encompassed the vertical distribution of sardine eggs and larvae. 

 Wide-ranging joint biological and oceanographic survey cruises 

 were resumed in 1949 with sardine as the focus; however, an 

 increasing interest in other biological components resulted in 

 the deepening of standard tows to 140 m in 1951. This marked the 

 beginning of truly quantitative ichthyoplankton sampling on 

 CalCOFI surveys. 



Data resulting from CalCOFI surveys in 1956 have been 

 published in a number of forms. Hydrographic data (Reid et al., 

 1963), zooplankton volumes (Thrailkill, 1957; Smith, 1971) and 

 ichthyoplankton data for selected species (Ahlstrom, 1958) were 

 presented in standard formats. The latter lists counts for eggs 

 and larvae of sardine and for larvae of northern anchovy 

 (Engraulis mordax) , jack mackerel (Trachurus symmetricus) , 

 Pacific mackerel (Scomber japonicus) , Pacific hake (Merluccius 

 productus) , and rockfishes (Sebastes spp.). Also, length 

 frequencies are listed for sardine, anchovy, jack mackerel, and 

 Pacific mackerel larvae. Distribution maps of larvae of 5 of 

 these taxa taken on CalCOFI surveys during 1956 are presented in 

 the CalCOFI Atlas series (Kramer and Ahlstrom, 1968; Ahlstrom, 

 1969; Kramer, 1970; Ahlstrom et al . , 1978). Other atlases 

 provided distribution maps of 6 mesopelagic fish larvae 

 (Ahlstrom, 1972) and 8 flatfish taxa (Ahlstrom and Moser, 1975) 

 taken during 1956. 



A computer data base for eggs and larvae of sardine and 

 anchovy and for larvae of hake, and the two mackerels was 

 established in 1969. The development of a data base for other 

 fish larvae is a complex undertaking because competency of 

 identification has evolved steadily over the past 38 years. We 

 began the task of producing a CalCOFI ichthyoplankton data base 

 and associated data report series in 1983. All available 

 original records for 1956 were subjected to an extensive 

 verification and editing process to produce this report. This 

 and previous (Ambrose et al., 1987a, b; Sandknop et al., 1987; 

 Stevens et al., 1987; Sumida et al., 1987) and subsequent reports 

 make the CalCOFI ichthyoplankton and station data available to 

 all investiqators and serve as quides to the computer data base. 

 The data base will be modified when additional errors are 

 discovered and when composite taxa from the earlier years are 

 reidentif ied. These reports are the fundamental reference 

 documents aqainst which subsequent chanqes in the data base can 

 be compared. 



SAMPLING AREA AND PATTERN 



In 1956, CalCOFI survey cruises were conducted at monthly 

 intervals. A total of 1407 stations included in this data base 

 was occupied on 12 cruises, with an averaqe of 117 stations per 

 cruise (ranqe of 36-239) . Coveraqe of the survey station 

 pattern varied amonq cruises and the entire quarter-million 

 square mile survey area was not covered on any sinqle cruise 

 (Figures 1-13; Table 1). The area off northern California (lines 



