Antibacterial Activity of Marine Sponge Extracts against Fish Pathogenic Bacteria

Abstract

Secondary metabolites of the marine sponges Acanthella elongata, Axinella donnani, Callyspongia diffusa, Callyspongia subarmigera, and Echinodictyum gorgonoides were collect- ed from fishing nets and their in vitro antibacterial properties against eight virulent marine fish pathogens were studied at incubation temperatures of 20°C and 30°C. Crude methanol extracts of the tested sponges showed species-specific antibacterial activity. The most active species was A. elongata which inhibited 100% and 87.5% of the tested bacterial isolates at 20°C and 30°C, respectively. Callyspongia subarmigera was the least active as it inhibited only 62.5% and 50% of the tested bacteria at those temperatures. Results suggest that fractionation and purifi- cation of the crude methanol extract of A. elongata has potential in the development of novel antibiotic substances for managing common bacterial diseases in aquaculture.