Ages and lengths for a hypothetical sample from Westerheim and Ricker (1979).
Ages and lengths for a hypothetical sample in Westerheim and Ricker (1979).
A data frame of 2369 observations on the following 3 variables:
Unique fish identifiers
Length of an individual fish
Age of an individual fish
Age-length data in 5-cm increments taken exactly from Table 2A of the source which was a sample from a hypothetical population in which year-class strength varied in the ratio 2:1 and the rate of increase in length decreased with age. Actual lengths in each 5-cm interval were simulated with a uniform distribution. The aged fish in this file were randomly selected and an assessed age was assigned according to the information in Table 2A.
Age-Length Key
Simulated from Table 2A in Westerheim, S.J. and W.E. Ricker. 1979. Bias in using age-length key to estimate age-frequency distributions. Journal of the Fisheries Research Board of Canada. 35:184-189.
str(WR79) head(WR79) ## Extract the aged sample WR79.aged <- subset(WR79,!is.na(age)) str(WR79.aged) ## Extract the length sample WR79.length <- subset(WR79,is.na(age)) str(WR79.length)
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