Fish *do* fart!

*bursts out laughing*

This pulsed chirp is 32-133 ms long (N = 11) and consists of a series of 7-50 (N = 11) transient pulses with a continuous reduction of the frequency emphasis (centroid frequency of first pulse 4.1 kHz and of last pulse 3.0 kHz, N = 11). The source level of the chirp is 73 ± 8 dB re 1 μPa rms (root mean square) at 1 m (N = 19).

http://itre.cis.upenn.edu/~myl/languagelog/archives/000269.html