Full Description

"We observed diminished loudness of mating choruses of male silver perch Bairdiella chrysoura in spawning areas when vocalizing bottlenose dolphins Tursiops truncatus, which hunt fish acoustically, were present. Experimental playback of bottlenose dolphin sounds revealed that male silver perch mating calls were reduced by an average of 9 dB."

"Silver perch Bairdiella chrysoura (Pisces: Sciaenidae) are marine fish in which breeding males produce nocturnal advertisement calls (Mok and Gilmore 1983) in unison-bout choruses that are associated with spawning (Fish and Mowbray 1970, Luczkovich et al. 1999)."

"The silver perch chorus loudness, adjusted for the covariate, averaged 110.4 (± 1.01) and 110.8 (± 1.13) dB for the"no sound"control and the 700-Hz"tone", respectively. The power spectral density for silver perch mating calls fell to an average of 101.8 (± 1.01) dB after a dolphin whistle was played, a significant decrease of 9 dB [ANCOVA, P = 0.000001 (among playback treatment adjusted means), P = 0.13 (among slopes of regression lines for each treatment), R^2 = 0.81, n = 54]."

"An alternate explanation is that fish in the vicinity of the sound source and hydrophone responded to the dolphin whistle playback by swimming away from that location, causing a decrease in the loudness of the chorusing."

"The duration of the lowered sound pressure levels was relatively short (- 60 s) in the playback experiment, but longer in the field sonobuoy recordings (> 90 s, the length of a sonobuoy recording)."

Observation Environment Quotes

"In order to document variations in the loudness of silver perch choruses and other soniferous organisms, we deployed eight autonomous recording sonobuoys daily during peak spawning season (18-21 May 1998) in water depths of 1-6m at random positions within a 10 km x 10 km grid superimposed over Ocracoke Inlet, North Carolina, USA."

Behaviour Description Quotes

"We observed diminished loudness of mating choruses of male silver perch Bairdiella chrysoura in spawning areas when vocalizing bottlenose dolphins Tursiops truncatus, which hunt fish acoustically, were present. Experimental playback of bottlenose dolphin sounds revealed that male silver perch mating calls were reduced by an average of 9 dB."

"Silver perch Bairdiella chrysoura (Pisces: Sciaenidae) are marine fish in which breeding males produce nocturnal advertisement calls (Mok and Gilmore 1983) in unison-bout choruses that are associated with spawning (Fish and Mowbray 1970, Luczkovich et al. 1999)."

Sound Name Quotes

"We observed diminished loudness of mating choruses of male silver perch Bairdiella chrysoura in spawning areas when vocalizing bottlenose dolphins Tursiops truncatus, which hunt fish acoustically, were present. Experimental playback of bottlenose dolphin sounds revealed that male silver perch mating calls were reduced by an average of 9 dB."

"There was a decrease in loudness of the silver perch chorus from 103.9 dB to 94.9 dB during 10-s intervals at 0009 EDT and 0025 EDT, respectively. This 9 dB attenuation represents an approximate 8-fold drop in sound intensity. After 0100, bottlenose dolphin whistles were no longer heard and silver perch chorusing resumed (Figure 2)."