[目的]研究危害舟山海水网箱养殖大黄鱼烂尾病的病原,为制订有效的防治措施提供技术依据。[方法]取深水养殖网箱之患病鱼分离病原菌,进行人工感染试验和药敏试验。[结果]从病鱼尾鳍和肌肉病灶分离到2个菌株,人工感染试验证明S030901菌株能导致试验鱼100%死亡,S030902菌株对试验鱼几乎无毒性。根据菌株的形态和生理生化特性实验结果,S030901菌株为哈氏弧菌(Vibrio.Harveyi),S030902菌株为溶藻弧菌(Vibrio alginolyticus)。药敏试验结果,S030901对诺氟沙星等17种药物高度敏感,对头孢拉定等7种药物中度敏感,对青霉素G等16种药物不敏感。[结论]哈氏弧菌是舟山海水网箱养殖大黄鱼烂尾病的病原菌。 [Objective] The research aimed to study the pathogens causing the end-rot disease of large yellow croaker in Zhoushan seawater cage culture and provide the technical basis for formulating effective control measures. [Method] The diseased fish isolated from deep-sea cages were used to isolate pathogens and perform artificial infection test and drug sensitivity test. [Result] Two strains were isolated from diseased fish caudal fin and muscle lesions. The artificial infection test showed that the strain S030901 could cause 100% death of the test fish, while the strain S030902 was almost nontoxic to the test fish. According to the morphological and physiological and biochemical characteristics of the strains, S030901 strain was Vibrio.Harveyi and S030902 strain was Vibrio alginolyticus. Susceptibility test results, S030901 norfloxacin and other 17 kinds of highly sensitive drugs, such as cephradine and other 7 kinds of drug sensitivity, penicillin G and other 16 kinds of drugs are not sensitive. [Conclusion] Vibrio harveyi was the causal agent of the rot disease of large yellow croaker cultured in Zhoushan seawater cage.