segregation of stocks toward the head of the bay. Fish 

 bound for the Nushagak and Naknek-Kvichak fishing 

 districts were still abundant in the offshore tagging 

 areas toward the head of the bay. Those bound for the 

 Ugashik and Egegik districts, however, were less 

 abundant at offshore locations and apparently had 

 already moved toward the coast and the mouths of 

 their home-river systems. 



Inshore Distribution 



The distribution of individual sockeye salmon 

 stocks in the inshore area of Bristol Bay was deter- 

 mined from unpublished data from tagging ex- 

 periments and related studies I conducted in inner 

 Bristol Bay in 1955-57 and 1959. The tagging sites 

 were located within and adjacent to the four 

 regulatory fishing districts in the inshore area: 

 Nushagak, Naknek-Kvichak, Egegik, and Ugashik. 

 Tagged fish were recovered by the commercial fishery 

 within these districts. Some tagged fish were seen at 

 weirs or from towers located on the major river 

 systems entering each fishing district. Tagging was 

 not carried out in all of the districts during the 4 yr of 

 the study; the schedule was as follows: 

 1955— Naknek-Kvichak and Egegik (Fig. 13); 

 1956— all four districts (Figs. 14 and 15); 

 1957 — Naknek-Kvichak (Fig. 16); and 

 1959— Nushagak (Fig. 17). 



Unfortunately, no sockeye salmon were tagged in a 

 large area in the middle of the inner bay, and in 

 analyzing the tag recovery data I therefore infer the 

 stock composition of fish in that region from the 

 results of both the offshore and inshore tagging. 



One additional method was used to show the dis- 

 tribution of sockeye salmon stocks in 1955. The age 

 group (2.3, 1.3, 1.2, etc.) of each fish tagged at seven 

 sites in the Naknek-Kvichak and Egegik fishing dis- 

 tricts (Fig. 13) was determined from scale readings. I 

 used the age group structure of the fish tagged at each 

 site to aid in explaining the distribution of Naknek- 

 Kvichak and Egegik River sockeye salmon stocks in 

 the inshore area. 



Capturing and Tagging Fish and Recovery of 

 Tags. — The sockeye salmon for tagging were cap- 

 tured in linen or nylon drift gill nets of the type (13.97- 

 cm stretch measure, 28 meshes deep) commonly used 

 in the Bristol Bay commercial fishery during the years 

 of tagging. 



Fish were marked with serially numbered red, blue, 

 green, white, and yellow Petersen disk tags used in 

 various color combinations so that the date and loca- 

 tion of tagging could be determined from visual obser- 

 vations. 



Recoveries of tags in the 4 yr of the study included 

 actual recaptures and visual sightings of tagged fish. 

 Actual recaptures were obtained from the commercial 

 gill net fishery operated in each district, the personal- 

 use gill nets operated on the major rivers above the gill 



net fishery, and the spawning grounds. The visual 

 sightings were made either from weirs built across 

 some of the major rivers or from towers located on 

 each bank of the other rivers. Observations were made 

 from these structures of tagged fish in the daily es- 

 capement to each major river system. Placards dis- 

 playing tag color combinations were placed at the 

 counting gates of each weir and at each tower to 

 facilitate positive identification of tagged salmon. 



Analysis of Recovery Data. — I used the tag 

 recoveries from the Nushagak, Naknek-Kvichak, 

 Egegik, and Ugashik fishing districts and the obser- 

 vations of the tags sighted in the escapements to the 

 individual river systems to show the distribution in 

 inner Bristol Bay of the stocks of sockeye salmon 

 bound for the four river systems. In addition, the 

 fishery recoveries from the 1959 tagging in Nushagak 

 Bay were grouped according to location of capture 

 within the Nushagak district. For this purpose the 

 district was divided into five subdistricts, and the dis- 

 tribution of fish from each tagging site within these 

 subdistricts was used to show the distribution of each 

 stock contributing to the total run to the Nushagak 

 district. 



Because the commercial catch of sockeye salmon 

 within the four fishing districts is composed of mixed 

 stocks, the distribution of tagged fish in the escape- 

 ment is a better indicator of the final destination of 

 fish released at various sites in inner Bristol Bay than 

 the distribution of tagged fish caught in the fishing 

 districts. Fish recaptured in the fishing districts have 

 been included in the analysis, however, because they 

 serve to complement the results shown by the dis- 

 tribution of tags in the escapement. When viewed 

 with the distribution of tags in the escapement, the 

 distribution of tags in the fishing districts aids in in- 

 terpreting the movement of individual sockeye 

 salmon stocks within these districts. In addition, both 

 types of tag recovery distributions indicate that the 

 mixing of several nondistrict stocks within a given 

 fishing district was not serious enough to prevent in- 

 terpretation of the distribution and migration routes 

 of individual sockeye salmon stocks in inner Bristol 

 Bay. 



I made several assumptions in interpreting the tag 

 recovery data: First, sockeye salmon of each river 

 system are assumed to be tagged in proportion to their 

 abundance in the area of tagging. If significant mixing 

 of stocks of two different ocean age groups ( .2 or .3) oc- 

 curred in that area of tagging, the selective action of 

 the gill nets (page 7) used to capture fish for tagging 

 could have resulted in a larger proportion of one stock 

 being caught and tagged than were actually present. 

 In general, the recovery distributions resulting from 

 tagging at several of the same locations but in 

 different years were similar. The magnitude of the run 

 as well as the size composition varied between fishing 

 districts in these years. The similarity of distributions 

 for different years indicates that such mixing of stocks 



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