among CI classes to the distribution of common 

 dolphins. Due to the small number of pilot whale 

 aggregations, the CI range was divided into four 



unequal classes to meet the statistical assumptions 

 for chi-square analysis (Dixon and Massey 1969). The 

 proportion of pilot whales in each of these classes 



34^ 



33^ 



32* 



120^ 



119< 



118' 



117° 



Figure 1.- Sightings of pilot whales, Giobicephala macrorhyyichus, and common dolphins, Delphinus delphis. The 

 study area is bounded on the west by long. 120°00'W and on the east by the coast of California between lat. 34°05'N and 

 32°24'N. Sightings may not accurately depict the geographic distribution of these species because the survey flights 

 were not uniformly distributed spatially or temporally. Encounters occurring outside the study area are not shown. 



Table 1. — Distribution among contour index classes of observed and expected ag- 

 gregations (sec text). 



473 



