Natural mortality estimation and rational exploitation of purpleback flying squid Sthenoteuthis oualaniensis in the southern South China Sea     

Wang  Xuehui  Qiu  Yongsong  Zhang  Peng  Du  Feiyan 《中国海洋湖沼学报》2017,35(4):902-911

Based on the biological data of purpleback flying squid(Sthenoteuthis oualaniensis)collected by light falling-net in the southern South China Sea(SCS) during September to October 2012 and March to April 2013,growth and mortality of 'Medium' and 'Dwarf' forms of squid are derived using the Powell-Wetherall,ELEFAN methods and length-converted catch curves(FiSAT package).Given a lack of commercial exploitation,we assume total mortality to be due entirely to natural mortality.We estimate these squid have fast growth,with growth coefficients(k) ranging from 1.42 to 2.39,and high natural mortality(M),with estimates ranging from 1.61 to 2.92.To sustainably exploit these squid stocks,yield per recruitment based on growth and natural mortality was determined using the Beverton-Holt dynamic pool model.We demonstrate squid stocks could sustain high fishing mortality and low ages at first capture,with an optimal fishing mortality 3.0,with the optimal age at first capture increased to 0.4-0.6 years when fishing mortality approached optimal levels.On the basis of our analyses and estimates of stock biomass,we believe considerable potential exists to expand the squid fishery into the open SCS,relieving fishing pressure on coastal waters.  相似文献   

Morphologies of eumelanins from the ink of six cephalopods species measured by atomic force microscopy     

Yulin Sun  Li Tian  Jing Wen  Juan Zhao  Wei Zhang  Chunyao Xie  Meiqing Zhou  Xiaoying Qiu  Daohai Chen 《中国海洋大学学报(英文版)》2017,16(3):461-467

The morphologies of eumelanin, isolated from the six cephalopods species Sepia esculenta, Sepia lycidas, Sepia pharaonis, Sepiella japonica, Euprymna berryi, and Uroteuthis (Photololigo) edulis, were investigated using atomic force microscopy (AFM). The results showed that the hierarchical aggregate structures of irregular spherical particles with different diameters are the common characteristics of these eumelanins. Furthermore, the diameters of these spherical particles present an uneven distribution in a wide range and mainly concentrate in the range of about 20-150 nm. In addition, the eumelanin from different cephalopods species show obvious differences in the morphologies, which is illustrated by different assembly forms of diverse aggregate units and the quantitative features of eumelanin particles derived from the images.  相似文献   

Seasonal export fluxes of size-fractionated particulate derived from polonium-210: A case study in Xiamen Bay     

杨伟锋  黄奕普  陈敏  邱雨生 《中国海洋湖沼学报》2010,28(2):379-386

Size-fractionated ²¹⁰Po and ²¹⁰Pb, in the size fractions >0.4 μm, >2 μm and >10 μm, were examined to determine the seasonal variability of particulate fluxes in Xiamen Bay. Good correlations between ²¹⁰Po and particulate organic carbon (POC) or non-Particulate Organic Matter (nPOM) suggested that ²¹⁰Po can be used to trace the export fluxes of POC and nPOM. Both steady-state (SS) model and nSS model were used to evaluate fluxes of size-fractionated ²¹⁰Po, results showed that nSS model was better than the SS model in coastal areas. Based on the nSS model, size-fractionated POC fluxes decreased with increasing particle size. For the particle size studied, maximum POC fluxes occurred in autumn, followed by spring, winter, and summer. Fluxes of nPOM were an order of magnitude higher than the corresponding size-fractionated POC fluxes. Differences between size-fractionated nPOM fluxes indicated that hydrodynamic conditions were the main factor regulating transportation of particulate out of the inner Bay. In winter most particulates, including >10 μm particles, were transported under the strongest hydrodynamic conditions. In contrast, only a fraction of the <2 μm particulates were transported from the inner Bay in spring. This study suggested that ²¹⁰Po is a powerful tracer of seasonal particulate export in coastal seas.  相似文献   

钻孔四分量应变观测自检内精度分析   总被引：5，自引：0，他引：5  

唐磊  邱泽华  宋茉 《大地测量与地球动力学》2010,30(Z2)

根据钻孔四分量应变观测特点,分析了评价该观测手段的质量指标:相对标定自检内精度.介绍了相对标定自检内精度方法以及存在的问题.通过对比分析平均值、相关系数等,提出不同的求偏差方法,改进了相对标定自检内精度法,使其能尽量客观地评价观测质量.  相似文献   

Effects of pyrene and fluoranthene on the degradation characteristics of phenanthrene in the cometabolism process by Sphingomonas sp. strain PheB4 isolated from mangrove sediments     

Yin Zhong  Shichun Zou  Tiangang Luan  Rongliang Qiu 《Marine pollution bulletin》2010,60(11):2043-2049

Cometabolism has been suggested as an attractive approach to enhance the degradation rates of high-molecular-weight polycyclic aromatic hydrocarbons (PAHs). However, the effects of these recalcitrant PAHs on the degradation characteristics of low-molecular-weight PAHs are largely unknown. This study was conducted to investigate the effects of pyrene (PYR) and fluoranthene (FLA) on the degradation characteristics of phenanthrene (PHE) in the cometabolism process by Sphingomonas sp. strain PheB4 isolated from mangrove sediments. Based on the kinetics and characteristics of PHE metabolites, it was proposed that the transformation of hydroxylated PHE into 1-hydroxy-2-naphthoic acid was a rate-limiting step in the degradation of PHE by strain PheB4. Compared to a single addition of PYR or FLA, the presence of a mixture of PYR and FLA decreased the degradation rate of PHE to a larger extent, which was likely because it could inhibit the production of 1-hydroxy-2-naphthoic acid more effectively.  相似文献   

地震三维灾情影像图生成技术系统研究     

马霁  陈化然  何宇飞  刘晓灿  李金垚  贺同江  邱虎 《国际地震动态》2010,(1):25-30

本文将计算机技术、遥感技术、地理信息系统、图形图像处理相结合,建立三维矢量数学模型,通过三维可视化技术,形象化地描述灾区的受灾状况和受灾程度,对三维地理空间信息进行可视化管理,实现快速查询、检索、显示、输出、统计、分析及三维可视化,为基于地理信息的决策和管理提供一个真三维的立体可视平台,为地震应急决策部门进行灾害的决策和管理提供三维可视化仿真环境系统。  相似文献   

Statistical Analysis of the Dynamic Parameters of Silty Clay in the Beijing Area     

Shi Chunhu  Lü Yuejun  Peng Yanju  Tang Rongyu 《中国地震研究》2010,24(1):117-127

Soil dynamic parameters, including dynamic shear modulus ratio and damping ratio, have important effects on the results of layered soil earthquake response. In this paper, the mean parameter values of silty clay in different depths are obtained after statistical analysis of the experimental soil dynamic data from 20 recent site seismic safety evaluation reports in the Beijing area. Furthermore, based on two typical engineering sites, the influence of four different soil dynamic parameters, the statistic mean values, experimental values, values recommended by Yuan Xiaoming, and the values recommended in the code for seismic safety evaluation of engineering sites ( DB001 -94) are analyzed. The result shows that mean statistical values are applicable to seismic safety evaluation work in the Beijing area, especially for some inter-layered silty clays whose undisturbed soil samples are hard to obtain.  相似文献   

地震前氡衰变引起大气温度与湿度异常问题讨论          下载免费PDF全文

谭延亮  屈景年  肖德涛  丘寿康 《地震学报》2010,32(1):88-93

强地震前地震区域会出现卫星热红外增温异常现象,S A Pulinets提出了一种新的解释,认为是震前地表大量析出的222Rn衰变产生的高能α粒子使得空气电离,这些离子很容易吸附水蒸气分子,导致大气中潜热的释放,使得空气温度、湿度发生显著变化.本文分析了高能α粒子对空气辐射电离后的主要物理、化学作用,估算了放热和吸附水蒸气分子数量的极大值,结果表明空气温度、湿度的变化是微不足道的.由此认为,地震前出现的温度升高、湿度下降的现象可能与氡浓度变化无关.  相似文献   

黏度时变性宾汉体浆液的柱-半球形渗透注浆机制研究   总被引：2，自引：0，他引：2  

杨志全  侯克鹏  郭婷婷  马秋 《岩土力学》2011,32(9):2697-2703

浆液黏度时变性对注浆扩散范围计算值影响很大。基于宾汉体浆液的流变方程与流体黏度时变性方程,建立了黏度时变性宾汉体浆液的流变方程与渗流运动方程,并依据某些假设,推导了时变性宾汉体浆液柱-半球形渗透注浆机制及探讨了半球体部分扩散半径l1与柱体部分扩散长度m的关系：m=(2l1 /3)(2n+1)。通过设计室内注浆试验对其进行了验证,结果表明：由黏度时变性宾汉体浆液的柱-半球形渗透机制计算的半球体部分扩散半径、圆柱体部分扩散长度及注浆扩散体体积的理论值与试验测量值虽分别有15%、10%及40%左右的差异,但都处于可接受误差范围内,因而,在总体上能较好地反映黏度时变性宾汉体浆液的柱-半球形注浆渗透规律,对注浆设计、施工和理论研究等方面具有一定的参考价值与指导作用  相似文献   

城市下垫面特性对辐射雾生消过程影响的数值研究     

陈龚梅  尹球  杨军 《热带气象学报》2015,31(3):395-402

针对城市下垫面条件进行合理的参数设置,将城市影响引入辐射雾模式,并结合NCEP/ CFSv2(Climate Forecaset System Verison2)资料及常规气象观测资料,对2010年2月8日发生在上海宝山的一次辐射雾过程进行数值研究。结果表明:(1) 受城市地表影响,感热输送成为城市地表加热大气的主要方式;城市下垫面的湍流交换作用较强,近地面湍流交换系数最大可达2.0 m2/s;(2) 城市辐射雾的起雾高度比农村高,雾首先在32 m高度上形成,且雾顶可发展到150 m高度;上部雾形成的主要原因是长波辐射冷却引起的水汽凝结;而8 m以下气层雾形成的主要原因是重力沉降导致的含水量的累积。   相似文献