Northland’s pest wars - turtles, wilding pines, wallabies and weeds

Some of Northland’s many weeds at Northland Regional Council’s recent Kaitaia weed-busters workshop. Photo / Mike Dinsdale

More than 60,000 wilding pines and 180 kilograms of grass carp were among the pests removed from Te Tai Tokerau in the past year.

The pests were among a swath of unwanted invaders wrangled in Northland Regional Council’s mahi, outlined in its 2023 draft annual report, due to be presented to the council yesterday for adoption.

The 60,000-plus wilding pines were removed from sand dunes, gumlands and wetlands under work led by Northland Regional Council (NRC) as part of the national wilding conifer control programme.

The 182kg of grass carp were removed during two joint Far North District Council, NRC and Ngāi Takoto kaitiaki ranger pest fishing events at Awanui’s Lake Heather. Their weight came from just 34 fish.

More than 300 highly invasive tench were also removed from Te Kopuru’s Lake Kapoai after two fishing events, bringing the total number of these fish removed in the past decade to more than 6000. The pest removal work is carried out with the Ministry for the Environment.

The fish threaten native ecosystems in lakes and rivers. Sightings must be reported under the Biosecurity Act.

NRC’s draft annual report also warned about red-eared slider turtles, which its pest hub described as one of the world’s worst invasive species.

“Red-eared sliders are becoming a significant issue for the northern regions of New Zealand and are a good example of a sleeper pest becoming an issue because of climate change,” the report said.

NRC was working with regional councils, DOC and the University of Waikato on a nationally co-ordinated approach to the growing pest issue.

Far North locals will learn about fighting pest weeds from Sara Brill, NRC biosecurity specialist - pest plants partnerships (standing) at an NRC workshop in Kaitaia. Photo / Mike Dinsdale

The council’s pest hub said adult red-eared sliders could become aggressive and attack bigger creatures. They were also known to take over water birds’ nesting sites.

A farmer reported to the council that he had at least 20 of the turtles in a pond, the report said.

Meanwhile, a two-year investigation into Far North koi carp confirmed that goldfish rather than the noxious fish were in Kaitaia’s Awanui, Parapara and Karemuhako rivers.

Koi carp were also the focus of investigations in Whangārei’s Kaka St drain near Mitre 10. A small-scale June 2023 netting operation successfully caught fish and confirmed they were instead goldfish. It is an offence to move or distribute koi carp under the Biosecurity Act, with offenders facing fines of up to $100,000 and/or up to five years imprisonment.

Kaipara’s Kaihu and Awakino rivers have been added to NRC koi carp surveillance after sightings were reported by the public.

Meanwhile, a wallaby indicator dog searched Waipoua Forest after a sighting of the kangaroo clan member.

The search, with support from the Ministry for Primary Industry’s Tipu Mātoro/Wallaby Free Aotearoa, included a 25-strong trail camera network, but no wallabies were found in six weeks of searching. No wallabies were found in Glenbervie and Pukenui forests near Whangārei either.

Wild deer were also part of the year’s pest wars. NRC is working with DOC, hapū and iwi, the deer farming industry and Auckland Council on a Te Tai Tokerau deer eradication strategy.

Russell State Forest has been the site for work towards eradicating about 35 wild sika deer.

NRC dealt with four reported deer incursions after escapes from farms in the first five months of 2023. Substandard or ageing deer fencing was a known issue across several permitted Northland deer farms.

Feral pigs have also exploded across Northland. NRC received daily landowner requests for help with feral pig damage.

Meanwhile, KiwiRail has become the only roading and rail organisation to develop a draft five-year weed management plan, as part of Northland’s biosecurity requirements. The council had been “repeatedly” working with organisations involved in the sector on the development of weed management plans.

■ Local Democracy Reporting is Public Interest Journalism funded through NZ On Air