In the foregoing pages it has been demonstrated that, if they 

 be properly prepared, scales and otoliths of juvenile pilchards 

 (Sardinops caerulea ), show ringg that are associated in number with 

 agfT It has been shown that these rings are formed once yearly, at 

 a definite ticie of year, namely, the summer and fall. They therefore 

 correspond in number with years of life. Though they are sometimes 

 relatively obscure, the rings present may be counted v/ith what appears 

 to be significant accuracy, say 85-95 percent for the first three year 

 classes; and results, which a later report will cover, give promise 

 of extending the use of scales to much older ages. Of the scales ex- 

 amined during this study, over 99 percent were considered legible. 

 Those npt legible were generally specimens that had been improperly 

 cleaned, or that had regenerated centers. The age detenninations were 

 in all cases made without reference to the size of the fish, and there 

 is evidence that the operators were not unduly influenced by the size 

 of the scales. 



The counts of annuli on otoliths v^ere found, by an independent 

 study, to agree with those on scales. It is the opinion of the writers, 

 however, that otoliths are less useful than scales for determining age 

 of pilchards beyond the third year. 



Judging from scales smd otoliths of juvenile pilchards taken from 

 the bait fisheries in California during 1938 and 1939, and from the 

 fall commercial fishery for adults in 1939, fish of the year class 1938 

 had a modal length around 70 mm. when they first appeared in the bait 

 fishery in June, 1938, growing to near 120 mm. by the following April, 

 by which time the first annual mark has formed; and fish of year class 

 1937 had a modal length near l60 mm. v/hen their second mark had formed. 

 Because of the rather complex selection resulting from the requirements 

 of the fisheries, as well as from variations in availability, the sampling 

 was highly imperfect, and these figures are mere approximations. Fur- 

 thermore, they apply only to fish taken from California fisheries. 



Young specimens collected in Lovrer California were larger than 

 those of corresponding age taken in California; and those taken in Oregon, 

 Washington, and British Columbia were smaller. These differences suggest 

 further applications of the study of pilchard scales, for they are, no 

 doubt, reflected in differences in corresponding scale growth increments 

 among the populations of the different regions. Thus the scales may prove 

 useful "for studying the migrations of the pilchard, as well as for deter- 

 mining their ages. 



LITERATURE CITED 



AIKAV/A, HIROAKI 



I9U0. On the age and race of the Japanese sardine, Sardinia 



melanosticta (Temminck and Schlegel). Records of Oceano- 

 graphlcTorks in- Japan, Vol. 11 (2), pp. 81-112, 10 figs. 



49 



