1990 



A statistical analysis of the 80,754 dives recorded during 6-hour summary periods is 

 shown in Tables 9 and 10. The data are depicted graphically in Figure 41. The number of 

 dives during a six hour period ranged from 55 to 920. Frequency histograms of the number 

 of dives/six hour period are shown for all whales combined (Figure 42) and each individual 

 whale (Figures 43 - 49). 



The average number of dives in a 6-hour period for all animals was 268 +. 159 dives 

 (x = 44.6/hr.). Individually, "Willie" (PTT #823) had a highest average number of dives (x 

 = 384 + 181). His 66dives/houT were 43% higher than "Van Halen" (PTT #843), another 

 adult male tagged in 1989. The maximum count for PTT #823 ranged from 698 to 920 dives 

 for the different periods while the maximum for all other whales was no higher than 413. 

 The highly mobile female with a calf, "Wart" (PTT #839), averaged only half as many dives 

 (192 dives ± 54) per period (x = 32/hr.) as PTT #823, despite a comparable distance 

 traveled. The periods with very high numbers of dives for PTT #823 occurred on 21 

 September coinciding with the animal's most southerly travel into an area of deep, warm 

 water at the edge of the Gulf Stream. 



The juvenile (PTT #833) and female with a calf (PTT #839) had an identical mean 

 number of dives. The fastest moving female (PTT #840) showed one of the lowest average 

 number of dives per period (x = 139 dives Ji96). The lowest number of dives was shown 

 by a two year old (PTT #827) with a mean of 126 ± 7 but may have been due to the 

 extremely small sample size (n = 5). For four of the six whales, the highest number of dives 

 occurred during the period from mid-day to dusk (Period 4) and the lowest number of dives 

 occurred during the period from midnight to dawn (Period 2). 



Both PTT #823 (Figure 43) and PTT #839 (Figure 48) have large sample sizes but 

 exhibit different dive distributions. Figures 50 and 51 show the distribution of the number 

 of dives in a six hour period versus the calendar date. The time scale was kept uniform to 

 determine if variations in dive count varied with weather. Only PTT #823 and PTT #839 

 had sufficient data for comparison and did not show any obvious trends in day to day 

 variation which would reflect changes due to weather. 



69 



