Table 4. — Average monthly plankton volumes In the area off central Baja California (lines 110-137) for 



January through October, 1951-60 



♦Not occupied. 



** An oceanographic survey of the North Pacific Ocean. 



April 14.18, May 13.21, June 15.66, and July 

 15.51°C.). Possibly the heavy plankton con- 

 centrations in May were transported into the 

 area by the west wind drift from the dense 

 subarctic populations (as shown in Raid, 

 1962). 



In the southern area (lines 110-137), during 

 7 of the 10 months sampled (January-Feb- 

 ruary, April-July, and October) plankton vol- 

 umes in 1960 were similar to the light volume 

 years (1958 and 1959). The August volumes 



for I960 fell about midway between the heavy 

 volume years (1951-56) and the light volume 

 years (1958 and 1959). The March and Sep- 

 tember volumes for 1960 were similar to the 

 heavy volume years (1951-56). 



A comparison, by months and area, of 

 the 1960 plankton volumes with the av- 

 erage volumes for 1951-56 and 1958-59 

 is presented graphically in figure 3. The 

 transition year, 1957, is not included in the 

 graph. 



