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Fishery Bulletin 90(4), 1992 



of these young fish (Donohoe 1990). Margulies (1989) 

 concluded that the visual perception of YOY seabass 

 improves with age, and that young fish begin to avoid 

 predators by moving to the drift. 



Our studies on white seabass settlement were under- 

 taken in southern California where the main fishery 

 for this species still exists. The specific objectives were 

 to (1) examine the patterns of abundance, distribution, 

 and settlement of YOY white seabass off the coast of 

 southern California between Point Conception and San 

 Mateo Point and along the coastlines of four of the 

 larger Channel Islands, and (2) identify environmen- 

 tal factors that may influence these patterns. 



Materials and methods 



YOY white seabass were captured during the summers 

 of 1988 and 1989 as part of the Ocean Resources 

 Enhancement and Hatchery Program (OREHP) of the 

 California Department of Fish and Game, which em- 

 phasized studies within the Southern California Bight. 

 Trawls were made over flat bottoms just offshore of 

 open sand beaches, using two 5.2 m whalers. At each 

 station four 5-minute replicate tows were made in the 

 shallow, potential nursery areas by two whalers 

 simultaneously sampling along each of two isobaths (5 

 and 10m) using a 1.6m beam trawl. The trawl was com- 

 prised of 4 mm mesh in the wings and 2 mm knotless 

 mesh in the codend. Calibration tows using a meter 

 wheel indicated that a 5-minute 

 tow covered an average of 183 m 

 of bottom, yielding a mean cover- 

 age of 293 m-. Bottom profiles 

 were monitored using depth 

 finders mounted in each whaler. 

 Temperature, salinity, dissolved 

 oxygen, and pH were monitored 

 at the surface and bottom at each 

 station at both isobaths, using 

 a Hydrolab Surveyor II Water 

 Quahty Measurement System. 

 Submerged aquatic vegetation 

 (drift algae) captured in each tow 

 was weighed (to nearest kg) at all 

 stations. White seabass were 

 measured to the nearest 0.1mm 

 standard length (SL). 



Sixteen stations were estab- 

 lished along the coast of southern 

 California from Point Conception 

 to San Mateo Point in 1988 (Fig. 

 1). These stations were approx- 

 imately lOnmi apart and were 

 sampled from June through Oc- 



tober. The sampling regime yielded 128 tow samples 

 (4 tows at 2 depths at each of 16 stations) over 5 

 months, for a total of 640 tow samples in 1988. 



In 1989, sampling was designed to examine the set- 

 tlement patterns along the mainland and around the 

 four largest offshore islands. Four mainland stations 

 and eight island stations were sampled each month 

 from May through August (Fig. 1). The mainland sta- 

 tions were those with the greatest consistency of catch 

 of YOY white seabass in 1988: Stns. 6 (Ventura), 10 

 (Malibu), 13 (Belmont Shore), and 15 (Laguna Beach). 

 Two new stations were established at each of four 

 Channel Islands: Stns. 17 and 18 (Santa Cruz), 19 and 

 20 (Santa Rosa), 21 and 22 (Santa Catalina), and 23 and 

 24 (San Clemente). The twelve stations sampled in 1989 

 were divided subjectively into three groups of four sta- 

 tions based on relative distance from shore or distance 

 blocks (DSTBLK). Stns. 6, 10, 13, and 15 were desig- 

 nated as being at the mainland (MAINLAND); Stns. 

 17, 18, 21, and 22 as near-island stations (NEAR ISL); 

 and Stns. 19, 20, 23, and 24 as far-island stations (FAR 

 ISL). The 1989 sampling regime yielded 96 tow samples 

 (4 tows at 2 depths at each of 12 stations) for each 

 month except May, when only 80 tows were made 

 because poor weather conditions prevented sampling 

 the Santa Rosa Island stations, for a total of 368 tows 

 overall. 



Analysis of variance, f-test, and correlation analyses 

 were completed using the CSS:Statistica for desktop 

 computers (Stat Soft, Inc., Tulsa). For 1988 data, a 



Map of locations of 

 seabass A. nobilis 



Figure 1 



mainland and Channel Island stations sampled during the YOY white 

 survey, 1988-89. 



