Many involved with fish health know well that quarantine is the best policy where “An Ounce of Biosecurity…Worth More Than a Pound of Cure” (phrase borrowed from an up coming conference talk title – http://www.vet.purdue.edu/2012fallconference).
But have you thought about doing something different? One of my colleagues came up with a radically new, brilliant idea that would change the way we do things and save a lot of fish lives!
At the moment, ornamental fish imported into Australia are held in quarantine for 1, 2 or 3 weeks depending on the requirements. Fish in quarantine are not allowed to be treated with any medications so that no signs of disease will be masked.
If significant deaths do occur, the entire population in the affected tanks would have to be destroyed and/or a sample of the fish will need to be tested at the government laboratories. Moreover, the current method cannot detect asymptomatic carriers of diseases.
Because the ornamental fish sector has been highlighted as a threat to Australian biosecurity, there have been moves to tighten the quarantine rules. It has been proposed that 60 or 120 individuals per species batch will have to be sacrificed for destructive testing by local authorities.
This will mean that it will significantly increase the price for fishes and more importantly, unnecessary loss of the lives of thousands of fish. So, what is this radical new method that was suggested by my colleague?
We are aware that environmentalists study sentinel species to give an indication of the health of the environment. Miners in the past used canaries in coal-mines to provide an early indication of pending danger from gas accumulation.
My colleague proposed that we apply this same methodology of using biological indicators to demonstrate disease freedom of imported fish. Here, the quarantine setup will be designed such that water from the quarantine tanks are hooked up to tanks that house several fish species that are susceptible to the diseases we want to keep out (i.e. cohabiting with sentinels). If disease is present, the sentinel fishes would show signs of illness and they can be tested. If there is no disease, then the sentinel fishes will remain in good health and there is no needless destruction of fish. Some of the fish/disease pairings can include Murray cod for gourami iridovirus; fork tailed catfish or barramundi for Edwarsiella ictaluri.
But according to my colleague who proposed the idea, he says that it’s not a novel idea but is standard practice around the world in specific terresterial animal disease monitoring.
There have been several occasions where this method of quarantine would have proven useful for my clients where recently imported fish were carrying a particular strain of pathogen that their resident fish had no immunity to. The imported fish showed no signs of disease during quarantine in a separate pond, but when introduced to the main pond, the resident fish started dying in numbers.
The other brilliant aspect of this proposal is that I believe it will have a much higher rate of acceptance and hence adoption by the industry. Other things I’d add to make this work includes microchipping of the sentinel fishes and faster turnaround time for reporting laboratory results.
Worth a try in ornamental fish? Your thoughts?
