PROGRESS IK BIOLOGICAL, INQUIRIES, 1921. 



7 



RESULTS OF MAEKING EXPERIMENTS. 



Mr. Kich has also submitted a report on " Returns from the ex- 

 periments on the marking of young chinook salmon on the Columbia 

 Elver." The experiments were started in 1916-17 and described in 

 Economic Circular No. 45. 



The percentage of returns of marked salmon was rather low, but the 

 results obtained are of some significance. Examination of the scales 

 of the marked fish which have returned after a period of three to 

 four years corroborates the theory that the arrangement of the con- 

 centric rings (circuli) provides an accurate record of the previous 

 history of the fish. A study of the scales of these marked fish will, 

 moreover, aid very materially in the solution of perplexing problems 

 which have arisen in interpretation of the scales of the chinook 

 salmon. 



Facts gathered during the investigation throw some light upon 

 the rate of spawning migration of adult chinooks, indicating that 

 the rate is approximately the same as that previously determined for 

 sockeye salmon passing through Puget Sound and the Eraser River, 

 that is, some 10 to 15 miles per day. 



Perhaps the most interesting and important contribution which 

 these experiments have made to our knowledge of the biology of the 

 salmons relates to the hereditary character of the factors determin- 

 ing the time of the year at Avhich the adults enter fresh water and 

 begin their upward migration to the spawning grounds. It is an 

 important practical question whether or not it is necessary to breed 

 from fish of the spring run in order to produce the spring-run fish, 

 which are more desired than the fall-run fish. The evidence of 

 the marking experiments gives some indication that spring-run fish 

 will be derived from spring-run parents and fall-run fish from fall- 

 run parents. 



A comprehensive program of experiment has been planned to ex- 

 tend over a period of several years. Two new marking experiments 

 have been started on the Columbia River in cooperation with the 

 Oregon Fish and Game Commission, nearly 100,000 young chinooks 

 having been marked at Little White Salmon station and the State 

 hatchery at Bonneville. 



SALMON INVESTIGATION IN YUKON RIVER.^ 



During 1920, from May until September, Prof. Charles H. Gilbert, 

 temporary investigator, and Henry O'Malley, field assistant in 

 charge of Pacific coast work, conducted an investigation in Yukon 

 River with reference to the runs of salmon, the commercial packs 

 in and near the mouths of the rivers, and the requirements of the 

 natives and others dependent on the runs of salmon in the Yukon 

 River system. Data were secured for a comparison of conditions 

 prevailing in 1919 and 1920. The primary object was to determine 

 whether or not commercial fishing for export should be allowed in 

 the Yukon River and its tributaries. 



While all five of the Pacific coast species of salmon make their 

 appearance at the mouth of the Yukon, only three species have sub- 



^ Cooperative investigation by Divisions of Fish Culture, Alaska Fisheries, and Scientific 

 Inquiry. Only the biological data are summarized here. The full report is published on 

 pp. 128-154 in Alaska Fishery and Fur-Seal Industries in 1920, by Ward T. Bower, Ap- 

 pendix VI, Report of the U. S. Commissioner of Fisheries for 1921, B. F. Doc. No. 909. 



