A second method is to pick characteristics 

 which are known to be genotypic, or which can 

 experimentally be determined to be genotypic, 

 and examine samples from the several spawn- 

 ing grounds with respect to these characteris- 

 tics. At present, the extent to which any 

 particular characteristic is an expression of 

 the genetic constitution of an individual is un- 

 known . Therefore, if this method is used, it 

 will first be necessary to establish experiment- 

 ally the genotypic nature of as many character- 

 istics as possible (by the use of chromatographic 

 and/or immunological techniques) . 



before reaching a decision about a tagging 

 experiment. 



A tagging experiment design is included 

 in an appendix . 



ACKNOWLEDGMENTS 



I am indebted to E.H. Ahlstrom, F.E. 

 Felin, O.E. Sette, B.A. TaftandT.M. Widrig, 

 all of the U. S. Fish and Wildlife Service, for 

 helpful suggestions and comments ensuing from 

 their critical reviews of this paper in manuscript. 



A third method is a tagging experiment, 

 with the tagging and recovering being done on 

 the spawning grounds . Of the several alterna - 

 tives, this method would provide the most direct 

 evidence and may have to be employed eventual- 

 ly, regardless of whatever approach is used 

 first. A tagging experiment is, however, a 

 large and costly undertaking, as may be seen 

 from the design described in the appendix. It 

 is therefore more practical to fully assess the 

 possibilities of the second method before reach- 

 ing a decision about the desirability of a tagging 

 experiment. 



SUMMARY 



LITERATURE CITED 



Ahlstrom, Elbert H. 



1954. Distribution and abundance of egg 

 and larval populations of the Pacific 

 sardine. U.S. Fish & Wildlife 

 Service, Fish. Bull. 56 (93):83-140, 

 32 figs . 



Bailey, Reeve M., and William A. Gosline 



1955. Variation and systematic significance 

 of vertebral counts in the American 

 fishes of the Family Percidae. 

 Univ. Mich., Mus. Zool . Misc. 

 Publ . no. 93, 44 pp., 4 figs . 



The subpopulation problem in the Pacific 

 sardine is concerned with the number and iden- 

 tity of genetically self-sustaining units within 

 the population . 



Balston, J.N.. andB.E. Talbot 



1952 . A guide to filter paper and cellulose 

 powder chromatography. H. Reeve 

 Angel & Co , Ltd., London. 145 pp. 



Evidence of many kinds shows that there 

 are between- and within- season, port and year 

 class differences. This evidence includes 

 migration, growth, meristic characteristics, 

 etc . 



It is not known whether these differences 

 are phenotypic or genotypic; the weight of the 

 evidence is that they are phenotypic . 



Boyd, William C . 



1947. Fundamentals of immunology . 2nd 

 ed., Interscience Publishers, Inc., 

 New YorK . xvi + 503 . 



Brock, V. E. 



1940. Report on the tagging of pilchards 

 by the Fish Commission of Oregon. 

 Rept. toComm., 1940, 10pp. 



Of the three possible methods of estimating Buzzati-Traverso, Adriano, and Andreas B. 



the exchange between space -time spawning areas, 

 a tagging experiment will yield the most direct 

 evidence. 



and 



Tagging experiments are costly, however, 

 it is more realistic to critically assess the 



possibilities of chromatography and immunology 



Rechmtzer 

 1953 . Paper partition chromatography in 

 taxonomic studies. Science, vol. 

 117, no- 3029, pp. 58-59, 1 fig. 



California Marine Research Committee 



1950. 



California Cooperative Sardine 



116 



