FISHERY BULLETIN: VOL, 69, NO. 3 



to keep them out of the river. There was no 

 reaction to the noise or music. The killer whale 

 sounds were only partially successful, appar- 

 ently because the playback level was too low. 

 His equipment was not designed for underwater 

 sound transmission. Most other woi-kers at- 

 tempting to influence the movement of wild 

 whales with sound have been unsuccessful. How- 

 ever, in nearly all of these experiments the 

 projected sounds did not exceed 140 to 150 db, 

 re 1 ^Newton/ m" ( = 40 to 50 db, re 1 dyne/cm') 

 at 1 m. One exception was a sound playback ex- 

 periment on California gray whales, Eschrich- 

 tius robustus, by Cummings and Thompson (this 

 issue of Fishery Bulletin) where a high-power 

 transmitting system was used and the whales 

 did react to the sounds. Their transmitting sys- 

 tem was similar to the high-power system de- 

 scribed here which we used to transmit killer 

 whale sounds to belugas in the Kvichak River 

 in June 1970. 



METHODS 



The primary high-jjower transmitting system, 

 operated from Station A (Figure 2) , consisted of 

 a Uher tape recorder," a small impedance-match- 

 ing preamplifier, a 250-w Optimation power 

 amplifier, and a sound projector developed and 

 built by the Naval Undersea Research and De- 

 velopment Center. Frequency response of this 

 system was ±3 db from 250 to 4000 Hz, limited 

 by the projector. A secondary, battery-operated 

 playback system, operated from a small boat at 

 Station B (Figure 2), utilized a Uher tape re- 

 corder, a 40-w Bogen amplifier powered by a 

 motorcycle battery, and a J-9 sound projector; 

 system response was =t3 db from 200 to 6000 Hz. 



A calibrated recording .system, consisting of 

 a Wilcoxon hydrophone, a Uher tape recorder, 

 a sonar calibration box, and a modified GR 

 Octave-Band Analyzer, was used to measure the 

 sound pressure level of the playback signals at 

 various points throughout the river and to record 

 the vocalizations from the belugas. This system 

 was described by Calderon and Wenz (1967). 



" The use of trade names is merely to facilitate de- 

 scriptions; no endorsement is implied. 



Figure 2. — Enlarged drawing of the study area. Trans- 

 mitting stations were located at A and B. The regions 

 indicated by numerals are locations where playback 

 sound pressure levels were measured. 



We selected killer whale, Orcimis orca. vocal- 

 izations for transmission because of their out- 

 standing acoustic properties and because killer 

 whales are known to kill and eat the relatively 

 slow-swimming white whales (Scammon, 1874: 

 92; Dergerbol and Nielsen, 1930; Kleinenberg 

 et al., 1964: 292). A long-play tape was made 

 from "screams" and clicks recorded from killer 

 whales at sea. We do not know, however, what 

 behavior was associated with their sound pro- 

 duction. 



In the first 10 playback trials, the sound, trans- 

 mitted only from Station A, was not turned on 

 until the approaching belugas were sighted. 

 But in subsequent trials, when we transmitted 

 from both A and B, we started the playback 

 as soon as the tide changed. Weather and light 

 permitting, a new trial started with each flood 

 tide and lasted from 15 min to 2 hr — as long as 

 necessary to either move the whales back down 

 the river (in those trials where they were per- 

 mitted to move part way up before the sound 



532 



