2 
Fishery Bulletin 1 13(1) 
comparable northward shift in fishing effort was docu- 
mented from 1957 to 1961 and was also coupled with 
a sharp increase in the number of vessels that entered 
the fishery (Vojkovich and Reed, 1983). During this pe- 
riod, commercial landings of white seabass reached a 
record high of more than 1500 metric tons in 1959, 36% 
of which came from the waters north of Point Concep- 
tion (Thomas, 1968; Vojkovich and Reed, 1983). Inter- 
annual shifts in the latitudinal distribution of white 
seabass have been suggested in the past (Skogsberg, 
1939; Young 3 ; Maxwell 4 ); however, fishery-independent 
data on movement patterns and stock structure of 
white seabass have been limited. 
Attempts to evaluate movement patterns of juvenile 
white seabass through a conventional tagging program 
in the mid-1970s were ineffective because of limited 
tag deployments (n= 58) and no reported tag recoveries 
(Maxwell 4 ). An evaluation of movement patterns based 
on historical fishery data indicates that white seabass 
occur off Baja California during winter and move north- 
ward along the coast of California as water tempera- 
tures increase during the spring and summer months 
(Skogsberg, 1939; Maxwell 4 ; Vojkovich and Crooke, 
2001). Spawning is thought to occur with northward 
advancement from March to July (Skogsberg, 1925; 
Thomas, 1968; Young 3 ), although little information is 
available regarding spawning activity north of Point 
Conception. Fish harvested along California and Baja 
California are currently considered to be from a contin- 
uous spawning population with a high level of genetic 
diversity (Maxwell 4 ; Coykendall, 1998; Rios-Medina, 
2008). Discrepancies in this single-stock model have 
been indicated by Franklin (1997), and the existence of 
regionally discrete stocks with limited rates of mixing 
has been considered (Vojkovich and Crooke, 2001). 
Despite a robust history of white seabass catch data 
since the 1890s, essential fishery information on the 
geographic distribution of stocks, habitat use, and sea- 
sonal movement patterns remains largely unavailable 
(Skogsberg, 1939; Vojkovich and Reed, 1983; CDFG 1 ). 
Additional uncertainties on spatial and temporal as- 
pects of white seabass depth distribution, residence pe- 
riods, and exploitation rates present major challenges 
for effective fishery management, particularly for a 
population that is harvested by more than one nation 
(Thomas, 1968; Maxwell 4 ; CDFG 1 ). Regulations that re- 
duce the likelihood of overexploitation are currently in 
place; however, additional research and adaptive man- 
agement strategies are necessary for the sustainable 
3 Young, P. H. 1973. The status of the white seabass re- 
source and its management. Calif. Dep. Fish Game Mar. 
Resour. Tech. Rep. 15, 10 p. [Available from http://aquatic- 
commons.org/756/l/Technical_Report_ 1973_No._15_A.pdf, ac- 
cessed April 2014.] 
4 Maxwell, W. D. 1977. Progress report of research on white 
seabass, Cynoscion nobilis. Calif. Dep. Fish Game Mar. Re- 
sour. Admin. Rep. 77-14, 14 p. [Available from http://aquat- 
iccommons.org/76/l/Marine_Resources_Administrative_Re- 
port_NoIlf_77-14.pdf, accessed April 2014.] 
use of this valuable fishery resource (Vojkovich and 
Reed, 1983; CDFG 1 ). Fishery-independent informa- 
tion on fine- and course-scale fish movements has been 
identified as essential to adequately assess fishery im- 
pacts and address questions related to seasonal distri- 
bution and stock structure of white seabass (Thomas, 
1968; CDFG 1 ). Our objectives were to assess movement 
patterns, temperature preferences, and recapture rates 
of adult white seabass off the California coast. 
Materials and methods 
Tagging procedure and sampling regime 
Cefas G5 5 and G5 long-life data storage tags (DSTs; Ce- 
fas Technology Limited, Lowestoft, UK) were surgically 
implanted in the peritoneal cavity of white seabass by 
using techniques modified from Stutzer (2004). Wild- 
caught white seabass were tagged and released around 
Santa Catalina Island (n=107) and along the southern 
coastline of California {n=6 6) during the spring and 
summer months of 2008-2011 (Table 1). After capture 
on hook and line, fish were brought alongside the ves- 
sel and transferred in a knotless nylon-mesh dip net 
(Duraframe, Viola, WI) to an onboard tagging cradle. 
A conventional identification marker (FIM-96; Floy Tag, 
Inc., Seattle, WA) was inserted into the dorsal muscula- 
ture traversing the dorsal-fin pterygiophores. Upon se- 
curing the fish ventral-side up within a tagging cradle, 
a 2-cm incision was made with a scalpel through the 
dermal layer adjacent to the ventral midline approxi- 
mately 8 cm anterior to the anal vent. A stainless steel 
trocar was used to penetrate the ventral musculature, 
and a DST was inserted into the peritoneal cavity. The 
incision was closed around an external identification 
stalk with a PDS II surgical-grade suture and a CP-1 
reverse cutting needle (Ethicon, Somerville, NJ) along 
with a 35-wide stainless-steel skin stapler (PGX-35W; 
3M, St. Paul, MN). 
Fish total length (TL) was measured to the near- 
est centimeter, sex was recorded, and the hook was 
removed before release. Sex was determined by both 
the audible detection of low-frequency sound produc- 
tion by males during the capture and tagging process 
and the presence or absence of milt upon application 
of pressure to the abdominal region. All tagging was 
conducted during the spawning season when mature 
males are consistently running ripe and characteris- 
tically produce low-frequency sound upon handling 
(Aalbers and Drawbridge, 2008; Gruenthal and Draw- 
bridge, 2012). Total handling time onboard the vessel 
ranged from 65 to 135 s. 
Because postrelease survival of white seabass 
hooked in the visceral region has been shown to be 
5 Mention of trade names or commercial companies is for iden- 
tification purposes only and does not imply endorsement by 
the National Marine Fisheries Service, NOAA. 
