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Age of Pymatuning Sanctuary (PA) Walleye (Sander vitreus) assessed from three calcified structures -- sectioned otoliths, sectioned dorsal spines, and scale impressions.

Format

A data frame with 61 observations on the following 4 variables:

otolith

Age (years) assigned from broken, ground, and polished otolith sections

spine

Age (years) assigned from dorsal spine sections

scale

Age (years) assigned from scale impressions

sex

Sex of fish (female and male)

Source

From Figure 2 in Kocovsky, P.M., and R.M. Carline. 2000. A comparison of methods for estimating ages of unexploited walleyes. North American Journal of Fisheries Management 20:1044-1048. CSV file

Note

Relationships between otoliths and spines and otoliths and scales are exact according to Figure 2. Relationship between spines and scales is approximate as Figure 2 did not show this exact relationship.

Topic(s)

  • Age Comparison

  • Age Precision

  • Age Bias

  • Ageing Error

Examples

data(WalleyePS)
str(WalleyePS)
#> 'data.frame':	60 obs. of  4 variables:
#>  $ otolith: int  1 2 2 2 2 2 2 2 2 2 ...
#>  $ spine  : int  2 3 3 3 4 4 5 NA NA NA ...
#>  $ scale  : int  1 2 2 2 2 2 2 2 2 2 ...
#>  $ sex    : Factor w/ 2 levels "female","male": 1 1 1 1 1 1 1 1 1 1 ...
head(WalleyePS)
#>   otolith spine scale    sex
#> 1       1     2     1 female
#> 2       2     3     2 female
#> 3       2     3     2 female
#> 4       2     3     2 female
#> 5       2     4     2 female
#> 6       2     4     2 female
op <- par(mfrow=c(3,2),pch=19)
plot(scale~otolith,data=WalleyePS,subset=sex=="female",main="Female")
plot(scale~otolith,data=WalleyePS,subset=sex=="male",main="Male")
plot(scale~spine,data=WalleyePS,subset=sex=="female",main="Female")
plot(scale~spine,data=WalleyePS,subset=sex=="male",main="Male")
plot(spine~otolith,data=WalleyePS,subset=sex=="female",main="Female")
plot(spine~otolith,data=WalleyePS,subset=sex=="male",main="Male")

par(op)