5 



Fish Health Management 



Control of diseases in hatchery fish can be achieved best by a program of 

 good management. This involves maintaining the fish in a good environ- 

 ment, with good nutrition and a minimum of stress. However, attempts 

 should be made to eradicate the serious diseases from places where they oc- 

 cur. Containment is accomplished by not transferring diseased fish into 

 areas where the disease does not already exist. Eradication, when feasible 

 and beneficial, involves the removal of infected fish populations and chemi- 

 cal decontamination of facilities and equipment. In some cases, simply 

 keeping additional disease agents from contaminated waters can result in 

 effective eradication. 



Fish tapeworms can be transmitted to people who eat raw fish but, in 

 general, fish diseases are not human health problems. The reasons for 

 disease control are to prevent costly losses in hatchery production, to 

 prevent transmission of diseases among hatcheries when eggs, fry, and 

 broodstock are shipped, and to prevent the spread of disease to wild fish 

 when hatchery products are stocked out. Although fish diseases themselves 

 rarely trouble humans, control measures can create a hazard if fish are con- 

 taminated with drugs or chemicals when they are sold as food. 



In local disease outbreaks, it is important that treatments begin as soon 

 as possible. If routine disease problems, such as bacterial septicemia, can 

 be recognized by the hatchery manager, treatment can begin sooner than if 



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