Wl'KSlCKT Al..; HKHAVIOK OK HI (WIIKAI > VVHAl.KS 



and at 185 km/h. While circling over whales, we 

 reduced speed to 148 km/h. Bowheads rarely ap- 

 peared to be disturbed by the aircraft when it re- 

 mained at or above 457 m (Richardson et al. in 

 press). 



The aircraft crew usually consisted of four biol- 

 ogists and the pilot. Three biologists were seated on 

 the right side of the aircraft, which circled clockwise 

 during behavioral observations. Biologists seated in 

 the right front (copilot's) seat and in the seat directly 

 behind it described behaviors. These descriptions 

 were recorded onto audiotape, onto the audio chan- 

 nel of the video recorder, and, in 1981, directly onto 

 data sheets by a biologist in the left rear seat. The 

 biologists in rear seats videotaped whales, handled 

 sonobuoys, and kept records. All personnel on board 

 were in constant communication through an inter- 

 com. 



While circling bowheads, we usually were able to 

 obtain consistent records of 12 variables and types of 

 behavior: 



1) Location of sighting (and, therefore, water 



depth); 



2) Time of day; 



3) Individually distinguishing features, if any, on 



whales; 



4) Number of individuals visible in area and 



number of calves; 



5) Headings and turns of each whale in degrees 



true; 



6) Distances between individuals (estimated in 



whale lengths); 



7) Length of time at surface, and sometimes 



length of dive; 



8) Timing and number of respirations or blows, 



including underwater blows; 



9) Possible indications of feeding: mouth open, 



defecation, mud streaming from mouth; 



10) Socializing, possible mating, probable nursing 



by calves; 



11) Aerial activity: breaches, tail slaps, flipper 



slaps, lunges, rolls; 



12) Type of dive: flukes out, peduncle arch, pre- 



dive flex. 



Descriptions of these behaviors appear later. 



In most parts of this paper we consider only the 

 observations under "presumably undisturbed" condi- 

 tions. Bowheads were considered "potentially 

 disturbed" if our aircraft was at < 457 m ASL, if a 

 boat was underway within 4 km, or if sonobuoys 

 showed that industrial noise was readily detectable 

 in the water. The "presumably undisturbed" 



n 1982 

 ^1981 

 □ 1980 



TIME OF DAY (MDT) 



Figure 2. - Hourly distribution of behavioral observation time from 

 the air of bowhead whales. 



w 20 



LJ 

 < 



'■% 



tr 



LjJ 



> 

 o 



CO 

 (T 



ZD 

 O 



X 



10 - 



5- 



7 

 6 

 5 



4  

 3 



2 -i 



I 

 



I I 1982 

 ^1981 

 □ 1980 



10 20 30 40 50 



1 



rrrr. 



h=H- 



o 



200 400 



DEPTH (m) 



600 



Figure 3. - Distribution of behavioral observation time from the air 

 by depth of water of bowhead whales. The inset shows effort for the 

 0-50 m range by 10 m intervals. 



behavioral observations were distributed by hour of 

 day and water depth as presented in Figures 2 and 3. 



Shore-Based Observations 



Shore-based observations were obtained in 1980 

 and 1981 from the east end of Herschel Island, 

 Yukon (lat. 69°35'N, long. 138°51'W), and about 225 

 km west of Tuktoyaktuk (Fig. 1). A surveyor's theo- 

 dolite was used from a high point (50 m ASL in 1980, 



359 



