The invasive weed was spread over 1km through Te Ara ō Wairākei. Photo / NZME
The invasive weed was spread over 1km through Te Ara ō Wairākei. Photo / NZME
The aggressive aquatic weed salvinia has been eradicated from a Pāpāmoa waterway.
The invasive weed was spread over 1km through Te Ara ō Wairākei, a waterway a few streets back from the original path of Wairakei Stream.
Biosecurity New Zealand deputy director-general Stuart Anderson said eradication took four years.
"It's an invasive aquatic pest that grows rapidly and can smother the surface of rivers and lakes, destroying the living environment for native life and causing a drowning hazard.
"So when it was detected in a Pāpāmoa waterway in early 2018, we took swift action towards eradication," he said.
Salvinia is an invasive aquatic pest that grows rapidly and can smother the surface of rivers and lakes. Photo / Supplied
Biosecurity New Zealand worked with Tauranga City Council and with support from Ngā Pōtiki and the Bay of Plenty Regional Council.
"Even very small fragments of salvinia can survive and grow, so working together was essential for eradication efforts to be effective," Anderson said.
"We value the expertise each of our partners brought and the role they played in successfully removing this pest."
Throughout eradication and management efforts, Ngā Pōtiki ensured appropriate cultural processes were respected. They also monitored for eels that might be affected by the removal operation.
"We are proud to have been involved in such a successful campaign to eradicate salvinia," Ngā Pōtiki ā Tamapahore trust chairwoman Verna Gate said.
"We aim to protect and enhance the mauri of any natural area that remains in our rohe. This Te Ara ō Wairākei green corridor and the surrounding landscape has significant historic, cultural, spiritual and ecological value to Ngā Pōtiki.
"It is closely associated with Ngā Pōtiki history in this area and our cultural worldview."
Gate thanked Biosecurity New Zealand, Tauranga City Council and Bay of Plenty Regional Council for helping to look after Te Ara ō Wairākei and the native wildlife, including taonga such as tuna, that call it home.
"This is a big win for the entire Pāpāmoa community."
The waterway has been visited regularly since salvinia was found and the initial removal cleared the blanket of weed. Because of its invasive nature, council staff continued to go back to the site to check for regrowth.
"The Te Ara ō Wairākei waterway is not only a key part of the Pāpāmoa flood control and stormwater system but an important cultural and ecological corridor that is well used and valued by the Pāpāmoa community," city council manager of drainage services Radleigh Cairns said.
"It was essential that the weed was completely eradicated from this area."
Anderson said it had been three years since there had been any sign of salvinia at the site.
"To be able to announce complete eradication of such an aggressive aquatic pest is exciting and a promising sign for our aquatic biosecurity."
How you can help
Biosecurity New Zealand is asking members of the public, particularly in the upper half of the North Island, to keep an eye out for the unusual-looking freshwater weed and report it if they see it.
Biosecurity New Zealand's aim, in partnership with iwi and local authorities, is to rid the country of every salvinia plant.
If you have salvinia in a pond or aquarium on your property or know where it is growing, please report it on 0800 80 99 66 or use the online form at Biosecurity New Zealand // Online Notifications (mpi.govt.nz).
