traversed or occupied by pilchards — there are no such fisheries of im- 

 portance north of San Francisco, or betvfeen tlonterey and Los Angeles 

 Counties, or between Turtle Bay and Magdalena Bay, nor do the bait boats 

 operate farther than about l5 miles offshore. In addition, the method 

 of fishing is such that only those fish schooling near the surface are 

 caught, while those schooling deeper are missed. Ivloreover, the fisher- 

 men tend to seek certain sizes; in some places the smaller fish, in 

 others the larger, depending on local demand. For these reasons only 

 a highly and variably selected part of the population could be available 

 to us. 



The effect of this selectivity might be partly eliminated by weight- 

 ing the samples according to the catch, or according to relative abun- 

 dance at the several localitiesf but statistics bearing on the bait fish- 

 ery or on regional abundance are not available, and such weighting is 

 therefore not at present practicable. Because the samples were of vari- 

 ous sizes they were all weighted equally (to 1000 fish); likev/ise, the 

 monthly totals of the vreighted samples at the several ports (to 1000 fish); 

 and the totals of all California ports thus weighted vrere summed by months. 

 The original data were divided into two parts, as indicated by vertical 

 lines in figure 1, the one comprising what was judged to be approximately 

 all the youngest year class, the other the older ones. Each part v/as 

 weighted separately, to 1000 fish, thus emphasizing the height of the 

 several modes vathout regard to their relative abundance. 



Judging from figure 1, a nevf complex of groups of fish first ap- 

 peared in appreciable numbers in the California samples in June, in 1938, 

 ranging in body length from about iiO to 95 mm., and having several modes, 

 the dominant one at 70 mm. Save for a few specimens in Ivlay, fish of that 

 size-range were not available earlier, in spite of every effort to obtain 

 them, and were not available again through May of the following year. 

 A fairlj'- similar group appeared in the bait fisher^' of San Pedro in 1922 

 (fig. 2; Higgins, unpublished manuscript), showing that such occurrence 

 is probably normal. It is probable that this group represents the young- 

 est year class. This conclusion is based on the following considerations: 

 In the most sinistral group of modes for June, 1938, in figure 1, there 

 is a range of about 55 mm. This leaves only UO mm. to the left in which 

 to include a possible younger year class. It wovild be extremely unusual 

 for the zero year class to have a narrower range than the I's; or to be 

 less widely separated from the I's than the I's are from the II' sj or 

 for the first year of growth to be less than the second. 3ut, neverthe- 

 less, even if there were an additional year class, then the fish in the 

 above mentioned UO-mm, range should have grown almost, or quite past 

 the hO-mm. point by the following Ii/lay. Before that time, they should 

 have been taken by the nets of the bait fishery, which, judging from 

 figure 1, could hold fish as small as UO mm. That no such fish were 

 taken in our samples is strong evidence that they did not exist in the 

 waters of the area studied. It seems beyond question, therefore, that 

 the most sinistral group of modes for June in figure 1 does represent 

 fish produced in the spawning season of 1938. 



36 



