28 DEPARTMENT OF FISH AND GAME 



STREAM AND LAKE SURVEYS 



Biological surveys are the building blocks on which all sound manage- 

 ment programs are based. As rapidly as other duties permit, initial sur- 

 veys are being made of all the streams and lakes in California. In addi- 

 tion, rechecks are being made on waters of particular concern for man- 

 agement purposes. 



The following list shows the principal initial surveys carried out 

 during the biennium in each district. Many rechecks and partial observa- 

 tions were also made, and several aerial reconnaissance surveys were 

 conducted. 



Shasta District. Seventy-four lakes in Trinity County were surveyed for inclusion 

 in the "Anglers' Guide" series. 



Lassen District. During the summer of 1951 surveys were completed of 15 lakes, 

 including 13 in the Thousand Lake Primitive Area in Shasta County. In Plumas 

 County, 16 lakes in the Gold Lake area were surveyed during the summer of 1950 

 and nine in the Spring Valley Lake area in 1951. Twenty-two lakes were surveyed 

 in Lassen County. 



Tahoe District. Surveys were made of 209 lakes and 33 streams in Alpine, Amador, 

 El Dorado, Nevada, Placer, Sierra, and Tuolumne counties. 



Coast District. During the biennium 166 streams and 9 lakes were surveyed. 



San Joaquin District. Survey work was highlighted by the inclusion of 82 waters 

 in the Humphreys Basin and French Canyon drainages. In all, 106 lakes and 27 

 streams were surveyed. 



Mt. Whitney District. During the biennium 142 lakes and 26 streams in Mono, 

 Inyo, Madera, Fresno, and Tulare counties were surveyed. 



Southern District. Approximately 40 streams and 15 reservoirs were surveyed. 



STUDIES ON SPECIAL WATERS 



In addition to the foregoing surveys to provide general basic informa- 

 tion, special studies were carried out on the following waters, exclusive of 

 Wildlife Conservation Board Projects, which are discussed in a separate 

 section of this report : 



Castle Lake, Siskiyou County. A complete census of all angler catches has been 

 maintained since 1941 to determine the relative effectiveness and costs of planting 

 such mountain lakes with various species and sizes of trout. During the biennium 

 eastern brook trout (Salvelinus fontinalis) were tested and hatchery plants 

 yielded high survivals to the creel. 



Sacramento River Test Stream, Siskiyou County. The survivals of catchable and 

 fingerling rainbow trout [Salmo gairdn-eri) planted in the South and Middle Forks 

 of the Sacramento River are being compared with the catches of native trout. 



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 principal supposed factor. 



Fall Creek Salmon Study, Siskiyou County. Different numbers of king salmon 

 (Oncorhynchus tshawytscha) are being permitted to spawn in this stream each 

 year, in order to determine the number of adults which will produce the highest 

 spawning efficiency. In 1950-51, 7 percent of the eggs of 750 females produced 

 fingerlings and in 1951-52. 10 percent of the eggs of 500 females produced finger- 

 lings. 



Eagle Lake, Lassen County. This study is designed to find waysi to prevent the 

 extinction of the unique Eagle Lake trout (Salmo gairdneri aquilarum) and to 

 restore trout fishing. Migrants to and from the lake were counted at a weir 

 near the mouth of its tributary. Pine Creek. 



Lake Almanor, Plumas County. The study of the yield to anglers of hatchery finger- 

 lings planted in the lake was concluded in 1951. The second phase will not be 

 started until catchable trout for planting in the lake are available in large numbers. 



