WILLASON ET AL.: ZOOPLANKTON IN CALIFORNIA CURRENT 



offshore regions for the north and south were 

 combined). 



Specimens of E. pacifica were captured in signifi- 

 cantly greater numbers north of Point Conception 

 (Table 3) and were rare or absent at most offshore 

 stations (regions III and IV). This species was espe- 

 cially abundant off Point Conception and just south 

 of Monterey Bay along the central coast (Fig. 4). 



These two areas were located close to the areas of 

 highest chlorophyll a concentration. The abundance 

 of E. pacifica was significantly correlated with 

 chlorophyll a over the entire grid (Table 4). 



The distribution of N. difficilis (Fig. 5) was quite 

 different from that of E. pacifica. This species was 

 captured at only 30% of the stations where E. 

 pacifica was found and was distributed farther off- 



Table 3.— Mean abundance and laminarinase activity (LA) of Euphausia pacifica and Nematoscelis difficilis 

 in the north and south regions. Numbers in parentheses are one standard deviation. Log values were used 

 for statistical comparisons. 



South Regions (I & 



North (Regions (II & IV) 



Males 



Females 



Males 



Females 



Euphausia pacifica 

 Abundance (No./1,000 m 3 ) 

 Log abundance 

 LA 



Log LA 

 No. of stations 



Nematoscelis difficilis 

 Abundance (No./1,000 m 3 ) 

 Log abundance 

 LA 



Log LA 

 No. of stations 



96.07 (100.4) 

 1.604 (0.623)* 



122.5 (47.8) 

 2.058 (0.167) 



16 



13.71 (12.78) 

 1.001 (0.327)* 



167.3 (87.5) 

 2.172 (0.237)* 



16 



96.41 (102.5) 

 1.647 (0.666)* 



165.1 (59.9) 

 2.186 (0.183) 



15 



18.06 (16.07) 

 1.061 (0.461)* 



208.6 (102.9) 

 2.270 (0.207)* 



18 



200.6 (234.4) 

 2.035 (0.551) 



109.7 (68.9) 



1 .965 (0.263) 



27 



55.11 (70.31) 

 1.530 (0.441) 



104.4 (41.9) 

 1.992 (0.174) 



20 



270.2 (337.3) 

 2.119 (0.579) 



153.2 (111.9) 

 2.099 (0.269) 



27 



75.17 (83.84) 

 1 .657 (0.453) 



130.4 (55.1) 

 2.041 (0.191) 



19 



indicates value(s) significantly different between north and south (P < 0.05, f-test). 



Figure 5.— Nematoscelis difficilis abun- 

 dance Expressed as number of 

 adults per 1,000 m 3 . 



Nematoscelis difficilis 



Abundance 

 Adults/1000 m3" 



>250 



50-250 



10-49 



<10 



None 



Captured 



'///..Point Conception 



San 



V^.Diego 



38< 



36 c 



34< 



32 c 



124° 



122 c 



120 c 



118 c 



163 



