CAUSES OF ULCERATIVE SYNDROME IN MARINE FISHES AND TRIAL TO CONTROL

CAUSES OF ULCERATIVE SYNDROME IN MARINE FISHES AND TRIAL TO CONTROL

Walaa T. El-Ekiaby

Fish Health and Management Department, Central Laboratory for Aquaculture Research, Agricultural Research Center, Egypt.

Abstract

The present study was carried out on one hundred and forty five naturally diseased marine fishes represented two species; seventy European seabass (Dicentrarchus labrax) and seventy five Gilthead sea bream (Sparus aurata) were collected from private fish farms in Damietta governorate. The collected fish submitted to full clinical, postmortem, bacteriological, mycotic, parasitological and histopathological examination. In addition, the physicochemical analysis of water pond holding fish was measured. The common clinical signs and the postmortem finding of examined fish were observed and recorded. The result of bacteriological examination revealed the isolation of V. alginolyticus from D. labrax and S. aurata with total prevalence rates 53.57% and 40.084%, respectively. Also, isolation of A.hydrophila from S. aurata with prevalence rate 33.75%. The antibiogram sensitivity of isolated strains were done and showed that of V. alginolyticus and A. hydrophila revealed that it was highly sensitive to Ciprofloxacin and Nalidixic acid. From the macroscopic and microscopic characters of isolated fungi from S. aurata, it cleared that the isolated fungi was Aphanomyces sp. with prevalence 26.16%. Parasitic examination of fish revealed infection of D. labrax with crustacean parasites identified as copepods of Caligus minimus with total prevalence rate 100%. The histopathological finding were studied. The trial of treatment of Copepoda by using Bafry D – 50/500 in a dose 0.75ml/L (375ppm) 10 minutes for successive 3 days was sufficient to eliminate all copepods without effect on fish health.