March and in October. The area between Pt. Conception, 

 California and Pt. San Juanico, Baja California (lines 80-137) 

 was surveyed in all 10 cruises. The area off southern Baja 

 California (lines 140-157) was surveyed in January and December. 

 Coverage usually extended seaward to stations 90 .or 100 

 (approximately 160-300 miles of f shore) •'■ in the main sampling 

 area, with an extended southern offshore pattern in January. 



Five vessels were employed on these cruises: the Crest, E. 

 W. Scripps, Horizon, Paolina T, and Spencer F. Baird of SIO. Two 

 vessels participated on each cruise except cruise 5404 which 

 employed three vessels. The Crest was used on all cruises and 

 the Horizon on all but 5408 and 5412. The other three vessels 

 each participated on a single cruise (Ahlstrom and Kramer, 1956; 

 Table 1) . 



SAMPLING GEAR AND METHODS 



The standard CalCOFI net used from 1949 to 1969 had a 1-m 

 diameter mouth opening (0.785 m^ area) and an overall length of 

 about 5 m. The net was constructed of 30xxx gauze, a heavy duty 

 grade of silk bolting cloth, with a mesh size of 0.55 mm after 

 shrinkage. The last 40 cm of the cone and the cod end were 

 constructed of 56xxx grit gauze which had a mesh size of 0.2 5 mm 

 after shrinkage. The net ring was fastened to a short 3-lead 

 bridle connected to several meters of line which attached to the 

 towing cable by a clamp. A current meter was suspended in the 

 center of the net mouth to measure volume of water filtered (see 

 Kramer et al., 1972, for further details). 



The standard tow from 1951 through 1968 was an oblique haul 

 to 140 m depth (to 15 m of the bottom in shallow areas) designed 

 to filter a constant amount of water per depth interval (ca. 

 3m-^/m of depth) over the vertical range of most ichthyoplankters. 

 Hauls were made at a ship speed of 1.5-2.0 knots and initiated by 

 clamping the net line to the towing cable with the 45 kg terminal 

 weight about 10-15 m below the surface. The net was lowered to 

 14 m depth by paying out 2 00 m of wire over a 4 minute period 



■'■CalCOFI lines (Figure 12) are arranged perpendicular to the 

 coastline and extend from the Canadian border (line 10) to below 

 Cape San Lucas, Baja California (line 157) . Stations were 

 established on the basis of a perpendicular to line 80 (off Pt. 

 Conception) at a point designated as station 60. Stations were 

 plotted seaward and shoreward from station 60 on each line. 

 Cardinal CalCOFI lines (those ending in "0") are 120 miles apart 

 and usually bracket two ordinal lines (ending in "3" or "7"), so 

 that lines are 40 miles apart over most of the pattern. Cardinal 

 stations are 40 miles apart and typically these are separated by 

 a station number ending in "5" so that stations are 20 miles 

 apart out to station 90 on most lines. Stations are placed at 

 closer intervals near the coast and islands to accommodate these 

 features (see Kramer et al., 1972 for further details). 



