FISHERY BULLETIN: VOL. 74, NO. 4 



sampled localities within the area. Thus, some 

 samples from station lines 77 (northern) and 97 

 (southern), or designated 80.80 (western), were 

 occasionally used. 



The samples were examined in the following 

 manner. An aliquot containing 100-200 E. pacifica 

 was counted; the specimens were measured to the 

 nearest millimeter of body length (tip of frontal 

 plate to tip of telson)]_adults were sexed; and the 

 degree to which the reproductive products were 

 developed was recorded. If, for adults (specimens 

 >10.5 mm in length), the initial aliquot contained 

 fewer than three specimens of any particular 

 length, a second aliquot of equal size was ex- 

 amined for specimens of that size or larger. In this 

 way, increasingly large fractions of the sample 

 were examined for specimens of those length 

 intervals which were progressively determined to 

 be fewest in the sample. This procedure made it 

 possible to count the rarer, large specimens with a 

 degree of accuracy comparable with that to which 

 the consistently more abundant small specimens 

 were counted. Usually, the entire sample was 

 examined for specimens of more than 14-mm body 

 length. This procedure was facilitated by the use 

 of the Folsom plankton splitter which, through 

 successive splitting operations, provides aliquots 

 of V2, Vi, Vs, . . . \/n. All counts were standardized 

 for 1,000 m-^ of water strained by the net. 



After standardization, the counts for a sample 

 (station) were weighted according to the propor- 

 tion of the survey area represented by that sta- 

 tion. When the nearest area surrounding the 

 station was equal to a 65 x 65 km square (a usual 

 spacing for CalCOFI stations), the weighting 

 factor was 1.0. When areas represented by sta- 

 tions were greater or less than 65x65 km, 

 weighting factors were proportionally greater or 

 less than 1.0. The study area was equal to 19 65 x 65 

 km squares. Therefore the sum of the weighted 

 abundances (for each size of E. pacifica) was 

 divided by 19, providing a mean standardized 

 abundance for the area for the given survey. (The 

 night stations were not at the same localities on 

 each cruise, though tracks followed by the vessels 

 were generally repeated. Furthermore, as is to be 

 expected, clusters of day stations tend to alternate 

 with clusters of night stations. Unsampled parts 

 of the area are expected to be better represented 

 by samples from stations nearest to that unsam- 

 pled part than by samples from more distant 

 localities.) 



Females were classified as 1) with ripe eggs 



736 



(Mauchline's [1968] egg phase IV) and with at- 

 tached spermatophore, 2) with ripe eggs and no 

 spermatophore, 3) with ripening eggs (approx. 

 Mauchline's phase II), or 4) ovary weakly 

 developed. Adult males were categorized as 1) with 

 ripe spermatophores, either protruding or inter- 

 nal, or 2) without ripe spermatophores. 



Biomass was calculated using abundance at each 

 body length (1-mm increment). Values are in 

 terms of wet displacement volume (wet weight) of 

 E. pacifica, given per body length increment in 

 Miller (1966). The following conversion factors 

 from Lasker (1966) may be applied: 



Dry weight = 17.2% of wet weight 

 Carbon = 42 ± 1.7% of dry weight 



Carbon = 7.2% of wet weight 



RESULTS 



Southern California Eddy in Relation 

 to the Rest of the California Current 



October 1955 data (cruise 5510) illustrated char- 

 acteristics of flow and temperature in the cur- 

 rent, and occurrences of E. pacifica larvae (Figure 

 la-c). These were general to fall-winter 1953-56 

 and placed the southern California area in broader 

 geographical perspective. At that time the land- 

 ward portion of the current, slow and cool, sup- 

 ported five centers of recruitment of E. pacifica 

 (Figure Ic): 1) off San Francisco, probably related 

 to the September peak off Oregon obsrved by 

 Smiles and Pearcy (1971), 2) north of Point Con- 

 ception, 3) southern California, 4) Point Colnett 

 (lat. 31°N), and 5) Point Canoas (lat. 29°N). The 

 three centers off California were then associated 

 with current reversals while the two centers off 

 Baja California were places w^here upwelling was 

 conspicuous. A Punta Eugenia center, farther 

 south (lat. 27°-28°N), usually supports E. pacifica 

 earlier, during the local peak of spring coastal 

 upwelling, May-June. 



Direction and intensity of coastal flow tends to 

 vary on a seasonal basis. During cruise 5510 and 

 through ensuing fall and winter months, coastal 

 currents off California provided means of north- 

 erly transport for portions of southern popula- 

 tions. During spring and summer, intensified 

 southerly currents off northern California are 

 expected to bring elements of the northern 

 population into the southern California area via 

 the offshore route west of Point Conception, 

 diverting shoreward near lat. 32°N. 



