Abstract

Fungal diseases of fresh water eggs and fishes are known to be a problematic disease. The aim of this study was to investigate the aquatic fungal flora specially oomycete fungi in rainbow trout hatcheries from west part of Iran during fall and winter 2008, an attempt to isolate fungi from the eggs and broodstocks showing fungal infection at the three rainbow trout farms. A total of 150 randomly selected eggs and 15 broodstocks were obtained. A sterile swab was taken from outer surface of body (skin, gills, fins), as well as eggs. Sabouraud dextrose Agar, Glucose Yeast Agar and Hemp seed in sterile tap water was used for fungi isolation. Identification of the fungi was based on their vegetative organs, including hyphae shape and size, asexual reproduction organs, shape of sporangium and spores, and generative organs, structure of oogonium, oosporangium and antheridium. In this study eight genus and species were identified and the most common were Penecillium sp., Acreomonium sp., Alternaria sp.,Fusarium solani, Aspergillus sp., Mucor sp., Saprolegnia sp. and Cladosporium sp. Among the above species Penecillium sp. with 23% and Saprolegnia sp. with 3% have more and less occurrence, respectively. Identification of Saprolegnia sp. which is an important pathogen in aquaculture needs further study in the future.

Key word: Fungal infection, fish, Saprolegnia, Iran.