Haemorrhagic areas in the mouth of farmed turbot, Scophthalmus maximus (L.)

Abstract. An epizootic in juvenile turbol reared on a farm located in The Ria de Vigo, Galicia, Northwest Spain, is described. The diseased turbot did not display unusual swimming behavior; the external signs of the disease were abdominal distension and haemorrbagic areas in the mouth. Internal examination of the fist showed an accumulation of reddish fluid in the peritoneal cavity. Microbiological analysis of the diseased fish revealed the presence, in pure culture in all the organs and lesions examined, of a bacterium which was characterized biochemically as Vibrio splendidus biotype I. The virulence tests showed that the V. splendidus biotype I isolate was pathogenic for rainbow trout (LD₅₀: 2.2 × 10⁴) and also for turbot (LD₅₀: 1.2 × 10⁴). The treatment of the fish using flumequine incorporated into the feed was effective in offsetting the mortality rate.