pest species – Page 7 – ANGFA Queensland

Targeting limnocharis for eradication

government, pest species, waterways/wetlands

Jun 032013

Limnocharis flava. Limnocharis presents a serious agricultural and biodiversity threat to northern Australia. To date infestations detected in northern Australia have included plants located in backyard ponds, ornamental lakes, farm drains and in natural waterways.

Biosecurity Queensland officers will be seeking out the exotic weed Limnocharis this month as they work towards removing every last plant in Australia.

Boat and foot surveillance will be conducted by Biosecurity Queensland officers along the Ross River to locate the weed.

The aquatic weed can grow up to one metre in height and produces small cup-shaped yellow flowers every two months.

It also traps sediment and slows water flow which provides a habitat for mosquitoes.

Young plants appear similar to water hyacinth, with the leaf blade becoming broader in mature plants.

Limnocharis has the ability to produce nearly 1,000 seeds every time it flowers and these either make the infestation worse, or they simply float away to create a new problem elsewhere.

Limnocharis was first detected in Townsville's Ross River in early 2012.

There have been 30 known Limnocharis infestations recorded in North Queensland, with almost half now officially eradicated.

It was first found in Australia in 2001, with infestations so far being limited to North Queensland between Townsville and Mossman.

The weed is believed to have been introduced by gardeners who were unaware of the severe damage caused by Limnocharis in Asia to rice paddies, irrigation channels and wetlands.

Limnocharis is a Class 1 declared pest due to its invasiveness and ability to invade wetlands, rivers and dams where it can displace native plants and animals.

--------------------------------------------------------

For more information about Limnocharis there's a Pest Profile at DAFF

Carp haul from south-west Qld waterways ‘incredible’

pest species, waterways/wetlands

May 132013

Carp are a well adapted pest species that are rapidly overtaking rivers and creeks in south-west Queensland (Amy Phillips, ABC)

Several hundreds of kilograms of carp, some as big as a meter long, are being pulled from waterholes in Queensland's south-west.

The natural resource management group, South-West NRM, has been working in the Paroo catchment extracting carp from some of the local creeks and waterholes.

Carp are considered to be Australia's worst freshwater fish pest.

Spokesman Craig Alison says it is still compiling data but the results so far suggest there may be breeding "hotspots" for the fish.

"The results that we're seeing from the upper Paroo, especially around the Yowah Creek, have been phenomenal," he said.

Seizing the carp

"The weight, the size and the volume of carp that are being extracted from the waterholes has been incredible.

"One event within 48 hours captured just on a tonne of carp. One of the largest ones was seven kilos and over a metre long."

He says the ecosystem is important to preserve.

"It dissipates into the Ramsar wetlands and also the Paroo is classified on the natural estate as a high ecological value aquatic ecosystem," he said.

"Once all the data is captured and collated, we are going to see hotspots of carp concentrations and then we will be able to look at environmental conditions within those waterholes."

Original ABC News Story

DNA Detection of Tilapia

Interest, pest species, waterways/wetlands

May 112013

Tilapia Oreochromis mossambicus (Peters). Mozambique mouthbrooder, or Mozambique tilapia. Photo: Australian Society for Fish Biology

One of North Queensland's most invasive species of pest fish may be tracked by its own DNA, in a new collaborative project between researchers from James Cook University and the Queensland Department of Agriculture, Fisheries and Forestry.

Professor Dean Jerry, Deputy Director of JCU’s Centre for Sustainable Tropical Fisheries and Aquaculture, along with DAFF fisheries researcher Dr Richard Saunders, have been awarded a grant from the Invasive Animals Cooperative Research Centre to conduct the two-year project.

Tilapia, which are declared noxious in Queensland, are freshwater fish that inhabit shallow streams, ponds, rivers and lakes.

Professor Jerry said tilapia, a highly aggressive and invasive fish species originating from Africa, were becoming particularly prevalent in warm water habitats throughout North Queensland and were threatening to invade streams and rivers in the Gulf of Carpentaria. This species has been shown to harass and prey on native aquatic fauna.

Professor Jerry said the project, eDNA as a Surveillance Tool for Tilapia, would help to track the species’ movements.

“Environmental DNA, or eDNA, is the material that is floating around in the aquatic environment in the form of free-cells shed or excreted from aquatic organisms,” he said.

“It could be individual cells sloughed from the skins, faecal material or mucus, for example.

“DNA technology has become so powerful over recent years that it is now possible to use eDNA as a detection and water body monitoring tool for a number of fish species, including that of invasive species.”

Professor Jerry said researchers would collect two-litre water samples from bodies of water and filter it to concentrate cells.

“We then extract the DNA and test the sample against tilapia species-specific DNA probes, which will indicate to us whether or not DNA from our target organism is present in the sample or not,” he said.

“If the test is positive, it shows that our target organism inhabits the water body.

“The advantage of this technology is that it will reduce the requirement to use previous labour-intensive sampling approaches such as electrofishing or netting, which are relatively expensive and often ineffective at detecting fish with low abundance.”

The work will take place in a range of North Queensland eastern streams, as well as potential invasion front sites in the Gulf of Carpentaria. Sampling and development of the test will occur over the next two years.

Professor Jerry said the use of eDNA as a surveillance tool for tilapia and other pest fish species was an innovative approach.

“It may enable new outbreaks to be detected much earlier than by using traditional methods, and potentially at a stage where the populations are geographically contained and not well established,” he said.

He said the project eventually aimed to develop a quick, effective DNA-based test that could be used to routinely monitor water bodies where tilapia were not currently present.

Collaborator Dr Saunders said the value of developing this DNA technology for Queensland was the rapid detection of new water bodies where tilapia had invaded, allowing a quick response which may help eradication efforts before the fish populations reached a level where eradication becomes impossible.

For interviews, contact: Professor Dean Jerry on (07) 4781 5586

JCU Media contact: Caroline Kaurila (07) 4781 4586 or 0437 028 175

Original JCU media release:
Pest fish to be tracked by its DNA

Newer Entries