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Errors Associated with a Systematic Sampling Creel Census
Author(s) -
Johnson Merle W.,
Wroblewski Leonard
Publication year - 1962
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1962)91[201:eawass]2.0.co;2
Subject(s) - census , sampling (signal processing) , statistics , sample (material) , fish <actinopterygii> , fishing , sampling error , geography , systematic error , environmental science , mathematics , observational error , demography , fishery , biology , population , computer science , telecommunications , chemistry , chromatography , sociology , detector
An analysis of errors associated with creel census estimates obtained by systematic sampling is presented. The sample census method makes use of instantaneous boat counts at regular intervals, and provides a sample of about 24 percent of the fishing hours. To evaluate the census method, samples representing two census patterns were extracted from complete creel census data from Many Point Lake, a 1,716‐acre walleye lake. Sampling errors at the 95‐percent level for a 142‐day summer census were about ± 13 percent for estimated man‐hours; ± 17 percent for estimated man‐trips; ± 17 percent for numbers of fish by species; and ± 19 percent for pounds of fish by species. Methods for calculating creel census error are presented and discussed. The largest component of error was associated with estimates of boat‐hours. Catch per boat‐trip also showed considerable error. Computation of estimates and error was greatly facilitated by calculating from a season‐long sample rather than by using summary calculations for shorter intervals. An even distribution of census days throughout the week appears preferable to separate consideration of weekdays and week‐end days with greater census effort on the latter.