QX is the “unknown organism” disease of oyster culture. QX is far
less of a disease in wild oysters. Why is that?
However, in culture, QX is a horrendous disease that causes mass mortality in
all well-known oyster culture species in Australia. Indeed, QX is the defining
problem in all Commercial Oyster Culture in Australia.
The type of Oyster Culture, in Australia, is basically known as intertidal ranching
of wild and hatchery juvenile stock. Intertidal Ranching has little culture
control and is very prone to QX. The two main species are commonly known as
The Pacific Oyster and the Sydney Rock Oyster. Both species do not like elevated
water temperatures.
So, QX has destroyed many generational family businesses and yet the many millions
spent on QX research have solved nothing.
Why is it so Professor?
I ask this question because, how can an industry thrive when an unknown disease
can exist and repeatedly wipe out years of production? Where is the science?
And what is this unknown disease organism?
Over thirty years ago I proposed a description of and a commercial solution
for QX in existing oyster culture. No one was listening and many scientists
were posturing. Arrogance will kill this country.
Indeed, the research that led to this positive observation was the reason why
Land Based Oyster Production (LBOP) was developed by my company, Aquafarmer
Australia.
Importantly, the LBOP process added levels of culture control not found in what
is basically traditional oyster ranching.
And the basis of that QX solution lies in simple observation. For many years
it has been my observed opinion that QX is not an organism at all.
QX is simply the result of a stress event!
An environmental stress event within the intertidal zone. Water toxicity, low
oxygen, excessive density, racks not placed 10 degrees out of tidal flow, a
build-up of faecal matter, excessive water temperatures and the variations in
usable food organisms. These environmental factors all represent the pre-curse
to disease and mass mortality, known as QX Disease.
To this day there exists a huge lack of biological awareness commercially and
smug indifference academically.
And all intertidal culture methods are plagued with QX pre-event issues. Understanding
these so-called “QX Organisms” and then adopting solutions was then
and still remains the only long-term commercial solution.
For example, Aquafarmer Australia designed a system of 100 meter long injection
moulded oyster trays that could be submerged for weeks on-end and or, easily
towed to other lease areas of lower biological stress. This method would reduce
oyster exposure to heat and low oxygen so common in traditional intertidal culture.
Such designs would then reduce QX Stress Events, but then the farmer would need
to understand oyster biology to be able to prevent the issue. Aquatic Biology
must play its commercial roll and so must its grant funding.
Aquafarmer Australia designed a type of roll-on roll-off punt that could clean
these tray systems at about 2 to 4 hundred meters per day. Unheard of applications
of technology, especially by those rivalling for grant funding. Where has that
funding gone?
So, Land Based Oyster Production was privately designed to add control to the
environment and prevent any of these climatic events while maintaining absolute
control over culture. And it did this with great success.
Please read the full story at http://www.aquafarmer.com.au/Land_Based_Oyster_Farming.html
So; QX is simply a stress event followed by an inevitable disease event. This
stress-process is simply a function of all life in general and is an absolute
certainty in all forms of aquaculture be that oysters, prawns or fish.
The real question is why has the solution been so over looked by so called scientists?
The answer is degree rich and observation poor. The science has lost its way
in political grant funding and designed outcomes.
In summation, a general stress event in oysters will be low oxygen and high
temperatures which could be combined with low level toxicity, high density of
culture, faecal contamination in low flow and or low levels of feed organisms.
Oysters becomes stressed, and weakened by these environmental pressures and
become vulnerable to all forms of invading organisms.
That is essentially, QX Disease.
So; the solutions are obvious in that the intertidal ranching process is consistently
vulnerable to environmental stress. The industry needs to move toward higher
levels of culture control. And the potential for upgraded designs are there
and injection moulding is well suited to such designs. It is a massive undertaking
toward success.
And finally, Technology and biological training could easily turn this failing
industry into the world renowned aquaculture it was fifty years ago.
Kel Gordon
Aquafarmer Australia