necessary to ascertain the color of the tag on each side 

 of the fish to determine where the fish had been tag- 

 ged. At the weirs this was a relatively simple task, 

 because the observer sat directly over an opening 

 through which each fish had to pass and both sides of 

 the fish could be seen easily. Identifying the color of 

 the tag on both sides of a fish from a tower was more 

 difficult, however. The observer did not sit directly 

 over the fish as they moved upstream, and if the fish 

 were some distance from shore, the observer could 

 identify the color of the tag on only one side. 

 Therefore, rivers with weirs probably had a higher 

 proportion of tagged fish identified correctly than did 

 rivers covered by towers. Because of such factors as 

 the magnitude of the run and turbidity of the water, 

 the ability to identify tagged fish from towers also 

 varied from day to day, between river systems, and 

 from year to year. The numbers of fish bearing each 

 tag color combination observed in the spawning es- 

 capement to each river system have not been adjusted 

 for possible differences in the ability of observers to 

 identify the color of both tags. When viewing the 

 recovery distribution in the discussion of the tagging 

 results, the reader should keep this point in mind. The 



actual number of tags in the spawning escapement to 

 rivers where tags were observed from towers was 

 probably higher than is shown in the results. 



Interpretation of Tagging Results. — Recoveries 

 and visual observations of the tagged fish released at 

 sites within and adjacent to the four regulatory fishing 

 districts in the inshore area in 1955, 1956, 1957, and 

 1959 (Figs. 13-17) are used in this section to show the 

 distribution of major sockeye salmon stocks. The 

 number of tagged fish recovered in the commercial 

 fishery in the inshore area and those observed in the 

 escapement at weirs, towers, or on the spawning 

 grounds on the five major sockeye salmon river 

 systems of Bristol Bay are listed in Appendix Tables 

 2-7. 



The relative sizes of the runs (catch plus escape- 

 ment) to each of the inshore fishing districts in the 4 

 study years (Table 3) must be taken into account 

 when drawing inferences about the distribution of 

 each major sockeye stock from the distribution of 

 tagged fish because the size of the runs to each district 

 varies from year to year. Tag recoveries have not been 

 weighted for size of run because, as will become ap- 



TAGGING SITES 



BOUNDARIES OF DISTRICT 



OPEN TO FISHING 



FISHING DISTRICT TAG RECOVERIES 



ESCAPEMENT TAG OBSERVATIONS 



157° 



RECOVERY AREA 



Figure 16. — Distribution of tags recovered in catch (commercial fishery) and observed in the escapements from 

 sockeye salmon released at two tagging sites in Naknek-Kvichak fishing districts (inshore area) in 1957. 



16 



