الفهرس 
introductionOnly 14 pages are availabe for public view
 |  | from | 159 |  |  |
| | | from | 159 | | |
Abstract
The present study was carried out on a total number of 440 specimens of cultured fish; Dicentrarchus labrax(sea bass), Dicentrarchus punctatas(spotted sea bass) and Argyrosomus regius(meager fish).The current study showed that the clinical signs and the postmortem lesions of the most examined fish revealed pathognomonic clinical abnormalities.some infested Dicentrarchus labrax fish showed pop eyes.Sluggish movment,emaciation as well as loss of condition. The infested Dicentrarchus labrax showed erosion,ulcers on different region of the examined fish. The heavily infested ones showed severe emaciation,anemia and large head than normal and slight abnormal destination. In addition, there were dull appearence and lethargy.Excessive mucus production and most fishes gathered at water surface(surface breathing)with gulping the atmospheric air.The percentage of the total infection in the studied fish was 40.9%. Dicentrarchus punctatas have the highest infestation rate (85.9%). Dicentrarchus labrax and Argyrosomus regius have infestation rate reached to 10.66% and 9.23% respectively. Seasonally, the highest infestation rate was observed in autumn and reached to 85.97%, while the lowest infestation rate was recorded in the spring. Infestation rate in the summer was 16.9% and in the winter reached to 21.64%. Dicentrarchus labrax were infected with three parasitic species: Caligus sp., Ergasilus sp., and Nerocila sp.,(Isopoda). Dicentrarchus punctatas were infected with four types of parasitic species:Nerocila sp. Lernanthropus sp., Paracamallanus sp. and Rhabdocona sp. Argyrosomus regius were infected with two types of parasities species:Anisakis sp. And Nerocila sp.In this study, the density of the parasute on the infected fish inveresely proportion to the temperature of water and this mean that with the increase of temperature of water, the density of the parasites decreases.The density of the parasities have directly proportional with the PH and that is mean that with the increase of pH of the water in which the fish live the density of the parasites increase.Water quality became low when the domain or subdomain groups of phytoplankton reached its maximum rate as shown in this study.Zooplanktons are good indicators of particular environmental conditions and their change as revealed by many studies.The high intensity of phytoplankton was in the summer and the lowest in autumn.zooplankton reaches its maximum rate in spring and the summer after thst and the lowest in the winter.