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首页> 外文期刊>ICES Journal of Marine Science >Estimating efficiency of survey and commercial trawl gears from comparisons of catch-ratios
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Estimating efficiency of survey and commercial trawl gears from comparisons of catch-ratios

机译：通过捕获比率的比较来估算调查和拖网渔具的效率

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摘要

Assumptions about gear efficiency and catchability influence estimates of abundance, mortality, reference points and catch potential. Despite the need to better quantify fishing effects on some target species and on many non-target species taken as bycatch, there are few gear efficiency estimates for some of the most widely deployed towed fishing gears in the northeast Atlantic. Here, we develop a method that applies generalised additive models to catch-at-length data from trawl surveys and a commercial catch and discard monitoring program in the North Sea to estimate catch-ratios. We then rescale these catch-ratios and fit relationships to estimate gear efficiency. When catches of individuals by species were too low to enable species-specific estimates, gear efficiency was estimated for species-groups. Gear efficiency (and associated uncertainty) at length was ultimately estimated for 75 species, seven species-groups and for up to six types of trawl gear per species or species-group. Results are illustrated for dab (Limanda limanda), grey gurnard (Eutrigula gurnardus) and thornback ray (Raja clavata), two common non-target species and a depleted elasmobranch. All estimates of gear efficiency and uncertainty, by length, species, species-group and gear, are made available in a supplementary data file.
机译：关于渔具效率和可捕性的假设会影响丰度，死亡率，参考点和捕捞潜力的估计。尽管需要更好地量化捕捞对某些目标物种和作为兼捕的许多非目标物种的捕捞影响，但对东北大西洋部署最广泛的一些拖曳式渔具的渔具效率估算很少。在这里，我们开发了一种方法，该方法将广义附加模型应用于来自拖网调查的长距离捕捞数据以及北海的商业捕捞和丢弃监测程序，以估算捕捞比。然后，我们重新调整这些捕获比率并拟合关系以估计齿轮效率。当按物种捕获的个体捕获量太低而无法进行特定物种的估算时，就可以估算出不同物种的渔具效率。最终估计了75种，7个物种组以及每个物种或物种组最多6种拖网渔具的齿轮效率（及相关的不确定性）。结果说明了两种常见的非目标物种和枯竭的弹性da鱼，包括轻（（Limanda limanda），灰（Eutrigula gurnardus）和棘背back（Raja clavata）。齿轮效率和不确定性的所有估计值（按长度，种类，种类组和齿轮）均在补充数据文件中提供。

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