44 DEPARTMENT OF FISH AND GAME 



are being compared with these same characteristics of a 15-mile stretch 

 below the source of pollution. It is planned to carry on this study through 

 all seasons for a period of about three years, so that reliable information 

 on both seasonal and annual variations will be available. 



Another example of the continuing pollution control program is fur- 

 nished by the copper pollution situation on the upper Sacramento River. 

 Several tributaries of Shasta Lake and the upper Sacramento River are 

 badly polluted by the drainage from abandoned copper mines and slag 

 deposits. Within the last year, investigations have been started to de- 

 termine the exact sources of this pollution and to find out to just what 

 extent they affect the Sacramento River. In addition, an experimental 

 program of abandoned mine sealing and waste treatment has been initi- 

 ated, to reduce the amount of copper entering the river if at all possible. 

 It is believed that these discharges are not endangering the Sacramento 

 River salmon and steelhead runs with the present flows, but serious 

 problems could result if the flow were reduced during a period when 

 there was considerable discharge from Spring Creek in Shasta County. 



FISH DISEASE AND NUTRITION STUDIES 



During the biennium 116 cases of diseased fish were investigated, 

 either during field trips or by examination of specimens submitted to 

 the laboratory. In the majority of cases specific treatments were recom- 

 mended for control of the diseases following diagnosis. 



The diseases diagnosed are placed into five groups as follows: 



Protozoan 28 



Helminths 34 



Bacterial 23 



Nutritional 18 



Miscellaneous 13 



Total 116 



The miscellaneous category includes tumors, cancer, copepods, lam- 

 prey parasitism, poisoning, and salpingitis. 



Of the 116 fish disease cases investigated, 51 were from State fish 

 hatcheries, 24 were from commercial fish hatcheries, and 41 involved 

 wild fish. 



In addition to the diagnostic work, research projects involving disease 

 and nutrition were carried on as follows : 



1. Screening of drugs and chemicals for fish disease control. Work under this 

 project has resulted in the screening and standardization of the dosage of 

 Phenothiazine used in controlling intestinal protozoan infections. Continued 

 drug screening involves Chloromycetin and various sulfa drugs. 



2. A continued study of Cryptooia sp., a blood and tissue protozoan parasite of 

 fishes. The investigation includes a study of its life history, cytology, and histo- 

 pathology. 



3. Development of hatchery food diets. Accompanying the expanding trout pro- 

 duction is the problem of obtaining hatchery fish foods. Several new diets using 

 vegetable and meat meals in pellet form have been formulated and are in use 

 at most of the State hatcheries. Field trials are being carried on with the 

 objectives of attaining lower costs and dietetically improved formulae. 



