130° 



120° 



110° 



40' 



30° 



20°- 



40° 



-30° 



130° 



120° 



110° 



FIGURE 2. — Inner boundary of Mecynocera for individual 

 CalCOFI cruises from June 1949 to July 1951 off California and 

 Baja California. 



study of plankton off La Jolla, Beers and Stewart 

 (1970), using 35-/um mesh nets, found that for 

 the three stations located 1.4, 4.6, and 12.1 km 

 from shore, naupliar densities averaged 63/liter, 

 33/liter, and 26/liter, respectively. 



The zone of maximum nauplii seems to be asso- 

 ciated with the Mecynocera boundary, which is 

 also indicated in Figure 3. The station of maxi- 

 mum nauplii for a line usually occurs one to three 

 stations onshore of this boundary. 



As may be seen in Figure 3, there appears to be 

 an association between the zone of maximum 

 nauplii and the tongue of relatively cold water 

 (13° and 14° isotherms) extending south of 

 Point Conception. This cold tongue probably is 

 nutrient rich water upwelled north of Point 

 Conception. Shoreward from this zone lies the 

 counterclockwise gyre of the Southern California 

 Bight, extending from Point Conception to north- 

 ern Baja California. Allen (1939) stated that his 

 most offshore station, located 120 km from the 

 coast, which is in the general vicinity of the 

 nauplii maximum, was consistently the richest 

 station for microcrustacea. Berner (1959) noted 

 that stations where he found anchovy larvae to 



125° 



FISHERY BULLETIN: VOL. 75, NO. 3 

 120° 115° 



30' 



028 



.019 



1 Point Conception 



\0| 



. V.098 • 



■039 / 



""'■'•. 031 

 '•., .'o34\ 



. '-A 85 : : •C.0I4 



026 >} S Q 



.033 ~ 



?,255 •. 



■;-. ° U J W © 



000 / •• X I9? 



.001 pQ. 

 ,031 I . : .185 



■ooo .• . I : 050 - 



:ooo V. •••;•. ••. / 



003 • \ .035-- 



000 - Number of nauplii (wider than 143pm) per liter 



-Nauplii maximum 



Inner boundary of Mecynocera 



Outer boundary of plutei 



- Isotherms at 10 meters 



30° 



125° 



120° 



115° 



FIGURE 3. — Distribution of copepod nauplii (wider than 143 /xm) 

 and their relation to some other biological and physical 

 variables during June 1950. 



130° 



120° 



110° 



40' 



30' 



20° 



-v^-Copepod nauplii 

 maximum 



San Francisco 



Pt. Conception 



San Diego 



40° 



20° 



130° 



120° 



no* 



FIGURE 4.— Copepod nauplii maxima for individual CalCOFI 

 cruises from June 1949 to July 1951. 



be feeding were in the area of the copepod nauplii 

 maximum as described by Arthur (1956). 



604 



