Three-year tag returns were received permitting the 

 calculation of basic mortality figures never before 

 available for largemouth bass. These were possible 

 only because a better tag was developed. Similar data 

 was obtained at Sutherland Reservoir, San Diego 

 County. 



Fish diseases and parasites, normally serious only in 

 crowded hatcheries, have not been thought to be a 

 problem in wild warmwater fish populations. In sev- 

 eral waters where the largemouth bass spawning suc- 

 cess was very high, serious infestations of heart nema- 

 todes were discovered. These may be one of the causes 

 for the great fluctuations in year classes that com- 

 monly occur in these waters. The effect of the parasite 

 is not fully known and a control method has yet to 

 be devised. 



NEW FISH 



In addition to the importation of new forage fish, 

 several new sport fish were brought into the State. 

 One of these, the redeye bass, brought in during the 

 previous biennium, was unsuccessful and none are 

 now found in the State. The redear sunfish was im- 

 ported in 1954 and propagated in Southern California 

 and at Central Valleys Hatchery. It has been planted 

 into ponds and lakes and is now being observed. The 

 range of the pumpkinseed sunfish in California was 

 extended by a series of experimental plants in the 

 colder ponds of the central coastal region. 



White crappie, and the native Sacramento perch 

 were both tried in new waters. Only the white crappie 

 has offered improved angling. 



The success of the landlocked striped bass in the 

 east, together with a need for a control on a stunted 

 panfish population resulted in an introduction of this 

 species into Millerton Lake in 1956. 



CATFISH STUDY 



Since World War II, the once lowly catfish has 

 risen rapidly in the esteem of California's anglers. An 

 indication of its popularity as a game fish is revealed 

 by the fact that approximately 19 percent of Cali- 

 fornia's license holders fished for them in 1955. The 

 total catch that \ear was 7,500,000 catfish, making 

 California the leading state in the Nation in sport fish- 

 ing for catfish. 



Increasing fishing pressure on the State's catfish pop- 

 ulations created an urgent demand for statistical data 

 on the major fisheries, and data on the life histories 

 of the most important catfish species. Information of 

 this type was necessary in order to establish a factual 

 basis for the proper management of the fisheries. 



An opportunity to obtain valuable information 

 about little known catfish was presented in 1951 with 

 the availability of federal aid funds for sport fish 

 investigations. 



Angler Phil Douglas displays big channel catfish he took horn the 

 Colorado River. 



(Fish and Game Photo) 



A Federal Aid Project was started in 1952, and was 

 the first freshwater investigation in California sup- 

 ported with funds derived from excise taxes on fish- 

 ing equipment. Having accomplished its original ob- 

 jectives, it was terminated on June 30, 1956. 



Tagging Studies 



Considerable effort during the biennium was directed 

 toward completion of tagging investigations already 

 in progress in the Sacramento-San Joaquin Delta, 

 Clear Lake, and the Colorado River. 



The Delta tagging experiments on white catfish 

 have been remarkably successful. Anglers have re- 

 turned over 1,300 tags from the 6,966 tagged fish 

 released since the inception of the project. The results 

 of these studies have made it possible to calculate the 

 vital statistics of the Delta catfish population with a 

 degree of accuracy seldom, if ever, realized before in 

 any similar studies conducted anywhere in the world. 

 \^alid measures of annual survival, rate of exploita- 

 tion, rate of natural deaths, and annual total mortality 

 have been obtained. Such data will be invaluable in 

 the conservation of the Delta catfish resource. 



The principal factors responsible for the success of 

 these experiments have been the development of a tag 

 that will remain on the catfish for three years or more 

 and the noteworthy cooperation of sportsmen who 

 voluntarily reported the capture of tagged fish. 



