Characterization of Sounds of the Blackspotted Croaker Protonibea diacanthus (Sciaenidae) and Localization of Its Spawning Sites in Estuarine Coastal Waters of Taiwan

摘要

The sounds produced by mature blackspotted croakers Protonibea diacanthus were surveyed along coastal areas adjacent to 9 major rivers in Taiwan. The sounds were composed of bursts of pulses with longer inter-pulse intervals than in other sympatric sound types recorded. Variations in the intervals and pulse numbers per call distinguished the blackspotted croaker's sounds into 2 types, one of which was rarely found. For the main sound type, the duration of calls ranged 256-820 ms, the pulse duration ranged 9-34 ms, the pulse repetition rate ranged 13.5-21.6 pulses/s, the mean inter-pulse interval was 60.3 ms, and the minimum and maximum frequencies of the fundamental frequency were 116 and 307 Hz, respectively. These sounds were found from Apr. to Aug. and were spatially restricted to the surveyed area adjacent to 2 rivers on the southwestern coast at depths of < 25 m (mostly < 15 m). A major area was located close to the largest sandbar in Taiwan. The areas where the sounds were found are considered to be the spawning grounds of this species in Taiwanese coastal waters. http://zoolstud.sinica.edu.tw/Journals/48.3/325.pdf