Weinrich et al Behavior of Megaptera novaeangliae during biopsy 



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Trumpet blow Loud, broad-band, wheeze-like sound 

 made during exhalation at the surface. 



In addition, the following behaviors showed a variation 

 in frequency during the special case of SI4's reaction 

 (discussed below): 



Belly-up Animal rolls so that the whale has its ven- 

 tral surface exposed above the surface (often for 

 longer than a second). 



Half fluke Animal rolls on its side exposing one fluke 

 above and perpendicular to the surface. 



Results 



Immediate behavioral reactions, or the absence thereof, 

 to the biopsy procedure were recorded for 71 biopsy 

 strikes during the period 1983-85. Of these, 22 (re- 

 corded in 1985) are paired samples including a 3U-min 

 prebiopsy and 30-min postbiopsy focal sample. Two 

 cases contained clearly unusual reactions, including one 

 from the 1985 paired samples. These cases are dis- 

 cussed separately. This leaves 21 paired samples of 

 behavioral data; however, in five cases some respira- 

 tions could not be accurately assigned to a whale within 

 the focal group, leaving 16 paired samples of complete 

 respiratory data for analysis. 



Immediate behavioral response 



Of the 71 total biopsy attempts for which immediate 

 behavioral reactions were recorded, 7.0% involved no 

 behavioral reaction, 26.8% involved a low-level re- 

 action, 60.6% involved a moderate reaction, and 5.6% 

 involved a strong reaction (Table 1). All the strong reac- 

 tions involved snagging of the flukes by the mono- 

 filament line attached to the biopsy dart. 



Immediate dives were the most common response to 

 the biopsy dart striking the animal, observed in 35 

 (49.2%) cases, hard tail flicks were present in 34 

 (47.8%), and trumpet blows were observed in 31 

 (43.6%) cases. Less than 20% of all reactions involved 

 immediate surges or visually detectable increases in 

 swimming speed. 



Although an immediate dive was a frequently ob- 

 served response, this may have been due to the time 

 it took to approach the whale for the biopsy strike, i.e., 

 the whale would have taken a dive at that point 

 regardless of the biopsy attempt. However, the mean 

 number of blows (4.89) during the surfacing interval 

 in which the biopsy dart was fired was significantly 

 lower than in the accompanying complete surfacings 

 immediately prior to the biopsy attempt (7.17) (paired 

 i-test: t -2.76, 15 df,jO 0.015),suggesting those dives 

 which occurred immediately after the strike of the 



biopsy dart were initiated as a response to the biopsy 

 procedure. 



Study animals could be categorized by age-class in 

 68 of the 71 trials. There was no significant difference 

 in the intensity of reactions by age-class (x" 2.88, 3 df, 

 p 0.41) (Table 1). However, 3 of the 4 reactions we 

 ranked as strong were from juveniles. Also, strong 

 reactions were always associated with a snagging of 

 the retrieval line on the animals' flukes. 



Respiratory and dive variables 



There were no significant differences between pre- vs. 

 postbiopsy focal samples for any of the four respiratory 

 variables (paired i-tests (15 df): blow interval t 0.82, 

 p 0.42; number of blows/surfacing interval t -0.93, 

 j3 0.36; surfacing interval ^1.65, jaO.ll; dive time 

 t 0.61, p 0.55). There was a significant decrease in 

 the surface-interval/dive-time ratios during postbiopsy 

 focal samples (Wilcoxon signed rank test, Z -2.11, 

 p 0.03). 



Substantial individual variation was found in 

 respiratory variables. Seven animals (43.8%) showed 

 a decrease in their mean blow interval following the 

 biopsy procedure, and eight (50.0%) showed an increase 

 (Table 2). Eleven individuals (68.8%) showed a decrease 

 in the number of blows per surfacing, while in only four 

 (25.0%) did it increase (Table 3). Similarly, eleven 

 whales (69.0%) reduced their surface interval in the 

 postbiopsy period, while in five (32.0%) this variable 

 increased (Table 4). Finally, eight of the 16 individuals 

 (50.0%) were found to decrease their dive times dur- 

 ing the postbiopsy period, while in the other eight 

 (50.0%) it increased (Table 5). The surface-interval/ 

 dive-time ratio also showed a decrease in 9 of the 16 

 animals (57.0%), while in 5 (32.0%) there was no change 

 and in 2 (13.0%) there was an increase (Table 6). Based 

 on binomial distribution, any case with 9 or more, or 

 2 or less, animals showing a change in a particular 



