238 SALMON OF THE KARLUK RIVER, ALASKA 



on the magnitude of the total run during a particular season. It was soon evident, 

 however, that information on the fluctuations in abundance was not sufficient. A 

 knowledge of the causes of the fluctuations was both desirable and valuable in pro- 

 mulgating sound and adequate regulations. 



The Karluk River on Kodiak Island, Alaska, was selected as an appropriate site 

 for the study of the causal factors responsible for the yearly fluctuations in the abun- 

 dance of a single population of red salmon, Oncorhynchus nerka (Walbaum). This 

 river supports a commercial red-salmon fishery of considerable importance. The 

 area in which the Karluk River red salmon are caught is confined to a readily delin- 

 eated zone near the mouth of the river within which very few red salmon from other 

 watersheds are taken, consequently the commercial catch can be determined quite 

 accurately. The stream bed and water flow of the river are of such a nature that 

 a counting weir for determining the number of salmon migrating upstream 

 can be operated successfully throughout the season. Karluk Lake, the source of 

 the river, and its tributaries are fairly accessible. Thus, this watershed fulfills 

 admirably the requirements essential for a study of the biological background of the 

 red salmon. 



The White Act (43 Stat. 464-467; June 6, 1924) provided that there should be 

 a 50 percent escapement of all salmon populations. Subsequent to the passage of 

 that act, commercial fishing in the Karluk area has been so regulated that the catch 

 of red salmon for a season has never exceeded the escapement. Unfortunately, this 

 restriction of the commercial catch has not increased the size of the runs of red 

 salmon in the river to the level of abundance that existed during the early years of the 

 fishery. Factors other than the total number of salmon spawning in the river sys- 

 tem each season have played an important role in the abundance of the runs. In 

 this paper a statistical review is presented of the Karluk River red-salmon fishery 

 from its inception in 1822 to 1936, together with a report on the major biological 

 studies carried on to date. 



STATISTICAL HISTORY OF THE FISHERY 



Statistics of the catch of Karluk red salmon presented in this report are not always 

 identical with those published by Gilbert and Rich (1927) but do agree for the years 

 1882 to 1920 with those given by Rich and Ball (1931) as these latter statistics are 

 considered more reliable for this period. From 1921 to 1927, the statistics of the catch 

 given herein are not identical with those presented by Rich and Ball, who include in 

 their figures for the Karluk catch only those fish caught between Cape Karluk and 

 Cape Uyak, although they mentioned that a large part of the fish caught to the north- 

 east of Karluk in later years were Karluk fish. The development of the fishery be- 

 tween Cape Uyak and Uganik Bay resulted in the capture of a part of the Karluk run 

 before it reached the mouth of the Karluk River. That fish caught as far north as 

 Uganik Bay were chiefly derived from the Karluk run was shown by a tagging experi- 

 ment (Rich and Morton 1929) carried on at West Point. The Karluk area, as defined 

 in this report, includes all of the coast line between Cape Karluk and West Point on 

 Kodiak Island. 



