Abstract

Sound production by goliath grouper was studied by placing a long-term acoustic recorder (LARS) at a known grouper spawning site (Cathy’s wreck) in the Gulf of Mexico on the northern border of the Tortugas Reserve off SW Florida from September 8-26, 2005. The LARS recorded 10 s of sound every three minutes. Sounds consisted of low-frequency individual pulses (50-100 Hz) that are consistent with sounds produced by a large fish. Low-frequency tonal sounds (120 Hz) were also occasionally recorded. Peaks in sound production occurred nightly after midnight, but sounds were also produced throughout the day. Levels of nightly sound production were similar throughout the time series, except from September 19 - 21 when little sound production was recorded. On September 21 Hurricane Rita passed through the Gulf of Mexico to the south of the study site, and sounds from increased waves during this time were recorded at the spawning aggregation site. The highest levels of sound production were recorded on the nights following the passage of hurricane Rita, whose eye passed about 38 nm to the south of the site. To further develop the use of passive acoustics in studying goliath grouper spawning behavior, the behaviors associated with sound production needs to be identified. In particular, it needs to be determined whether any specific sounds are associated with spawning. At the very least, passive acoustic surveys could be used to identify potential goliath grouper spawning aggregation sites over large spatial scales.

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