WR79: Ages and lengths for a hypothetical sample from Westerheim...

Description Format Details Topic(s) Source Examples

Description

Ages and lengths for a hypothetical sample in Westerheim and Ricker (1979).

Format

A data frame of 2369 observations on the following 3 variables:

ID

Unique fish identifiers

len

Length of an individual fish

age

Age of an individual fish

Details

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.

Topic(s)

Source

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.

Examples

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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)

FSA documentation built on July 17, 2021, 5:07 p.m.

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