Molecular identification of water molds (oomycetes) associated with chum salmon eggs from hatcheries in Japan and possible sources of their infection

Representative Organization: Japan Agency for Marine-Earth Science and Technology

2014/11/25 - 2015/03/31

Chum salmon hatcheries in Iwate Prefecture

Field survey

Molecular identification of water molds with chum salmon eggs, and detection of their infection sources using eggs collected from chum salmon hatcheries in Iwate Prefecture

We detected oomycetes in infected chum salmon Oncorhynchus keta eggs at two hatcheries in northern Japan, in the source water used for egg incubation, and in the air at the hatcheries to clarify the source(s) of oomycete transmission using a DNA molecular marker. Seven oomycete taxa, belonging to Saprolegniaceae and Pythiaceae, were detected from the infected eggs. From the source water used for egg incubation and the air at the hatcheries, nine oomycete taxa, including those found on infected eggs, were detected, suggesting that both water and air are potential sources of oomycete transmission. There is no report of airborne transmission of these oomycetes detected in this study so far. Regarding protection and sterilization against oomycete infection in aquaculture hatcheries, not only water used at hatcheries but also the air in hatcheries may need to be considered hereafter.

FY2014 Molecular identification of water molds (oomycetes) associated with chum salmon eggs from hatcheries in Japan and possible sources of their infection

Sequences of the ITS 2 region of ribosomal RNA genes from oomycetes