Aalbers and Sepulveda: Seasonal movement patterns and temperature profiles of adult Atractoscion nobilis off California 
9 
A 
Cycles per day (CPD) 
B 
Figure S 
Results of spectral analysis conducted through the application of a fast Fourier transform algorithm 
to the 3 tracks of white seabass (Atractoscion nobilis ) with the longest duration (721-740 days; fish 
A02118, A03595, and A03609) to identify potential depth periodicities on (A) diurnal and (B) monthly 
cycles along the coast of California and Baja California, Mexico, during 2008-2011. T=time period. 
Other factors that may have resulted in an under- 
estimate of the recapture rate include tag shedding 
and nonreporting of recaptured individuals. Although 
a $200 reward was offered for the return of DSTs, it is 
possible that some recoveries were not reported. Four 
of the tags recovered in this study were not returned 
for up to 15 months after the recapture date, further 
indicating the possibility of under reporting. There- 
fore, the reported 24% recapture rate is conservative 
because it does not account for tags that were shed or 
recaptures that were not reported by the time of the 
analyses for this study. Given that the average time at 
liberty was 468 days, the recapture rate may increase 
further with additional tag recoveries. 
The age and size structure of the fish tagged in this 
study were representative of fish captured in the com- 
mercial fishery, as more than 50% of white seabass 
harvested in California in 2010-2011 were >10 years 
of age (>112 cm TL) (CDFG 2 ). Given that the mean size 
of white seabass captured in this study was 118 cm TL, 
all individuals were mature and most tagged fish were 
>10 years old, and some individuals exceeded 20 years 
of age (>150 cm TL) (Clark, 1930; Thomas, 1968; Romo- 
Curiel et ah, in press). The ratio of commercial (67%) to 
recreational (33%) landings in California in 2010 was 
consistent with the ratio of recaptured white seabass 
observed in this study, with 68% of tags recovered by 
commercial fisheries and 32% from recreational anglers 
(in U.S. waters) (CDFG, 2011). 
Of the white seabass tag recaptures, 95% occurred 
from April to October, a period that directly aligns with 
seasonal decreases in depth distribution (Fig. 2) and 
heightened surface-oriented behavior (Fig. 7). Only a 
single individual was recaptured from December to 
March, indicating that white seabass are less vulner- 
able to exploitation upon their dispersal to deeper 
waters during the winter months. The associations 
between fish depth distribution and catchability ob- 
served in this study are consistent with conclusions 
on seasonal fishery dynamics from Skogsberg (1939) 
and others (McCorkle 6 ), who have reported that gill 
nets traditionally were deployed near the surface until 
mid-October and then set along the bottom from mid- 
October to December as fish retired to deeper waters. 
After December, landings were reduced substantially 
because fishermen were often unable to locate white 
seabass until the following summer (Skogsberg, 1939). 
Seasonal recapture trends align with historical fishery 
data, which indicate that the majority of white seabass 
landings in California occur from April to September 
(Skogsberg, 1925; Thomas, 1968). All tag deployments 
occurred from March to July and peaked in June, a pe- 
riod that directly aligns with the white seabass spawn- 
ing season (Aalbers, 2008) and validates a heightened 
vulnerability to capture when fish aggregate to spawn. 
6 McCorkle, M. 2010. Personal commun. Commercial fish- 
erman, Santa Barbara, CA 93109. 
