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1.
SHIN‐ICHI ITO MICHIO J. KISHI YUTAKA KURITA YOSHIOKI OOZEKI YASUHIRO YAMANAKA BERNARD A. MEGREY FRANCISCO E. WERNER 《Fisheries Oceanography》2004,13(Z1):111-124
A fish bioenergetics model coupled with an ecosystem model was developed to reproduce the growth of Pacific saury. The model spatially covers three different oceanographic spatial domains corresponding to the Kuroshio, Oyashio, and interfrontal (mixed water) regions. In this coupled model, three (small, large, and predatory) zooplankton densities which were derived from the lower trophic level ecosystem model were input to the bioenergetics model of saury as the prey densities. Although certain model parameters were imposed from other species’ bioenergetics, several model parameters were estimated from observational data specific to Pacific saury. The integrated model results reproduced appropriate growth rates of Pacific saury. Model sensitivities to water temperature and prey density are examined and observational methods to evaluate the model parameters are discussed. 相似文献
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构建资源节约型渔业之刍议 总被引：1，自引：0，他引：1
建立资源节约型、环境友好型社会,既是调解我国当前资源瓶颈制约的有效途径,又是落实科学发展观、实现经济增长方式转变和走新型工业化道路的重要内容和重大举措。本文就如何建设资源节约型渔业,从理论上探讨其内涵、特点和规律,以及资源节约型渔业结构、重点领域与主要途径。 相似文献
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A Lagrangian ensemble model of Calanus finmarchicus coupled with a 1D ecosystem model 总被引：2，自引：0，他引：2
A population dynamics model of Calanus finmarchicus based on Lagrangian particles has been coupled with a 1-D ecosystem model. Each of the particles represents a variable number of copepods which experience the same fate. Therefore all copepods of a single particle represent a cohort and are characterized by a common set of individual properties such as age, development-stage, depth, structural weight (length), lipid pool or food satiation. The physical environment is parameterized by a 1-D-water column with a vertical resolution of 1 m and a maximum depth of 800 m. Copepod food supply is provided by an interactive Eulerian NPZD model where Z represents microzooplankton. The model correctly reproduces both the dynamics of the ecosystem and the life history of the copepods in the Norwegian Sea. Simulated results of trajectories of particles in the water column, and of individual growth and stage development were analysed. Results on seasonal abundance, development time, number of generations, depth profiles, and patterns of diurnal and ontogenic migration are compared with field data from OWS India. 相似文献
5.
基于网具模型试验的金枪鱼围网性能分析 总被引：1，自引：0，他引：1
模型试验根据田内准则,选择大小尺度比分别为:λ=20∶1,λ￠=1∶1,制作的模型网规格为:网衣长109 m,网高15.6 m,上纲80.9 m,下纲98 m,下纲基本重量为0.663 kg/m,浮力配备25 N/m,模型网和实物网的缩结系数相同。试验结果显示,围网中部下纲沉降深度(D)和时间(t)的关系:D=–0.0014t2+0.276t–0.6476(R2=0.9953);下纲重量对沉降性能有显著影响,而放网速度对沉降性能的影响并不显著,但两者交互项对沉降深度有显著影响;在0.531~0.663 kg/m的范围内,随下纲重量增加,沉降深度呈大幅度增加趋势,而沉降速度呈递减趋势;在0.663~0.759 kg/m范围内,沉降深度小幅度递减,而沉降速度大幅度提高。当下纲重量为0.663 kg/m时,沉降速度随放网速度的增加而增加;随着沉降时间的增加,下纲张力在0~20 s范围内波动较大,之后保持一定的平稳状态。本研究通过对金枪鱼围网模型网制作的分析与探讨,旨在更好地通过模型试验研究金枪鱼围网网具性能。 相似文献
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Edward A. Laws 《Aquacultural Engineering》1986,5(2-4):161-170
Predictions derived from the unstructured food web model developed by Isaacs (1972, 1973) and later modified by Lange and Hurley (1975) can be derived straightforwardly from a simple box model involving plant biomass, heterotroph biomass, and detritus. Differential equations rather than matrices are used to describe the transfer of materials between these boxes. By recasting these equations, several restrictions present in the original model as well as in the Lange and Hurley reformulation can be relaxed. The model was therefore generalized to allow for (1) a distinction between organic inputs due to plant photosynthesis and to applied feeds, (2) a difference in the turnover rates of the plants, heterotrophs, and detritus, and (3) the effect of harvesting a cash crop. This more general model is used to predict the potential biomass of heterotrophs in a freshwater prawn pond, and to predict the outcome of simple managerial manipulations on the system. 相似文献
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Hydrodynamic characteristics are needed to optimize the design of kelp aquaculture systems. To support this need, the objective of this study was to resolve both the normal and tangential drag forces acting on a dense aggregate of kelp blades using full-scale physical model tests. The physical model was designed to match the exposed length, individual blade flexural rigidity, the number of blades per unit width, the mass/length of biomass, and the aggregate mass density of kelp cultured at the University of New England experimental aquaculture lease site in Saco Bay, Maine USA. Tow tests were conducted at the United States Naval Academy in a tank with the dimensions of 116m × 7.9m × 4.9 m. The large tank size enabled the use of the full-scale physical model, minimizing dynamic similarity issues. In a series of tests, the model was towed in orientations both aligned and perpendicular to the tow direction. Horizontal and vertical reaction forces were measured for five tow speeds, along with the deflection of the dense kelp aggregate. With these datasets and the wet weight biomass per length of the model, normal and tangential drag forces were calculated. Drag components were processed into corresponding normal and tangential drag-area values. The drag-area representation was chosen since reference areas were ambiguous for both the actual kelp and model. At the higher speeds, the total horizontal drag in the aligned configuration were slightly lower than for the perpendicular orientation. Normal drag-areas as a function of tow speed ranged from 2.36 m2/m to 1.39 m2/m for the aligned case and from 2.49 to 1.88 m2/m for the perpendicular case. Tangential drag-areas as a function of tow speed ranged from 0.264 m2/m to 0.0325 m2/m for the aligned case and from 0.213 to 0.0415 m2/m for the perpendicular case. A transition from a bluff body to a streamlined body occurred as the tow speeds increased. To investigate this transition, horizontal components of the normal and tangential drag forces were reconstructed with the results of the tow tests. The reconstructed forces were obtained using a force balance system of equations with drag-area values for tow speeds less than 0.25 m/s extrapolated from the experimental datasets. For both aligned and perpendicular orientations, the model-aggregate reconfigured at a threshold of 0.25 m/s. We defined the threshold for reconfiguration as the tow speed at which the horizontal component of tangential drag equaled or exceeded the horizontal component of the normal drag. The drag-area results from this study can be incorporated into a dynamic fluid-structure interaction model representing kelp aggregates as a finite element beam prescribed with in-situ values of length, volume, mass density and flexural-rigidity of kelp material. 相似文献
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There are few studies on flow fields generated by aerators in fish larvae rearing tanks. The flow varies with aeration rates and tank proportions resulting in different larvae survival rates. The effects of aeration rate and aspect ratio AR (the ratio of liquid depth to tank radius) on overall flow patterns were investigated experimentally using flow visualization techniques. Two distinct types of flow patterns, a single-pair vortex system and a two-pair vortex system, were observed as the value of tank aspect ratio varied from about 1.0 to 2.0. In addition, corner vortex structures were observed in both the region between the free surface and the upper sidewall, and between the bottom wall and the lower sidewall of the tank. On the sidewall, reattachment and separation points were found, which were closely related with these vortex structures. 相似文献
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Walleye (Sander vitreus) is an important sport fish throughout much of North America, and walleye populations support valuable commercial fisheries in certain lakes as well. Using a corrected algorithm for balancing the energy budget, we reevaluated the performance of the Wisconsin bioenergetics model for walleye in the laboratory. Walleyes were fed rainbow smelt (Osmerus mordax) in four laboratory tanks each day during a 126-day experiment. Feeding rates ranged from 1.4 to 1.7 % of walleye body weight per day. Based on a statistical comparison of bioenergetics model predictions of monthly consumption with observed monthly consumption, we concluded that the bioenergetics model estimated food consumption by walleye without any significant bias. Similarly, based on a statistical comparison of bioenergetics model predictions of weight at the end of the monthly test period with observed weight, we concluded that the bioenergetics model predicted walleye growth without any detectable bias. In addition, the bioenergetics model predictions of cumulative consumption over the 126-day experiment differed from observed cumulative consumption by less than 10 %. Although additional laboratory and field testing will be needed to fully evaluate model performance, based on our laboratory results, the Wisconsin bioenergetics model for walleye appears to be providing unbiased predictions of food consumption. 相似文献
10.
This study predicts the long-term economic effects of a genetic improvement program of Australian abalone. A detailed bioeconomic model was constructed, which allows the combination of the biological, technological, and economic aspects of genetic improvement. This research focuses on analyzing various traits through an aggregate breeding value and selection index. In this study, the traditional formula of annual genetic gain is used to allow a detailed analysis of biomass future behavior in terms of the intertemporal evolution of the traits analyzed. The results showed that the production program of genetic management in Australian abalone is profitable but only in the very long term, and it is influenced mainly by the progressive increase in the biomass of each abalone and the survival rate. Sensitivity analysis showed that the weight at harvest is the most important trait, suggesting that it is more beneficial for a farmer to focus on genetically improving this trait. In addition, reproductive factors (especially survival from competent larvae until sexual maturity) had a particularly strong impact on the results, much more than the factors related to genetic improvement and economics, such as the discount rate and selling price. 相似文献
11.
为了对4种不同开口大小的六边形开口方形人工鱼礁在4种迎流角度下数值模拟和水槽模型试验的阻力系数进行对比验证,分别利用水槽模型和数值模拟试验方法对4种不同开口比（γty=0.0625,0.14,0.25,0.39）六边形开口方形人工鱼礁在4种迎流角度（θ=0°,15°,30°,45°）状态下的阻力进行测定,并计算两种方法的阻力系数。结果表明：（1）在数值模拟和水槽模型试验中,人工鱼礁模型阻力均随着开口比的增大而减小;礁体迎流角度的变化可改变礁体阻力,且在4种迎流角度下,人工鱼礁阻力在θ=30°时最大。（2）人工鱼礁数值模拟与水槽模型试验中,当θ为15°、30°和45°时,阻力系数均随着开口比的增加而增加,具有明显的线性关系,且阻力系数在迎流角度θ=30°时最大。（3）数值模拟与模型试验阻力的相对误差在0.12%~17.18%,平均误差7.43%;礁体阻力系数的相对误差在0.03%~14.64%,平均误差5.26%。阻力及阻力系数误差均在20%以下。水槽模型试验与数值模拟阻力和阻力系数相关系数R分别为0.99和0.80,P<0.001,具有极强的相关性。因此,利用数值模拟精细化研究人工鱼礁水动力性能是可行的。 相似文献
12.
Coupling of an individual-based population dynamic model of Calanus finmarchicus to a circulation model for the Georges Bank region 总被引：2，自引：0，他引：2
CHARLES B. MILLER DANIEL R. LYNCH FRANÇOIS CARLOTTI WENDY GENTLEMAN & CRAIG V. W. LEWIS 《Fisheries Oceanography》1998,7(3-4):219-234
An individual-based life history and population dynamic model for the winter–spring dominant copepod of the subarctic North Atlantic, Calanus finmarchicus , is coupled with a regional model of advection for the Gulf of Maine and Georges Bank. Large numbers of vectors, each representing individual copepods with elements for age, stage, ovarian status and other population dynamic variables, are carried in a computation through hourly time steps. Each vector is updated at each time step according to development rate and reproductive functions derived from experimental data. Newly spawned eggs are each assigned new vectors as needed. All vectors are subject to random mortality. Thus, both life history progression and population dynamics of C. finmarchicus are represented for the temperatures in the Gulf of Maine–Georges Bank region in the active season. All vectors include elements representing depth, latitude and longitude. This allows coupling of the population dynamics to the tide- and wind-driven Dartmouth model of New England regional circulation. Summary data from the physical model are used to advance vectors from resting-stock locations in Gulf of Maine basins through two generations to sites of readiness for return to rest. Supply of Calanus stock to Georges Bank comes from all of the gulf and from the Scotian Shelf. The top of the bank is stocked from western gulf basins; the North-east Peak is stocked from Georges Basin and the Scotian Shelf. All sources contribute to stock that accumulates in the SCOPEX gyre off the north-west shoulder of Georges Bank, explaining the high abundance recurrently seen in that region. There is some return of resting stock to Wilkinson Basin in the western gulf, but other basins must mostly be restocked from upstream sources to the north-east. 相似文献
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连续形Fox产量模型在模拟和实际渔业评估中的应用 总被引：1，自引：0，他引：1
剩余产量模型因为具有形式简单和所需数据少的特点,在渔业资源评估中被广泛应用。文章应用连续形Fox产量模型对3种模拟渔业以及北大西洋剑鱼渔业进行了评估,并对模拟渔业的评估结果进行了比较,以发现连续Fox产量模型比较适宜的渔业条件。蒙特卡罗（Monte Carlo）分析表明,模型在产量和捕捞努力量随时间波动的波动性渔业中评估效果最好,可能是由于该类型渔业过程比较完整,数据中包含的信息比较丰富。比较不同的白色噪音水平,当白色噪音小于10%时评估结果偏差较小,小于3.3%;当白色噪音为50%时,评估结果偏差较大,最大偏差为36.7%。 相似文献
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The economics of enforcement is traditionally modelled using rational agents assumed to act according to their expected economic utility. In this investigation we derive this expectation by implementing a stochastic simulation model to integrate across associated levels of uncertainty using Monte Carlo. The model is developed for the South Georgia toothfish longline fishery, in which legal catches are strictly managed according to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) conservation measures. Assuming full compliance in the legal fishery, this investigation deals with the role of a fishing patrol vessel (FPV) in excluding illegal fishing vessels. Both legal and illegal fleets are dynamic. For the legal fleet, catch is set by a harvest control rule within the model framework, with vessels leaving if fishing becomes unprofitable. The illegal catch is determined by the number of vessels operating, which predicts catch on the basis of an estimated production function. The exit of illegal vessels is determined by the probability of detection by the FPV, which is a function of days spent on patrol, and estimated profits. The entry of illegal vessels occurs at a fixed mean rate, with the model integrating over uncertainty in this parameter. An obvious trade off exists in that higher levels of illegal activity lead to lower expected returns to the legal fleet. We thus provide a cost-benefit framework for investigating the trade-offs associated with decisions on enforcement in the fishery, and confirm that current enforcement effort levels are well justified. 相似文献
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A generalized linear mixed model (GLMM) that treats year and spatial cell as fixed effects while treating vessel as a random effect is used to examine fishing power among chartered industry-based vessels and a research trawler, the FRV Miller Freeman, for bottom trawl surveys on the upper continental slope of U.S. West coast. A Bernoulli distribution is used to model the probability of a non-zero haul and the gamma distribution to model the non-zero catch rates of four groundfish species. The use of vessel as a random effect allows the data for the various vessels to be combined and a single continuous time-series of biomass indices to be developed for stock assessment purposes. The GLMMs fit the data reasonably well. Among the different models examined, the GLMM incorporating a random vessel × year effect had the smallest ΔAIC and was thus chosen as the best model. Also, estimated random effects coefficients associated with the industry-based vessels and the FRV Miller Freeman for each year suggests that these vessels can be assumed to be from a common random effects distribution. These results suggest that combining data from the chartered industry-based vessels and from the research trawler may be appropriate to develop indices of abundance for stock assessment purposes. Finally, an evaluation of variances associated with abundance indices from the different models indicate that analyzing these data as a fixed effect GLM may underestimate the level of variability due to ignoring the grouped nature of tows within vessels. As such, use of a mixed model approach with vessel as a random effect is a reasonable approach to developing abundance indices and their variances. 相似文献
16.
Most of the traditional assessment models are age-structured. However, many biological and exploitation processes are more length-dependent than age-dependent, and the required length–age conversion of available data is often not reliable. Consequently, length-structured or age–length structured models have undergone considerable development in recent years. The growth transition matrix used to model the mean growth and growth variability of the population, is of primary importance in a length-structured matrix model. Building this growth transition matrix is not trivial and it is necessary to assess the impact that various assumptions may have to identify robust model structures. In this study, we assess the effects of (1) time and length discretisation, (2) the distribution of individuals within length classes and (3) the statistical distribution used to describe growth variability, by fitting a growth matrix model to individual quasi-continuous simulated growth data. The study quantitatively demonstrates that the choice of the time step and of length class width is the key point when building a length-structured population growth model. The use of a gamma distribution for the growth increments and/or a uniform distribution of individuals within length classes were found to make the model more robust. 相似文献
17.
用鳗弧菌腹腔注射牙鲆进行人工感染实验,对感染牙鲆进行血液生理生化指标的测定,并观察描述患病牙鲆的外观症状及有关组织器官的病理变化,以高效液相色谱(HPLC)法为定量手段研究达氟沙星在健康和感染牙鲆体内的药动学特征。结果表明,(1)每公斤体重腹腔注射鳗弧菌2.0×107~3.0×107cells可复制出疾病模型;(2)与健康鱼相比,患病鱼的红细胞数、血红蛋白、血小板数、Cl-、Na 等显著下降,而白细胞数、谷丙转氨酶(ALT)、谷草转氨酶(AST)、碱性磷酸酶(ALP)、乳酸脱氢酶(LDH)、肌苷(Cr)、K 极显著增加,说明经鳗弧菌感染后,牙鲆在药物吸收、代谢等方面的生理功能受到严重损害;(3)患病鱼的肝、肾、脾等组织细胞均发生实质性病变,而对照组外观正常,组织器官未见病理变化;(4)达氟沙星在感染牙鲆体内的吸收、分布和消除均减慢,生物利用度降低。鳗弧菌感染必将影响药物在体内的分布和血浆蛋白结合率,改变药物及其代谢物从体内消除的速度和程度,进而影响药物的疗效。该模型复制的方法可靠且具有可重复性,它对探讨药物在患病鱼体内的动力学规律,揭示疾病对药动学的影响机理和指导临床合理用药等具有理论和实践意义。 相似文献
18.
对当前水产品加工企业食品安全管理体系的基本方式进行了分析,并指出了其存在的缺陷,设计了水产品加工企业新的食品安全管理体系模式,拟订了新体系文件的主要内容,使企业能够把GMP、HAC-CP法规和ISO9001I、SO22000的认证标准要求条款,直接应用于生产实际工作中。 相似文献
19.
A hydraulically integrated, serial turbidostat algal reactor (HISTAR) was mathematically modeled and developed for the mass production of microalgae. HISTAR, which hydraulically links precisely controlled turbidostats with continuous-flow stirred-tank reactors (CFSTRs) into a single production technology, was conceptualized emphasizing contaminant mitigation at the design stage to maintain system stability. This paper discusses the conceptual basis for the development of HISTAR and presents a theoretical overview of the CFSTRs. Mathematical modeling, using first-order algal growth kinetics combined with CFSTR reactor kinetics, was used to investigate the effects of system dilution rate, Ds; net algal specific growth rate, Ua; number of reactors, N; input algal biomass, Xi; and contaminant concentration, Cn, on algal productivity, as well as local dilution rate, Dn, on suspended contaminant washout. The simulation results allowed the determination of preliminary design ranges for prototype development. 相似文献
20.
A three-dimensional biophysical nutrient–phytoplankton–zooplankton model was used to investigate the spatial and temporal dynamics of food resources for young walleye pollock in the western Gulf of Alaska, to further understanding of recruitment processes for pollock. We modeled nitrogen, phytoplankton, a large herbivorous grazer parameterized as Neocalanus spp. (the biomass dominant copepod in the Gulf), and the 13 stages (egg, naupliar and copepodite) of Pseudocalanus spp. (a major constituent of the diet of pollock) so that the appropriate size class of food for each size of larval pollock was represented. Model results identified an area between the Semidi and Shumagin Islands that may not be suitable as a nursery area early in the year due to low prey abundance. Modeled mesoscale eddies, previously hypothesized to be important for larval pollock retention in Shelikof Strait, contained higher prey concentrations than the surrounding waters when they were cyclonic. This work also help to understand the consistency of pollock spawning in time and space in Shelikof Strait, by examining the timing and location of prey availability which, along with transport, narrows the window for optimal spawning. 相似文献