176 



Fishery Bulletin 89|2). 1991 



The number of dives/hour for the entire trip was 

 greater for shallow divers than for deep divers (Mann- 

 Whitney, P = 0.02). The maximum number of dives/ 

 hour for deep divers was 2.5 (x 2.0, SD 0.31), where- 

 as the minimum number of dives/hour for shallow 

 divers was 3.4 (x 4.1, SD 0.75). Although deep divers 

 tended to execute more dives per hour at night than 

 during the day, the difference was not significant 

 (Mann- Whitney, P = 0.11). Shallow divers did, how- 

 ever, make more dives per hour at night than during 

 the day (Mann- Whitney, P = 0.02). Regardless of which 

 diving pattern females exhibited, they always made 

 more dives per hour at night than during the day. 



Diving bouts 



No differences in the total number of dive 

 bouts per trip were detected between shal- 

 low and deep divers (Table 5). Although the 

 number of dives that did not meet the dive- 

 bout criteria tended to be greater for the 

 deep divers, this difference was not signifi- 

 cant (Mann- Whitney, P = 0.07). Differences 

 in bout durations, number of dives per bout, 

 and number of dives per hour within bouts 

 were all greater for shallow divers (ANOVA, 

 P = 0.01 for duration, P = 0.01 for dive num- 

 ber, P = 0.02 for dives/hour). 



When all bouts were divided into those 

 less than 75 m and those greater than or 

 equal to 75 m, the percent of time spent 

 below the surface was significantly differ- 

 ent for shallow- and deep-diving bouts 

 (ANOVA, P = 0.01). A greater percent of 

 time was spent below the surface for shallow bouts 

 (<75m, x 0.35 hour, SD 0.11, n 59) than for deep 

 bouts (>75m, x 0.29 hour, SD 0.12, n 102). 



Pelagic fur seal studies 



During the hours 0600-1000, the stomachs of 740 post- 

 partum females were sampled, 504 over the shelf and 

 236 off the shelf (Table 6). From 1400 to 1900 hours, 

 750 postpartum females were sampled, 513 over the 

 shelf and 237 off the shelf. 



Females collected in the morning hours off the con- 

 tinental shelf were more likely to have food in their 



