| Summary: | The salmon life cycle begins in freshwater streams when adult salmon spawn, leaving fertilized eggs which hatch in the stream. Juvenile salmon migrate downstream to the ocean, where they spend several years until they reach reproductive age. Upon reaching sexual maturity, they return to their natal streams to spawn. The number of mature salmon migrating from the marine environment to freshwater streams is defined as escapement. Escapement data are the enumeration of these migrating fish as they pass upstream, and are a widely used index of spawning salmon abundance. These data are important for fisheries management, since most salmon harvest occurs in 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. These data are the result of a multi-year effort by the Alaska Department of Fish and Game, Division of Commercial Fisheries, Arctic-Yukon-Kusokwim (AYK) Region to create a salmon database management system that centralizes AYK salmon data in a standard format, making the data more accessible to management agencies and the general public. The escapement data portion of this database includes data from more than 70 projects conducted by the Alaska Department of Fish and Game, federal agencies, non-governmental organizations, and the Canadian Department of Fisheries and Oceans. Data span the time period of 1965 to present, and were collected on 58 unique rivers in four management areas. These areas are Kotzebue, Kuskokwim, Norton Sound-Port Clarence, Yukon and Yukon-Canada. The five Alaskan salmon species (Chinook, Chum, Coho, Pink, Sockeye) are all represented in this dataset, in addition to two salmonids (Dolly Varden, Arctic Char).
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