Striped bass (Morone saxatilis) juveniles raised in an intensive culture system had chronic mortality resulting from infections with Mycobacterium marinum. Approximately one-half of a population of 900 yearlings succumbed to the disease and 80% of those remaining were infected. The bacteria were isolated on Petrignani's medium after 7 days at 25 C and subcultures grew at temperatures from 20 to 37 C. The disease was characterized by systemic nodular lesions in all major organs. Older tubercles contained numerous acid-fast bacilli. Chemotherapy by feeding rifampin (6 mg/100 g of food for 60 days) was not an effective treatment. Subclinical mycobacteriosis in adult striped bass may be the source for vertical transmission to their progeny.

This content is only available as a PDF.