Figure 6.
Sex and region differences in ontogeny of dive duration. Model-fitted values for daily mean total dive duration (a,b), bottom time (as proportion of total dive duration; c,d), and time spent diving (as proportion of 24 h period; e,f) over time since leaving the colony. Solid lines show population mean responses by region (North Sea (NS) left, Celtic and Irish Seas (CIS) right), with associated GEE-based 95% confidence intervals (shaded areas). Pups increased their dive duration rapidly over the initial 40 days (a,b), and there was no sex difference in dive duration. Females (red) had higher bottom time than males (blue) (c,d), although this was more marked in CIS pups (d). Females spent more time diving than males in the third month (e,f). Rug plots top and bottom show the distribution of data, colour-coded by sex, and associated numbers indicate pup sample size.