Attraction of Free-Ranging Sharks by Acoustic Signals in the Near-Subsonic Range.
Technical rept. Sep 73-Dec 75,
ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE MIAMI FLA
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Series of extensive field experiments were conducted over the deep waters of the Florida Straits and the Tongue of the Ocean, Bahamas to provide information on the differential attractiveness of various acoustic signals in the near sub-sonic range 10 to 20 Hz, 20 to 40 Hz, and 40 to 80 Hz to free-ranging silky sharks Carcharhinus falciformis and oceanic whitetip sharks C. longimanus. Ambient noise measurements were accurately determined in the study areas. Findings included ambient noise determination from 10 to 1000 Hz, demonstrated preferential attraction by sharks to sounds having a frequency spectrum between 10 and 40 Hz, and behavioral information on both species of sharks, attracted. A summary of all studies on the acoustic attraction of sharks is included in the discussion.