the escapement period each year. All spawning 

 groups would thereby receive tags in proportion 

 to their size, and recoveries from days of 

 tagging could be compared directly with the 

 size of daily escapements. It was not possible 



to conform to this ideal design because escape- 

 ment size and duration were largely unknown 

 before the fish appeared. 



The rate of tagging each year was as follows: 



Year 



Days of 

 tagging 



Tags 

 attached 



Escapement 



during tagging 



period 



Ratio, tagged to untagged 



Tagged 



Untagged 



The tagging effort was distributed throughout 

 each day so that periods of "no tagging" were 

 as short as possible. 



Tags were recovered by (1) field personnel 

 of FRl, (2) local residents who fished salmon 

 for their personal use, and (3) residents and 

 visitors hunting or fishing in the region. 



Personnel from FRI collected tags during 

 routine population enumeration and size and 

 age sampling on the spawning grounds. Re- 

 coveries were from both live and dead fish 

 that were obtained usually with gaffs or 

 spears. Personnel waded in the streams or 

 stood in boats or on the pontoons of the plane. 

 Tags were taken from live fish only when the 

 fish were believed to have reached the stream 

 or beach where they would spawn. In this way 

 the danger of crediting fish of one spawning 

 ground to spawning grounds occupied by another 

 was minimized. Usually dead fish can be as- 

 sumed to be on the grounds where they 

 spawned, though they may drift and carry 

 tags to other places. 



In ponds and streams where fish could be 

 seen readily tag recovery was relatively easy, 

 but in large rivers and beaches where spawning 

 took place in deep, swift, or turbid waters, 

 recovery was frequently difficult. Recoveries 

 from these sources were often at a low level. 

 Moreover, beach spawners and transient fish 

 often mingled briefly over the beaches. Since 

 fish could not be assigned definitely to either 

 stream or beach populations at such times, 

 recovery effort was delayed until transient 

 fish entered the streams. 



Personal-use fisheries accounted for 3 

 percent to well in excess of 10 percent of the 

 total recoveries each year, as residents of 

 native villages may take more than 100,000 

 fish annually. Personnel from FRI visited 

 villages to pick up tags from the personal-use 

 fishery and to encourage the native fishermen 

 to record dates and locations where tags were 

 taken. The recovery program was publicized 

 in advance by mimeographed notices (fig. 3) 

 circulated by mail and by members of the FRI 

 staff. 



Analysis 



The relative segregation of spawning groups 

 was shown by distribution of recoveries on the 

 spawning grounds from each day of tagging at 

 Igiugig. If salmon from each day's tagging were 

 distributed on the spawning grounds in propor- 

 tion to total numbers of spawning fish, segre- 

 gation in time at Igiugig would be minimal. On 

 the other hand, if salmon tagged each day 

 went to different spawning grounds, segrega- 

 tion would be complete. 



Proportions were studied in two ways: 

 (1) By a visual comparison of all recoveries 

 from days of tagging plotted on maps of the 

 system and (2) by a statistical test of re- 

 coveries from days of tagging on major 

 spawning grounds. 



For the visual comparison, distributions 

 of all recoveries from days of tagging were 

 plotted by year and by experiment at recovery 

 locations on maps of the spawning grounds. 



