Coverage of the four areas between Point 

 Conception and Point San Juanico was obtained 

 consistently during the first 7 months of each 

 year and also in October. During the other 4 

 months, coverage was sometinnes comprehen- 

 sive, but more often was limited to a portion 

 of the range. When restricted, coverage was 

 more frequent off central Baja California in 

 August and September, and off southern Cali- 

 fornia during November and December. Cov- 

 erage off central California {lines 60-77) was 

 achieved most consistently during April 

 through July. 



THE QUARTERLY SURVEY CRUISES 

 OF 1961-64 



Beginning in 1961 survey cruises were 

 spaced at quarterly intervals. The pattern 

 covered on most surveys was from line 60 to 

 140. The cardinal lines were covered on most 

 cruises by a Scripps Institution of Oceanog- 

 raphy vessel, either the Horizon or the Alex- 

 ander Agassiz , and the ordinal lines by the 

 Bureau of Commercial Fisheries vessel Black 

 Douglas . Most cruises extended over 2 months. 



Two cardinal lines, 60, off central Cali- 

 fornia, and 90, off southern California, were 

 extended seaward to station 200--an offshore 

 distance of over 600 miles. Only lines 63, 67, 

 73, and 77 were abbreviated as compared 

 with the usual coverage obtained on monthly 

 survey cruises. Many station lines were ex- 

 tended farther seaward than was usual during 

 nnonthly survey cruises. 



METHODS OF SAMPLING 



The plankton net employed since the begin- 

 ning of CalCOFI surveys has been constructed 

 of No. 30xxx grit gauze (heavy bolting silk). 

 The shape of the net is cylindrical-conical; 

 a forward cylindrical section, about 1 m. long, 

 precedes the conical portion of the net, which 

 is about 3 m. long. The net terminates in a 

 detachable cod end. The net is 1.0 m. in diam- 

 eter at the mouth (0.7854 m. 2); the ratio of mesh 

 aperture area to mouth area is about 3:1. 



Plankton hauls are made obliquely from 

 about 140 m. to the surface, depth of water 

 permitting. The net is lowered by paying out 

 200 m. of towing wire at a rate of 50 m. per 

 minute. It is retrieved at a rate of 20 m. per 

 minute, after allowing 0.5 minute for the net 

 to come to equilibrium. Hence, a standard 

 plankton haul requires 14.5 minutes. The haul 

 is made at a vessel speed of about 1.5 to 2 

 knots. Vessel speed is carefully controlled to 

 maintain the angle of the towing cable at 45°. 



It has been established by attaching a 

 depth-time recorder to the bridle of a net 

 that there is a linear relation between the 

 wire angle as measured at the surface and the 



depth of the net at any instant. Actual depth 

 is the product of the amount of wire out 

 times the cosine of the surface wire angle. 

 The amount of water strained during a haul 

 is about 500 m.^. 



LABORATORY PROCEDURES 



CalCOFI surveys initially were oriented to 

 the Pacific sardine, but from the inception of 

 the cooperative cruises, eggs and larvae of all 

 fishes taken in plankton hauls were separated 

 and most were identified and counted. Larvae 

 of the four species commonly grouped together 

 as "wetfishes"-- sardine, northern anchovy. 

 Pacific mackerel ( Scomber diego ), and 

 jack mackerel ( Trachurus symmetricus )-- 

 have been counted by size; hence comparable 

 information is available for all four species. 



Plankton samples containing fish eggs and 

 larvae are handled in three steps in our 

 laboratory. 



1. Each sample is exannined, usually in its 

 entirety, for fish eggs and larvae. Eggs and 

 larvae of sardines and anchovies are separated 

 from other fish eggs and larvae and counted. 

 This initial count is designatedas the "sorter 's 

 count." 



2. The larvae of sardine and anchovies are 

 measured to the nearest half-millimeter 

 (standard length). The numbers derived from 

 counts made on measured larvae constitute 

 our accepted counts. 



3. The larvae are grouped into the size 

 categories used in our published records 

 (mostly by 1.0 mm. length intervals), and these 

 numbers are standardized to the number of 

 larvae under 10 square meters of sea surface. 

 This method of standardization nnakes hauls 

 comparable to one another, and also permits 

 meaningful integration of numbers of eggs or 

 larvae over area. 



This report deals primarily with the total 

 standardized numbers of sardine and anchovy 

 larvae in our survey collections. For the 

 years 1951-59, we are including monthly 

 summaries of size information for sardine 

 and anchovy larvae. This information is de- 

 rived from our published records for 1951-57 

 (Ahlstrom, 1953, 1954a, 1958, 1959a; Ahlstrom 

 and Kramer 1955, 1956, 1957) and from a 

 manuscript for the years 1958 and 1959. 

 Similar information will be available soon 

 for all collections obtained through 1964. 

 Information about sardine and anchovy larvae 

 collected on cruises in 1950 was published 

 by Ahlstrom (1952). The 1949 data are un- 

 published for anchovy but were summarized 

 for sardine by Ahlstrom (1954b). 



In studies dealing with distribution and 

 abundance of sardine and anchovy larvae, 

 total numbers per haul are much simpler to 

 use than are more detailed numbers by size. 

 Most tables included in this report are based 



