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首页> 外文期刊>ICES Journal of Marine Science >Onshore biological sampling of landings by species and size category within auction sites can be more efficient than trip-based concurrent sampling
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Onshore biological sampling of landings by species and size category within auction sites can be more efficient than trip-based concurrent sampling

机译：拍卖网站内物种和大小类别的着陆的陆上生物学抽样可以比基于跳闸的并发采样更有效

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摘要

Since 1996, the European Union has required that fishery products of 35 fish species or groups of species, including crustaceans and cephalopods, be graded before being landed on the basis of commercial size-categories. A multi-stage sampling scheme to estimate catch-at-length and catch-at-age compositions of total annual landings has been conducted in Portuguese waters since 2009. All species and their size-categories are sampled concurrently from random trips within representatively selected site-days annually. In an effort to improve cost-efficiency of the biological catch sampling of commercial landings in Portugal, a size- category sampling scheme was tested during 2017, taking advantage of the stratification of horse mackerel landings, induced by the mandatory grading of landings by size-category. The total number of site-days (primary sampling units), fish boxes sampled, and specimens of horse mackerel sampled for length and age across strata during the pilot study were 30%, 57%, and 12% of the sampling carried out under the standard concurrent scheme, respectively. The assignment of horse mackerel length to the six commercial size-categories was highly consistent across site-days. Our study shows that the concurrent sampling, where trips are subsampled within site-days, could miss some size-categories by chance, resulting in poor estimates of catch-at-length especially for small fish present at the market during a site-day. The size-category sampling scheme ensured subsamples of fish from all size-categories within a site-day, and achieved data on catch-at-age that are fit-for purpose at 24% of the total cost for the standard concurrent sampling. The effect of sampling designs and sample sizes on horse mackerel stock assessment outputs showed that the onshore biological sampling to estimate catch-at-age compositions for stock assessment is optimized with the size-category sampling scheme. Pilot field experiments should be carried out for selected species that evidence consistent size grading among commercial categories.
机译：自1996年以来，欧洲联盟要求渔业产品35种鱼类或物种组，包括甲壳类动物和头孢粒ods，然后在被商业规模类别的基础上降落之前进行评级。自2009年以来，葡萄牙水域估算了每年年龄较长和年龄组成的多阶段采样方案已经在葡萄牙水域中进行了葡萄牙水域。所有物种及其规模类别都是从代表选择的网站内的随机旅行中兼出的每年。在努力提高葡萄牙商业着陆的生物捕获采样的成本效率，2017年测试规模 - 类别采样方案，利用马鲭鱼着陆的分层，通过规模的强制性分级引起的类别。在试点研究期间，现场日（主要采样单位），鱼箱采样的鱼箱采样的鱼箱和马鲭鱼的标本为30％，57％和12％的采样标准并发方案分别。马鲭鱼长度与六个商业规模类别的分配在跨境天数高度一致。我们的研究表明，旅行在现场日期内的同时采样可能会错过偶然的一些规模类别，导致在网站日期间市场上存在的小鱼，导致捕获量的估计差。尺寸类别采样方案确保了网站日内所有大小的鱼类的亚排，并在标准并发采样总成本的24％上实现了适合的捕捞时间的数据。采样设计和样品尺寸对马鲭鱼股票评估产出的影响表明，陆上生物取样估计股票评估的捕捞时间组合物的尺寸 - 类别采样方案进行了优化。试验现场实验应为所选物种进行，证明商业类别中一致规模分级。

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