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Survey Count Data

Much data are collected during the course of managing salmon fisheries or operating stock assessment and research in AYK. We have attempted to categorize related data into “types” allowing them to reside in separate databases which can accommodate their different data structure. Not all data “types” have been added to our DBMS. Currently we include ASL, CPUE, Escapement Counts, Harvest, and Survey Counts data. This is in contrast to data relating to radio telemetry locations of salmon, environmental measurements (temperature, water depth, velocity, etc.) or juvenile salmon data which could be added at a later time.

The survey counts data type consists of counts of migrating, pre-, or post- spawning salmon (Oncorhynchus sp) in the AYK Region. Counts of salmon were made by observers conducting surveys using aircraft, boats, or while walking in or along waterways. Surveys were conducted by ADF&G, federal agencies, and non-governmental organizations. The accuracy of survey count data can be highly variable and is dependent upon a number of factors such as weather and water conditions, timing of survey, altitude, experience of pilot and observer, streambed coloration, and species of salmon enumerated. Surveyors evaluate and record environmental conditions affecting survey quality, rate a survey as poor, fair, or good, and include notes helpful in data interpretation. Counts, survey location, date collected, observer, agency, and environmental conditions are included in the data set. Counts of salmon do not necessarily represent total abundance at that location for at least two important reasons. First an observer is rarely able to see all salmon present and the percent observed can vary by observer and weather conditions. Secondly, not all salmon that will migrate into the survey location are present on the day a survey is flown. Some may have arrived much earlier, spawned and their carcasses washed out and some have yet to arrive. Thus the counts are only an index of abundance. Surveys are generally timed to coincide with peak salmon spawning activity but may be conducted earlier to assess the build up of salmon in a river for fishery management purposes. You should also note that all salmon may be counted but the timing of the survey was chosen to coincide with peak spawning of only one species.  

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