Total catch figures (table 2) for the years 

 1946-50 are those given in the unpublished 

 Annual Reports for Bristol Bay, U.S. Fish 

 and Wildlife Service,* and those for 1951-59 

 are taken from Simpson (1960). At times the 

 seasonal catches given in the Management 

 Agent's reports differ from the seasonal 

 catches obtained by combining the catches 

 from all fishing periods. This discrepancy 

 is no doubt partly due to the fact that catch 

 data by fishing periods frequently were as- 

 sembled in the field and included chum salmon, 

 which inflated the catch figures. But no cor- 

 rection was made for chum salmon in cal- 

 culating the weighting factors for the length 

 frequency curves. 



From the Spawning Escapement 



Escapement magnitude . — The spawning 

 grounds used by red salmon in the Nushagak 

 watershed are found in three major and two 

 minor areas. The Wood River system was 



1 On file. Bureau of Commercial Fisheries Biological 

 Laboratory, Auke Bay, Alaska. 



the dominant production area during the period 

 under study, followed in order of importance 

 by the Igushik River system (Lakes Ualik and 

 Amanka), and the Nuyakuk River system (Lakes 

 Tikchik, Nuyakuk, and Chauekuktuli). The two 

 minor areas were Snake River (Nunavaugaluk 

 Lake) and the main Nushagak River including 

 the tributary Mulchatna and Kokwok Rivers 

 (fig. 2). 



Escapements to these areas during the 

 period 1946-52 were estimated by combined 

 aerial and ground surveys (table 2). The sur- 

 veys in 1946 and 1947 were made to determine 

 the time and place of the major red salmon 

 spawning. After 1947, the surveys were di- 

 rected toward more quantitative methods. 

 Ground survey estimates were largely re- 

 placed by aerial survey methods. Beginning in 

 1953 the escapement to the Wood River lakes 

 was determined more precisely by enumeration 

 from towers on Wood River. Daily estimates 

 of Wood River red salmon escapements, 1953- 

 59, are listed in table 3, Towers for counting 

 salmon were also established by the Bureau 



Sources of catch statistics: 



1946-50 



1951-59 

 Sources 



Annual reports for Bristol Bay, U.S. Fish and Wildlife Service, on file at Biological Laboratory, 



Auke Bay. 



Simpson (1960). 



of escapement statistics : 



1946-57: John R. Gilbert. 1958. An appraisal of the Nushagak spavming survey data, 1946-1957. 



Fisheries Research Institute, University of Washington, unpublished report, 50 p. 

 1958: John R. Gilbert. 1958. Spawning ground surveys in the Nushagak District in 1958. Fisheries 



Research Institute, University of Washington, unpublished report, table 10. 

 1959: Nelson (1960). 



Sources of escapement counts at trunk river tower sites : 



1953-59: Fisheries Research Institute, University of Washington, unpublished records (for Wood River). 

 1958-59: Annual report for Bristol Bay, by Fishery Management Biologists, U.S. Fish and Wildlife Service 



(for Igushik, 1958-1959, and Tikchiks 1959), on file Biological Laboratory, Auke Bay. 



