54 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



able for Karluk Lake and are used for comparison 

 in the discussion that follows. 



We wish to express our thanks to Allen IMc- 

 Cready, William Pogue, and Patrick Tomlinson 

 for aid in developing and conducting field opera- 

 tions, and to Theodore R. Merrell and John B. 

 Owen of the Bureau of Connnercial Fislieries, for 

 reviewing the manuscript. 



COLLECTION AND TREATMENT 

 OF MATERIALS 



Ovaries used in these studies were obtained 

 from females trapped at adult innnigration sites 

 at both lakes. They were taken throughout the 

 season and over the size range of females in the 

 stocks. A few females killed during beach-sein- 

 ing and gill-netting operations in Brooks Lake 

 were also used. Only females not fully ripe were 

 examined. This reduced the possibility of includ- 

 ing partially spawned females. 



Both ovaries were removed intact and placed 

 in 20-percent formalin. An identification tag was 

 attached to the right ovai-y to distinguish it from 

 the left. After hardening for at least 48 hours, 



ovaries were removed from the formahn and tlior- 

 oughly washed in water. The eggs were stripped 

 from the ovarian tissue by hand and also thor- 

 oughly washed in water. Total numbers of eggs 

 were counted in each ovary of each female 

 sampled at both lakes. A mechanical hand tally 

 was used. 



Sampling niethods involving volume or weight 

 were experimented with at Brooks Lake in 1958. 

 The most reliable method was to extract 3 ran- 

 dom 100-egg samples from each gonad and esti- 

 mate the total count from the average count- 

 weiglit relation of the selected samples. Fecundity 

 was usually estimated within 2 percent of the 

 actual count. This method is sufficiently accu- 

 rate and should be considered where extensive 

 fecundity studies are scheduled. 



RELATION BETWEEN SIZE OF FISH 

 AND FECUNDITY 



A relation exists between the size of fish and 

 the number of eggs in the body cavity. Bicker 

 (1932) shows that the relation between fish length 

 and egg count in brook trout (S'ah'efhn/.s: font'm- 



5000' 



(9 



o 



4000" 



cc 

 liJ 

 m 



=3 3000- 



2000- 



1957 BROOKS LAKE • 

 n = 38 



958 BROOKS LAKE • 

 n=22 



1958 KARLUK LAKE + 

 n = 39 



I '  ' ' I   '  I  



45 50 55 60 



MIDEYE-FORK LENGTH IN CENTIMETERS 



65 



FioiiRE 2. — Relation of egg coniils lo niideye-fork length for rod salmon at Krouks Lake, 1».'>T and l!)r,,s, and at 



Karluk Lake, 10.">S. 



