Does unreported catch lead to overfishing?

Catches are commonly misreported in many fisheries worldwide, resulting in inaccurate data that hinder our ability to assess population status and manage fisheries sustainably. Under‐reported catch is generally perceived to lead to overfishing, and hence, catch reconstructions are increasingly used to account for sectors that may be unreliably reported, including illegal harvest, recreational and subsistence fisheries, and discards. However, improved monitoring and/or catch reconstructions only aid in the first step of a fisheries management plan: collecting data to make inferences on stock status. Misreported catch impacts estimates of population parameters, which in turn influences management decisions, but the pattern and degree of these impacts are not necessarily intuitive. We conducted a simulation study to test the effect of different patterns of catch misreporting on estimated fishery status and recommended catches. If, for example, 50% of all fishery catches are consistently unreported, estimates of population size and sustainable yield will be 50% lower, but estimates of current exploitation rate and fishery status will be unbiased. As a result, constant under‐ or over‐reporting of catches results in recommended catches that are sustainable. However, when there are trends in catch reporting over time, the estimates of important parameters are inaccurate, generally leading to underutilization when reporting rates improve, and overfishing when reporting rates degrade. Thus, while quantifying total catch is necessary for understanding the impact of fisheries on businesses, communities and ecosystems, detecting trends in reporting rates is more important for estimating fishery status and setting sustainable catches into the future.     

Design standards for experimental and field studies to evaluate diagnostic accuracy of tests for infectious diseases in aquatic animals

Design and reporting quality of diagnostic accuracy studies (DAS) are important metrics for assessing utility of tests used in animal and human health. Following standards for designing DAS will assist in appropriate test selection for specific testing purposes and minimize the risk of reporting biased sensitivity and specificity estimates. To examine the benefits of recommending standards, design information from published DAS literature was assessed for 10 finfish, seven mollusc, nine crustacean and two amphibian diseases listed in the 2017 OIE Manual of Diagnostic Tests for Aquatic Animals. Of the 56 DAS identified, 41 were based on field testing, eight on experimental challenge studies and seven on both. Also, we adapted human and terrestrial‐animal standards and guidelines for DAS structure for use in aquatic animal diagnostic research. Through this process, we identified and addressed important metrics for consideration at the design phase: study purpose, targeted disease state, selection of appropriate samples and specimens, laboratory analytical methods, statistical methods and data interpretation. These recommended design standards for DAS are presented as a checklist including risk‐of‐failure points and actions to mitigate bias at each critical step. Adherence to standards when designing DAS will also facilitate future systematic review and meta‐analyses of DAS research literature.     

水产动物育种分析与管理系统的开发和应用

针对国内水产动物多性状选择育种研究处于起步阶段的现状,以BLUP遗传评定为核心的水产动物多性状复合育种技术体系为依托,结合国内水产动物育种项目研究,开发了一套适合大多数水产动物育种分析与项目管理的软件系统。该系统是在WindowsXP环境下利用MicrosoftSQLServer2000数据库和基于ObjectPascal语言的DelphiIDE工具开发完成的。主要包括6个功能模块:系统管理、基本信息、种质管理、性能管理、育种分析和销售管理等,覆盖整个育种项目周期,并对流程实行标准化,能够自动化完成种质和性能测定数据的管理、遗传参数估计、育种值计算和配种方案制定等主要工作。软件已经在中国对虾、大菱鲆和罗氏沼虾等育种项目中得到应用,其推广和应用能够有效提升行业的整体育种技术水平,推动我国水产动物育种工作的发展。     

Addressing Reproducibility in Cryopreservation,and Considerations Necessary for Commercialization and Community Development in Support of Genetic Resources of Aquatic Species

For the past six decades a repeated cycle of developing new cryopreservation protocols or simply reinventing them to counteract a lack of reproducibility has led to hundreds of published studies that have offered little to the establishment of a genetic resources community for aquatic species. This has hampered repository development and inhibited industrial application. Most protocols were developed without standardized approaches, leading to irreproducible studies and questionable or meaningless comparisons. Thus cryopreservation of germplasm in aquatic species would greatly benefit from strategies to facilitate reproducibility. Our objectives were to: (1) identify major sources of irreproducibility across research, small‐scale, repository, and commercial‐scale development levels; (2) provide recommendations to address reproducibility challenges; and (3) offer suggestions on how researchers can directly influence commercial development and application of cryopreservation research. Sources of irreproducibility include lack of standardized procedural approaches, lack of standardized terminology, and lack of reporting guidelines. To address these challenges, we propose implementation of standard operating procedures, support of stock centers and internet content for development of training programs, and strengthening of the role of scientific journals and reviewers in reducing the frequency of irreproducible outcomes. Reproducibility is the foundation for quality management programs and product reliability, and therefore, standardization is necessary to assure efficient transition to commercial‐scale application and repository development. Progress can only be possible through community‐based approaches focused on coalescence and consensus of disparate groups involved in aquatic species cryopreservation and management of genetic resources.     

Developing a standard approach for assessing the hydromorphology of lakes in Europe

相似文献   

Evaluation of juvenile salmon behavior at Bonneville Dam,Columbia River,using a multibeam technique

In recent years, with increased effort to bypass and guide fragile stocks of juvenile salmon in the Columbia Basin past hydroelectric projects, it has been increasingly important to obtain fine-scale fish behavior data in a non-intrusive manner. The Dual-Head Multibeam Sonar is an emerging technology for fisheries applications that addresses that requirement. It has two principal advantages over traditional hydroacoustic techniques: 1) it allows for simultaneous large-volume coverage of a region of interest, and 2) it affords three-dimensional tracking capability. The use of Dual-Head Multibeam Sonar in this study resulted in an unprecedented insight into fine-scale smolt behavior upstream of a prototype surface collector at the Bonneville Dam first powerhouse in 1998. Our results indicated that outmigrant juvenile salmon had an increased likelihood of milling or holding. This discovery will lead to better design criteria for future bypass and collector systems. Future fisheries multibeam sonar systems will likely be fully integrated systems with built-in real-time tracking capability. These systems may be used to track targets relative to physical guidance structures or other behavior-modifying stimuli such as light, turbulent flow, electrical/magnetic fields, or low-frequency sound and vibration. The combination of fine-scale fish behavior data and environmental parameters will yield better design criteria for the safe passage of listed or endangered species of Pacific salmon.     

Reforming Wakame Aquaculture in Japan with Relaxed Processing Standards: From Consumer and Producer Viewpoints

This study investigated potential production reforms of wakame aquaculture in Japan through modification of processing standards. The research focused on the destemming process and examined both the consumers’ and producers’ perspectives. An auction experiment was conducted to measure consumer preferences for wakame with different destemming standards (1, 4, 7, and 10 mm). It was found that, although consumer preferences were diverse, there was no preference between the present (1-mm) and 4-mm standards. In addition, a production experiment was used to measure the amount of labor that could be saved (and thereby the improvement in profit) by relaxing the standard from 1 mm to 4 mm. It was concluded that this new standard would increase productivity by 13.3% without affecting consumer demand, which will improve the structure of this industry for competition against cheaper foreign products.     

Barriers to biodiversity conservation in marine fishery certification

Two global certification and ecolabelling systems – the generic global dolphin‐safe ecolabel and the global Marine Stewardship Council (MSC) ecolabel – are assessed for their present and potential contributions to improving biodiversity conservation in marine capture fisheries. The dolphin‐safe ecolabel appears to have played a minor role in a reduction of dolphin mortality in tuna fisheries, but dolphin populations in the worst‐affected area have not recovered, and it appears that the current level of dolphin by‐catch sanctioned by present‐day fishery management and the ecolabel is not effective enough to achieve population recovery. The MSC ecolabel has established a poorly expressed environmental standard that has resulted in variable interpretations by certifiers, creating an apparently systematic bias in application of the standard to the certified fisheries. Without substantial revision of both these systems, it seems unlikely that they will be able to make major contributions to marine biodiversity conservation because of barriers created by limitations in programme design, lack of robust linkages between the certification standard and biodiversity conservation outcomes, and unclear standards and their inconsistent application in the certification of fisheries.     

A feed is only as good as its ingredients – a review of ingredient evaluation strategies for aquaculture feeds

The evaluation of feed ingredients is crucial to nutritional research and feed development for aquaculture species. In evaluating ingredients for use in aquaculture feeds, there are several important knowledge components that should be understood to enable the judicious use of a particular ingredient in feed formulation. This includes information on (1) ingredient digestibilities, (2) ingredient palatability and (3) nutrient utilization and interference. Diet design, feeding strategy, faecal collection method and method of calculation all have important implications on the determination of the digestible value of nutrients from any ingredient. There are several ways in which palatability of ingredients can be assessed, usually based on variable inclusion levels of the ingredient in question in a reference diet and feeding of those diets under an apparent satietal or self‐regulating feeding regimes. However, the design of the diets, the parameters of assessment and the feeding regime can all be subject to variation depending on subtleties of the experimental design. Clearly, issues relating to feed intake are the key performance criteria in palatability assessments, and it is important that such experiments maintain sufficient stringency to allow some self‐discrimination of the test feeds by the fish. The ability of fish to use nutrients from the test ingredient, or defining factors that interfere with that process, is perhaps the most complex and variable part of the ingredient evaluation process. It is crucial to discriminate effects on feed intake from effects on utilization of nutrients from ingredients (for growth and other metabolic processes). To allow an increased focus on nutrient utilization by the animals, there are several experimental strategies that can be adopted, which are based on variations in diet design and feeding regime used. Other issues such as ingredient functionality, influence on immune status and effects on organoleptic qualities are also important consideration in determining the value of ingredients in aquaculture feed formulations. A key aspect to note is the need to design all experiments with sufficient experimental capacity to detect significant effects.     

Are fishers poor? Getting to the bottom of marine fisheries income statistics

Fishers’ economic status is hard to assess because fisheries socio‐economic data, including earnings, are often not centrally available, standardized or accessible in a form that allows scaled‐up or comparative analyses. The lack of fishing income data impedes sound management and allows biased perceptions about fishers’ status to persist. We compile data from intergovernmental and regional data sets, as well as case‐studies, on income earned from marine wild‐capture fisheries. We explore the level and distribution of fishers’ income across fisheries sectors and geographical regions, and highlight challenges in data collection and reporting. We find that fishers generally are not the poorest of the poor based on average fishing income from 89 countries, but income levels vary widely. Fishing income in the large‐scale sector is higher than the small‐scale sector by about 2.2 times, and in high‐income versus low‐income countries by almost 9 times. Boat owners and captains earned more than double that of crew and owner‐operators, while income from fisheries is greater than that from agricultural work in 63% of countries in this study. Nonetheless, incomes are below national poverty lines in 34% of the countries with data. More detailed fishing income statistics is needed for quantitative scientific research and for supporting socio‐economic policies. Key gaps to address include the lack of a centralized database for fisheries income statistics and the coarse resolution at which economic statistics are reported internationally. A first step to close the gap is to integrate socio‐economic monitoring and reporting in fisheries management.     

Development of a modified cortisol extraction procedure for intermediately sized fish not amenable to whole-body or plasma extraction methods

The corticosteroid hormone cortisol is the central mediator of the teleost stress response. Therefore, the accurate quantification of cortisol in teleost fishes is a vital tool for addressing fundamental questions about an animal’s physiological response to environmental stressors. Conventional steroid extraction methods using plasma or whole-body homogenates, however, are inefficient within an intermediate size range of fish that are too small for phlebotomy and too large for whole-body steroid extractions. To assess the potential effects of hatchery-induced stress on survival of fingerling hatchery-reared Spotted Seatrout (Cynoscion nebulosus), we developed a novel extraction procedure for measuring cortisol in intermediately sized fish (50–100 mm in length) that are not amenable to standard cortisol extraction methods. By excising a standardized portion of the caudal peduncle, this tissue extraction procedure allows for a small portion of a larger fish to be sampled for cortisol, while minimizing the potential interference from lipids that may be extracted using whole-body homogenization procedures. Assay precision was comparable to published plasma and whole-body extraction procedures, and cortisol quantification over a wide range of sample dilutions displayed parallelism versus assay standards. Intra-assay  %CV was 8.54 %, and average recovery of spiked samples was 102 %. Also, tissue cortisol levels quantified using this method increase 30 min after handling stress and are significantly correlated with blood values. We conclude that this modified cortisol extraction procedure provides an excellent alternative to plasma and whole-body extraction procedures for intermediately sized fish, and will facilitate the efficient assessment of cortisol in a variety of situations ranging from basic laboratory research to industrial and field-based environmental health applications.     

Activity and energetics of free-swimming fish: insights from electromyogram telemetry

Electromyogram (EMG) telemetry studies that involve remotely monitoring the locomotory activity and energetics of fish are contributing important information to the conservation and management of fisheries resources. Here, we outline the development of this rapidly evolving field and formulate the studies conducted that utilize this technology. To date, more than 60 studies have been conducted using EMG telemetry that spans 18 species. Several general trends were observed in the methodology of the studies that we have highlighted as standards that should be adopted associated with transmitter customization, electrode placement and surgical technique. Although numerous studies have been methodological, there are still some deficiencies in our basic understanding of issues such as the need for individual calibration and the method of reporting or transforming data. Increasingly, this technology is being applied to address issues in conservation, management and aquaculture production. At present, the technology has been most frequently applied to the study of animal activity or energetics and to migration. Several recent studies have also focused on addressing more basic questions in ecological and evolutionary biology (e.g. parental care dynamics) similar to the large body of literature that has been collected for other taxa (e.g. marine mammals, birds), using activity telemetry. Collectively, studies conducted using EMG telemetry have contributed important information on free‐swimming fish that was previously difficult to obtain. EMG telemetry is particularly effective for examining behaviour at temporal and spatial scales that are difficult using other techniques. The development of an ultrasonic transmitter based on the same proven principles as those used in the current radio transmitter technology will permit studies in other environments (i.e. marine, brackish, deep water) and on different species of fish. We encourage the continued development and refinement of devices for monitoring the activity and energetics of free‐swimming fish, and also encourage researchers to consider EMG telemetry as a tool for addressing questions that are not effectively answered with other techniques.     

中国渔船标准化发展进程概述

回顾了中国渔船标准化发展基本进程,分析了不同时期的关键进展;统计分析了现行相关标准和规范体系,探讨了中国渔船标准和规范存在的问题;归纳总结了中国渔船结构强度和稳性、水动力和运动性能、节能减排、新型材料应用等领域的研究成果,以探寻渔船技术研究的方向。中国渔船标准化在标准船型评选、标准和规范制定、渔船相关技术研究等各个领域上取得了重要成果,为渔船的安全性、经济性、舒适性、耐波性和高效性提供保障;但存在渔船船舶行业标准和规范滞后、相关技术探讨较少较浅、先进技术和设备普及应用较慢等问题。渔船标准化是一项长期而艰巨的任务,不但要加大渔船的研究力度,加快渔船相关标准和规范的制定,还要相关政策制定部门的大力支持,才能不断完善中国渔船标准化建设。     

水产品真空冷冻干燥技术的研究现状与展望

随着生活水平的提高,人们对水产品品质提出了更高的要求,因此开发新的加工技术势在必行。冻干食品以其优良的营养品质,易流通、贮藏和方便食用,迎合了这一发展趋势。本文综述了水产品真空冷冻干燥过程中前处理工艺(切片处理、超声波处理、浸渍处理、涂膜处理等)、冻干工艺参数(预冻工艺参数、干燥条件等)、品质变化(感官、质构、营养、风味、滋味、复水性)和品质预测模型的研究现状,并重点探讨水产品真空冷冻干燥技术今后的研发趋势,为水产真空冷冻干燥制品的研究与应用提供参考。     

SLODS™: slow dissolving standards for water flow measurements

Slow dissolving plaster standards (SLODS™) were developed to obtain integrated water flow measurements over a time scale of 20–30 days, and tested in giant clam farms in the Solomon Islands under steady flow environments. SLODS™ are composed of a gypsum plaster formulation known as Specially Prepared Gypsum (SPG). This plaster has a considerably higher compressive strength; 10 000–13 000 psi, compared with approximately 1000 psi for more common formulations of Plaster-of-Paris. Experimental calibrations in a water motion simulator over 12 days demonstrated a highly significant relationship between fractional weight loss (FWL) of SLODS™ per day, and water velocity (r²=0.96). The SLODS™ simultaneously measured water flow (over a 21 day period in August 1997) at 12 giant clam grow-out sites spread across 400 km of island archipelagoes. Mean water velocity ranged from 5 to 11 cm s⁻¹ and significantly influenced growth of giant clams. SLODS™ compared well with the established methodology of clod cards (r=0.69; P<0.01), with a clear advantage in their ability to integrate water motion over an extended time period into a single measurement. A practical application of SLODS™ to aquatic research will be the development of standardized SLODS™ (produced in a variety of sizes and shapes) calibrated to different factors affecting dissolution. This will require a more detailed analysis of the performance of SLODS™ under different flow, salinity, dissolved solute's, and temperature environments.     

Developing a standard approach for monitoring freshwater pearl mussel (Margaritifera margaritifera) populations in European rivers

相似文献   

Estimates of fishing gear loss rates at a global scale: A literature review and meta‐analysis

Abandoned, lost or otherwise discarded fishing gear (ALDFG) represents a significant, yet ultimately unknown amount of global marine debris, with serious environmental and socioeconomic impacts. This study reviews 68 publications from 1975 to 2017 that contain quantitative information about fishing gear losses. Gear loss estimates reported by the studies ranged widely, with all net studies reviewed reporting annual gear loss rates from 0% to 79.8%, all trap studies reporting gear loss rates from 0% to 88%, and all line studies reporting gear loss rates from 0.1% to 79.2%. Information obtained from this review was used to perform a meta‐analysis that provides the first synthetic, statistically robust estimates of global fishing gear losses. The meta‐analysis estimates global fishing gear losses for different major gear types. We estimate that 5.7% of all fishing nets, 8.6% of all traps, and 29% of all lines are lost around the world each year. Furthermore, we identified key gear characteristics, operational aspects and environmental contexts that influence gear loss. These estimates can be used to support sustainable fisheries development through informing risk assessments for fisheries and monitoring and assessment efforts to reduce gear losses.     

Estimating recreational harvest using interview‐based recall survey: implication of recalling in weight or numbers

For many overfished marine stocks, recreational fishing continues even though recovery plans are implemented and commercial landings regulated. In such cases, unbiased and precise estimates of recreational harvest are important for successful management. Harvest estimation often relies on interviewed‐based surveys where fishers are asked to recall harvest within a given timeframe. However, the importance of whether fishers are requested to provide figures in weight or number is unresolved. Therefore, a recall survey aiming at estimating recreational harvest was designed, such that respondents could report harvest using either weight or numbers. It was found that: (1) a preference for reporting in numbers dominated; (2) reported mean individual weight of fish caught, differed between units preferences; and (3) when an estimate of total harvest in weight are calculated, these difference could result in a substantial bias through the conversion from numbers to weight. Based upon these results it is recommended that recreational harvest should be requested in numbers and not weight.     

Design and performance of recirculating aquaculture system for marine finfish broodstock development

Tropical and subtropical climatic conditions in India present an ideal and unique opportunity for being the leader in tropical marine finfish aquaculture. However, the problem persist due to non-availability of marine finfish seed for the culture. In response to this problem, broodstock development of different tropical marine finfishes for seed production was started. The present study was undertaken to design a recirculating aquaculture system (RAS) and studying their performance in managing the various water quality required for the marine finfish broodstock development and breeding. The design of RAS, developed in the present study, included a broodstock tank, egg collection chamber, electrical pump, rapid sand filter, venturi type protein skimmer and biological filter. Two RAS were designed, one was stocked with a demersal fish species, orange spotted grouper (Epinephelus coioides) and the other was stocked with a pelagic fish species, Indian pompano (Trachinotus mookalee) at the rate 1 and 0.5 kg/m³ with a sex ratio of 1:1 and 1:2 (female: male) respectively. Various physio-chemical parameters, viz, total ammonia nitrogen (TAN), nitrite, nitrate, pH, alkalinity, temperature, free carbon dioxide (CO₂) and dissolved oxygen (DO) of both tank water were analyzed to assess the performance of recirculating aquaculture system in maintaining the water quality. Gonadal development of the fishes was assessed and the spawning performance was recorded and finally, economic performance of the system was also evaluated. During the entire experimental period, mean monthly total ammonia nitrogen was less than 0.07 and 0.06 mg L⁻¹ and mean monthly nitrite was less than 0.02 and 0.01 mg L⁻¹ in orange spotted grouper and Indian pompano RAS tanks respectively. The pH (7.8–8.2), DO (>4 mg/L) and alkalinity (100–120 mg/L) were found to be in optimum range in both recirculating aquaculture systems. Carbon dioxide was found to be nil during the entire experimental period in both the systems. In fact these levels were comparable or less than that is reported as the permissible limits for broodstock development. Indian pompano and Orange spotted grouper matured and spawning was obtained with production of fertilized eggs round the year. Economic evaluation showed the price of 10,000 fertilized eggs of orange spotted grouper to be US $ 1.33. The design of RAS devised in the present study is efficient in controlling and maintaining optimum water quality for broodstock development of both demersal and pelagic finfishes. The fishes stocked in RAS attained final maturation and round the year spawning was obtained.     

我国渔船气胀式救生筏的质量与相关法规分析

救生筏是一种较为理想的海上救生设备。针对渔用救生筏产品进行监督抽查,发现了诸如救生筏主体胶布物理性能偏低、粘接工艺易开裂、YJ型救生筏安全性能较差、A型救生筏充气启动拉力过大和顶篷封口水密性差、救生筏备品属具存在"短斤缺两"现象等问题。结合我国渔业船舶用产品已制定颁布的相关法规、标准现状,分析认为,我国渔船的相关法规与救生筏标准的制修订速度已经跟不上产品技术发展及国际公约的更新进程。针对救生筏现行技术规则中存在的问题,建议:进一步明确救生设备产品法定检验的基本技术依据;加快包括救生设备在内的渔船用产品检验规则的修订进程;修订规则淘汰安全性较差的YJ型简易救生筏;提高Y型救生筏主体胶布物理指标。