Survey of rainbow trout mortality in cage culture farms in Hasanloo Dam, west Azerbaijan province

In late June 2013, because of sudden and unjustified increase in mortality of apparent healthy fish in Hasanloo dam cage culture, random sampling was convicted from a live dying and dead fishes. Forty fishes (20 alive and 20 dead fishes) from two cage with the weight of 200-300 gr were sampled. Samples were sent to private factor laboratory ice pieces for evolution. Some physicochemical parameters of Hasanloo dam water including nitrite, nitrate, ammonium, soluble solid materials, temperature, dissolved oxygen and pH was measured. To investing the probability of bacterial, fungal and parasitic discover outbreaks sample were taken from the kidney, gills and skin of fish. The result of different investing revealed the presence of algal bloom, oxygen shortage, executive problems and fishing net fountain obstruction due to accumulation of planktons and suspended material. Because of increase in light intensity, nutritive substances level, warming of water temperature and static suability of water hydrological status, algal blooming had occurred in Hasanloo dam that not only destroyed the gills of fish but also created competition for soluble oxygen at night with some phytoplankton species causing hypoxia and death of salmon in the breeding farm. The result of general bacterial cutler was negative and mild secondary infection with S aprolegnia species was detected in PGYEA culture. The result of liver histopathology indicated the presence of hepatic ceroidosis because of non-standard diets with high levels of carbohydrates. Gill blade inflammation and hyperplasia was the observed. Due to high amounts of ionized ammonia among culture nets resolving from summer mortality syndrome