| minnow {MQMF} | R Documentation |
minnow contains weekly growth data for use with seasonal growth curves
Description
minnow is a dataset of mean length against time in weeks for minnows (Phoxinus phoxinus), derived from Pitcher & Macdonald (1973) for use when fitting growth curves, especially seasonal growth curves. The data exhibit increases and decreases in length as each year progresses because these are mean lengths rather than individual measurements (which would, more typically, be used these days). The data have been read off a graph within the original paper as it is not reported explicitly, and are therefore only approximate, but will do for our purposes (but expect different parameters to those reported in the original paper). This is length at time not age. Though time is being used as a proxy for age there is no age 0.
Format
A data.frame of mean length-at-time data
- week
the week of sampling minnows for lengths
- length
the estimated mean length in the corresponding week in mm
Subjects
seasonal growth curves
von Bertalanffy
Model residuals
Source
data measured from Figure 2, page 602 in Pitcher, T.J., and P.D M. MacDonald. (1973) Two models of seasonal growth. Journal of Applied Ecology 10:599–606.
Examples
data(minnow)
oldpar <- par(no.readonly=TRUE)
plot1(minnow$week,minnow$length,type="p",pch=16,cex=1.2,
xlab="Week",ylab="Length mm")
par(oldpar)