Long-term trends in maximum size of sport-caught chinook salmon (Oncorhynchus tshawyt
By Robert Fagen
Fisheries Research, Volume 6, Issue 2, January 1988, Pages 125-134, ISSN 0165-7836, DOI: 10.1016/0165-7836(88)90032-X.
Weights of first-prize chinook salmon vary with time in four competitive, pulsed Southeastern Alaska recreational fisheries. In the long-established Juneau (1947-present) and Ketchikan (1948-present) derbies, weights of winning fish decrease at average rates of 0.22 and 0.13 kg year-1. Sitka (1956-present) and Haines (1972-present) fish exhibit no demonstrable overall size trend. Exploratory analysis of the derby data indicates additional variation over time. The analysis illustrates fisheries research applications of recent exploratory and graphical data analysis methods, including residual analysis, robust regression, and lowess scatterplot smoothing.