98 



Water 



Figure 83. Regional pattern of 

 water temperature and salinity 

 at the surface and at a depth 

 of 200 meters during the Ma- 

 rine Life Research cruise of 

 February 1950. Note the sur- 

 face area of low temperature 

 and high salinity between Santa 

 Cruz and San Nicolas Islands 

 and its absence at 200 meters. 



the temperature near the southwestern cor- 

 ner of Chart I exhibits a smaller range, from 

 14.5 to 18.0°, and the temperature near San 

 Diego a greater range, from 14.0 to 19.5° 

 (Fig. 84). Fewer than 10 per cent of the 

 observations differ by more than 2.0° from 

 the average curves; however, these small 

 variations may have important ejffects on the 

 fishing industry, as will be discussed in a 

 later section. Almost identical average re- 

 sults for the area near San Diego were ob- 

 tained by McEwen (1916) in a summary of 

 results of cruises made between 1908 and 

 1915, and by Emery, Butcher, Gould, and 

 Shepard (1952) in a summary of cruises 

 between 1942 and 1945. In contrast to the 

 temperatures at the water surface, those at 

 200 meters are nearly uniform throughout 

 the year; at the same three stations 80 per 

 cent of the temperature measurements at 200 

 meters are between 8.0 and 9.0° C. 



During many of the cruises the same 

 general area of lowest temperatures is 

 characterized by slightly higher salinities 

 than elsewhere, slightly lower oxygen con- 

 tent (Fig. 85), and much higher concentra- 

 tions of phosphate-phosphorus. Because 



Figure 84. Annual variation of water surface tempera- 

 ture at three localities for 49 Scripps cruises during the 

 years 1937-1941 and 1949-1952. Temperatures at 200 

 meters for all three localities are plotted together because 

 of their similarity. 



