Species selectivity in different sized topless trawl designs: Does size matter?
Species selectivity in different sized topless trawl designs: Does size matter?
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DOI：
10.1016/j.fishres.2015.07.010
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发表时间：
2015-12-01
影响因子：
2.4
通讯作者：
Mieske, Bernd
中科院分区：
文献类型：
--
作者：
Krag, Ludvig A.;Herrmann, Bent;Mieske, Bernd
大多数底层拖网捕捞是在多鱼种环境中进行的，渔获物包括几个不同的鱼种。这类渔业的一个固有挑战是对个别波动的种群和船只或船队的特定配额进行生物和经济上可持续的开发。开发无顶拖网设计是为了提高这种渔业对特定鱼种的选择性。在无顶拖网中，底绳位于比顶部更靠前的位置，以允许鱼向上逃逸，而在传统拖网设计中，顶部位于前面。在这项研究中，我们进行了双拖网与无顶拖网拖曳平行类似的标准拖网，我们测试了无顶拖网设计的小拖网低标题高度和较大的拖网高标题高度。我们进行了拖曳在肾（Nephrops norvegicus）定向混合渔业。对于小型和大型拖网，我们发现了一个显着的无上装的影响黑线鳕（Melanogramus aeglefinus）和没有影响的Nephrops。对于大西洋鳕鱼（Gadus morhua），我们发现了一个显着的无顶效果低标题拖网，但没有影响高标题拖网。在东大西洋和西大西洋，无顶拖网已作为法律的鳕鱼选择性拖网设计被采用。然而，这项研究表明，对不同尺寸的类似拖网进行相同的渔具修改，并在同一渔业中使用，可能会导致不同的结果。(C)2015 Elsevier B.V.版权所有。
Most demersal trawl fisheries are conducted in a multispecies setting, and the catch consists of several different species. An inherent challenge in such fisheries is to provide both biologically and economically sustainable exploitation of individually fluctuating stocks and vessel- or fleet-specific quotas. The topless trawl design was developed to improve species-specific selectivity in such fisheries. In a topless trawl, the foot rope is located more forward than the headline to allow fish to escape upwards, whereas the headline is located in front in traditional trawl designs. In this study we conducted twin trawls with a topless trawl towed parallel to a similar standard trawl; we tested a topless trawl design on a small trawl with a low headline height and on a larger trawl with a high headline height. We conducted the tows in the Nephrops (Nephrops norvegicus) directed mixed fisheries. For both the small and large trawls, we found a significant topless effect for haddock (Melanogramus aeglefinus) and no effect for Nephrops. For Atlantic cod (Gadus morhua) we found a significant topless effect for the low headline trawl but no effect for the high headline trawl. In both the eastern and western Atlantic, topless trawls have been introduced as legal cod-selective trawl designs. However, this study demonstrates that identical gear modifications made to similar trawls of different sizes and used in the same fishery can lead to different results. (C) 2015 Elsevier B.V. All rights reserved.