計畫目標:國內養殖魚類近來連續發生體表嚴重潰瘍之症狀,除了出現於淡水養殖的香魚、虹鱒以及觀賞魚錦鯉外,亦經常發生於半淡鹹水與海水養殖烏魚、海鱺及鯛類等養殖魚類.體表潰瘍不但增加病原生物的感染機率,嚴重損害商品價值,甚者往往伴隨其他病原生物的入侵或傳播,造成養殖產業的嚴重負擔.本年度計畫擬探討造成魚類體表發生潰瘍之主要原因及其相關之感染致病原,並針對不同環境因子及養殖管理方式對本症狀發生之影響進行比較.除了解造成養殖魚類體表出現潰瘍之機制外,並期望能有效地提供環境管理與微生物製劑之妥善運用以消弭造成病害原因,作為養殖魚類防治體表潰瘍病害之參考.架構: 1. 罹病魚隻採樣與病原菌分離鑑定. 2. 不同季節罹病魚隻採樣與調查. 3. 不同養殖池環境水質與微生物相調查. 4. 致病菌株對不同養殖魚類之攻擊試驗. 5. 不同溫度對魚類之抗病能力試驗.預期效益:了解不同環境因子及管理方式與造成養殖魚類體表出現潰瘍之關聯性,並期望能有效地提供環境管理與微生物製劑之妥善運用以消弭造成病害原因,作為養殖魚類防治體表潰瘍病害之參考. Project Object: Recently, ulcerative syndrome was frequently found on skin surface of cultured fish in Taiwan. This syndrome occurred in fresh water cultured fish (Ayu, rainbow trout and koi) and seawater cultured fish (grey mullet, cobia and sea breams). Th ulcerative skin may not only enhance the infectivity of other pathogens but also sewously reduce market acceptance. In severe cases, pathogens may here on invade or spread leading to be a heavy burden to the industry. This project intends to investigate the cause of the occurrence of ulcerative syndrome on fish skin surface and the identification of possible causative agents. The affection of environmental factors and culture management on the disease outbreak will be studied and compared. After understanding the mechanism of pathogenicity, the suggestion of effective management measures and suitable use of probiotics may be useful for the disease control in various cultured fish. Structure: 1. Sampling of moribund fish, isolation an identification of bacteria. 2. Sampling of noribund fish in different season. 3. Water quality analysis and microbial flora. 4. Virulence tests of bacterial pathogens in various fish species. 5. Resistance of fish cultured at different temperatures. Propective: The results provide information concerning the association of environmental factors and management with the occurrence of ulcerative syndromeon fish skin surface. In addition, the suggestions for environment management and suitable use of probiotics will be useful for disease control.