40 SALMON AND TROUT IN ALASKA. 



been bred in fresh water for several generations, the 4-year fish weigh 

 from 2 to 4i pounds. These are from the Sacramento fish which 

 average between 15 and 20 pounds. At the same time the number 

 of eggs has diminished from a normal number of about 6,000 to 

 only 1,300 to 1,400. 



These examples demonstrate a possible effect of fresh-water resi- 

 dence. Dwarf sockeyes occur in such lakes as Alturas, Wallowa, 

 Seton, Ozette, etc., in all of which fish may come and go at will. No 

 other species of the genus breeds in lakes or exclusively in lake tribu- 

 taries. It may be that the sockeye is in process of evolution from an 

 anadromous form to a permanent fresh-water resident. Part of the 

 young apparently possess the primal instinct to return to sea at once 

 the first year, another and greater part have changed to become one- 

 year residents, and the smallest part have lost the to-ocean instinct 

 entirely and remain to reach maturity in the lakes. Experiments as 

 to the action of artificially reared young of the two races would be of 

 the utmost interest and no little value to fish-culturists. The exist- 

 ence of marine and fresh-water forms of the same species is well known 

 in Atlantic Salmonid?e, and as well in other families. The effect of 

 change of habitat in the two forms respectively has in no instance 

 been worked out, and remains for solution, one of the most interesting 

 and important problems in ichthyology and fish-culture. 



KING SALMON. 

 AGE AND SEASON OF MIGRATION. 



The observations on the Sacramento River have demonstrated that 

 the king salmon young in that stream for the most part leave the 

 fresh water as soon as they are able to swim and feed. All the 

 spawning occurs in the upper parts of the river and its tributaries, 

 yet fry with unabsorbed yolk were sometimes taken only a short dis- 

 tance above tidal influence.^ This same action was noted in the 

 Karluk. On Jul}^ 3 a trap which had been set overnight at the 

 mouth of that river just above the lagoon took 1,300 fry, nearly all of 

 which w^ere king; there were only 4 humpback and 7 sockeye fry among 

 the examples saved. As the collector did not differentiate species it 

 is impossible to sa}' whether 7 were all of the sockeye fry in the 1,300, 

 or whether that number w^as only the natural proportion among the 

 180-odd specimens saved. The humpback being of striking appear- 

 ance, however, it is probable the 4 saved were the entire catch of that 

 haul. It should be stated that the haul also contained 5 sockeye year- 

 lings, 25 coho fingerlings, a few sticklebacks, flounders, and young trout. 

 No other sets of this trap were made; hence it is impossible to state 



oRutter, Natural history of the quinnat salmon. Bulletin U. S. Fish Commission, 

 vol. XXII, 1902, p. 92. 



