Disease Causing Organisms in Procambarus cla-rkii and Gambusia affinis with Emphasis on their Role in Biomonitoring of Aquatic Pollution

THE HEALTH status of red swamp crayfish, Procambarus clarkii and mosquito fish, Gambusia affinis collected from Elmansoria canal, Giza, Egypt was investigated. The canal is known to receive lofty loads of pollutants from diverse anthropogenic sources. 113 bacterial isolates were obtained from the investigated fish specimens. Isolates were phenotypically identified as, Aeromonas hydrophila 26.54%, Vibrio parahaemolyticus 21.23%, Pseudomonas fluorescens 14.15%, E. coli 10.61%, Citrobacter sp. 7.96%, Enterobacter sp. 8.84%, Staphylococcus sp. 4.42% and Micrococcus sp. 6.19%. High gill infestations with Centrocestus sp. encysted metacercariae were noticed in mosquito fish. No parasitic infestations were recorded in crayfish. Challenge experiment confirmed the pathogenicity of Aeromonas hydrophila isolates. The water analysis revealed high heavy metals levels with values, Ni 0.71, Pb 0.34 and Cd 0.2 ppm while Zn and Cu were in normal values. Metals analysis in crayfish and mosquito fish tissues denoted bioaccumulation. Crayfish muscles showed, Ni Zn Cu Pb Cd while their levels in mosquito fish demonstrated, Ni Zn Pb Cd Cu. Proliferative, degenerative and necrotic alterations were evident in histological sections. Results suggest that both crayfish and mosquito fish can serve as carriers for some fish disease pathogenic agents and a convenient tool for biomonitoring aquatic pollution.