THE SURVEY PATTERN AND AREA 



The pattern of stations (Fig. 1) covered by 

 most of the CalCOFI surveys was designed orig- 

 inally on the basis of a centric-systematic-area 

 sampling scheme (Milne, 1959) to determine the 

 major spawning areas of the Pacific sardine off 

 the coasts of the United States and Baja Cali- 

 fornia, Mexico. This was done by conducting 

 surveys on lines spaced 120 miles apart from the 

 Columbia River to Sebastian Vizcaino Bay. As 

 the spawning areas were delimited, additional 

 lines of stations were added between the cardi- 

 nal lines, and the surveys were concentrated off 

 the coasts of California and Baja California. 



The original lines of the pattern were based 

 on line 80 off Point Conception, Calif., and set 

 parallel to that line 120 miles apart, north to 

 line 10 off the United States-Canadian border, 

 and south to line 120 off Point Eugenia, Baja 

 California. They were plotted to extend 30° 

 southwest of lines of latitude, thus perpendicular 

 to the coast of central California, north of Point 

 Conception. It was intended that the 120-mile 

 spacing would allow for additional lines to be 

 plotted 12 miles apart between the cardinal lines 

 and still be designated by whole numbers with- 

 out resorting to fractions. However, when lines 

 were added between cardinal lines, it was deemed 

 sufficient to space them at 40-mile intervals. 

 Thus, the major pattern consists of the cardinal 

 lines in multiples of 10 ending in O's and the or- 

 dinal lines ending in 3's and 7's. During the 

 course of the investigations, lines were added 

 finally to include line 157 just south of Cape 

 San Lucas, Baja California. 



The stations on the lines were laid out on the 

 basis of a perpendicular to line 80, at a point 

 designated station 80.60. The perpendicular, 

 through all lines parallel to line 80, aligned the 

 stations designated as 60's. 



Most of the original stations shoreward and 

 seaward from station 60 were plotted 40 miles 

 apart, which allowed stations between the 40- 

 mile points to be plotted as close as 4 miles apart 

 and still retain whole numbers. In most cases, 

 stations between the 40-mile points have been 

 only 20 miles apart. Those closer than 20 miles, 

 e.g., inshore or near islands, were so placed sim- 

 ply because a 20-mile spacing would have placed 

 a station on land and the omission of such a sta- 

 tion would have left too large a space between 



the last plotted station and the land. Closer spa- 

 cing than 4 miles, using fractions for station 

 numbers, has been resorted to in some instances, 

 e.g., to locate the eggs of the increasingly rare 

 Pacific sardine during the peak of its spawning 

 season. 



DATA COLLECTION 



The Research Vessel 



A vessel used to collect oceanographic data 

 should be a relatively stable platform at sea and 

 be capable of reasonably rapid coverage of large 

 areas for long periods of time. Today, most ves- 

 sels used for biological and hydrographic re- 

 search on the high seas are 100 or more feet long, 

 powered to cruise at 10 to 15 knots, and capable 

 of staying at sea for 14 to 30 days. Some ships 

 are of multipurpose design in that they can col- 

 lect plankton and hydrographic data and convert 

 to fishing operations to handle large fishing nets, 

 trawls, seines, etc. 



Gear common to the collections of plankton 

 and hydrographic data are power winches 

 equipped with high-strain wire, an over-the-side 

 platform for handling gear clear of the ship's 

 side, and a weight at the end of the wire. Ship- 

 board facilities should include sheltered spaces 

 for laboratory work and adequate storage spa- 

 ces for gear and samples. 



Essential gear for the collection of plankton 

 are fine mesh plankton nets with detachable cod 

 ends, rings to keep net mouths open, a bridle 

 assembly to tow the nets, a cable clamp to attach 

 a lead line to the towing cable, an inclinometer 

 to measure angles of stray during a net tow, and 

 flowmeters to measure water volume strained 

 by the nets. 



Some of the gear described here have spe- 

 cifications included in figure captions for which 

 simple descriptions will suffice to allow duplica- 

 tion without need for further details. Some are 

 purchased from their manufacturers or distrib- 

 utors. Others have specifications too detailed to 

 be included here. Table 1 lists all of the gear 

 and materials described, the figures in which they 

 are illustrated, and the places of their descrip- 

 tions, and or sources of specifications and sup- 

 pliers. 



The winches used for plankton tows or hydro- 

 graphic casts should be electric or hydraulic and 



