Salmon age, sex, and length data from Arctic-Yukon-Kuskokwim Region of Alaska, 1960-2017

Age, sex and length data provide population dynamics information that can indicate how populations trends occur and may be changing. These data can help researchers estimate population growth rates, age-class distribution and population demographics. Knowing population demographics, growth rates and trends is particularly valuable to fisheries managers who must perform population assessments to inform management decisions. These data are therefore particularly important in valuable fisheries like the salmon fisheries of Alaska. This dataset includes age, sex and length data compiled from annual sampling of commercial and subsistence salmon harvests and research projects in the Arctic-Yukon-Kuskokwim region of Alaska. It includes data on five salmon species: chinook, chum, coho, pink and sockeye. There is some data on non-salmon species (whitefish, sheefish, longnose sucker, Dolly Varden) in the Yukon dataset. There is an additional data table for more specific information about the locations where samples were collected. Age estimates were made by examining scales or bony structures (e.g. otoliths - ear bones). Scales were removed from the side of the fish; usually the left side above the lateral line. Scales or bony structures were then mounted on gummed cards and pressed on acetate to make an impression. The number of freshwater and saltwater annuli (i.e. rings) was counted to estimate age in years. Fish sex was determined by either examining external morphology (eg. head and belly shape) or internal sex organ. Length was measured in millimeters, generally from mid-eye to the fork of the tail. This data package includes the original data files, reformatting scripts that reformat the original data files into a consistent format, and the reformatted datasets.

年龄、性别与体长数据可提供种群动态相关信息，用以揭示种群趋势的发生规律与变化态势。此类数据能够辅助研究人员估算种群增长率、年龄结构分布以及种群统计特征。掌握种群统计特征、增长率及变化趋势，对于需要开展种群评估以制定管理决策的渔业管理者而言具有重要价值。因此，此类数据对于阿拉斯加鲑鱼渔业这类高价值渔业而言尤为关键。
本数据集包含从阿拉斯加北极-育空-库斯科奎姆（Arctic-Yukon-Kuskokwim）区域内商业性、自给性鲑鱼捕捞及相关研究项目的年度采样中整理得到的年龄、性别与体长数据。数据集涵盖5种鲑鱼：大鳞大麻哈鱼（chinook）、狗鲑（chum）、银鲑（coho）、粉鲑（pink）及红鲑（sockeye）。育空数据集内还收录了部分非鲑鱼类物种的数据，包括白鲑（whitefish）、sheefish、长鼻吸口鱼（longnose sucker）、多丽沃登鱼（Dolly Varden）。本数据集附带一张额外的数据表，用于记录采样点位的详细信息。
年龄估算通过观察鱼鳞或骨骼结构（如耳石（otoliths，即耳骨））完成。鱼鳞通常取自鱼体左侧侧线以上区域。随后将鱼鳞或骨骼结构粘贴在涂胶卡片上，并压印在醋酸纤维膜上以获取样本印迹。通过计数淡水生长环与海水生长环（即年轮）的数量，以估算鱼类的年龄（以年为单位）。鱼类性别通过两种方式判定：一是观察外部形态特征（如头部与腹部形态），二是解剖观察内部生殖器官。体长以毫米为单位进行测量，通常测量起点为眼部中点，终点为尾鳍分叉处。
本数据包包含原始数据文件、用于将原始数据文件统一格式化为标准格式的格式化脚本，以及格式化后的数据集。