FORTY-FIRST BIENNIAL REPORT 81 



STUDIES ON SPECIAL WATERS 



In addition to the foregoing surveys to provide general information, 

 special studies were carried out on the following waters, not including 

 Wildlife Conservation Board Projects, which are discussed in a special 

 section of this report : 



Castle Lake, Siskiyou County. The program at Castle Lake is designed to find 

 out what species of trout should be planted in similar lakes, and to study the 

 costs of planting various species and sizes in terms of yield to the angler. 



Sacramento River Test Stream, Siskiyou County. The present objective of this 

 investigation is to determine the effectiveness of planting fingerling trout in 

 similar streams. Marked hatchery trout are planted and the returns checked by 

 creel census and electric shocking. Results to date show that a very small 

 percentage of planted fingerlings reach a length of six inches. 



Klamath River Investigation, Siskiyou County. This program consists of a long- 

 range study of the factors affecting the survival of salmonids in the Klamath 

 River system. One year is being devoted to the study of each jjrincipal supposed 

 factor. 



Eagle Lake, Lassen County. This study was initiated to find ways to prevent 

 the extinction of the Eagle Lake trout and to restore trout fishing. 



Lake Almanor, Plumas County. The study of this lake was started in 1941 to 

 determine causes for the reported poor trout production and to measure the 

 yield to the angler from plants of hatchery-reared fingerling trout. The study 

 was discontinued during the war, before any results could be obtained, but was 

 resumed in 1946 with the planting of marked trout fingerlings. Catch data are 

 now being analyzed. 



Lake Tahoe Fishery Survey, Placer and El Dorado Counties. Field studies were 

 conducted on Lake Tahoe during the summer seasons of 1948 and 1949 by a 

 college graduate student employed as a Student Biologist, in partial fulfill- 

 ment of his requirements toward a Ph.D. degree. This work included studies 

 of the food and habits of the various species of fishes present and of their 

 physical environment. 



Echo Lakes, El Dorado County. The very low trout catch despite heavy stocking 

 in these lakes has been the subject of a continuing investigation by the personnel 

 of District 3. Early in the biennium, limnological and population studies were 

 conducted and in the fall of 1949 a fish trap was constructed in the outlet. 

 Marked rainbow trout have been planted and it is hoped that recoveries of both 

 marked and unmarked fish in the trap will yield valuable information on losses 

 through the outlet. 



Clear Lake, Lake County. A detailed study of the fishes and fishery of Clear Lake 

 was completed during the biennium. This work resulted in definitive reports on 

 the food of young black bass and on the life histories of the greaser blackfish, 

 Sacramento perch, hitch, and Sacramento squawfish. Of immediate interest was 

 an intensive study of the possible value of a closed season on warmwater fishes. 

 This study was done largely at Clear Lake, but drew upon data from other 

 waters. The study concluded that there was no management value in a closed 

 season. The Clear Lake investigation also led to the conclusion that the game 

 fish population could be increased if the forage fish supply was augmented. The 

 golden shiner was selected for introduction and a rearing pond was constructed 

 and stocked with shiners from San Diego County. A detailed study of the effect 

 of TDE on fish life and other aquatic organisms led to recommendations that 

 insured a minimum loss to sport fishing when Clear Lake was treated with this 

 chemical in 1949 to eliminate the Clear Lake gnat. 



Millerton Lake, Fresno/Madera Counties. An intensive study of the Millerton 

 Lake warm-water fishery, as a typical example of the large fluctuating reservoirs 

 along the west slope of the Sierra Nevada, was started in 1949. Present evidence 

 indicates a lack of forage fish to be the main factor limiting the fishery. At the 

 request of sportsmen, and in an attempt to improve the deficiency of food for 

 bass, a subimpoundment in which to raise bluegill fingerlings was tried, but 

 without appreciable success. 



