The average monthly plankton volumes by 

 years, 1951-60, along with the monthly av- 

 erage for 1951-56, in the area comprising 

 lines 80-107 is given in table 3. Data for 

 August and September are not included be- 

 cause the coverage during those months was 

 incomplete in recent years. Similar infor- 

 mation for the southern area (lines 110-137) 

 is given in table 4. 



Annual plankton volumes may be char- 

 acterized as heavy in 1951-56, light in 1958 

 and 1959, and apparently transitional in 1957 

 (when volumes were greater than the 1951-56 

 average in January- April, and smaller in 

 May-December). The average plankton vol- 

 ume for 1960 was between the heavy volumes 



for 1951-56 and the light volumes for 1958 

 and 1959. 



In the northern area (lines 80-107) the 1960 

 average monthly volumes were less than the 

 1951-56 average volumes during January, 

 February, April, June, July, and October, and 

 greater during March and May. The high av- 

 erage standardized plankton volunne (374 cc.) 

 for May I960 was due primarily to the heavy 

 hauls at a group of 9 of the 72 stations in this 

 80-107 area. These stations, between 90.65 

 and 90.85, and 93.70 and 93.90, inclusive, had 

 an average plankton volume of 1,573 cc. The 

 average 10-m. water temperatures in this 

 area during May were the lowest of the 5- 

 month period, March- July (March 13.84° C,, 



Table 3. — Average monthly plankton volumes in the area off southern California and 

 adjacent northern Baja California (lines 80-107) for January through July, and October, 

 1951-60 



* Not occupied. 



