ABSTRACT 



This report provides ichthyoplankton and associated station 

 and tow data from California Cooperative Oceanic Fisheries 

 Investigations (CalCOFI) cruises conducted off California and 

 Baja California in 1956. It is the sixth report in a series that 

 presents these data for all biological-oceanographic CalCOFI 

 surveys from 1951 to the present. A total of 1407 stations was 

 occupied during 12 monthly multivessel cruises over the guarter- 

 million sguare mile survey area which extends from the 

 California-Oregon border to Cape San Lucas, Mexico and seaward to 

 several hundred miles. The data are listed in a series of 6 

 tables; the background, methodology, and information necessary 

 for interpretation and guantitative analysis of the data are 

 presented in an accompanying text. All pertinent station and tow 

 data, including volumes of water strained and standard haul 

 factors are listed in the first table. Another key table lists, 

 by station and month, standardized counts of each of the 136 

 larval fish categories identified from survey samples. This and 

 previous and subseguent reports make the CalCOFI ichthyoplankton 

 and station data available to all investigators and serve as 

 guides to the newly developed computer data base. 



INTRODUCTION 



This report, the sixth of a series, provides ichthyoplankton 

 and associated station and tow data from California Cooperative 

 Oceanic Fisheries Investigations (CalCOFI) joint biological- 

 oceanographic survey cruises conducted in 1956. The CalCOFI 

 program was initiated in 1949, under the sponsorship of the 

 Marine Research Committee of the State of California, to study 

 the population fluctuations of the Pacific sardine (Sardinops 

 sagax) and the environmental factors that may play a role in such 

 fluctuations. CalCOFI, known as the California Cooperative 

 Sardine Research Program from 1949 to 1953, was made up of 

 representatives of the South Pacific Fisheries Investigations 

 (SPFI) of the U.S. Fish and Wildlife Service [now the La Jolla 

 Laboratory, National Marine Fisheries Service (NMFS) ] , the 

 Scripps Institution of Oceanography (SIO) , the California 

 Department of Fish and Game (CDFG) , the California Academy of 

 Sciences (CAS) and the Hopkins Marine Station of Stanford 

 University. The first three of these agencies supplied ships and 

 personnel to conduct the sea surveys. NMFS processed the 

 plankton samples and analyzed the ichthyoplankton from them. SIO 

 processed and analyzed the hydrographic samples and measurements 

 and also analyzed invertebrate groups from the plankton samples. 



The boundaries, station placement, and sampling freguency 

 for the CalCOFI survey area were based on the results of joint 

 biological and oceanographic cruises conducted by NMFS and SIO 

 during 1939-41. Those cruises were designed to collect sardine 

 eggs and larvae and associated hydrographic data over the entire 

 areal and seasonal spawning range of the species. On these 

 survey cruises, plankton tows were made to 70 m, a depth which 



