NOAA 
National Marine 
Fisheries Service 
Fishery Bulletin 
fa- established 1881 n?. 
Spencer F. Baird 
First U S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Seasonal movement patterns and temperature 
profiles of adult white seabass {Atractoscion 
nohilis ) off California 
Abstract— To better understand the 
seasonal movement patterns of adult 
white seabass ( Atractoscion nobilis ), 
173 depth- and temperature-sensi- 
tive data storage tags were deployed 
at various sites within the Southern 
California Bight during 2008-2011. 
Commercial and recreational fishing 
crews recaptured 41 tagged individ- 
uals (24%) between La Salina, Baja 
California Norte, Mexico (32°01'N, 
116°53'W), and Half Moon Bay, Cali- 
fornia (37°28'N, 122°28'W ). Tagged 
fish were at liberty for an average 
duration of 468 days (range: 9-1572 
days), and mean net displacement 
between the points of release and 
recapture was 229 km (range: 2-624 
km). Collectively, 9130 days of ar- 
chived data revealed distinct sea- 
sonal trends in depth distribution, 
and significantly deeper profiles 
during the winter months. Minor 
differences in mean depth values 
were evident between daytime (14.9 
m [±standard deviation (SD) 5.1]), 
nighttime (15.5 m [SD 5.1]), and twi- 
light periods (16.8 m [SD 6.8]). How- 
ever, the vertical rate of movement 
(VROM) was significantly greater 
during twilight hours (48.9 m h _1 
[SD 12.3] when compared with day 
and night VROM values (39.6 m h -1 
[SD 10.8] and 41.1 m hr 1 [SD 13.2]). 
The greatest depth achieved by any 
individual was 245 m; however, 95% 
of all depth records were less than 
50 m. Ambient water temperatures 
ranged from 8.7° to 23.6°C, and had 
a mean value of 15.2°C (SD 1.4°C). 
A vertical shift toward the surface 
as water temperatures increase dur- 
ing the spring and summer months 
contributes to heightened vulner- 
ability during the spawning season, 
presenting management challenges 
toward the long-term sustainability 
of this resource. 
Manuscript submitted 13 August 2013. 
Manuscript accepted 27 October 2014. 
Fish. Bull. 113:1-14 (2015). 
doi: 10.7755/FB.113.1.1 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
Scott A. Aalbers (contact author) 
Chugey A. Sepulveda 
Email address for contact author: scott@pier.org 
Pfleger Institute of Environmental Research (PIER) 
2110 South Coast Highway, Unit F 
Oceanside, California 92054 
The white seabass (Atractoscion no- 
bilis) supports lucrative recreational 
and commercial fisheries through- 
out California and Baja California, 
Mexico (Vojkovich and Crooke, 2001; 
Rosales-Casian and Gonzalez-Cama- 
cho, 2003). Because of their high rec- 
reational and market value, white 
seabass are targeted opportunisti- 
cally and fishing effort is influenced 
by local availability (Skogsberg, 
1939; MacCall et al„ 1976; CDFG, 
2011). During periods of heightened 
abundance, persistent localized ef- 
fort is directed toward white seabass 
by both recreational and commercial 
operations throughout much of the 
range of this species (Whitehead, 
1929; MacCall et al., 1976). 
Over the past century, landings 
and catch per unit of effort (CPUE) 
of white seabass in California have 
fluctuated dramatically, reaching 
peak levels in the early 1920s and 
late 1950s that were followed by 
troughs in the late 1920s and 1960s 
(Whitehead, 1929; MacCall et ah, 
1976; CDFG 1 ). Vojkovich and Reed 
(1983) suggested that prolonged in- 
tervals of reduced landings off Cali- 
fornia are likely a response to pe- 
riods of overexploitation and other 
1 CDFG (Calif. Dep. Fish Game). 2002. 
Final white seabass fishery manage- 
ment plan (WSFMP), 161 p. [Available 
from https://nrm.dfg.ca.gov/FileHandler. 
ashx?DocumentID=34195&inline=true, 
accessed March 2014.] 
unknown factors. Collective land- 
ings and CPUE from California rec- 
reational and commercial fisheries 
have steadily increased since 1998, 
indicating a recent stock resurgence 
from levels of record-low abundance 
in the 1980s (Vojkovich and Reed, 
1983; Allen et al., 2007; CDFG, 2011). 
The majority of California’s white 
seabass harvest typically occurs 
from April to September along the 
southern coast from Point Concep- 
tion to San Diego and throughout 
the Channel Islands (Skogsberg, 
1925; Thomas, 1968). Landings north 
of Point Conception have increased 
dramatically since 2008; commercial 
hook-and-line catches north of Point 
Arguello increased from 1% of the 
total California harvest in 2008 to 
22% of annual state landings in 2010 
(CDFG, 2009; 2011). Over the same 
period, recreational catches north of 
Point Arguello increased from 3% to 
38% of total state landings. Height- 
ened landings from the northern re- 
gion have been coupled with a sharp 
increase (266%) in the numbers of 
vessels entering the white seabass 
fishery (CDFG 2011), rising from 93 
permitted boats in 2009 to 254 com- 
mercial vessels in 2011 (CDFG 2 ). A 
2 CDFG (Calif. Dep. Fish Game). 2012. 
White seabass fishery management plan 
annual 2010-2011 review, 6 p. [Avail- 
able from https://nrm.dfg.ca.gov/File- 
Handler.ashx?DocumentID=75302&inli 
ne=true, accessed March 2014.] 
