Characterization of North Atlantic right-whale (Eubalaena glacialis) sounds in the Bay of Fundy

Hydrophone recordings, made in the presence of North Atlantic right whales (Eubalaena glacialis) in the Bay of Fundy during the daytime in July 1999, are used to determine the characteristics of the recorded sounds. A spectrogram-based method was implemented to discriminate whale sounds from background noise and the time-frequency envelope of the primary harmonic in the spectrogram was used as the basis for sound characterization. Sounds were typically (82%, n=45) in the 300- to 600-Hz range with up- and downsweeping modulations. Lower (<200 Hz) and higher (>900 Hz) frequency sounds were relatively rare. Most sounds were frequency modulated, with 95% of the observed instantaneous relative frequency variation being within +-4.5% of the mean peak frequency. Harmonics were observed in 18% of the sounds. The average sound duration was 0.42 s+-0.26 SD. The sounds occurred at a rate of between 0.3 and 0.7 min/sup -1/. The time intervals between adjacent sounds (2-700 s) were not randomly distributed. The number of sounds occurring among different waiting times did not reflect a Poisson distribution and a clustering of sounds (2 to 5 cluster/sup -1/) was observed. The sound characteristics are compared to those documented elsewhere and as reported for the southern right whale.