Evaluation of separation performance on selective fishing device for fisheries resources management.

渔业资源管理选择性捕捞装置分离性能评价。

基本信息

批准号：
14560145
负责人：
TOKAI Tadashi
金额：
$ 2.05万
依托单位：
Tokyo University of Marine Science and Technology (2004)東京水産大学 (2002-2003)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

The size selection curve of fine mesh for Anchovy larvae were estimated by using an extended SELECT model for analyzing size frequency distribution constructed from pockets catches and sampling the cod-end catches, and from covered-net experiments. Higher catch volume were decreasing escape opportunities and selectivity.Capture process of clam by dredge was modeled. First, Master curve equation of size selectivity of dredge bagnet for a clam, equilateral Venus Gomphina melanaegis was estimated by using cover-net fishing experiments with test bagnets of several mesh sizes. The size selectivity of dredge bagnet was a kind of contact selection of bagnet mesh. Second, The effect of various tooth-spacing on the contact selection and the net-mouth available selection of a dredge for the equilateral Venus clam Gomphina melanaegis was evaluated by applying a contact-probability model based on the SELECT method to the data of paired-gear tests with a control dredge of 12mm tooth spacing and fou … More r test dredges of tooth spacing 16,20,24,and 35mm. A master selection curve was estimated to be s(R)=exp(-11.23R+4.799)/[1+exp(-11.23R+4.799)], where Ris Id, the ratio of the shell length 1 to the tooth spacing d. The shell width of 50% retention was slightly smaller than the tooth spacing, which means that size selectivity of teeth was a type of contact selection which was dependent on the tooth spacing. Contact probability δ of the clams coming into contact with the teeth were 0.625,0.467,0.563,0.670,and 0.976 for tooth spacing 12,16,20,24,and 35mm, respectively. This indicates that some clams entered the dredge bagnet without contacting the teeth as the sand clogging the tooth spacing carried them into the bagnet. Available selection curve of the dredge net-mouth with teeth was obtained as δ s(R)+1-δ and examined in terms of the minimum landing size of the Venus clam.A method for assessing species-separation performance of size-selective fishing gear is presented. Species composition in catch by selective fishing gear is often discussed to assess the performance of the selective device. However, the catch number (and weight) depends on body size composition in the population when the fishing gear has size selectivity, and thus species composition varies and is not suitable as gear performance index. In fact some selective devices, e.g.mesh panel, grid, and escape-vent have been reported to be size-selective. When a selective device has retention probabilities of body size 1, r_w(l) and r_u(l) for wanted and unwanted species, respectively, separation efficiency p(l_w, 0l_u) between l_w size wanted and l_u-size unwanted species is defined as r_w(l_w)+[1-0r_u(l_u)]-1. The efficiency is 1 when wanted species is completely retained and unwanted is excluded as expected, and is -1 in the exact opposite of the expectation. The equation implied that the separation efficiency is likely to be high as there is larger difference in body size between the two species. Less

通过使用扩展的选择模型来估算an鱼幼虫的尺寸选择曲线，用于从口袋捕获和采样COD-END捕获量的分析尺寸频率分布以及从覆盖网络实验中进行的。较高的捕捞量正在降低逃生机会和选择性。挖掘的蛤capture过程被建模。首先，通过使用盖网钓鱼实验进行了几个网状尺寸的测试袋，估算了挖掘袋子对蛤lam的尺寸选择性的等效性。 Dredge Bagnet的尺寸选择性是Bagnet网眼的一种接触选择。其次，通过应用基于选择方法的方法数据，以12mm的牙齿间距和FOU测试裁判的控制疏其他方法来评估，各种齿间隔对等效金星Gomphina Melanagis的疏水格的影响以及可获得的等效性金星Gomphina Melanagis的疏水材料的效果。主选择曲线估计为s（r）= exp（-11.23r+4.799）/[1+exp（-11.23r+4.799）]，其中RIS ID，壳长1与牙齿间距的比率d。 50％保留率的壳宽度比牙齿间距稍小，这意味着牙齿的尺寸选择性是一种取决于牙齿间距的接触选择。与牙齿接触的蛤的接触概率δ分别为0.625,0.467,0.563,0.670，牙齿间距为12,16,20,24和35mm，分别为0.976。这表明，当沙子堵塞牙齿间隔时，有些蛤bagnet进入了法官的行李板，而没有接触牙齿。在金星蛤的最小降落尺寸方面，获得了带有牙齿的法官净嘴的可用选择曲线。经常讨论选择性渔具中的物种组成，以评估选择性装置的性能。但是，当渔具具有尺寸选择性时，气体数（和重量）取决于人群中的体型组成，因此物种组成范围不适合作为齿轮性能指数。实际上，据报道，某些选择性设备，例如网格面板，网格和逃生式漏洞是尺寸选择性的。当选择性设备具有1尺寸1，R_W（L）和R_U（L）的保留可能性时，分别用于通缉和不需要的物种时，L_W大小和L_U大小不需要的物种之间的分离效率P（L_W，0L_U）被定义为R_W（L_W（L_W）+[1-0r_u（l_u（l_u（l_u l_u））-1-1-1。效率为1时，完全保留了通缉物种，并且不需要预期的是不需要的物种，而预期的恰恰相反。方程表示，由于两个物种之间的体型差异较大，因此分离效率可能很高。较少的