Spawning groups would be completely segre- 

 gated in time of escapement if they passed 

 Igiugig one by one, but this is far from the 

 case. More than 50 recognized spawning groups 

 in the system pass through the Kvichak River 

 within a 3- to 5-week period (Becker, 1962). 

 If these groups could be sampled separately 

 and their daily escapements plotted against 

 time of passage, the resultant frequency curves 

 would be found to overlap greatly. The extent 

 of segregation of Kvichak spawning groups is 

 therefore related to the degree of separation 

 they exhibit if they can be plotted as described. 



Unfortunately the degree of segregation can- 

 not be determined by direct observation at 

 Igiugig because individual fish are not identi- 

 fiable as members of recognized spawning 

 groups. Salmon, therefore, were tagged 

 throughout the run at Igiugig and were re- 

 covered on the spawning grounds where segre- 

 gation of spawning groups is more or less 

 complete. Recoveries could then be related 

 back to their time of passage at Igiugig. By 

 this procedure the separation and sequence of 

 spawning groups at Igiugig were postulated, 

 and the feasibility of managing these groups 

 in the fishery was evaluated. The underlying 

 premise here is, of course, the homing ten- 

 dency of particular stocks to particular 

 spawning grounds (Thompson, 1959). 



Capturing and Handling the Fish 



Red salmon for tagging were captured in a 

 beach seine fished from the shore of Iliamna 

 Lake immediately above the outlet. When bad 

 weather prevented lake shore seining, salmon 

 were seined from the river. In 1959 the adult 

 enumeration program at Igiugig was supple- 

 mented by assigning men to watch for salmon 

 that had been tagged on the high seas. To 

 provide a maximum recovery effort for tags 

 sighted, the Igiugig seining was close to the 

 observation points about a mile below the 

 outlet of the lake. An electric shocker similar 

 to the one described by Thompson (1960) was 

 also used to recover tagged salmon. 



Fish were generally captured at a rate of 

 30 to 35 per seine haul and were transferred 

 to a holding bag beside the skiff. They were 



then transferred individually to a measuring 

 trough lined with foam rubber. Tags were 

 attached, scale samples taken, and length 

 measurements and other pertinent data were 

 obtained before the fish were permitted to 

 continue their journey uplake. 



Tags and Pins 



The salmon were marked with Petersen 

 tags. Nickel wire pins were used almost 

 exclusively, but the point of attachment and 

 size of the tag were not the same each year. 



In 1957 white tags of 7/8-inch diameter were 

 used, and a small 3/16-inch buffer tag was 

 placed between the numbered tag and the head 

 of the pin. This may have decreased loss 

 caused by pins pulling through the tag, though 

 no experimental control was used to test it. 

 To relate live tagged salmon seen on the 

 spawning grounds to time of tagging even though 

 the fish were not recovered, the 1957 tags 

 were placed in one of three positions under 

 the dorsal fin: the leading edge, the middle 

 section, or the trailing edge. This procedure 

 did not prove useful, however, because the 

 positions of the tags could seldom be posi- 

 tively identified while fish were in the water. 

 Colored tags were not used in 1957 because 

 the Bureau of Commercial Fisheries was 

 using colored tags in Bristol Bay that year, 

 and the presence on the spawning grounds 

 of similar tags would have caused confusion. 



In both 1958 and 1959, tags of 5/8-inch 

 diameter were used. They were of four different 

 colors and were applied in several color com- 

 binations of blank and numbered disks under 

 the leading edge of the dorsal fin, the con- 

 ventional point of attachment. All color com- 

 binations were readily distinguished on the 

 spawning grounds, though combinations of red 

 and white were found to be most readily seen 

 under most conditions of water and lighting. 



Rate of Tagging 



Ideally tags would have been applied in pro- 

 portion to daily escapements and throughout 



