MAF has informed Otago Fish & Game that the hatchery trout infected with the Aeromonas bacteria is not the ‘typical’ strain of the disease.
“The ‘typical’ version of the bacteria is of most concern to hatchery and fish-rearing facilities so it’s encouraging that this has been ruled out,” says Otago Fish & Game chief executive Niall Watson.
MAF has advised Fish & Game that further testing is needed to prove whether it is the more common ‘atypical’ variant.
While Mr Watson and his staff are still very concerned about any disease affecting trout, he says at this stage the latest development appears to be encouraging.
“We understand that if further tests return a positive for the ‘atypical’ strain, then this is less virulent in trout.
“We welcome the news from MAF and await further laboratory results. We’ll also be considering the implications of this development over the next few days. At this stage, though, it appears to be positive news.”
Mr Watson says there have been no further fish mortalities at the Macraes hatchery and stock held there all appear to be in a healthy condition.
“We are continuing to monitor the situation closely. Since the discovery of the disease we’ve enforced strict hygiene controls on-site and have a self-imposed restriction on further fish releases.
“We will review the situation in mid-November and make a decision then on whether or not to recommence releases from the hatchery.”
Mr Watson says there have been no reports of infected trout from waterways where releases were made before the discovery of the infected hatchery fish.
Otago Fish & Game remains concerned about what, if any, impact the disease will have on native fish species.