Ozone disinfection of marine fish eggs for eradication of bacteria and vertically transmitted diseases such as piscine nodavirus, Part II

Description

Haddock (Melanogrammus aeglefinus) are a fast growing temperate species that could be used to diversify the aquaculture industry in Atlantic Canada. As with the development of any new commercial aquaculture species, certain obstacles must be overcome to ensure success. Vertically transmitted diseases (diseases transmitted from parents to progeny) are a major cause for concern. Piscine nodavirus, also known as viral nervous necrosis (VNN), viral encephalopathy and retinopathy (VER), or fish encephalopathy has been reported in cultured gadoids (i.e., haddock and cod (Gadus morhua)) in Atlantic Canada and New Hampshire, USA, in 2001 and 2002. Atlantic halibut (Hippoglossus hippoglossus) aquaculture was almost a viable commercial industry in Norway until nodavirus severely reduced juvenile production and crippled the industry.

Dissolved ozone has been used successfully to disinfect halibut and striped jack (Pseudocaranx dentex) eggs against nodavirus. The purpose of this research is to determine what levels of ozone fertilized haddock eggs tolerate, and to determine if this level is sufficient to kill the haddock strain of nodavirus. This information can then be used in hatchery settings to disinfect eggs, controlling outbreaks.

Nodavirus has been reported in wild fish populations, indicating that it is present in natural waters. Disinfecting incoming seawater to a hatchery is necessary to prevent outbreaks. Nodavirus isolate will be diluted in seawater, and then exposed to ozone to determine what levels of ozone are required to kill the virus when it is in seawater (not adhered to eggs). The information determined from this aspect of the research can be applied directly to hatcheries to help them design incoming watering disinfection systems.

Program Name

Aquaculture Collaborative Research and Development Program (ACRDP)

Year(s)

2003 - 2004

Ecoregion(s)

Atlantic: Gulf of Maine, Scotian Shelf

Principal Investigator(s)

Debbie Martin-Robichaud
Email: Debbie.Martin-Robichaud@dfo-mpo.gc.ca