River users urged to beware of sagittaria spread

As a local not-for-profit organisation that helps the Burdekin Dry Tropics community to sustainably manage its natural resources, NQ Dry Tropics said it was important that Ross River users understood the risks of cross-contamination for North Queensland waterways.

NQ Dry Tropics chief executive officer Scott Crawford said Ross River had a reputation for hosting one of the largest populations of pest species out of any waterway in Australia, and sagittaria weed – also known as delta arrowhead – was of particular concern.

“Sagittaria is a nationally significant, highly invasive weed that restricts water flow and contributes to localised flooding by blocking irrigation channels and drains, degrading natural wetlands, and impacting biodiversity,” Dr Crawford said.

“In this region, its occurrence appears to be limited to Ross River,” he said. “The cross-contamination risk of sagittaria to the regional community is huge, and can occur in a number of ways; even through recreational boat users who use their vessels in Ross River and then travel to other waterways.”

To minimise the risk of spreading sagittaria to other waterways, river users can take some basic measures; including always thoroughly washing down boats and trailers after every trip to the river, and before using it in any other waterway.

Unlike floating or submerged weeds, sagittaria is anchored in soil under the water where it spreads and can grow in depths of up to 1.2m.

Additional sightings of sagittaria can be reported to NQ Dry Tropics at 4722 5700.

For more information about Sagittaria Platyphylla (Delta Arrowhead) – download our 2015 Technical report & future management options, published by our Burdekin Dry Tropics Regional Pest Management Group.