Table 1. Research vessels participating In CalCOFI airvey cruises, 1958. 



Cruise Number BLACK SPENCER F. PAOLINA 



number vessels DOUGLAS BAIRD HORIZON STRANGER T. ORCA 



Month 



3 

 2 

 2 



4 

 3 

 3 



4 

 1 

 2 

 4 

 1 

 1 



X 

 X 

 X 

 X 

 X 

 X 

 X 

 X 



X 

 X 



X 

 X 

 X 

 X 

 X 



X 



X 



X 



X 



X 

 X 



X 



X — 



— X 



Table 2. Area covered and number of stations occupied on the monthly CalCOFI 

 cruises during 1958 



Month 



Cruise 

 number 



Area covered 

 station lines 



Number of 

 stations occupied 



60-157 

 80-150 

 70-150 

 60-137 

 60-137 

 50-137 

 40-137 

 110-137 

 110-137 

 60-153 

 80-100 

 80-100 



150 



132 



159 



268 



232 



212 



273 



37 



34 



250 



42 



45 



of approximately 140 meters to the 

 surface, except in shallow water. 



The volume of plankton in each 

 sample w^as determined by displace- 

 ment as foUow^s: The plankton was 

 separated from its preserving liquid 

 (3 percent formalin) by filtering, al- 

 lowed to drain, then placed into a 

 graduated cylinder to which was added 

 a known volume of 3 percent formalin. 



Two volumes were obtained for each 

 sannple: (1) the total volume of all 

 plankton material and (2) the volume 

 of smaller organisms after removal 

 of larger organisms, such as jellies, 

 fish, squid, salps, pyrosomes, larger 

 mollusks and larger crustaceans. Our 

 criterion for a "larger" organisnn 

 (except juvenile or adult fish) was one 

 whose volume, as an individual, ex- 

 ceeded 5 cubic centimeters. 



