(Narrator) This is a scientific detective story
in which a biologist discovers a
disturbing new source of environmental danger.
(Doctor Gustaaf Hallegraeff) The evidence of species
that contaminate aquaculture products,
that can kill humans, has been decisive evidence
for the Quarantine and Inspection Service
finally to get their act together.
[Music plays]
(Narrator) Doctor Gustaaf Hallegraeff is a Dutch born marine biologist
working for CSIRO’s Division of Fisheries based in Hobart.
Here he is taking samples of phytoplankton,
the tiny microscopic plants which float in seawater.
(Doctor Gustaaf Hallegraeff) These are among the first living organisms
to evolve on our planet more than 400 million years ago.
These are the organisms that produce the oxygen
in the atmosphere that we breathe today;
these are the organisms that contributed significantly
to the oil research that some of us use to drive our cars to work.
They’re single celled organisms,
and when you look at them under the electron microscope
you’re overwhelmed by their beautiful patterns of geometry.
They have horns, wings,
all the structures that humans thought they invented,
like the wheel, the plankton already invented more than 400 million years ago.
(Narrator) One group of phytoplankton, called Dinoflagellates,
forms long chains.
A few of these species are the villains of our story.
They produce potent neurotoxins
which can cause paralysis and death in human beings.
It’s called PSP, or paralytic shellfish poisoning.
For shellfish farmers Gustaf’s research has very practical implications.
Mussels, oysters and scallops eat the Dinoflagellates
and concentrate the poison in their bodies.
They are immune,
but the toxin can kill birds, seals, whales and humans.
Until recently these shellfish were free of the toxic plankton;
it had never been found in Australian waters.
Here a fresh mussel has always been a safe mussel.
But in 1986 Doctor Hallegraeff dropped his net into the Derwent Estuary
and changed the shellfish industry forever.
(Doctor Gustaaf Hallegraeff) I just had
been transferred from Sydney to Hobart,
and my very first plankton sample that I collected
outside these laboratories in the Derwent River
contained a bloom of these toxic Dinoflagellates.
I knew my literature, and I knew that this organism had killed children in Mexico.
(Narrator) Doctor Hallegraeff immediately notified
the Tasmanian Department of Sea Fisheries.
(Doctor Gustaaf Hallegraeff) Just found first evidence for the presence
of the toxic Dinoflagellates species in the Derwent River,
and this organism has the potential to contaminate commercial shellfish farms
in the D’Entrecasteaux Channel and the Huon River.
(Narrator) The Department set up a monitoring system
to check the oysters for contamination.
It turns out they were only just in time.
That summer the first toxic concentrations appeared.
A dozen oyster and mussel farms were closed for several months.
By winter the toxins had disappeared and the bans were lifted.
Since then contamination alerts have become an essential fact of life.
The monitoring program is economically very important.
It guarantees purity for the lucrative international market.
(John Bailey) We really can get into almost any country in the world
with our shellfish sanitation program,
so that opens the world for us.
We can sell our shellfish really almost anywhere.
(Narrator) Doctor Hallegraeff was left with a question
where did the Dinoflagellates come from?
He sampled the sediment in the estuary
and found no evidence of toxic phytoplankton in the past.
He suspected they’d been brought in accidently by large ships,
mostly Japanese woodchip vessels.
These ships come to Australia empty.
For stability they are loaded with thousands of tonnes of ballast.
They use seawater, which usually comes from heavily polluted coastal areas.
Every year 60 million tonnes
of imported water is dumped around Australia.
Mud samples taken from the bottom of the ballast tanks
of visiting cargo vessels
provided conclusive proof to Gustaaf and his colleagues.
Nestled in the mud were thousands of Dinoflagellates spores,
the tough resting state which is rather like a seed.
(Doctor Gustaaf Hallegraeff) These spore stages are extremely resistant
and they can be sleeping in these sediments for ten, 20 years,
and when the conditions are suitable they germinate
and produce new toxic Dinoflagellates blooms in the water column.
And we’ve found these species now in the ports of Hobart,
Adelaide and Melbourne.
(Narrator) The shellfish industry all around Australia
is vulnerable to many other creatures hitchhiking in ballast tanks.
Our marine agriculture
is now protected by voluntary quarantine guidelines.
(Doctor Gustaaf Hallegraeff) These guidelines include,
for example, ships coming to Australian ports have been asked
to exchange and clean out their ballast tanks in the open ocean,
far away from Australian waters,
and under no conditions should any discharge of ballast water
be permitted in sensitive aquaculture areas.
(Narrator) Doctor Hallegraeff has conclusively proved
that ballast seawater is a dangerous carrier of marine pests.
There are many more organisms
which could travel the same international route.
Now that the alert has been sounded
the Australian system will probably be adopted
by governments around the world.
[Music plays]