Analysis of soundproduction in estuarine aggregations of Pogonias Cromis, Bairdiella Chrysoura, and CynoscionNebulosos (Sciaenidae)

From December 1979 to June 1980 hydrophone recordings were made of sounds produced by the black
drum, Pogonias cromis, silver perch, Bairdiella chrysoura and spotted seatrout, Cynoscion
nebulosus in the Indian River lagoon, east-central Florida, U.S.A. Species specific
sound qualities were determined and described. Pogonias cromis produced
two principal sound types characterized as a "loud drum'' and a "short grunt", while
B. chrysoura produced a series of sound combinations all based on a sequence of
"knocks". Cynoscion nebulosus produced a complex series of sounds characterized as
"grunts", "knocks" and "staccato". Diel and seasonal changes in sound production
associated with specific recording locations were also determined. Maximum daily
sound production for all three species occurred between 1700 and 2200 hr and was
coincidental with the appearance of eggs and larvae in the water column at the
recording sites. Seasonal peaks in sound production occurred during the winter for
P. cromis, spring for B. chrysoura and spring to summer for C. nebulosus. Peak sound
production in all species occurred at specific locations and time periods coincidentally
with the known principal spawning period for the species. All three species were
found to produce sounds of maximum intensity in the deeper portions of the estuary along the Intracoastal Waterway.