Figure 55. Frequency histogram of average dive duration (seconds) 



during all 6-hour summary periods for all 1990 PTTs 

 (#823, #825, #827, #831, #833, #839, #840) 50 



Figure 56. Frequency histogram of average dive duration (seconds) 



during all 6-hour summary periods for PTT #823 51 



Figure 57. Frequency histogram of average dive duration (seconds) 



during all 6-hour summary periods for PTT #825 52 



Figure 58. Frequency histogram of average dive duration (seconds) 



during all 6-hour summary periods for PTT #827 53 



Figure 59. Frequency histogram of average dive duration (seconds) 



during all 6-hour summary periods for PTT #831 54 



Figure 60. Frequency histogram of average dive duration (seconds) 



during all 6-hour summary periods for PTT #833 55 



Figure 61. Frequency histogram of average dive duration (seconds) 



during all 6-hour summary periods for PTT #839 56 



Figure 62. Frequency histogram of average dive duration (seconds) 



during all 6-hour summary periods for PTT #840 57 



Figure 63. Chronological comparison of the average dive durations 



during the 1990 tracking study for PTTs #825, #827, #831, 



#833 and #840. 58 



Figure 64. Chronologlical comparison of the average dive durations 



during the 1990 tracking study for PTTs #823 and #839 59 



Figure 65. The percent time submerged versus calendar date 



and area for PTT #843 101 



Figure 66. A comparison of the average percent time submerged 



between 4-hour summary periods for PTT #843 102 



Figure 67. A comparison of the average percent time submerged 



between PTTs #823, #825, #827. #831, #833, #839, and #840 

 (1990) 105 



vui 



