106 SALMON AND TROUT IN ALASKA. 



ner nature secures the offspring of the well-developed mature males, 

 which offspring is known to be stronger and more thrifty than that of 

 the younger fish. 



The exhibition of beauty in color and form in the male, which hp-s 

 been thought to be the result of sex selection, can hardly be so con- 

 sidered in the case of these fish. The female apparently has no option 

 in the matter. The larger male will drive away the smaller and take 

 possession. The peculiar compression of the male, with the flattening 

 of the ventral aspect, increases its ability to work through the shallow 

 water, which the small size of the female, without such change, allows 

 it to enter. 



RETURN OF ADULTS TO SALT WATER. 



To test the question of the return of salmon to salt water after once 

 entering a river system, Rutter, in 1903, made two experiments. 

 Eight hundred salmon (species not noted, but probably mainl}^ if not 

 all sockeyes) were tagged and released in Karluk Lagoon (brackish 

 water) 1 mile from the sea. Four hundred of these were released 

 June 12 and 15. One was retaken outside in a cannery seine 1 hour 

 after release, 3 were retaken entering Karluk Lake after 11, 13, and 34 

 days, respectively; 2 were retaken by seines in the lagoon, and 1 died in 

 the lagoon. Doubtless many of the tags were lost, and perhaps many 

 fish entered the lakes or were retaken outside and unobserved. 



Five hundred and fourteen were tagged and released on June 30. 

 One of these was retaken in New Red (Ayakulik) River, 40 miles down 

 the coast, 3 days later. One reached the lake in 10 days; another was 

 found spa'wuing there August 2 ; one was seined in the lagoon 2 days 

 after release; and another, a green female somewhat fungused and 

 worn, 27 days after. No others were reported. 



This experiment is ver}^ incomplete and most desirable data are 

 lacking, especially as to whether the fish were taken into the lagoon 

 in a live car or were seined in the lagoon after voluntary entrance. 

 The influence of the tag, clamped to the lower jaw by a strong ring, 

 in irritating; the fish and stimulating unnatural action can not be 

 estimated. The results point to the probability that some fish 

 remain in the lagoon for several days, some reenter the ocean, and 

 others spend varying times somewhere between the lagoon and lake. 



Another experiment was the tagging of 255 individuals at the 

 mouth of the lake, from July 3 to 25. Of these, 123 were males, 64 

 of which were ripe and 66 showing more or less of decay, fungus, etc.; 

 132 were females, 23 ripe, and 70 in poor condition. These fish were 

 taken in a trap built at the outlet of the lake, but on the shallow or 

 small current side. This location unfortunately led to the securing 

 of a large percentage of weak fish, and made the results less valuable. 

 In general, fish reach the lakes in sound condition. Of these tagged 



