Salmon age, sex, and length data from Bristol Bay, Alaska, 1957-2009

Age, sex, and length (ASL) data provide population dynamics information that can indicate how population 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 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 Bristol Bay, Alaska from 1957-2009. It includes data on five salmon species: chinook, chum, coho, pink, and sockeye. 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 freshwater and saltwater ages 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 a .csv of formatted ASL data (ASL_formatted_BristolBay.csv), an R script detailing the data processing steps (ASL_Formatting_BristolBay.R), the original .csv file (BB_ASL.csv), and the Microsoft Access Database file from which the original .csv was extracted (ADFG_Bistol Bay ASL and count.mdb).年龄、性别与体长（Age, sex, and length，简称ASL）数据可提供种群动态信息，用以揭示种群趋势的发生与变化规律。此类数据能够帮助研究人员估算种群增长率、年龄级分布及种群人口统计学特征。明确种群人口统计学特征、增长率与发展趋势，对于需开展种群评估以制定管理决策的渔业管理者而言尤为关键。因此，这类数据对于阿拉斯加鲑鱼渔业这类高价值渔业而言至关重要。 本数据集涵盖1957年至2009年间，从阿拉斯加布里斯托尔湾商业性与自给性鲑鱼捕捞的年度采样及研究项目中整理得到的年龄、性别与体长数据，涉及5种鲑鱼：奇努克鲑（chinook）、狗鲑（chum）、银鲑（coho）、粉鲑（pink）及红鲑（sockeye）。 年龄估算通过检视鳞片或骨性结构（如耳石——耳骨）完成。鳞片取自鱼体侧线以上的左侧区域（通常为该位置）。随后将鳞片或骨性结构粘贴于涂胶卡片，并压印于醋酸纤维膜上以留存印痕。通过计数淡水与海水生长轮（即年轮）的数量，以年为单位分别估算淡水生长年龄与海水生长年龄。 鱼类性别可通过检视外部形态（如头部与腹部形态）或内部生殖器官确定。体长以毫米为单位测量，通常的测量起点为眼部中点，终点为尾叉处。 本数据集包含格式化后的ASL数据CSV文件（ASL_formatted_BristolBay.csv）、详述数据处理流程的R脚本（ASL_Formatting_BristolBay.R）、原始CSV文件（BB_ASL.csv），以及用于提取原始CSV文件的Microsoft Access数据库文件（ADFG_Bistol Bay ASL and count.mdb）。