Below is an extract from a newspaper article dating back to the mid 80’s when Peter Venn was
operating full time in aquatic weed control.
Peter Venn uses his hovercraft to spray the voracious water hyacinth.
Water hyacinth is the world's worst water weed - and the deadliest.
It comes from South America and was brought to Australia in the late nineteenth century as an
ornamental plant for ponds and aquariums. Now, it chokes and destroys water systems and the
surrounding environment.
"It is a magnificent flower and I guess you can't blame people for wanting to keep it, but they are
unaware of what damage it can do." research scientist Tom Anderson said.
"It is totally incompatible with our native plants and wildlife."
"When it gets into the water system it forms a carpet right across the top."
"That blanket suffocates the water so it cannot breathe and then drives off the ducks and birds
and kills the fish. In summer, the blanket doubles in size every 10 days or so and it can easily get
out of control and cause up to four times the loss of water over normal water surface
evaporation."
As with most noxious weeds, humans are responsible for their rapid distribution.
"It goes wherever people are," Mr. Anderson said.
"The normal way you get it is someone who is interested in goldfish or aquariums and when they
get sick of them, they just toss it all in the nearest creek or water supply."
"The CSIRO introduced a range of insects from the plant's native land in Brazil that helped control
it and stopped it reproducing, but these only work in northern Queensland." Specially developed
formulations are used and that's where Mr. Venn and his hovercraft step into the battle.
"His hovercraft gives him access," Mr. Anderson said.
"You cannot row a boat on the blankets."
"You will start and the blanket just bulges up like a carpet and as soon as you stop rowing, it
pushes you back to where you started. It's just like elastic."
Mr. Venn has done many, many hours, in fact more than 11,000 man hours in hovercrafts using
chemicals to control these obnoxious weeds, including salvinia.
As an example, Mr. Venn attended an urgent job at Mt Isa's Lake Moondarra which was covered
in another deadly weed, salvinia. "We faced up to 1000 ha of salvinia and when we saw it, I just
couldn't believe my eyes," he said. "It just went over the horizon."
"With a hovercraft, because its hull is 23 cm above the water, it allows the plants to flow through
underneath so you have no friction. It all comes down to access."
Salvinia, a free-floating aquatic fern with no flowers, and water lettuce are two other noxious
weeds that can be found in dams, creeks and rivers around south-east Queensland."
Like water hyacinth, they are spread by people, have evolved in jungle conditions in South
America, and form carpets over the water. Salvinia is also controlled by a combination of
insect and a herbicide mixture, as is water lettuce.
"What we like to do is to use an integrated approach so we use some insects and some
herbicides," Mr. Anderson said. "The real key to this is education and raising awareness in
people."
