Sperm whales (Physeter catodon L-1758) do not react to sounds from detonators

A number of observations show that sperm whales (Physeter catodon L. 1758) react to various man-made pulses with moderate source levels. The behaviora l responses are described to vary from silence to fear. Click rates of five submerged male sperm whales were measured during the discharge of eight de tonators off Andenes, northern Norway. In addition, the behavioral response of a surfaced specimen was observed. Click rates of the submerged whales a nd the behavior of the surfaced specimen did not change during the discharg es with received sound levels of some 180 dB re 1 mu Pa peRMS. The apparent lack of response to the discharges could be due to similarity between sper m whale clicks and detonations. Accordingly, it can be speculated that the discharges may have been perceived as isolated clicks from conspecifics. (C ) 2000 Acoustical Society of America. [S0001-4966(00)03401-9].