围绕"以专业课程改革为中心推动学生实践能力和创新能力培养,以科创项目和学科竞赛为抓手务实学生对专业课程的学习和专业知识能力的应用",对课程教学方法和人才培养模式进行了较好的探索和实践.

在麦穗鱼鱼群中,随着邻居鱼的靠拢,其影像在本鱼眼睛中占的视角会变大.为了进一步探究其他的鱼群是否也存在相同的规律,本实验选用个体体长较小的喜成群的红吻半线脂鲤[由30尾组成,平均体长:(20.3±0.2) mm]作为对比研究对象,将其放置在水深5 cm的水族缸(78.0 cm×52.0 cm×65.0cm)中,使用摄像机从正上方拍摄鱼群影像.逐幅提取鱼群影像中各个体的头部、质心(近头部1/3处)、尾部的二维数据,经过数据处理,分析视角与NND间的关系.结果表明:1)红吻半线脂鲤与麦穗鱼的视角均集中在80°内,即本鱼观察邻居鱼的视角不大于80°.2)在体长差异较大的两种鱼群中,邻近个体占据本鱼的视野范围不会因为鱼体的增大而增加.3)邻近个体占据本鱼视野的最大视角与二者NND间满足以下关系:xy=A,y为视角(用弧度表示),x为NND(单位:BL),A为常数.该规律适用于麦穗鱼与红吻半线脂鲤群体.4)该关系式表示,当邻居鱼靠近本鱼时,为了避免碰撞,鱼类个体用视角作为控制的主要参数,调整相互距离.研究表明,视觉在起主导作用,而侧线、嗅觉、电感觉、磁感觉等即使起作用,也处于次要的地位.

为了提高网片水动力系数的计算精度,本文通过动水槽实验对5种网片的水动力学性能进行测试.测试的参数包括水流对网片的冲角、流速、网片的水平缩结系数ET等,网片的水动力学升力系数CL、阻力系数Cd、升阻系数比K等.结果表明:(1)当雷诺数Re小于1 500,冲角小于45°时,阻力系数呈现先增后减的趋势;而冲角大于45°时,阻力系数呈减小的趋势.雷诺数Re大于2 800时,阻力系数基本趋于稳定.(2)升阻系数比K最大值出现在20°附近;在30°～ 90°之间,K值呈减小趋势;(3)升阻力系数随d/a的增大先增大后减小;(4)升阻力系数随线面积系数的增大而减小;(5)通过多元非线性拟合得出升阻力系数的经验公式,拟合度较好.本实验经验公式为拖网阻力的计算提供了依据.

为了探究麦穗鱼群体动态结构的特征参数,以及这些参数可能反映的行为机理,本实验使用2台摄像机从俯视和侧视2个方向同时拍摄由13尾麦穗鱼组成的群体,获取连续时间内麦穗鱼群体中各个体的三维位置数据,对个体间最近邻近距离、视角、转角变化量、个体游泳速度等参数进行分析.结果表明:麦穗鱼个体最近邻近距离多数处于0.5 ～2 BL,偏好的最近邻近距离为0.6～0.8 BL;麦穗鱼总是将最邻近的个体保持在本鱼80°视野范围内;避免碰撞时,个体鱼转角改变量为0 ～30°;在无人为干扰的自然环境下,个体鱼以0.75 BL/s左右的速度配合其他个体保持运动速度一致性.实验观察证实,视觉对麦穗鱼个体间的分布起着关键性作用,此外麦穗鱼群体动态结构还受到个体状态(饱食与饥饿)的影响.

This study aimed to improve the estimation of the cylinder drag coefficient, and its accuracy for fishing gears. Five surveys on tuna longline fishing grounds were conducted between 2005 and 2010. Collected data include three dimensional current velocities in different water layers and hook depth. Hook depths were calculated by drag coefficients of the cylinder with a perpendicular flow (C-N90) of 1.04 to 1.40 (interval of 0.02), and compared with measured depths. The coefficient of variation (CV) was calculated for 70% of the hooks at their measured depths. Additionally, a t-test was conducted comparing depths predicted by the model against measured depths of the remaining sites, totaling 30%. The results showed that the hydrodynamic forces on longline gear have a C-N90 between 1.08 and 1.16, and the drag coefficient decreased with increasing Reynolds number (Re, Re < 10(3)). These results suggest that numerical modeling and at-sea measurement can be used to determine the drag coefficient (C-N90) of cylinders such as ropes and lines, and that a drag coefficient of 1.08 to 1.16 are reasonable values for cylinder components of longlines. (C) 2014 Elsevier Ltd. All rights reserved.

On the basis of the data collected from October 2010 to January 2011 in the tuna longline survey, the soak time calculation models of every branch line in each operation were developed by both modes of hook re-trieval. The soak time of longline gear divided into one hour interval for the quantity of hooks and the individuals of bigeye tuna (Thunnus obesus) and yellowfin tuna (Thunnus albacores), respectively. The respective catch rates (CPUEs) of bigeye tuna and yellowfin tuna in each hour interval were calculated. The results showed that (1) both CPUE of bigeye tuna and yellowfin tuna presented increasing at first and then decreasing trend along the increase of soak time. The reason was the lure effect fluctuation of bait and the lose of hooked fish; (2) the quadratic curves can be fit the relationships between soak time and the CPUE of bigeye tuna, and yellowfin tuna; (3) the CPUE of bigeye tuna and yellowfin tuna was the highest when soak time was 9.9 h and 10.1 h, respectively. This study suggested that (1) the soak time of each hook lasted about 9.5-10.5 h in the tuna longline operation for improving the fishing efficiency and decreasing the bycatch; (2) the soak time of the longline gear could be considered as the effective fishing effort and used to standardize the CPUE. The results will be applied to improve the fishing effi-ciency and to decrease the bycatch and will be applied for the references to the fishing strategy and CPUE stan-dardization.

The most of fish species have the schooling behavior,due to the different causes and mechanism of schooling,which are presented by varied definitions of different words,such as shoal,cluster or aggregation, even swam or flock,etc. This article describes and analyses the definitions and classification based on their characteristics,and recommends the word"schooling"is mostly reflecting the phenomenon of fish migration in group. The way to explore the mechanism of schooling,the factors having impact on their behavior,and the methods used in the varied studies are reviewed. And the characteristics of the structure of fish school,subgroups,the phenomena of self-organization,etc. are summarized. It is recommended that the mathematics model and simulation technique are effective methods to explore the mechanism of fish self-organization phenomenon. This is a way to understand nature by "linkage by phenomena only",based on observation data,experience and phenomena observed,building mathematics model for predicating and forecasting the fish behavior and schooling structure,and the results of simulation will again be compared with the actual observation records. It might speculate or determine the dominant factors affecting the schooling phenomenon or mechanism. Meanwhile,computer technology provides support for the creation of complex models using simulation technology as an effective tool to study fish schooling behavior in recent years.

This study developed a whole-implicit algorithm and virtual neural lattice to model and simulate the dynamics of pelagic longline gear. The programming, model calculation and behavior simulation of longline dynamics were implemented in R language. Equilibrium state and stable solution of the models were reached. The hooks were more stable in the deepest water layer than that in the midwater layer. It indicated that the whole-implicit method and virtual neural lattice were high efficient and accurate in solving the complicated engineering equations of longline gear, also in the presentation of the motion of longline in sea water.

To better understand the relationships between vertical distribution of bigeye tuna(Thunnus obesus) and water temperature,salinity,chlorophyll-a,dissolved oxygen,horizontal current,and vertical current,and to understand the environmental preferences of bigeye tuna in waters near Gilbert islands,thus to increase the catch rate of bigeye tuna,reduce the bycatch of non-targeting species and select the dominative environment variables as the input to the CPUE standardizing model,longliner Shenliancheng No.719,equipped with a super-spool,was used as the platform for sampling in waters near Gilbert islands from September to December in 2009.The data collected included CTD(XR-620),TDR(2050),and three dimensional current(ADCP2000) profiles,amount of fishing hooks,deploying position and time,course and speed,shooting speed of main line,number of hooks between successive buoys,the time interval between two hooks,beginning time and position of retrieving line,wind force and direction,the drifting speed and direction to the ground and hook code.The capture depth,water temperature,salinity,chlorophyll-a,dissolved oxygen,horizontal current,and vertical current of bigeye tuna area were anayzed.The methods adopted were as follows: ① Calculating the theoretical hook depth by the catenary curve hook depth equation;②Modeling the relationship between the theoretical hook depth and predicted hook depth by means of regression method;③ Calculating all the predicting hook depth based on the predicting hook depth model;④Obtaining a vertical profile reflecting the relationships between temperature,salinity,chlorophyll-a,dissolved oxygen,horizontal current,and vertical current and depth,recorded by XR-620 and ADCP2000,the profiles could be used for calculating temperature,salinity,chlorophyll-a,dissolved oxygen,horizontal current,and vertical current based on the predicted hook depth;⑤ Estimating the catch rate of bigeye tuna at different depths,temperature,salinity,chlorophyll-a,dissolved oxygen,horizontal current,and vertical current ranges based on the sample data.Results indicated that in tuna longline fishing grounds of waters near Gilbert islands,the depth,water temperature,salinity,chlorophyll-a,dissolved oxygen,horizontal current,and vertical current preference range of bigeye tuna was about 200.0-240.0 m,14.0-15.0 ℃,35.00-35.10,0.24-0.26 μg/L,3.0-4.0 mg/L,0.00-0.20 m/s,and 0.03-0.04 m/s,respectively.In general,subadult bigeye tuna prefers temperature from 14.0 to 17.0 ℃ in vast salinity range and at least 0.8 mg/L of dissolved oxygen.

延绳钓钓具系统可以视为不承受扭矩和挤压力、仅承受拉力的柔性线系统。本文以有限元分析为基础，将延绳钓钓具系统离散化成由大量仅有轴向拉力的杆单元组成；杆单元与杆单元之间为无摩擦铰链联接；采用动力学方法，分析各节点的运动。对各节点列出一系列动力学方程组，建立金枪鱼延绳钓渔具三维动力学模型，利用隐式欧拉法对上述二阶微分方程进行求解，并利用R语言对建立的模型进行编程求解。本文所建立的延绳钓渔具系统动力学模型可用来计算获得在各种三维海流下，各节点运动速度、节点张力、延绳钓空间形状的变化情况。

A request was m ade by the chair of WGECO for input by WGFTFB in the risk based assessment w ork related to fisheries impact. A m ethod is being adopted by Ireland to determ ine which fishing gears will be allow ed in m arine protected areas in Irish w a­ ters. The m ethod has been developed in A ustralia and adopted for risk assessment for m ost Australian fisheries. The m ethod has been developed to be flexible, com pre­ hensive, scientifically defensible, and understandable for fisheries m anagers and involves stakeholders. There is a need for data to be fed into the m ethod on selectivity, effects of gear altera­ tions and effects of introduction of alternative gears. WGFTFB holds the expertise to provide the necessary input. The cooperation of WGFTFB is thus requested. The request firstly holds the question w hether there is any interest in WGFTFB to allocate effort to this topic. If positive, the way forw ard should be determ ined. A possibility w ould be the organization of a w orkshop to collate the data. It will be investigated w hether some finances can be found to organize the workshop. 18 .1 .2 Ecological Risk Assessment for the Effects of Fishing Susie Brown1, Emer R ogan1, D avid R eid2 School of Biological, Earth and Environm ental Sciences, University College Cork, Cork, Ireland. 2M arine Institute, Rinville, Oranmore, Co. Galway, Ireland.