Spawning activity and associated sound production in the white seabass Atractoscion nobilis (Sciaenidae)

Male white seabass, Atractoscion nobilis, produce sounds by contracting sonic musculature against the swimbladder. The purpose of this study was to characterize sounds associated with spawning in 62 white seabass contained within a net pen moored in Catalina Harbor. Here I provide the first description of identifiable spawning sounds within the family Sciaenidae. In 2001--2003, consistent spawning was documented from March to July and peaked in May. Spawning peaked around 1900 hours and occurred predominantly in water temperatures of 15--18°C, throughout the lunar and tidal cycles. Five distinct sound categories were identified: 'single' and 'multiple pulse-trains' during courtship, 'drum-rolls' and 'thuds' during spawning, and 'booms' during burst swimming. Fish exhibited seasonal and diel increases in the rate and level of sound production surrounding spawning. Spawning behaviors and sound patterns within the net pen resembled those documented around Santa Catalina Island, suggesting that results can be extended to wild spawning stocks.