Department disease laboratory men (Harold Wolf, left, and Bill Schafer) investigate a trout disease threat in a commercial hatcfiery tfiat supplies fish to 



private waters connected witf} public fishing wooers. 



(Fish and Game Photo) 



of the snails and the wild fish in the hatchery water 

 supply. 



The second trout disease to receive special attention 

 during the bienniuni was redmouth, a bacterial disease 

 of the blood and various tissues of rainbow and eastern 

 brook trout. 



It was found that some commercial trout hatcheries 

 in other states were seriousl\' affected by this disease. 



It was shown in a survey that about 1,000,000 live 

 trout a year were entering the State and that the num- 

 ber would increase. 



Inspection of Shipments 



After this was established, an investigation showed 

 that there was a danger of introducing diseased fish 

 into state waters. It was then decided that each ship- 

 ment of live trout would be inspected for redmouth 

 as well as other diseases, and only if found to be free 

 of disease could they be delivered into California. At 

 the same time all the commercial trout hatcheries and 

 all the state-owned hatcheries in California were in- 

 spected for redmouth. The disease was found in seven 

 commercial hatcheries and one state hatchery. 



Treatment of the infected fish with sulfa drugs was 

 recommended and these lots of fish were quarantined 

 until inspection showed that they were free of the 

 disease. It is believed that redmouth will not cause 

 the State serious trouble as long as infected trout are 

 prevented from entering California, and as long as 



routine inspection of all trout hatcheries, both com- 

 mercial and state-owned, is continued. 



WARMWATER FISH STUDIES 



The emphasis of the state-wide warmwater research 

 program remained on the problem of providing forage 

 for largemouth bass. 



Five species of small fish thought to have potential 

 value as forage have been planted throughout the 

 State. The fathead minnow and golden shiner have 

 become established in several lakes and reservoirs but 

 have not provided the forage expected of them. The 

 plains red shiner has been extremely successful in the 

 Colorado River area, but its value is not clear else- 

 where. Although the native freshwater smelt found in 

 the lower reaches of the Sacramento and San Joaquin 

 Rivers has been introduced into three colder foothill 

 reservoirs, no evidence of reproduction has been found. 



THREADFIN SHAD 



The threadfin shad, imported from the Tennessee 

 River in 1953, has been very successful and shows 

 great promise as a forage species. 



It was introduced into San Vicente Reservoir, San 

 Diego County, in June, 1954, and has successfully 

 reproduced. It is now found throughout the reservoir 

 and is being utilized by the sport fish. Its effect on the 

 fishery' in terms of increased angling success has not 

 had time to become apparent. The fluctuation of the 



