Fisheries Investigations in Crater Lake, Oregon, 1937-1940 by Arthur D. Hasler and D. S. Farner
Natural Reproduction Vs. Stocking
If we assume random sampling for the scale collections, the percentage composition of the year-classes as recorded in Tables 3 and 4 can be applied to the catches reported in the creel census (Table 5) and the yield of the year-classes correlated with the history of stocking (Table 6). There was little or no correlation between stocking and yield to the creel. Indeed, the largest catch of trout was from the 1934 year-class. There were no fishes planted in that year according to the official records of the Park. There was also a catch of trout of the 1938 year-class in which year no fishes were planted. These data show that natural reproduction plays a dominant role in the maintenance of the population and stocking, by present methods, only a minor one.
Table 5 – Summary of Creel Censuses at Crater Lake, Oregon
Similarly there was a large catch of salmon from the 1939 hatch in which year none was stocked. There was also a catch of salmon of the 1938 hatch when none was stocked, which indicates that salmon reproduce in the lake.