More than 1000 people signed a petition presented to the Otago Regional Council this week demanding the council take more responsibility for tackling lagarosiphon in Lake Dunstan. Pam Jones finds out the mixed views about the noxious weed that is taking over some of our waterways.
Some weeds are good, but not this one.
It clogs waterways, stops boats and swimmers in their tracks and looks bad. Native plants in a lake, supporting its habitat? Good. Exotic, invasive lagarosiphon, ruining our waterways? Bad.
That is the view of the Guardians of Lake Dunstan and the more than 1000 people who signed a petition demanding the Otago Regional Council (ORC) take action to prevent lagarosiphon taking over the lake. They say the ORC has avoided its responsibilities in the past and continues to do so. If nothing is done soon, Lake Dunstan will be ruined, they say.
On the other side of the debate, the ORC defends its stance and spending. There are also some from other groups — such as the Clutha Fisheries Trust and Otago Fish and Game Council — who say there are some positives from the lagarosiphon in Lake Dunstan, that it has a valuable ecological role and benefits fish and other wildlife in the lake.
So where does the truth lie?
Guardians of Lake Dunstan members have been trying to publicise the issue for years, but many say it is the arrival of ORC Dunstan councillor Michael Laws in Cromwell that has given the issue traction.
Guest speaker at a special meeting of the Guardians group in April, Mr Laws told those attending it was time to "make some noise" about the issue.
"It’s time to get angry. This area [Cromwell] has been neglected and fed nonsense [about lagarosiphon] for the last 20 years," he said.
"You haven’t got upset enough. Politics works on a very simple principle. Those that make the most noise get the most action."
He encouraged the Guardians group to start a petition asking the ORC to take more responsibility and provide more funding for the issue and that petition was presented to the ORC at its meeting in Dunedin on Wednesday.
At the meeting the ORC also decided to allocate $25,000 towards lagarosiphon control work in Lake Dunstan this financial year, following a request from Land and Information New Zealand (Linz) for $50,000. After an initiative from Cr Laws at an earlier council committee meeting, the $25,000 will now be funded from a general levy of all Otago ratepayers, not just from Central Otago and Queenstown Lakes ratepayers, as previously proposed.
The ORC received 20 submissions on its 2017-18 annual plan about lagarosiphon, all asking for more ORC funding and resources to be allocated to the problem.
The council’s hearing committee, which recommended the $25,000 be provided, noted "while ORC is not responsible for controlling this weed, funding would assist work being undertaken to reduce the risk of transferring the weed into high-value water bodies, in accordance with the pathway management plan for Lake Dunstan".
Mr Laws labelled the $25,000 funding as "genuinely pathetic".
Lagarosiphon is listed as a pest in the ORC’s 2009 Otago pest strategy and one of the ORC’s roles is to control pests and noxious plants (a review of the strategy is planned for this financial year).
However, it has never provided any specific funding for lagarosiphon work in Lake Dunstan. In response to questions from the Otago Daily Times earlier this year, an ORC spokesman said the council did not fund any physical work with lagarosiphon but contributed about $30,000-$40,000 of staff time annually to inter-agency work.
At present, Land and Information New Zealand (Linz), as the owner of the lake bed, is officially the lead agency for lagarosiphon, contributing $50,000 a year towards the issue in Lake Dunstan alongside another $50,000 annually from Contact Energy (next year Linz’s contribution will rise to $100,000).
But Mr Laws said the ORC should be the lead agency for dealing with lagarosiphon, as it had a statutory responsibility to protect the environment, and the lack of clarity over who had responsibility for controlling the weed was at the crux of the issue.
"Every agency says it’s not their problem — Linz, Contact, Fish and Game and the ORC. There’s a race to the exit to get away from responsibility."
The Otago Daily Times emailed more questions to the ORC this month about lagarosiphon in Lake Dunstan, asking for comment about the petition that was presented; which of the Central lakes (Dunstan, Wanaka or Wakatipu) was the most important in the fight against lagarosiphon; if the ORC should assume responsibility for controlling lagarosiphon; and if it was possible to remove lagarosiphon from Lake Dunstan or if containment was the only possibility. The ODT also asked for further comment on allegations from Mr Laws that the ORC is being misleading when it says it has no money to tackle lagarosiphon in Lake Dunstan, when it has more than $50million in reserves.
In reply ORC communications team leader Mark Peart said "having answered all these questions for you in April and traversed similar themes in those responses, we don’t have anything to add, because nothing material has changed since we did that".
In April the ORC had confirmed it had $56million in reserves, no debt and a net asset of $440million through its ownership of Port Otago.It said each of the three lakes had "different challenges and goals in relation to lagarosiphon management".
The priority for Lake Wakatipu was to exclude lagarosiphon; for Lake Wanaka to ensure sustainable management of lagarosiphon and reduce its spread to other water bodies and within the lake; and for Lake Dunstan to protect other bodies from lagarosiphon transfer and minimise the effects of lagarosiphon on lake users in high value areas (HVAs) in the lake.
As well as the Lake Dunstan funding, in 2016-17 Linz provided almost $500,000 of funding for control work mostly in Lake Wanaka but also in Lake Wakatipu and the Kawarau River. Partner funding of $15,000 from the ORC, $20,000 from the Queenstown Lakes District Council and an anonymous donation of $50,000 (all for Lake Wanaka) were on top of that. In 2017-18, combined agency funding for Lake Wakatipu will increase and a new joint-agency weed management group will investigate short and long-term solutions for the lake. Linz biosecurity manager Dave Mole said there was no "one size fits all" approach to controlling lagarosiphon.
A 10-year management plan for lagarosiphon in Lake Dunstan (2016-25) was released by Linz last year. It was developed in conjunction with the National Institute of Water and Atmospheric Research (Niwa) and endorsed by a local management group led by Linz.
The plan, which Mr Mole said was backed by science, gave "more tools in our toolbox" for managing lagarosiphon, including both herbicide and mechanical solutions.
"While we’ll never get rid of the weed completely, this plan will enable us to strategically manage and monitor high-value areas more effectively," Mr Mole said.
Group members and fisheries representatives defended the plan at the Guardians’ April meeting, but Mr Laws and others criticised it.
The plan says Lake Dunstan is at present ‘‘saturated’’ by lagarosiphon (all available weed habitat is occupied) and it is present upstream in both rivers feeding the lake.
"This reality limits the aims of management to ‘sustained control’. One important driver for weed management is the risk that lagarosiphon presence at this important hub for water-based recreation poses to the other uninvaded Otago waterways. The second impetus is to mitigate the impacts of lagarosiphon on amenity values of Lake Dunstan for boating and swimming. In contrast, it is acknowledged that a highly valued recreational fishery is supported by the lagarosiphon weed beds that have replaced/excluded native submerged vegetation."
Otago Fish and Game officer Cliff Halford said those positive attributes of lagarosiphon were important; despite its "nuisance value", the weed sustained a "very productive and highly valued sports fishery" in Lake Dunstan, as well as valuable habitat for a range of waterfowl and other protected wildlife.
Views along the same lines from some others at the Guardians’ April meeting were labelled by Mr Laws as "absurd".
Mr Burton said the Guardians group only wanted lagarosiphon properly contained, as it was impossible to get rid of it.
But Mr Laws said there was "promising" international research about the potential for eradication, if only more funding could be allocated towards the issue.
Lagarosiphon
• A South African aquatic oxygen weed introduced to New Zealand for use in aquariums. Thought to have been accidentally introduced to Central-Lakes waterways in the early 1970s through drains and ponds. Can spread to other waterways through transfer of fragments on boats.
• Once present in a lake, lagarosiphon can grow to a depth of 6.5m and up to 5m in height, displacing native plants and choking waterways.
• Already in Lakes Dunstan, Roxburgh and Wanaka, and parts of the Clutha and Kawarau Rivers. It is not yet in Lake Wakatipu.
• In Lake Dunstan it is estimated there are about 500ha of lagarosiphon, but authorities manage only about 70ha in "high-value areas", mainly boat ramps and camping spots. The control methods in Lake Dunstan are the herbicide diquat, and some mechanical cutting.
