CUMMINGS ET AL.: SOUND FROM BRYDE AND FINBACK WHALES 



were feeding on red crabs, Pleuroncodes planipes, 

 that swarmed at the surface during the early morn- 

 ing and evening. We distantly accompanied two of 

 the whales which were swimming at 18 km/h and 

 surfacing every 1 to 1.5 min. They rose high enough 

 above the surface for us to clearly identify them as 

 finbacks. Extensive sound recordings were made 

 among the large concentration of whales near shore 

 (Contact 7) and also much farther offshore (Contact 

 8), away from the main group. 



Recordings of whale sounds from Contacts 9 and 

 10 were made in Ballenas Channel near finned 

 whales on the west side of Isla Angel de la Guar- 

 da. 



Analysis of Whales Sounds 



Most sounds attributed to Bryde and finback 

 whales, other than those from blows, were in a class 

 we called "moan'— emissions longer than 0.2 s and 

 <250 Hz in frequency. Many other sounds of 

 biological origin, including clicks, knocks, etc, were 

 recorded in the presence of the whales, but only 

 when other possible sources were present, such as 

 porpoises and sea lions. 



Bryde Whales 



As seen in Figures 2 and 3, upper, Bryde whale 



IV RMS 



LU 

 LU Q 



< j 

 -«Ol 



CO 5 







LU 



70 



LU 



03 



C/) 



SEC 



4 







HZ 



100 



Figure 3— Waveform and spectrum (/Hz) for Bryde whale (upper) and finback whale (lower). 

 Effective analyzing filter bandwidth was 0.75 Hz (Bryde whale sound), 0.375 Hz (finback whale). 



363 



