150 
Fishery Bulletin 106(2) 
reproductive activity (Connaughton and Taylor, 1995; 
Gilmore, 2003). 
The rate of white seabass sound production in- 
creased 20-fold during the release of gametes, estab- 
lishing the highest rate and second highest intensity 
for all sounds. Measurable increases in the intensity 
of white seabass spawning chants and postspawning 
multiple pulse-trains were consistent with the audible 
detection of these sounds through the net-pen pipes 
and the hull of an adjacent boat. A chorus of orange- 
mouth corvina sounds increased ambient noise within 
the Salton Sea by 50 dB during the spawning season 
(Fish and Cummings, 1972). All of the distinct white 
seabass sound types were present on audio record- 
ings during spawning. In spotted seatrout, four major 
sound types were reported, all of which occurred dur- 
ing courtship and spawning (Gilmore, 2003). 
Sound function 
Direct correlations between spawning activity and 
sound production substantiate the hypothesis that 
white seabass sounds function to enhance reproduc- 
tive success. Weak single and multiple pulse-trains 
that were audible throughout the spawning season 
may help white seabass maintain aggregations. Single 
pulse-trains before spawning may augment courtship 
behaviors or communicate reproductive readiness. 
Intense multiple pulse-trains after spawning may 
serve to attract surrounding females into spawning 
aggregations. Identifiable spawning chants recorded 
during actual spawning likely function to enhance 
reproductive success by synchronizing the release of 
gametes. 
Conclusion 
This study provides a strong correlation between veri- 
fied white seabass spawning activity and sound pro- 
duction patterns. The noninvasive techniques used in 
this study can be extended to examine reproductive 
characteristics of other sound-producing fish species 
and alleviate difficulties associated with documenting 
spawning after dark. The essential fisheries information 
provided on key reproductive characteristics will help 
fisheries managers in designing strategies to sustain 
this economically important species and reduce the 
likelihood of another severe population decline. Baseline 
findings from this work can be extended to acoustically 
monitor white seabass spawning aggregations in order 
to investigate critical spawning habitat and to help 
determine better placement of marine protected areas 
throughout California. 
Acknowledgments 
Project support was provided by Hubbs-SeaWorld 
Research Institute, the Catalina Seabass Fund, Cali- 
fornia State University Fullerton, University of Southern 
California Wrigley Institute of Environmental Research, 
and Two Harbors Enterprises. I thank M. H. Horn, S. N. 
Murray, C. A. Sepulveda, R. G. Gilmore Jr., and anony- 
mous reviewers for constructive suggestions, and A. E. 
Bowles, K. M. McClune, P. E. Gardiner, K. C. Lafferty, 
G. M. Stutzer, K. A. Miller, and E. Forsman for project 
assistance. I appreciate substantial technical support 
and editorial comments provided by W. C. Cummings, 
K. A. Dickson, and M. A. Drawbridge. I am grateful to 
P. H. Offield and T. Pfleger for their continued dedication 
to preserving our marine resources. 
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