Daily salmon escapement counts from the OceanAK database, Alaska, 1921-2017

As salmon migrate from the marine environment to freshwater streams to spawn, a certain number are allowed to pass through, or escape the salmon fishery (frequently located near the mouth of the freshwater stream) as a management strategy to preserve the species. Escapement data are the enumeration of these migrating fish as they pass upstream, and represent an index of the total abundance of spawning salmon in that particular stream. These data are important for fisheries management, since most salmon harvest occurs in or near freshwater rivers during this migration. Escapement data are collected in a variety of ways. Stationary projects utilize observers stationed along freshwater corridors who count salmon as they pass upriver through weirs or past elevated towers. Sonar equipment placed in the river can also give a stationary escapement count. These counts usually represent a sample, and are expanded to represent a 24h period. Escapement data can also be collected using aerial surveys, where observers in an aircraft provide an index to estimate escapement. In general, escapement counts do not represent total abundance, but instead an index of abundance. Surveys are usually timed to coincide with peak spawning activity, generally in the summer, but in the case of Coho salmon in the fall as well. This dataset contains salmon escapement data extracted from the Alaska Department of Fish and Game's OceanAK database, and contains data from multiple regions in Alaska.

当鲑鱼从海洋环境洄游至淡水溪流产卵时，作为保护该物种的管理策略，部分个体被允许通过或逃脱鲑鱼捕捞区（通常位于淡水溪流入海口附近）。
逃脱数据（Escapement data）是对这些向上游移动的洄游鱼类的计数，代表特定溪流中产卵鲑鱼总数量的指标。
这些数据对渔业管理至关重要，因为大多数鲑鱼捕捞发生在洄游期间的淡水河流内或其附近。
逃脱数据的收集方式多样。
固定监测项目通过在淡水通道沿线部署观察员，统计鲑鱼通过鱼梁或经过高架塔向上游移动的数量。
河流中部署的声呐设备也可提供固定逃脱计数。
这些计数通常为样本数据，并会被扩展以代表24小时周期的情况。
逃脱数据也可通过航空调查收集，飞机上的观察员会提供估算逃脱数量的指标。
总体而言，逃脱计数不代表总数量，而是数量指标。
调查通常安排在产卵高峰期进行，一般在夏季，但银鲑（Coho salmon）的调查也会在秋季进行。
本数据集包含从阿拉斯加渔猎部OceanAK数据库提取的鲑鱼逃脱数据，涵盖阿拉斯加多个区域的数据。