Zooplankton Volumes off the Pacific Coast, 

 1954 



This report, the fifth in a series, contains a 

 record of the volumes of zooplankton collected on 

 the survey cruises of the California Cooperative 

 Oceanic Fisheries Investigations off the Pacific 

 coast of California and Baja California during 1954. 

 Regular survey cruises were made at monthly in- 

 tervals, except in September and November . The 

 vessels participating in cruises during 1954 included 

 the CREST, E. W. SCRIPPS, HORIZON, PAOLINA T. 

 and SPENCER F . BAIRD, all operated by the Scripps 

 Institution of Oceanography . 



The tables in this report are designed to serve 

 a twofold purpose: (1) to record the volumes of 

 plankton collected during the 1954 survey cruises 

 (columns 9 and 10), and (2) to put on record the data 

 for all plankton tows made during 1954, including 

 station number (column 1), location (columns 2 and 3), 

 date and time of collection (columns 4-6), volume of 

 water strained (column 7), and the estimated depth of 

 the haul (column 8) . 



The volumes of plankton given in the following 

 tables are "wet" volumes. Each sample was filtered 

 from its preserving fluid and its volume determined 

 by displacement. T\vo volumes are given for each 

 station: (1) the total wet volumes standardized to the 

 amount in iOOO cubic meters of water strained (column 

 9), and (2) the volume of smaller organisms after the 

 removal of larger ones such as jellies, fish, larger 

 mollusca, crustaceans, and squid (column 10). 



The nets used in the collection of the plankton 

 samples were the same as those used on all cruises 

 since 1949 . They were made of No . 30xxx grit gauze 

 (an extra -strong silk bolting cloth), conical in shape, 

 with a one -meter mouth opening, and about five meters 

 long. The last 40 cms. of the cone, and the cod-end 

 bags were made of No . 56xxx silk grit gauze . The 

 procedure for taking net tows was similar to that 

 followed since 1951 . Each haul was an oblique tow 

 made from approximately 140 meters deep to the sur- 

 face (depth of water permitting) . 



The procedures followed in determining the volume 

 of water strained during each haul are outlined in pre- 

 vious reports in this series (refer to Special Scientific 

 Reports: Fisheries Nos. 100 and 125). The numbering 

 system for cruises, which differs from that used in 

 the 1949-1952 reports, is explained in Special Scien- 

 tific Report: Fisheries No. 132 (Zooplankton Volumes 

 for 1953). 



is being investigated by the South Pacific Fishery 

 Investigations of the United States Fish and Wildlife 

 Service, the latter by the Scripps Institution of 

 Oceanography of the University of California . 



These investigations are part of the California 

 Cooperative Oceanic Fisheries Investigations, a 

 program sponsored by the Marine Research Com- 

 mittee, and carried out by the Scripps Institution of 

 Oceanography of the University of California, the 

 Bureau of Marine Fisheries of the California Depart- 

 ment of Fish and Game, the California Academy of 

 Sciences, the Hopkins Marine Station of Stanford 

 University, and the South Pacific Fishery Investiga- 

 tions of the Fish and Wildlife Service . 



Four earlier publications deal with plankton vol- 

 umes collected on survey cruises of the California 

 Cooperative Oceanic Fisheries Investigations. These 

 are: 



STAFF, SOUTH PACIFIC FISHERY INVESTIGATIONS 



1952 . Zooplankton volumes off the Pacific coast, 



1951. U. S. Dept. Interior, Fish and 

 Wildlife Service, Spec. Sci. Rept.: 

 Fisheries No. 73, 37 pp. 



1953. Zooplankton volumes off the Pacific coast, 



1952. U. S. Dept. Interior, Fish and 

 Wildlife Service, Spec . Sci . Rept . : 

 Fisheries No. 100, 41 pp. 



1954. Zooplankton volumes off the Pacific coast, 

 1949-50. U. S. Dept. Interior, Fish and 

 Wildlife Service, Spec . Sci . Rept . : 

 Fisheries No . 125, 54 pp . 



1954 . Zooplankton volumes off the Pacific coast, 



1953. U. S. Dept. Interior, Fish and 

 Wildlife Service, Spec. Sci. Rept.: 

 Fisheries No. 132, 38 pp. 



The plankton samples are used in studying the 

 early Life histories (particularly the distribution and 

 abundance of spawning and the rate of larval survival) 

 of the sardine and other commercially important or 

 potentially important fishes, and also in studying the 

 productivity of sardine spawning areas . The former 



