Fish tank plants checked for potential weed menace

Identifying potential major aquatic weeds in home fish tanks or fish ponds was an important component of protecting Australian waterways, NSW Minister for Primary Industries, Ian Macdonald said today.

Mr Macdonald said the NSW Department of Primary Industries (DPI) weeds unit at Grafton was working with communities to identify possible weed problems before they cause devastation to our waterways.

"As many as three-quarters of our current aquatic weeds were introduced into Australia through the aquarium plant trade and have escaped into waterways following sale,” he said.

“So it makes sense that future serious aquatic weed threats could come from the same source.”

To catch these weeds before they get to our waterways, NSW DPI, in partnership with New Zealand’s National Institute of Water and Atmospheric Research, are conducting a research project with funding from the federal government’s Defeating the Weeds Menace program.

Mr Macdonald said the project would involve a risk assessment of aquatic plants sold within the aquarium and nursery trade to identify aquatic plants with high potential to become weeds.

“Growth patterns of high risk species will be researched in a purpose-built facility at DPI’s Grafton research station to better determine their level of threat to waterways,” he said.

“Results will be used to guide future aquatic weed declarations in all of Australia's states and territories, and it is likely to involve removing species with high weed risk from sale.

Mr Macdonald said cabomba and salvinia were examples of introduced aquarium plants that had become significant environmental weeds.

"Both are now included on the list of 20 Weeds of National Significance," Mr Macdonald said.

“They originated from South America and now pose serious economic and environmental threats to Australia, including reduced habitat values, poor water quality and clogging of irrigation channels.

“Several million dollars is spent on managing these weeds in NSW alone, which is on top of the lost agricultural/fisheries production and environmental costs.”

Cabomba, a submerged plant, was once a popular aquarium plant and has spread to waterways in far north Queensland, NSW, Victoria and the Northern Territory.

Salvinia is a floating aquatic weed that was also introduced as an ornamental plant. Its current distribution includes the South Coast of NSW through to Cairns in Queensland and also parts of Western Australia and Kakadu.

“In the future, we hope to identify and remove any such weed threats from sale before their introduction into waterways - and prevent some of the future aquatic weed problems," he said.