An Outbreak of Gliding Bacterial Disease in Hatchery-born Red Seabream (Pagrus major) and Gilthead (Acanthopagrus schlegeli) Fry in Hiroshima

Abstract

A gliding bacterial infection was associated with the death of red seabream- and gilthead fry reared in floating net cages. The disease occurred among the fry grown to the size of 15 to 60 mm (mainly 20 to 40 mm) in total length, and caused the mortality of 20 to 30 percent of the populations. Eroded mouth, frayed fins and rotten tail were characteristic symptoms of the disease. Large numbers of gliding bacteria grew in the lesions and assumed whitish yellow color. The organism was a gram-negative, chytochrome oxydase-positive, flexble rod measuring 0.3-0.5µ x 2-6µ. It did not utilize agar, cellulose or chitine. There was no growth on Ordal's medium (modified) without seawater. An attempt artificially was made to infect red seabream- and gilthead fry by smearing the culture on the surface of mouth or caudal fin. The experimentally infected fish displayed essentially same symptoms as the naturally infected ones. © 1977, The Japanese Society of Fish Pathology. All rights reserved.