Abstract
Mass mortality occurred in dusky spinefoot, Siganus fuscescens, captured at Urasoko Bay and reared in a tank at Fukui Prefectural Fisheries Experimental Station. Diseased fish showed dark body color and hemorrhage in the mouth and eyes and at the base of the pectoral and ventral fins.
The bacterium isolated from the diseased fish was found to be pathogenic to dusky spinefoot by intraperitoneal injection. From morphological and biochemical characteristics, the isolate was identified as Streptococcus iniae.
