Abstract: A long-term experiment on studying fluctuations of the parameters of pulsed sound signals in a shallow sea was carried out in the region of the northeastern coast of the Black Sea in autumn, 2004. The data were collected on a 1.2-km fixed propagation path at a 2-km distance from the coastline. During the entire experimentation, observations of temperature fluctuations near the receiving point were performed by the using the line temperature sensor. Fluctuations of the shape, energy, and propagation time of the pulsed signals were studied. An attempt of their relation to the hydrodynamic processes on the shelf was taken. The change in the shape and the energy level of the signals was analyzed for the moment of passing the anticyclonic topographic eddy over the coastal zone. It was shown that the fluctuations of the propagation time were sometimes as high as 17.6 ms. An enhance of the short-period acoustic fluctuations accompanying the intensification of the internal waves was observed.