An evaluation of the potential influence of SST and currents on the oceanic migration of juvenile and immature chum salmon (Oncorhynchus keta) by a simulation model

Using a salmon migration model based on the assumption that swimming orientation is temperature dependent, we investigated the determining factors of the migration of juvenile and immature chum salmon (Oncorhynchus keta) in the North Pacific. We compared the predictions of the model with catch data of immature and juvenile chum salmon collected by Japanese research vessels from 1972 to 1999. The salmon migration model reproduced the observed distributions of immature chum salmon and indicates that passive transport by wind‐driven and geostrophic currents plays an important role in the eastward migration of Asian salmon. These factors result in a non‐symmetric distribution of Asian and North American chum salmon in the open ocean. The directional swimming component contributes to the northward migration in summer. The model results indicate that during the first winter Asian chum salmon swim northward against the southward wind‐driven currents to stay in the western North Pacific. This suggests that Asian chum salmon require more energy to migrate than other stocks during the first winter of their ocean life.     

基于贝叶斯方法的FAO48.1区南极磷虾渔业资源评估

南极海域南极磷虾资源丰富,开发潜力已经得到世界范围的关注。由于南极海洋生物资源养护委员会（Commission for the Conservation of Antarctic Marine Living Resources, CCAMLR）多年来始终将联合国粮食及农业组织（Food and Agriculture Organization of the United Nations,FAO）在南极海域内设立的48.1区的捕捞限额控制在1.55×105 t,从而引发了众多争议,采用CCAMLR公布的2006-2015年生产统计数据,利用基于贝叶斯方法的非平衡剩余产量模型,对FAO 48.1区南极磷虾（Euphausia superba）的渔业资源进行评估,结果显示：当前48.1区南极磷虾资源的环境容纳量为（1.93～7.84）×107 t;渔业资源综合种群的内禀增长率为0.4～0.6;2016年48.1区南极磷虾的平均生物量为3.88×107 t;48.1区南极磷虾资源当前最大持续产量（MSY）为5.5×106 t;当前的触发产量远低于MSY的阈值,48.1区内南极磷虾资源几乎处于原始未开发状态。建议提高48.1区南极磷虾的触发产量至5.5×105t。     

池塘养殖尾水灌溉稻蟹共生稻田中水稻的生长

为了探求新型稻渔共作模式对水稻生长及产量的影响,在宁夏回族自治区银川市贺兰县光明渔村开展了新型稻渔共作模式的实践。不同情况下稻田灌溉模式影响了水稻的生长以及产量。实验分为每隔5 d灌溉一次鱼塘水,每隔7 d灌溉一次鱼塘水以及不灌溉鱼塘水。水稻种植品种为“吉宏6号”,水稻平均亩产544.97kg,总体旱田亩产量高于水田,不同灌溉周期亩产量5 d灌溉一次>7 d灌溉一次>不灌溉鱼塘水。地上部分生物量旱田大于水田。灰色关联度分布为0.576～0.907。各水稻根茎秆构成因子与水稻产量关联度由强到弱排序依次为：根长（0.907）＞秆基部外径(0.863)=穗基部外径(0.863)＞秆长(0.846)＞株高(0.829)＞穗长(0.776),其中与水稻产量关联度最大的根茎秆构成因子是根长,关联度最小的是穗长;水稻产量构成因子与水稻产量关联度由强到弱排序依次为：有效穗数(0.869)＞穗粒数(0.847)＞生物量(0.813)＞结实率(0.806)＞千粒质量(0.759)＞每公顷穴数(0.715)＞根干质量（0.625）＞成穗率(0.576),其中与水稻产量关联度最大的产量构成因子是有效穗数,关联度最小的是成穗率。     

Accounting for uncertainty in pedotransfer functions in vulnerability assessments of pesticide leaching to groundwater

A simulation tool for site-specific vulnerability assessments of pesticide leaching to groundwater was developed, based on the pesticide fate and transport model MACRO, parameterized using pedotransfer functions and reasonable worst-case parameter values. The effects of uncertainty in the pedotransfer functions on simulation results were examined for 48 combinations of soils, pesticides and application timings, by sampling pedotransfer function regression errors and propagating them through the simulation model in a Monte Carlo analysis. An uncertainty factor, f(u), was derived, defined as the ratio between the concentration simulated with no errors, c(sim), and the 80th percentile concentration for the scenario. The pedotransfer function errors caused a large variation in simulation results, with f(u) ranging from 1.14 to 1440, with a median of 2.8. A non-linear relationship was found between f(u) and c(sim), which can be used to account for parameter uncertainty by correcting the simulated concentration, c(sim), to an estimated 80th percentile value. For fine-textured soils, the predictions were most sensitive to errors in the pedotransfer functions for two parameters regulating macropore flow (the saturated matrix hydraulic conductivity, K(b), and the effective diffusion pathlength, d) and two water retention function parameters (van Genuchten's N and alpha parameters). For coarse-textured soils, the model was also sensitive to errors in the exponent in the degradation water response function and the dispersivity, in addition to K(b), but showed little sensitivity to d. To reduce uncertainty in model predictions, improved pedotransfer functions for K(b), d, N and alpha would therefore be most useful.     

沈阳市区2种空气质量数值模式预报结果的对比分析

建立了一个简单空气质量数值模式预报系统(SAQMS)。该系统是由中尺度数值预报模式(MM5)、Pielke中-β尺度气象模式和Eu-ler大气平流-扩散模式以及Erisman干沉降模式所组成。分别利用该系统和中科院大气物理研究所提供的高分辨率化学模式预报系统(HRCM)对沈阳地区的SO2浓度值进行了预报试验,结果表明,这2个模式的预测值都非常接近实测值,初步说明该模式系统可用于沈阳市的空气质量预报业务。     

Comparison of dietary essential amino acid requirements determined from group‐housed versus individually‐housed juvenile bluegill,Lepomis macrochirus

Two 60‐day experiments were conducted sequentially to determine (i) lysine requirement of juvenile bluegill, Lepomis macrochirus based on the dose–response method, (ii) requirements for other essential amino acids (EAAs) using whole‐body amino acid profile and (iii) whether differences in growth rates of group‐housed versus individually‐housed bluegills lead to different lysine requirement levels because of the presence and absence, respectively, of social hierarchies. Seven, semi‐purified, experimental diets (isonitrogenous, isocaloric) were prepared to contain graded levels of digestible lysine (10–31 g kg⁻¹). Experiment‐1 involved group‐housed bluegills (approximately 27 g, n = 10 fish/chamber, 4 chambers/diet) whereas experiment‐2 involved individually‐housed bluegills (approximately 30 g, n = 1 fish/chamber, 14 chambers/diet). Fish were fed twice daily to apparent satiation. Bluegill growth responses in both experiments generally improved (P < 0.05, anova ) with increasing dietary lysine levels from 10 to 16 g kg⁻¹, and then levelled off with further increase in lysine level (P > 0.05). Optimal dietary lysine level (digestible basis) was estimated to be 15 g kg⁻¹ based on broken‐line regression analyses of relative growth rate and feed conversion ratio with no differences being observed between the two rearing methods. Determined dietary requirement levels for other EAAs ranged from 2.4 g kg⁻¹ (tryptophan) to 15.3 g kg⁻¹ (leucine).     

冬季居住区不同功能绿地PM2.5浓度变化及其与气象因子的关系

以杭州市临安区林水山居为研究对象,在2017年冬季采用实地测量法对居住区内3个不同功能绿地和对照点的PM 2.5 浓度、气象因子(温度、相对湿度、风速和光照强度)进行监测,评价绿地对居住区环境降低大气PM 2.5 浓度的作用,同时探讨环境因素对PM 2.5 浓度的影响。结果表明,居住区3个不同功能绿地和对照点的PM 2.5 浓度日变化趋势基本一致,呈“单峰单谷”型;PM 2.5 浓度均值从大到小依次是道路绿地>宅旁绿地>中心绿地>对照点。居住区的PM 2.5 浓度与温度呈负相关关系(R^2=0.794 6);与相对湿度呈正相关(R^2=0.642 5);与风速呈负相关;与光照强度呈负相关,可拟合为线性方程 y=95.3-4.7x,(0.05

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