As soon as they turned their heads away, the ultrasonic beam was no longer focused on the barracuda and it fled at a very high speed. Obviously this beam was tightly focused and required the dolphins' heads to be pointed directly at the target. The strength of the beam could be changed also. When hunting it could be directed at small fish and amplified to lethal levels, causing instant death. Some believe that this is also used when dolphins kill sharks, by ramming them.
Autopsies show the sharks' internal organs have been literally shattered.
The beam can also be controlled to produce a stun effect as in the case of the barracuda. The result was physical paralysis and disorientation. I believe that this is the very same technique used by the Greys in abductions. The similarities are overwhelming. Every abductee says that when they are abducted they are paralyzed and become mentally disoriented.