UTTER ET AL.: STOCK COMPOSITION OF 1983 CHINOOK SALMON 



Table 2.— Polymorphic enzymes providing genetic information for baseline popula- 

 tions and stock mixtures. Tissue used were eye (E), and liver (L). Explanations for 

 locus and allele designations and for buffers are given in text. 



structure of North American chinook salmon stocks. 

 The general locations of baseline samples and mixed 

 fisheries are outlined in Figure 1. 



The data base of six major groupings used to ana- 

 lyze the ocean fisheries was derived from the data 

 of the 88 collections as follows: 1) Contingency tests 

 were used to combine data for populations lacking 

 significant allelic differences, thus reducing the 

 number of groups to 65. 2) GSI estimates were 

 made from weighted (by catch) samples of genotypic 

 data from each fishery; based on this information, 

 those groups estimated by maximum likelihood (see 

 below and Milner et al. 1983^) to contribute less 

 than 0.034% (30 fish) to the total catch of all fish- 

 eries sampled were eliminated. This brought the 

 number of groups down to 50. 3) Estimates made 

 for each of the 50 groups were combined into the 

 six major groupings of Table 1 to permit a particular 



^Milner, G. B., D. J. Teel, and F. M. Utter. 1983. Genetic stock 

 identification study. Unpubl. rep., 66p. Northwest and Alaska 

 Fisheries Center, National Marine Fisheries Service, NOAA, 2725 

 Montlake Blvd. E., Seattle, WA 98112. (Final Report of Research 

 to Bonneville Power Administration, Agreement DE-A179- 

 82BP28044M001.) 



focus on tule and upriver bright stocks in the Colum- 

 bia River. 



Estimates of the composition of the 1 September 

 gill net fishery in the Columbia River were obtained 

 for each of the 11 Columbia River fall run collec- 

 tions and combined as indicated in Table 1. 



Population Mixtures 



Almost all of the ocean sampling was done at port 

 of landing. Eye fluid, the only tissue, was collected 

 in tubes placed on chipped ice, stored in various 

 freezers, and shipped weekly in a portable freezer 

 to the laboratory where storage was at - 90°C until 

 preparation for electrophoresis. The September gill 

 net fishery was sampled for livers only. Samples ob- 

 tained by Washington Department of Fisheries 

 (WDF) personnel from fish buyers in Ilwaco and 

 Chinook, WA, and Astoria, OR, were collected and 

 shipped on dry ice, and electrophoresis was carried 

 out immediately following their arrival. 



Electrophoretic data were collected only for those 

 polymorphic loci that were expressed in the collected 

 tissues: 



17 



