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 (
femaleandmale)
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.
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)