EN
The natural occurrence of the shrimp (Penaeus monodon Fabricius, 1798) and seagrass (Cymodocea rotundata Asch. & Schweinf.) is found in the area of Indian Ocean, Indonesia, for central Pacific. Vibriosis can cause death in larvae, juvenile and adult shrimp almost close to 100%. Antibacterial substances from secondary metabolites are produced by plants and animals to reduce the use of synthetic antibiotics. The purpose of this research was to determine the ability of secondary metabolites contained in the bacterial extract of the association of sea grass Cymodocea rotundata (isolate code BA.1) to treat vibriosis in tiger shrimp (Penaeus monodon). This research was conducted at the Laboratory of Integrated Biotechnology and Laboratory of Aquaculture, Fisheries and Marine Sciences Faculty, Universitas Padjadajaran, and at the Brackish and Southern Ocean Aquaculture Development Center Pangandaran, from June to September 2018. The research method used was experimental, with completely randomized design (CRD) consisting of five treatments with three replications including; control treatment (concentration of 0 mg·L–1), 150 mg.L–1, 300 mg·L–1 , 450 mg·L–1 and 600 mg·L–1. Observations made include clinical symptoms (morphology, behavior) and survival rate. Clinical symptoms of infected tiger shrimp during the in vivo test were red spots on the abdomen and necrosis of some leg and tail segments. The behavior of tiger shrimp mostly shows less responsive movements to fish-feed on the first day, and showing responsive and active behavior on the fifth day. In vivo test results for 14 days showed that the highest survival rate of 51.67% was in case of the addition of antibacterial extracts of BA.1 with a concentration of 300 mg·L–1.