BRINTON: POPULATION BIOLOGY OF EUPHAUSIA PACIFIC A 



NO OF 

 SAMPLES 



CRUISE NUMBER (YEAR & MONTH ) 



I I I I I I I I I I I I I I I I I I I I I I I I I I III I III! I II I II I III I 



12 17 13 14 16 21 17 17 7 12 10 14 24 24 18 21 19 15 16 16 17 18 12 14 14 13 20 18 18 774 14 7616 14 II 15 1220 15 21 



I I I 

 19 18 20 



Figure 4.-a, Inferred monthly index of upwelling intensity per 100 m of southern California coastline, 1953-56 (from Bakun 1973). b. 

 Temperature range and mean, by cruise, in study area, c. Estimated densities of ripe eggs and <;4.5 mm larvae of Euphausia pacifica in 

 area, d, Densities of ripe females, three body-length groups. Number of samples examined are indicated by cruise. 



ning in December 1954, and the first significant 

 recruitment was in February (cruise 5502). This 

 increase in spawning continued through March, 

 but recruitment did not increase markedly until 

 May, following an April egg maximum. Thereafter 



egg production peaked in alternate months, June 

 (the annual upwelling maximum), September, and 

 November-but recruitment was generally low 

 (<2,500 larvae/ 1,000 m^ in the area) except during 

 May and July. July yielded the year's peak in 



741 



