Sciaena umbra (Linneaus, 1758) is one of the four species of Sciaenidae that are present in the Mediterranean Sea. It lives in rocky reefs or in Posidonia grass meadows; it is a nocturnal predator, sexes are separated and eggs are buoyant. It has been known to produce sounds since 1947 at least, when Dijkgraaf described sounds of Sciaena umbra observed in the Zoological Station A. Dohrn of Naples. In the UNEP Asp-protocol of 1995 it was included in the list of species whose fishery needs regulating. In the Miramare Marine Reserve (north-eastern Adriatic Sea, Trieste, Italy), S. umbra is very abundant from May to September along the artificial rocky reefs under the pier of Miramare castle. Sounds were recorded digitally at 44.1 kHz sampling rate with a Reson TC 4032 hydrophone from the pier. Recording 10 minutes each hour for a whole day (24h) confirmed that sounds are present only from late afternoon until 1 a.m. Therefore all subsequent recordings of 10 minutes each hour were carried out from 19.00 to 24.00 only. Sounds are repetitive knocks composed of 1-11 pulses, more or less regularly spaced (131.6ms ± 33.8 SD), with the main frequency components within each pulse ranging between ca. 100 and 1,200 Hz. Based on time interval between sounds, there are at least three different acoustic patterns, named irregular, regular and chorus. Sounds are emitted from May till September with irregular patterns usually followed by regular ones during a daily session. Chorus patterns were recorded only in June and July and not consistently. If S. umbra is a serial spawner like most other Sciaenidae, chorus pattern might indicate spawning bouts.
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