Pollution kills thousands of birds at globally significant wetland
Whangamarino was supposed to be a sanctuary but its poisoned waters are killing wildlife, writes
Astrange silence has gripped Whangamarino. It’s a deathly silence. The corpses of thousands of dead birds have piled up around the extensive mosaic of swamps, fens, bogs and open water between Waikato’s Meremere and Te Kauwhata.
The wetlands are usually an oasis for rare wildlife: home to the largest population of Australasian bittern, or matuku, in the world.
But large populations of Whangamarino’s birds have fallen sick with avian botulism, dying a gruesome death after losing the ability to walk and use their wings.
The paralysis eventually robs them of the ability to hold up their heads and they drown in the waters that were once a haven.
Now, appalled by the outbreak, Fish & Game New Zealand has launched a stinging attack on Waikato Regional Council, accusing the local authority of permitting dairy intensification and failing in its statutory obligation to protect freshwater environments.
Fish & Game chief executive Corina Jordan said the disease outbreak, which is in its third month, was ‘‘appalling’’ and a wake-up call for ‘‘urgent action’’.
Devastated Fish & Game staff and community volunteers, have collected almost 2000 birds, including matuku, in the past month.
Although classed as internationally significant, the wetland has long faced environmental challenges, overloaded with sediment and nutrients from farming and industrial run-off and storm water. Poor water quality and changes to how the water flows have contributed to low oxygen levels in the swamp.
Lake Waikare, one of the world’s most polluted lakes, was diverted into the wetland as part of a flood control scheme. Locals call it Fanta Lake because of its vivid, orange colour.
As the pools become stagnant, this creates the perfect breeding conditions for bacteria which produces a botulism toxin deadly to birds but harmless to humans.
The toxin is consumed by fish and aquatic invertebrates, which are then eaten by waterfowl.
When the Sunday Star-Times visited on Friday, some of the
waters were orange and there was an overwhelming, rotting stench.
Jordan said even freshwater eels, which are hardy and able to tolerate low-oxygen environments for short periods, had perished.
‘‘We are concerned at the rhetoric we hear from authorities labelling these incidents as natural,’’ Jordan, who is a freshwater ecologist, said. ‘‘Parts of this wetland have been without oxygen for the best part of three months, leading to massive aquatic deaths of even the hardiest freshwater species such as eels. This isn’t normal in healthy freshwater wetland systems.’’
Jordan said the council must now take a ‘‘hard look’’ at how the catchment is managed and limit discharges into the waterways. She also wants to see a long-term plan for managing Whangamarino.
Nga¯ti Naho said it wants ‘‘answers not excuses’’.
‘‘We are tired of the hui with consultants that lack followthrough or hollow speeches from iwi leaders or mayors that go nowhere,’’ Nga¯ ti Naho Trust chief executive Haydn Solomon said.
‘‘Our waterways are getting hammered. Our wetlands, lakes, rivers and springs are at breaking point, yet nothing substantive and meaningful is done.’’
He is cynical about consultation
exercises. ‘‘Sometimes you are lucky if the local or iwi officials show up to the meeting at all on the waterways. But when it comes to the big flash infrastructure projects like the Auckland to Hamilton [transport] corridor, highdensity housing, solar farms, expansion of the rubbish dump, or taking more water and sand from our river for Auckland they are all there to clip the ticket.’’
The council’s science manager Mike Scarsbrook said the council is seeking to control intensification of land use and control the sources of nutrients and sediments into the Waikato and Waipa rivers through a regional plan change.
But it has come up against legal action, with more than 20 appeals.
‘‘Unfortunately, this has been a prolonged process that currently sits under appeal to the Environment Court,’’ he said.
Sarah Lealand, the council’s lower Waikato zone manager, pointed to work with landowners in the Waikare and Whangamarino catchments to stabilise hill country and stream banks and said flood protection infrastructure was continuously being improved.
‘‘The flood scheme provides an important function in protecting rural and residential properties and key national infrastructure, such as roading, from flooding.’’
Covering 7290 hectares, Whangamarino is the second largest wetland complex in the North Island. A draw for duck hunters, it is a roosting and feeding ground for dabbling duck, mallard, grey and shoveler.
It is also the only remaining location for the extremely rare, tiny swamp helmet orchid and a stronghold of the black mudfish. In 1989 it was listed as a wetland of international importance under the Ramsar Convention.
Wetlands reduce the impacts of flooding, absorbing heavy rain and releasing water gradually. They are also a buffer for floods and tsunamis, a recognised tool in climate
‘‘Our waterways are getting hammered. Our wetlands, lakes, rivers and springs are at breaking point, yet nothing substantive and meaningful is done.’’ Haydn Solomon
Nga¯ti Naho Trust chief executive
change mitigation, and our densest natural carbon store.
But New Zealand has less than 10% of its original wetlands left. Between 1996 and 2018, 5761 hectares were lost, mainly drained for farming. Last month, Stuff revealed the Government had rowed back wetland protections, introduced in 2020, after pressure from industry groups.
The Department of Conservation says it believes at least 1400 birds have been affected, but has had no reports of dead or sick matuku, or mudfish, but confirmed eels have died.
Tinaka Mearns, Hauraki, Waikato and Taranaki director of operations, said the outbreak is concentrated on the Whangamarino and Maramarua rivers.
‘‘Historically there has been a matrix of management models and organisations that need to work together to manage wetlands like Whangamarino and other waterways across the country,’’ she said.
‘‘New Zealand as a wholeis getting to grips with this legacy and DOC is working constructively with other agencies, tangata whenua, land-owners and other stakeholders to address these issues. We are optimistic and motivated to work with others to improve our wetlands.’’