Zooplanlcton Volumes off the Pacific Coast , 1955 



This report, the si:<;th in a series, contains a record of the voliomes of 

 zooplankton collected on survey cruises of the California Cooperative Oceanic 

 Fisheries Investigations off the Pacific coast of California and Baja Cali- 

 fornia during 1955. Survey cruises v/ere made at monthly intervals except in 

 August, September and November. During August, four vessels of the California 

 Cooperative Oceanic Fisheries Investigations cooperated with vessels of other 

 organizations (Pacific Oceanic Fishery Investigations of the United States 

 Fish and V/ildlife Sei'vice, the University of Washington, the Pacific Oceano- 

 graphic Group of the Fisheries Research Group of Canada, and a number of 

 Japanese organizations) in making a synoptic oceanographic survey of the 

 Pacific Ocean north of 20" north latitude. The operation has been designated 

 "Norpac", and data collected during this cruise will be published separately. 

 Special cruises v;ere made off southern California in September and November, 

 and data from these also will be published separately. 



Vessels participating in cruises during 1955 included the "Crest", 

 "Horizon", "Stranger", "Spencer F. Baird", and "Paollna T.", operated by the 

 Scripps Institution of Oceanography of the University of California, and the 

 "Black Douglas", operated by the South Pacific Fishery Investigations of the 

 United States Fish and Wildlife Service, 



The tables in this report are designed to serve a twofold purpose: (1) 

 to record the "wet" volumes of plankton samples collected on 9 survey cr-uises 

 made in 1955 (coliornns 9 and 10), and (2) to put on record the data for each 

 haul, including station niamber (coluimi l) , location (columns 2 and 3)i date 

 and time of collection (columns 4-6), volume of water strained (column 7) and 

 the estimated depth of the haul (column 8), 



The nets used in the collection of samples, the methods of collection, 

 and procedures followed in standardizing data are identical to those described 

 in previous reports in this series. Each haul was an oblique tow made from 

 approximately 140 meters deep to the surface (depth of water permitting). 



Plankton collections are used in studying the early life histories of the 

 sardine and other commercially important or potentially important fishes, and 

 also in studying the productivity of spawning areas. The former investigations 

 are being conducted by the South Pacific Fishery Investigations of the Fish 

 and Wildlife Service, the latter by the Scripps Institution of Oceanography 

 of the University of California, These investigations are part of the Cali- 

 fornia Cooperative Oceanic Fisheries Investigations j a program sponsored by 

 the Marine Research Comma.tbee, and carried out by the Scripps Institution of 

 Oceanography of the University of California, the Bureciu of Marine Fisheries 

 of the California Department of Fish and Game, the C/ilifornia Academy of 

 Sciences, the Hopkins Marine Station of Stanford University, and the South 

 Pacific Fishery Investigations of the Fish and V/ildlife Service, 



