Spatially explicit estimates of stock size, structure and biomass of North Atlantic albacore tuna (Thunnus alalunga) in the North Atlantic for the period 1987-2011, compiled from statistics about ICCAT fishery region L6@en

The development of the ecosystem approach and models for the management of ocean marine resources requires easy access to standard validated datasets of historical catch data for the main exploited species. They are used to measure the impact of biomass removal by fisheries and to evaluate the models skills, while the use of standard dataset facilitates models inter-comparison. North Atlantic albacore tuna is exploited all year round by longline and in summer and autumn by surface fisheries and fishery statistics compiled by the International Commission for the Conservation of Atlantic Tunas (ICCAT). Catch and effort with geographical coordinates at monthly spatial resolution of 1° or 5° squares were extracted for this species with a careful definition of fisheries and data screening. In total, thirteen fisheries were defined for the period 1956-2010, with fishing gears longline, troll, mid-water trawl and bait fishing. However, the spatialized catch effort data available in ICCAT database represent a fraction of the entire total catch. Length frequencies of catch were also extracted according to the definition of fisheries above for the period 1956-2010 with a quarterly temporal resolution and spatial resolutions varying from 1°x 1° to 10°x 20°. The resolution used to measure the fish also varies with size-bins of 1, 2 or 5 cm (Fork Length). The screening of data allowed detecting inconsistencies with a relatively large number of samples larger than 150 cm while all studies on the growth of albacore suggest that fish rarely grow up over 130 cm. Therefore, a threshold value of 130 cm has been arbitrarily fixed and all length frequency data above this value removed from the original data set.海洋生态系统管理方法与海洋资源管理模型的研发，亟需获取针对主要捕捞鱼种的经标准化验证的历史捕捞数据集。此类数据集既可用于量化渔业生物量移除的影响、评估模型性能，同时标准化数据集的应用也可助力开展模型间的比对研究。 北大西洋长鳍金枪鱼（North Atlantic albacore tuna）全年均受延绳钓捕捞，夏秋季则同时面临表层渔业捕捞；相关渔业统计数据由大西洋金枪鱼养护国际委员会（International Commission for the Conservation of Atlantic Tunas, ICCAT）汇编整理。 本数据集针对该鱼种提取了空间分辨率为1°或5°方格、按月度统计的捕捞量与捕捞努力量数据，并对捕捞作业类型与数据筛选流程进行了严格界定。研究时段为1956年至2010年，共划定13类捕捞作业，涉及延绳钓、曳绳钓、中层拖网与诱饵钓四种渔具类型。 不过，大西洋金枪鱼养护国际委员会数据库中已空间化的捕捞努力量数据仅占总捕捞量的一小部分。本研究同时针对1956-2010年的上述捕捞作业类型，提取了按季度统计的捕捞体长频率数据，其空间分辨率范围为1°×1°至10°×20°。体长测量所用的组距也存在差异，分别为1、2或5厘米（叉长，Fork Length）。 数据筛查过程中发现了一处矛盾：存在大量体长超过150厘米的样本，但现有长鳍金枪鱼生长研究均表明，该鱼种极少能长至130厘米以上。因此，研究人员设定了130厘米的阈值，将所有超过该值的体长频率数据从原始数据集中剔除。