effort data in complex fisheries with technology change

Standardization of commercial catch and effort data is important in fisheries where standardized abundance indices based on fishery-dependent data are a fundamental input to stock assessments. The goal of the standardization is then to minimize bias due to the confounding of apparent abundance patterns with fishing power. There is a high risk of confounding between fishing power and abundance in fisheries where the fleet has altered their fishing technology over the years. Also, the spatial aspects and the fishing history can be so heterogeneous that any standardization really involves an extrapolation, for example to a hypothetical standard vessel. When the standardization involves an extrapolation, then the appropriate modeling strategy is to build a so-called estimation model, rather than a predictive model. Strategies to build such an estimation model from fishery-dependent data include: pay careful attention to subject matter, and collect information about potential confounding effects to include in the model (putting a high value on the acquisition of data on covariates); model variable catchability at a highly disaggregated scale; aim for realistic coefficients when fitting the model and pay relatively less attention to achieving precision or maximizing explained variance; adopt modern statistical methods to combine data from different sources; and if data are deficient, then apply precautionary allowances. These strategies offer some protection against bias due to confounding, in the absence of formal criteria for identifying the best model.     

Improving Fishing Pattern Detection from Satellite AIS Using Data Mining and Machine Learning

A key challenge in contemporary ecology and conservation is the accurate tracking of the spatial distribution of various human impacts, such as fishing. While coastal fisheries in national waters are closely monitored in some countries, existing maps of fishing effort elsewhere are fraught with uncertainty, especially in remote areas and the High Seas. Better understanding of the behavior of the global fishing fleets is required in order to prioritize and enforce fisheries management and conservation measures worldwide. Satellite-based Automatic Information Systems (S-AIS) are now commonly installed on most ocean-going vessels and have been proposed as a novel tool to explore the movements of fishing fleets in near real time. Here we present approaches to identify fishing activity from S-AIS data for three dominant fishing gear types: trawl, longline and purse seine. Using a large dataset containing worldwide fishing vessel tracks from 2011–2015, we developed three methods to detect and map fishing activities: for trawlers we produced a Hidden Markov Model (HMM) using vessel speed as observation variable. For longliners we have designed a Data Mining (DM) approach using an algorithm inspired from studies on animal movement. For purse seiners a multi-layered filtering strategy based on vessel speed and operation time was implemented. Validation against expert-labeled datasets showed average detection accuracies of 83% for trawler and longliner, and 97% for purse seiner. Our study represents the first comprehensive approach to detect and identify potential fishing behavior for three major gear types operating on a global scale. We hope that this work will enable new efforts to assess the spatial and temporal distribution of global fishing effort and make global fisheries activities transparent to ocean scientists, managers and the public.     

Survival analysis with time-varying regression effects using a tree-based approach

Nonproportional hazards often arise in survival analysis, as is evident in the data from the International Non-Hodgkin's Lymphoma Prognostic Factors Project. A tree-based method to handle such survival data is developed for the assessment and estimation of time-dependent regression effects under a Cox-type model. The tree method approximates the time-varying regression effects as piecewise constants and is designed to estimate change points in the regression parameters. A fast algorithm that relies on maximized score statistics is used in recursive segmentation of the time axis. Following the segmentation, a pruning algorithm with optimal properties similar to those of classification and regression trees (CART) is used to determine a sparse segmentation. Bootstrap resampling is used in correcting for overoptimism due to split point optimization. The piecewise constant model is often more suitable for clinical interpretation of the regression parameters than the more flexible spline models. The utility of the algorithm is shown on the lymphoma data, where we further develop the published International Risk Index into a time-varying risk index for non-Hodgkin's lymphoma.     

台风灾害下海岸带城市社会-生态系统脆弱性评估——大数据视角

2016年莫兰蒂台风对厦门城市社会-生态系统造成重创,该系统在灾害影响下的脆弱性成为亟待研究的重要问题。基于新浪微博平台进行大数据挖掘,结合统计年鉴及空间基础数据,建立台风灾害影响下基于暴露-敏感-应对-恢复力体系的海岸带城市社会-生态系统脆弱性指标体系,评估灾前灾后台风对厦门不同地区的影响;同时根据微博大数据的定位信息,对不同受灾信息进行灾情跟踪及分析,结果表明,在本次台风灾害中思明、湖里区表现出的脆弱性较低,而海沧、集美区表现出的脆弱性较高,主要是由于思明、湖里区的应对能力明显高于其他各区,从大数据显示的恢复情况来看,除海沧区外,其他三区在电力方面的恢复速度都较为迅速。研究成果能够为台风灾害背景下的城市脆弱性评价提供新的方法与技术,为灾前防治、灾后恢复提供决策参考。     

Using rapid assessment and demographic methods to evaluate the effects of fishing on Heterodontus portusjacksoni off far-eastern Victoria, Australia

A rapid semi-quantitative ecological risk assessment method (productivity and susceptibility analysis) indicated that, despite its low biological productivity, the Port Jackson shark Heterodontus portusjacksoni is at low risk to all fishing methods in far-eastern Victoria, Australia, under the present fishing practices, because of its low catch susceptibility. The risk to this population, however, would increase if the shark gillnet fishery operating in the region were to retain the species as a by-product. Demographic analysis indicated that the species has medium intrinsic population growth rate and potential rebound in comparison with other chondrichthyan species, juveniles have higher elasticity than mature females and both juvenile and mature females have higher elasticities than hatchlings. Because of its low biological productivity and moderate resilience to the effects of fishing, cautious management measures will be necessary to ensure the sustainable use of H. portusjacksoni if its marketing increases in the future. Information on the dynamics of a population that is valuable to provide management advice can be obtained through demographic methods, but rapid assessment methods can also provide complementary information on the effects of fishing by considering the catch susceptibility of the population to each fishing method.     

Valid historical data for probabilistic risk analysis in natural disasters

With the changes in the nature and the society, risks will inevitably change. It implies that, with the passage of time, some historical data would be invalid for probabilistic risk analysis. In this paper, a model to acquire the valid data is suggested, which is based on the Mann- Kendall test to detect abrupt change-point on time series data. What's more, the typhoon risk analysis in Guangdong Province, China is used as a case study to show how to apply the model. The valid data of the intensities of typhoons and the related losses in the province for the probabilistic risk analysis is obtained from the data during the time from 1984 to 2012. Comparing with the results based on the set of invalid data and the set of all collected data, the assessed risk based on the valid data is more reliable, which could reflect the dynamics of the typhoon risk.     

Regional Ecological Risk Assessment of a Near Shore Marine Environment: Cherry Point,WA

We conducted a regional ecological risk assessment for a near shore marine environment in northwestern Washington State using the Relative Risk Model. The objectives of this study were threefold: (1) to analyze cumulative impacts from multiple sources of chemical and non-chemical stressors in the near shore region and upland watersheds of Cherry Point (2) to determine the utility of Monte Carlo type uncertainty analysis in a rank-based regional risk assessment and (3) to investigate the effects of model habitat characterization on risk estimates. We used geographic information systems to compile and compare spatial data to determine ranks for sub-regions within the study area. By quantitatively combining ranks with exposure and effects filters, we estimated total relative risk between sub-regions and relative contributions of stressors. Finally, we used Monte Carlo analysis and an alternative ranking scheme to evaluate the effects of model and parameter uncertainty on risk predictions. The regional risk assessment results suggest the major contributors of risk are vessel traffic, upland urban and agricultural land use and shoreline recreational activities. This assessment demonstrated the applicability of regional risk assessment to marine near shore regions and the benefit of Monte Carlo analysis in describing uncertainty in a Relative Risk Model regional risk assessment.     

南极半岛北部南极磷虾渔业空间点格局特征

南极磷虾作为南极生态系统中的关键物种,在空间分布上常表现出集群特征.这也反映到磷虾渔业生产的空间格局特征上.为了探讨捕捞能力有明显差异的船队在高/低单位捕捞努力量渔获量(CPUE)的情况下空间点分布格局特征及其生态学效应,基于南极半岛北部海域的两艘中国南极磷虾渔船(船A为专业南极磷虾渔船,船B为在智利竹筴鱼渔场与南极磷虾渔场转换的兼作渔船)的磷虾渔业数据,从空间点格局的角度出发,分别从两船的高、低CPUE的空间点格局在不同尺度上聚集特征,高、低CPUE在不同尺度上的二元点格局相关关系,以及CPUE点标记格局下的相关性关系等3个方面进行了分析.Ripley的L函数和标记相关函数分析结果表明: 研究对象在空间窗口所有尺度上的空间格局均表现为聚集性,高、低CPUE下均有聚集发生;在15 km尺度上,聚集强度近最大,在15~50 km尺度下,聚集程度稳定;总体上点格局分布的聚集强度依次为:船A高CPUE>船B低CPUE>船B高CPUE>船A低CPUE.船A高、低CPUE在0~75 km尺度上为正相关关系,在大于75 km尺度上为随机关系;船B在所有尺度上的高、低CPUE均为正相关,说明了低CPUE点事件伴随高CPUE的点事件同步发生,两者在大部分尺度下均显著相关.这是磷虾集群模式的动态性和复杂性造成.船A各点的CPUE值在0~44 km尺度上呈正相关,在44~80 km尺度上呈负相关;船B各点的CPUE值在50~70 km尺度上呈负相关,在其他尺度上无显著相关性;正相关反映了磷虾密集集群的种群分布特性,而负相关表明了磷虾群间由于食物和空间原因存在一定的竞争关系.捕捞能力强的船A和捕捞能力较弱的船B在点格局分布上存在较大差异.专业南极磷虾渔船更适于开展磷虾作业空间点格局分析及相关科学调查工作.     

Pavement model in Internet of intelligences and applications in risk analysis online

In this article, I suggest a model to study the risk issue that can be mapped into a query on how to pass a road safely. The model is called the pavement model, which can be used in the Internet of intelligences. The model has three components: object, value of success or failure, and duration of the value. An object is mapped into a section of road, the value is defined by the truth value of success or failure passing the road, and the duration represents the number of parts with the value in the session. The case of choosing milk powder shows that the model can perfectly integrate childcare experiences to be a rank that indicates which milk powder should be the first choice and which milk powder is not recommended to buy. The case of assessing typhoon risk shows that the model can dynamically assess typhoon risks with respect to different months and landing situations.     

Fishing,reproductive volume and regulation: population dynamics and exploitation of the eastern Baltic cod

The relative importance of exploitation rate and environmental variability in generating fluctuations of harvested populations is a key issue in academic ecology as well as population management. We studied how the eastern Baltic cod (Gadus morhua) is affected by fishing and environmental variation by using a newly developed single species state-space model. Survey data and auxiliary environmental data were used to estimate the model parameters. The model was then used to predict future development of the eastern Baltic cod under different fishing mortalities and abiotic conditions. Abiotic condition was represented by an index: reproductive volume which is the volume of water suitable (in terms of salinity and oxygen content) for the successful development of the early life stages of Baltic cod. The model included direct density dependence, fishing, and a lagged effect of reproductive volume. Our analysis showed that fishing rate is approximately three times more important than reproductive volume in explaining the population dynamics. Furthermore, our model suggests either under- or over-compensatory dynamics depending on the reproductive volume and long term catch levels. It follows that fishing can either reduce or increase temporal oscillations of the cod stock depending on whether the dynamics is over- or undercompensatory, respectively. The sustainable level of fishing rate is however dependent on reproductive volume. Our model predicts a dual role of fishing rate, stabilizing when reproductive volume is high and destabilizing when it is low. Exploitation rate may therefore increase or decrease the risk of the population of cod dropping below a given biomass reference point depending on the environmental conditions, which has practical implications for fisheries management.     

Enforcement Co-operation between Norway and Russia in the Barents Sea Fisheries

This article measures the Indonesian legal framework governing fishing vessel registration and fishing vessel licensing against the relevant international fisheries instruments. It is argued that the current Indonesian regulatory framework for vessel registration and licensing is not adequate to implement Indonesia's obligations under international fisheries instruments to combat illegal, unregulated, and unreported (IUU) fishing.     

A Regional Ecological Risk Assessment of the Kaipara Harbour,New Zealand,Using a Relative Risk Model

A regional ecological risk assessment was conducted for the Kaipara Harbour catchment in New Zealand. The Relative Risk Model was used to prioritize management of the sources of stress and habitats of concern in the basin. Semi-structured interviews with 25 representative stakeholders were conducted to obtain the resource-users’ perspectives and to identify the regional stressor sources and receptor habitat data for the model. For this risk analysis we divided the catchment into nine ecological districts. Mixed-methodological approaches including content analysis, geospatial analysis, and source documentation were used to categorize source and habitat rankings, based on the relative abundance of each in the nine ecological districts. Risk characterization revealed that fishing pressure and tidal energy pose the largest sources of perceived risk to the catchment; shellfish and Maui dolphin habitats are the receptors estimated to be at greatest risk; and the Kaipara and Rodney ecological districts are the sub-regions estimated with the greatest combined risk. A Monte Carlo analysis confirmed the source inputs and revealed greater uncertainty than the estimated habitat input results. The results of this assessment can be used by policy-makers, conservation groups, and municipalities to inform the future management efforts in the harbor and catchment.     

Real-time detection of vessel diameters with ultrasound.

Transcutaneous vessel imaging is a frequently used ultrasound imaging modality in medicine. The measurement of vessel diameters can be done with conventional B-mode imaging systems, which work at frame rates up to 100 Hz. Furthermore, there are special systems available, which can track vessel walls very precisely using the phase of signals that are sent at frame rates up to several thousand Hz. Though, such systems are usually not able to provide the examiner with 2D images of the object. With respect to brachial artery flow-mediated vasodilatation (FMD), which is frequently used as a measure of endothelial function, it is necessary to observe diameter changes of small arterial vessels noninvasively for several minutes at a high resolution. In the past, the diameter had to be measured manually in tedious postprocessing of ECG-gated image sequences. We developed a system composed of a Siemens Omnia ultrasound system with a VF13-5 transducer (9 MHz center frequency) and a personal computer, that is capable of calculating vessel diameter changes with an accuracy below the wavelength of the ultrasound system in real-time at a frame rate of 27 Hz. We implemented a two-dimensional active contour model using the Viter-bi-algorithm and a phase-sensitive vessel wall tracking algorithm, in order to guarantee both, geometric information and accuracy. Results from carotid and brachial arteries show that arterial pulsations below 0.1 mm can be visualized reliably over several minutes. With this system we want to find out, if FMD is suitable for an individual assessment of the risk for cardiovascular diseases.     

Preliminary stock assessment of the Patagonian toothfish longline fishery around the Falkland Islands

An experimental fishery for Patagonian toothfish Dissostichus eleginoides was opened in Falkland Island waters briefly in 1992 and then from April 1994. One to two longlines per vessel were usually deployed at night, mostly fishing for 12–30 h at depths between 600 and 2000 m. The characteristics of the vessel, gear, fishing activities and the data collection and analyses methods are described. An initial evaluation of the authors' current understanding of toothfish biology and population dynamics in Falkland Island waters is given. A first analysis of toothfish numbers caught in 1994 suggests that these are changing at rates faster than expected from simple demographic processes. Therefore, despite an intensive monitoring of catch and fishing effort of each vessel, it is still not possible to derive reliable estimates for the size of the toothfish population currently exploited around the Falkland Islands. Migration patterns in and out of the fishery need to be understood before a reliable assessment of the fishery can be made. These results, together with current and future lines of research, are discussed in the light of data available from other toothfish fisheries in austral waters.     

Scenario-Based Multi-Objective Optimum Allocation Model for Earthquake Emergency Shelters Using a Modified Particle Swarm Optimization Algorithm: A Case Study in Chaoyang District,Beijing, China

The correct location of earthquake emergency shelters and their allocation to residents can effectively reduce the number of casualties by providing safe havens and efficient evacuation routes during the chaotic period of the unfolding disaster. However, diverse and strict constraints and the discrete feasible domain of the required models make the problem of shelter location and allocation more difficult. A number of models have been developed to solve this problem, but there are still large differences between the models and the actual situation because the characteristics of the evacuees and the construction costs of the shelters have been excessively simplified. We report here the development of a multi-objective model for the allocation of residents to earthquake shelters by considering these factors using the Chaoyang district, Beijing, China as a case study. The two objectives of this model were to minimize the total weighted evacuation time from residential areas to a specified shelter and to minimize the total area of all the shelters. The two constraints were the shelter capacity and the service radius. Three scenarios were considered to estimate the number of people who would need to be evacuated. The particle swarm optimization algorithm was first modified by applying the von Neumann structure in former loops and global structure in later loops, and then used to solve this problem. The results show that increasing the shelter area can result in a large decrease in the total weighted evacuation time from scheme 1 to scheme 9 in scenario A, from scheme 1 to scheme 9 in scenario B, from scheme 1 to scheme 19 in scenario C. If the funding were not a limitation, then the final schemes of each scenario are the best solutions, otherwise the earlier schemes are more reasonable. The modified model proved to be useful for the optimization of shelter allocation, and the result can be used as a scientific reference for planning shelters in the Chaoyang district, Beijing.     

Assessing the port to port risk of vessel movements vectoring non-indigenous marine species within and across domestic Australian borders

Biofouling of vessels is implicated as a high risk transfer mechanism of non-indigenous marine species (NIMS). Biofouling on international vessels is managed through stringent border control policies, however, domestic biofouling transfers are managed under different policies and legislative arrangements as they cross internal borders. As comprehensive guidelines are developed and increased compliance of international vessels with 'clean hull' expectations increase, vessel movements from port to port will become the focus of biosecurity management. A semi-quantitative port to port biofouling risk assessment is presented that evaluates the presence of known NIMS in the source port and determines the likelihood of transfer based on the NIMS association with biofouling and environmental match between source and receiving ports. This risk assessment method was used to assess the risk profile of a single dredge vessel during three anticipated voyages within Australia, resulting in negligible to low risk outcomes. This finding is contrasted with expectations in the literature, specifically those that suggest slow moving vessels pose a high to extreme risk of transferring NIMS species.     

Consumption of deep-sea shrimp by bigeye flounder Hippoglossina macrops in fishing grounds off northern Chile

Feeding of the bigeye flounder Hippoglossina macrops on the shrimp Heterocarpus reedi was analysed between 20 November and 4 December 1995. Feeding on H. reedi intensified between 0900 and 1600 hours with a second, smaller peak between 2300 and 0200 hours. Assuming an exponential gastric evacuation model, the gastric evacuation rate was estimated as 0·197 % W h ⁻¹ (95% CI=0·025–0·369). The daily ration decreased latitudinally from north to south from 3·62 to 2·66 and from 2·06 to 0·41 %W , respectively. Consumption was related positively to shrimp biomass and influenced by flounder size structure in the three fishing zones analysed and was estimated as 0·08–0·02% of the total shrimp biomass.     

Prevalence and Correlates of HIV and Hepatitis C Virus Infections and Risk Behaviors among Malaysian Fishermen

Fishermen in Southeast Asia have been found to be highly vulnerable to HIV, with research evidence highlighting the role of sexual risk behaviors. This study aims to estimate the rate of HIV as well as hepatitis C virus (HCV) infections among Malaysian fishermen, and the risky sexual and injection drug use behaviors that may contribute to these infections. The study also includes an assessment of socio-demographic, occupational and behavioral correlates of testing positive for HIV or HCV, and socio-demographic and occupational correlates of risk behaviors. The study had a cross-sectional design and recruited 406 fishermen through respondent-driven sampling (RDS). Participants self-completed a questionnaire and provided biological specimens for HIV and HCV testing. We conducted and compared results of analyses of both unweighted data and data weighted with the Respondent-Driven Sampling Analysis Tool (RDSAT). Of the participating fishermen, 12.4% were HIV positive and 48.6% had HCV infection. Contrary to expectations and findings from previous research, most fishermen (77.1%) were not sexually active. More than a third had a history of injection drug use, which often occurred during fishing trips on commercial vessels and during longer stays at sea. Of the fishermen who injected drugs, 42.5% reported unsafe injection practices in the past month. Reporting a history of injection drug use increased the odds of testing HIV positive by more than 6 times (AOR = 6.22, 95% CIs [2.74, 14.13]). Most fishermen who injected drugs tested positive for HCV. HCV infection was significantly associated with injection drug use, being older than 25 years, working on a commercial vessel and spending four or more days at sea per fishing trip. There is an urgent need to strengthen current harm reduction and drug treatment programs for Malaysian fishermen who inject drugs, especially among fishermen who work on commercial vessels and engage in deep-sea fishing.