The acoustic activity of Russian sturgeon Accipenser guldenstadti and other sturgeon species increases considerably during the pre-spawning period. During induced maturation of Russian sturgeon, 25 records each of fifteen minutes long were made, and 1358 signals (100%) identified as sturgeon sounds were registered. The males (90%) and females (10%) produce the following signals: "Tone'' (4%), "Frequency Modulated or FM'' (50%), "Wide Band with Continuous Frequency Spectrum'' (30%), "Series of Wide Band Pulses'' (16%). The number of "FM'' signals produced by fishes correlates with the fishes' readiness to spawn and it increases after injection. The males reduced the maximum number of these signals 16-22 hours after the injection of sturgeon pituitary preparation. The females produced it 22-28 hours after the injection. The number of signals of the other types did not change noticeably. Most often Russian sturgeon produces FM signals having one component in which the frequency varies inversely as the square root of the time from 13.8-14.8 kHz to 6.8-6.9 kHz. Duration of these signals is as a rule 68-73 ms. While emitting one of such signals near to the transducer, the fish locomotor activity of both sexes increased and some fishes moved towards the transducer.