Figure 2.10. Acoustic signals of the plainfin midshipman fish, Porichthys notatus.
Shown here are spectrograms (top) and oscillograms (bottom) of a representative
hum, growl, and grunt train from the nest of the same type I male midshipman
(21.5 cm standard length); nest temperature was 16.0°C (Brinnon, WA, June, 1997;
recorded between 12:00 and 3:00 h). The amplitude scale is relative (but see Fig.
2.12). The hum shown here is a short segment from one that lasted 1 min 48 sec; the
fundamental frequency was 102 Hz, with several prominent higher harmonics. The
growl is a segment from one that lasted 4.64 sec with a fundamental frequency
of 75.4 Hz. The grunt train shows 15 consecutive grunts from a grunt train that
included a total of 22 grunts. The average duration of each grunt is 48.64 msec; the
fundamental frequency is 107 Hz. The background hums of neighboring males can
be seen in the grunt train record. Recordings courtesy of M. Marchaterre, Cornell
University.
Figure 2.11. Shown here are the concurrent hums (acoustic beat) of two neighboring type I male midshipman fish in nests separated by 16 feet 8 inches (nest temperature 16.1°C; Brinnon, WA, June, 1996). (A, B) Temporal waveform. (C) Power
spectrum showing multiple harmonics. (D) Expansion of the first peak in (C) shows
the two harmonics (200 and 204 Hz) for the fundamental frequencies of the two
hums, which were 100 and 102 Hz. Recordings courtesy of M. Marchaterre, Cornell
University. (Modified from Bass et al. 1999.)
᭣