CUMMINGS ET AL.: SOUND FROM BRYDE AND FINBACK WHALES 



meters, this received level would indicate an overall 

 source level of 152 dB in the effective bandwidth. 

 The whales were close enough and the frequencies 

 low enough that attenuation was probably minimal. 

 However, these particular moans could possibly have 

 been emitted by the other whale that was about 500 

 m away at the time In this case, the estimated overall 

 source level would have been 157 dB in the effective 

 bandwidth. 



Weak exhalation sounds were recorded simultan- 

 eously from underwater and in the air from the near- 

 by surfaced Bryde whale. The exhalation sounds 

 received underwater were nearly obscured by splash- 

 ing sounds as the animal broke the surface (Fig. 4). 



For the 35 moans analyzed from the Bryde whale 

 of Contact 3, the mean frequency of the strongest 

 component was 132 Hz and the mean duration was 

 0.40 s, both values close to those from Contact 2 

 (Table 2). However, the overall source level estimates 

 of 168 and 174 dB (in the effective band widths) were 

 greater. 



The nearby Bryde whale (Contact 2) was totally 

 submerged as it produced all of its moaning sounds, 

 but no other apparent behavior was associated with 

 the moans. 



Finback Whales 



In addition to miscellaneous moans (Fig. 5) that 

 were similar to, but lower in frequency than those 

 recorded from Bryde whales, the sounds of identified 

 finback whales (Contacts 7, 8) included unique moans 

 characterized by a long 68-Hz component that was 

 usually followed by another component at 34 Hz 

 (Figs. 6, 3 (lower)). Of the miscellaneous moans 

 analyzed from recordings of the finback whales of 

 Contacts 7 and 8, the mean frequency of the strong- 

 est component was 59.8 and 65.5 Hz, and the mean 

 duration was 0.59 and 0.73 s, respectively (Table 2). 

 Typically, these moans showed some frequency 

 shift with <10% of the signals changing more than 

 20 Hz, generally downward. Overall source level 



200 



100 - 



M 



I 



> 



u 



z 



LU 



o 



Sf 200 



100- 



1 



TIME IN SECONDS 



Figure 5— Spectrograms of miscellaneous whale moans from finback whales off Isla Angel de la Guarda. The effective analyzing filter 



bandwidth was 3 Hz. 



365 



