FORTY-THIRD BIENNIAL REPORT 



35 



Station 



Klamathon Racks 



Shasta Racks 



Sweasey Dam 



Benbow Dam 



Stream 



Klamath River 



Shasta River 



Mad River 



Eel River, Soutli F( 



rk 



South Fork of the Eel River 

 Year (Benboiv Da?n) 



King Silver Steel - 



salmon salmon head 



1952-53 7,256 3,711 19,448 



1953-54 ...._ 7,948 3,052 15,425 



lakes and streams closely enough to know if the desired 

 results were being achieved, or, if not, to change the 

 management programs. 



These routine surveys were carried on primarily 

 under regional supervision. 



Initial surveys were made of 142 streams and 261 

 lakes. (See Table 23.) Rechecks were made of many 

 other waters. 



Fish Counts and Inventories 



For some years the Inland Fisheries Branch has 

 carried out counts of spawning runs of steelhead and 

 salmon at various stations. Such counts provide a basis 

 for management programs and for recommendations 

 in connection with proposed large dams. The follow- 

 ing stations were operated during the past biennium; 



Population Studies 



A knowledge of the sizes of fish populations has 

 become more and more essential in recent years for 

 a basic understanding of both theoretical and practical 

 fishery problems and their solutions. Particularly de- 

 sirable is comparative information on the status of fish 

 populations for both fished and unfished waters. 



Warmwater impoundments in the Central Valley of 

 California might be expected to yield large numbers of 

 game fish. Yet data has been presented which indicates 

 that the Central Valley with its many impoundments 

 contributes rather small catches of warmwater fish 

 compared with the Sacramento-San Joaquin Delta or 

 the San Diego region. 



While it is true the impounded waters of the Central 

 Valley lie near the heavily fished Sierra and Delta 

 areas, which are presently preferred by many fisher- 

 men, there is little doubt that they would be much 

 more popular if they provided better fishing. Learning 

 why they are so unproductive is the first step toward 

 discovering how to improve them. 



The problem is largely one of population size. Are 

 the reservoirs productive? Do they have large fish 

 populations? Is there competition between desirable 



and trash species? Is there a sufficient forage popula- 

 tion to support desirable predatory species? A knowl- 

 edge of the numbers of the various fishes present will 

 obviously go a long way toward providing answers to 

 questions like these. 



Determination of fish population estimates is by no 

 means a simple task. However, several well established 

 methods are available. Of these, the mark-and-recap- 

 ture technique presently seems to ofTer the greatest 

 possibilities. Following methods developed in 1951 and 

 1952, the technique has been extended to several 

 California reservoirs such as Dallas-Warner (Modesto) 

 in Stanislaus County. 



Partial population-composition studies by the use of 

 rotenone have also been carried out throughout the 

 State. 



One of the most noteworthy developments during 

 the biennium was the increased use of electro-fishing 

 to make population inventories. Shockers which stun 

 the fish temporarily were used in the San Lorenzo 

 River, Santa Cruz County, to evaluate the steelhead 

 populations. They were used in the Pit River in con- 

 nection with cooperative studies with the Pacific Gas 

 and Electric Company on the effect of disminished 

 flows on the game fish population. Studies on the sur- 

 vival of catchable trout and the effects of stream 

 improvement were started in Southern California to- 

 wards the close of the biennium. 



Creel Censuses 



In addition to such long range inventories and popu- 

 lation studies, the department conducted creel censuses 

 on 118 lakes and streams. 



A few of these, such as Castle Lake, Siskiyou 

 County, and Rush Creek, Mono County, were special 

 test waters where the results of study can be applied 

 to like waters. However, the majority of the counts 

 were aimed at obtaining information which will be of 

 direct application to the censused waters. 



The principal creel censuses carried out during the 

 biennium are tabulated in Table 10, Appendix. 



