Mass Mortality Caused by Pseudomonas anguilliseptica in the Pond-cultured Ayu Plecoglossus altivelis

Abstract

Pseudomonas anguilliseptica infections have not been reported in cultured ayu Plecoglossus altivelis in Japan since a few occurrences in the 1980s. In the spring of 2013, however, mass mortality was encountered at an ayu rearing facility in Akita Prefecture, Japan, and the causative agent was identified as P. anguilliseptica. In this study, biochemical characterizations and 16S rRNA gene sequences of the isolates from the present event were shown to be identical to previously reported isolates of P. anguilliseptica from ayu. LD50 of the present isolate against ayu in the infection test was 1.7 × 10 cfu/fish.