Halioticida infection found in wild mantis shrimp Oratosquilla oratoria in Japan

Abstract

In December 2006, a Halioticida infection was found in wild mantis shrimp Oratosquilla oratoria in Tokyo Bay, Japan. Fungi were found in the gills of mantis shrimp, isolated from lesions using PYGS agar, and identified by morphological observation and molecular analysis. The fungi formed fragments in the hyphae and several discharge tubes developed from each fragment. Zoospores were formed within the fragments and released into the seawater through the tops of discharge tubes. Based on the characteristics of zoospore production mode, the fungi were classified into the genus Halioticida. Fungal isolates NJM 0642 and NJM 0643, isolated from mantis shrimp, were compared by molecular analysis of the D1/D2 region of the large subunit ribosomal RNA gene (LSU rDNA) with other fungi belonging to Peronosporomycetes, isolated from various marine crustaceans and abalones Haliotis spp. As a result, both isolates were identified as Halioticida noduliformans, which has been isolated from abalone. Moreover, experimental infection demonstrated that the fungus was pathogenic to mantis shrimp. This is the first report of fungal disease caused by Peronosporomycetes in mantis shrimp. © 2009 The Japanese Society of Fish Pathology.