FISHERY BULLETIN: VOL. 87, NO. 2. 1989 



relative to indigenous populations (Withler 1982; 

 Altukhov and Salmenkova 1987; Reisenbichler 

 1988). Transfers from maladapted populations not 

 only waste effort and resource, but also carry the 

 risk of disrupting locally adapted genomes through 

 interbreedings (Reisenbichler and Mclntyre 1977; 

 Shields 1982). Sets of data such as those reported 

 here are valuable in outlining at least the maximum 

 distribution of locally adapted gene pools and there- 

 by provide guidelines for stock transfers. In the 

 absence of any other data, it would be inadvisable 

 to translocate populations between sites such as the 

 lower Columbia River and the Washington or Ore- 

 gon coasts. 



Stock transfers within major genetic units should 

 also be performed with caution. Each of the indivi- 

 dual or pooled populations within the nine units is 

 also genetically distinct for some loci sampled in this 

 study from other populations within the unit; they 

 are therefore divergent from such populations at a 

 much larger number of additional loci throughout 

 the genome. It is pertinent to recall that a consid- 

 erable amount of the total gene diversity results 

 from population subdivision (4.4/12.3 = 35.8%) 

 resided within the population units (Table 5, column 

 3). Likewise, slight or no divergence between two 

 populations based on samplings of polymorphic pro- 

 tein-coding loci does not necessarily mean these 

 populations are identically adapted (discussed in 

 Utter 1981). For example, two groups of rainbow 

 trout in the Snake River drainage having similar 

 allele frequencies at five polymorphic loci are 

 adapted to drastically different local environments 

 and life history patterns (Wishard et al. 1984). 



CONCLUDING OBSERVATIONS 



Three points require emphasis following this ini- 

 tial outline of population units. First, it warrants 

 restating that each of the nine units represents a 

 genetically heterogeneous grouping. It is important 

 that this heterogeneity be recognized and main- 

 tained within the respective units. 



Second, these units are based on limited data 

 within the range of sampling and, in some instances, 

 on arbitrary decisions; the units are intended to be 

 modified as more information accumulates and 

 therefore to serve as guidelines for further inves- 

 tigation. For purposes of clarification, allelic data 

 beyond those listed in the Appendix have been intro- 

 duced at various places in the text. Additional alleles 

 and polymorphic protein-coding loci are continual- 

 ly being identified through ongoing investigations, 

 and further clarification is inevitable as these data 



accumulate. Genetic data other than from protein- 

 coding loci are accumulating on chinook salmon 

 populations within the geographic range of this 

 study. Such genetic data show differences among 

 populations in mitochondrial DNA (E. Berming- 

 ham'"), and life history variables (Nicholas and 

 Hankin 1988; Schreck et al. 1986), and provide com- 

 plementary insights that will ultimately result in a 

 much more detailed understanding of genetic struc- 

 turing of these chinook salmon populations. 



Third, numerous distinct population units exist in 

 North America beyond the sampling area of this 

 study (e.g., Gharrett et al. 1987) and nothing is 

 known of Asiatic populations. The nine units pre- 

 sented here, then, are viewed as a necessary part 

 of a much more complete picture of the genetic 

 structure of chinook salmon that will ultimately 

 emerge. 



ACKNOWLEDGMENTS 



Assistance in sampling was provided by person- 

 nel of agencies including the Canadian Department 

 of Fisheries and Oceans, California Department of 

 Fish and Game, Oregon Department of Fisheries 

 and Wildlife, and Washington Department of Fish- 

 eries. Valuable technical assistance was provided by 

 P. Aebersold. Valuable reviews were provided by 

 C. Mahnken, G. Winans, A. Gharrett, Northwest 

 and Alaska Fisheries Center and three anonymous 

 reviewers. 



LITERATURE CITED 



Aebersold. P. B., G. A. Winans. D. J. Teel. G. B. Milner, 

 AND F. M. Utter. 

 1987. Manual for starch gel electrophoresis: A method for 

 the detection of genetic variation. U.S. Dep. Commer., 

 NOAA Tech. Rep. NMFS 61, 19 p. 

 Allendorf, F. W. 



1975. Genetic variability in a species possessing extensive 

 gene duplication: Genetic interpretation of duplicate loci and 

 examination of genetic variation in populations of rainbow 

 trout. Ph.D. Thesis, Univ. Washington, Seattle, 98 p. 

 Allendorf, F. W., D. M. Espeland, D. T. Scow, and S. Phelps. 

 1980. Coexistence of native and introduced rainbow trout in 

 the Kootenai River drainage. Proc. Mont. Acad. Sci. 39: 

 28-36. 

 Allendorf, F. W., and N. Ryman. 



1987. Genetic management of hatchery stocks. In N. Ryman 

 and F. M. Utter (editors). Population genetics and fishery 

 management, p. 141-159. Univ. Wash. Press, Seattle. 

 Allendorf, F. W.. and G. H. Thorgaard. 



1984. Tetraploidy and the evolution of salmonid fishes. In 

 B. Turner (editor), Evolutionary genetics of fishes, p. 1-53. 



'"E. Bermingham, NMFS, 2725 Montlake Boulevard East, 

 Seattle, WA 98112, pers. commun. November 1987. 



252 



