talien in 1956 and 1955 respectively, 

 to obtain reliable forecasts. 



Emphasis will continue on improving indexing methods 



Fish and Wildlife Service research was expanded during 1957 • A new study to develop 

 "better methods of sampling the catch and escapement to ascertain the age and size composi- 

 tion of the runs was begun. It has been shown that gill nets select the larger, older 

 fish from the run leaving younger, smaller fish for escapement. Frequent samples were 

 taken from the Egegik and Naknek- Kvi chok gill net fisheries and were compai'ed with samples 

 taken from the escapement into these systems. Several methods of sampling fish from the 

 escapement were explored, with beach seining providing the best results. A partial ana- 

 lysis indicates that the Naknek escapement was divided almost equally between progeny of 

 1951 and 1952 spawning escapements. About two-tiiirds of the Egegik escapement were pro- 

 duced by the 1951 escapement and one-third by the 1952 escapement. 



lagging studies were concentrated in the Naknek- Kvi chak system. Diree tagging crews 

 of three men each on a standard Bristol Bay gill net boat captured and tagged red salmon 

 at the lower fishing boundary (fig. 28). Special test set nets recovered tagged fish at 

 the upper boundary as they left the fishery. A total of 9*^72 tagged fish was released 

 between June 21 and July 2k. By the end of December 3,^1^ tags were reported from the 

 cammercial fishery. Of these, 28I were from Egegik and 28 from Nushagak, 3 from the 

 Ugashik with the remainder taken from Naknek- Kvi chak. In addition, 1,272 tags were 

 sifted in Bristol Bay rivers and about I90 were recovered by foot survey parties. 



A partial analysis indicates tliat: (a) About 80 percent of the tags recovered from 

 the Naknek- Kvi chak fishery were taken by the end of the second fishing period after 

 tagging; (b) Kvichak fish are available to the fishery longer than Naknek fish. On the 

 Kvi chak, 55 percent of tags captured at test set nets on the upper boundary \rere taken in 

 three or less days. On the Naknek, 72 percent of the test set net recoveries were rea- 

 lized on the third day after tagging (fig. 29); (c) most tagged fish escaping into the 

 Naknek pass the weir in tliree or less days after entering the fishery; (d) fish tagged 



during an open fishing period, or at the begin- 

 ning of a closed period, were recovered from the 

 fishery in fewer niimbers than those tagged during 

 the middle or end of closed periods (fig. 30); 

 (e) tag recoveries from the Naknek- Kvi chak fishery 



FISHING BOUNDARY-- 



50 . 



40 . 



>- 

 q: 



O 30 

 o 



UJ 



Q: 20 



10 . 

 I- "^ 



z 



UJ 



o 

 a: 



UJ 



'^ 20 



10 . 



NAKNEK RIVER 



EZ3 PERCENT OF NORTH BANK TOTAL 

 I — r PERCENT OF SOUTH BANK TOTAL 



KVICHAK RIVER E3 PERCENT OF WEST BANK TOTAL 

 I 1 PERCENT OF EAST BANK TOTAL 



m 



Figure 28. --Bristol Bay red salmon 

 tagging sites, 1957 



2 3 4 5 6 7 



DAYS AFTER TAGGING 

 Figure 29. --Bristol Bay test set net 

 tag recoveries, 1957 



16 



