Abstract
The occurrence of runt sturgeon in stocks reared in recirculating aquatic systems is highly undesirable for both production and fish welfare. The aim of this study was to describe the anatomopathological and histopathological changes accompanying the phenomenon of runt sturgeon reared in fully controlled recirculating aquatic conditions. These individuals were characterized by emaciation and cachexia. Histopathological analysis indicated severe chronic non-purulent inflammation of the gastrointestinal tract and exfoliation of enterocytes into the lumen, accompanied by chronic, non-purulent pancreatitis. All pathological findings were probably the result of malnutrition, which further escalated into the disorders observed.