310 



FISH HATCHERY MANAGEMENT 



Figure 84. Grayish-white necrotic lesions in the kidney of a rainbow trout with 

 bacterial kidney disease. (Courtesy National Fish Health Laboratory, Leetown, 

 West Virginia.) 



fish. Fish and frogs that recover from the disease usually become carriers 

 and may contaminate water supplies if they are not destroyed. The disease 

 has been identified throughout the world and apparently infects any 

 species of freshwater fish under conditions favoring the bacteria. 



Observation of strict sanitary practices and the elimination of possible 

 carrier fish from the water supply are extremely important to the control of 

 bacterial hemmorhagic septicemia on trout and salmon hatcheries. For 

 warmwater fish, everything possible should be done to avoid stressing the 

 fish during warm weather. As a prophylactic measure, broodfish can be in- 

 jected with 25 milligrams active Terramycin per pound of body weight or 

 fed medicated feed before they are handled in the spring. 



Outbreaks of MAS in channel catfish and other warmwater fish that will 

 eat artificial food can be treated by feeding them 2.5-3.5 grams active Ter- 

 ramycin per 100 pounds of fish for 7-10 days. 



Outbreaks in salmonids have been treated successfully by Terramycin 

 fed at 3.6 grams TM-50 per 100 pounds of fish daily for 10 days. Sulfam- 

 erazine fed at 10 grams per 100 pounds of fish per day for 10 days also has 

 been used with reasonable success. A combination of sulfamerazine and 

 NF-180 Inot registered by the Food and Drug Administration) has been 

 very effective in treating outbreaks on trout hatcheries in the western 

 United States. 



VIBRIOSIS 



Vibriosis is a common systemic disease of marine, estuarine, and (occasion- 

 ally) freshwater fishes. It is known also under the names of red pest, red 



