Sea urchins growth — urchin

Size at age for a cohort of farmed sea urchins, Paracentrotus lividus.

Usage

urchin_growth

Format

An object of class data.frame with 7024 rows and 3 columns.

Details

The same cohort of farmed sea urchins being measured at various time intervals, the observations are not completely independent from each other: the same individuals are repeatedly measured here. As the sea urchins are not individually tagged, it is not possible to track them from one measurement to the other. However, the whole dataset is representative of the growth, and spreading of growth in a single cohort. Also, mortality could be derived from the number of measurements made at each time period, since all the individuals still alive are measured (no sub-sampling).

Examples

library(ggplot2)
ggplot(urchin_growth, aes(age, diameter)) +
  geom_jitter(alpha = 0.2) +
  xlab(label(urchin_growth$age, units = TRUE)) +
  ylab(label(urchin_growth$diameter, units = TRUE)) +
  ggtitle("Growth of a cohort of sea urchins")