taken in Noveraber were greater in average length by 17 mm, (0.67 

 inches) in 1943, 22 mm, (0,83 inches) in 1944, and 30 mm, (1.18 

 inches) in 1945, than migrants of the same brood year netted in 

 Maroh. Oocasional specimens, captured by the fyke nets in March 

 of the year follovring their hatching, average 82 mm, (3,23 inches) 

 in length in 1943, 79 mm, (3,11 inches) in 1944, 75 mm. (2,95 inches) 

 in 1945, and 73 ram. (2.87 inches) in 1946. These lengths are probably 

 less than the averages which could be obtained from aeries of seunples 

 collected by means other than fyke netsj fish larger than 70 mm (2.76 

 inches) in length are able to avoid capture in most stationary fyke nets. 



Sex ratios of adults 



The matter of sex ratios in a given population of migjrating adult 

 king salmon has been the subject of considerable research effort. 

 Apparently, the consensus of opinion to date favors the concept of 

 equal numbers of males and females in the original stock with in- 

 equalities resulting almost entirely from the early maturation and 

 migration of a certain portion of the males of any given year class. 

 Snyder (1931, p. 103) established a sex ratio of 1 female to 1.07 males 

 from 9,439 salmon taken in the commercial ocean catch off Monterey, 

 California, during the years 1919-21. The ratio for the individual 

 years varied only slightly, being 1:1.10 in 1919; 1:1.02 in 1920} and 

 1:1.05 in 1921, From, these results, he maintains that sea fishing does 

 not discriminate in any great measure against either sex. It is also 

 fairly obvious that the sex ratio in the sea is Ijl as would be expected. 

 Determinations of the sex of salmon fingerlings sampled at Lewiston in- 

 dicate a ratio approximating equality. The sex ratio of 166 young salmon 

 taken during 1943 was 1 female to 1,05 males, and a sample of 116 taken 

 during 1945 revealed a ratio of 1:0,97, These samples were composed of 

 fish ranging frcwi 50 to 100 mm, (1.97-3.94 inches) in length. 



Sex ratios established frcwi obsairvations on migrating adult 

 populations are quite certainly affected by the type of fishing which 

 the migration has had to pass. Gill-net fisheries are especially 

 selective since most of the mesh sizes are fixed by law for the 

 protection of the smaller sized fish in the run. Snyder (1924) re- 

 porting sex determinations made on a seunple of 340 king salmon taken 

 at Hoopa in late September 1920, found 260 males all less than 2 5 inches 

 long, 47 males greater tl-ian 25 inolies in length, and 33 females. These 

 fish were taken from Trinity River below the Indian fishing weir and 

 probably represented a fair cross section of the migrant population 

 after it had passed the gill-net fishery at the mouth of Klamath River, 

 The sex ratio derived from this sample is 1 female to 9.3 males. 

 The preponderance of males far exceeds anything observed at Lewiston 



34 



