Tahereh Bagheri - Offshore Fisheries Research Center, Iranian Fisheries Science Research Institute, Agricultural Research Education and Extension Organization, Chabahar, Iran,
Seyed Abbas Hosseini - Offshore Fisheries Research Center, Iranian Fisheries Science Research Institute, Agricultural Research Education and Extension Organization, Chabahar, Iran.

Caspian Sea, one of the largest lakes in the world, is main habitat of sturgeon species, including beluga (Huso huso). Several factors, such as over exploitation and oil spills as a result of inundation of low-lying oil fields along the northeastern coast and offshore drilling activities diminish beluga population [1] Since the study on hematotoxicity and immunotoxicity of diesel on this valuable fish is not well established, a study conducted on Great sturgeon to determine sublethal effects of direct diesel oil on hematological and immunological parameters and evaluate their potential toxicity.