A deadly botulism outbreak has killed thousands of birds including some rare indigenous species in the Waikato.
The latest outbreak of the deadly bacteria, which produces a toxin that can paralyse and kill birds, follows multiple and increasing outbreaks during summers in and around the Waikato region over the past decade, Fish and Game NZ said.
This has seen Fish and Game NZ launch a stinging attack on the Waikato Regional Council saying the latest outbreak of botulism that killed thousands of waterfowl is another "wake-up call for urgent action".
"Poor water quality and changes to water flows as a result of human activities contributes to low oxygen levels, creating the perfect growing conditions for this bacteria," Fish and Game NZ said.
This results in fish dying, followed by birds before botulism spreads to other surrounding wetland environments, Fish and Game NZ said.
Fish and Game New Zealand chief executive Corina Jordan said the outbreak is an "appalling" situation.
"This has had a massive impact on fish and bird populations in these wetlands, and we have grave concerns for the welfare of the wider bird populations in the area," Jordan 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 there is no quick fix, but the Waikato Regional Council needs to take a "really hard look" at how the system is managed and limit discharges into these waterways to help decrease the likelihood and severity of this occurring again.
"Degradation of waterways and associated environments, along with predictions of longer hotter summers, means these types of botulism outbreaks are likely to become more common," Jordan said.
Fish and Game’s southern game bird manager for the Auckland/Waikato region David Klee said the situation is "grim".
"Botulism is symptomatic of severely degraded ecosystems and this area is being adversely impacted by human activity to the point where its resilience is severely compromised," Klee said.
"Fish & Game, the Department of Conservation, Mana Whenua, and hunter volunteers, in conjunction with contractors, have recovered close to 1500 dead birds and rescued hundreds of sick ones from the wetland, an important step in trying to minimise the size and scale of the outbreak."
Klee said it's an appalling situation in terms of animal welfare and the environmental impact.
Ngati Naho Trust CEO Haydn Solomon has been assisting in the clean-up operations and is concerned by the lack of action being taken.
"Our Whanau want answers from authorities, not excuses. We are tired of the hui with consultants that lack follow-through or hollow speeches from our leaders or mayors that go nowhere. Our waterways are getting hammered," Solomon said.
"Our wetlands, lakes, rivers and springs are at breaking point, yet nothing substantive and meaningful is done."
Waikato Regional Council's science manager Mike Scarsbrook told Stuff the council is trying to control the intensification and nutrients and sediments into the Waikato and Waipa rivers through a regional plan change.
The council told Stuff they have been working with landowners in the Waikare and Whangamarino catchments while also improving flood protection infrastructure.
Whangamarino wetland, which covers almost 7000 hectares, is recognised by the Ramsar Convention as a significant global wetland worthy of protection and conservation.
It is the second largest freshwater wetland in the North Island and was chosen as one of three nationally significant wetland sites in the Department of Conservation’s Arawai Kākāriki wetlands restoration programme.
