Regional council must act on deadly botulism outbreaks

Monday 20 March 2023, 10:02AM

By Fish and Game NZ


Fish & Game New Zealand Chief Executive Corina Jordan
Fish & Game New Zealand Chief Executive Corina Jordan Credit: Fish and Game NZ


An outbreak of avian botulism in Waikato’s Whangamarino wetland that has killed thousands of waterfowl including some rare indigenous species is yet another wake-up call for urgent action, says Fish & Game New Zealand.

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.

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. This results in fish dying, followed by birds before the botulism spreads to other surrounding wetland environments.

Covering almost 7,000 ha in Waikato, Whangamarino wetland 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.

Fish & Game New Zealand Chief Executive Corina Jordan says 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.

"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.

"There have been long-term systemic failures in freshwater policies and a lack of implementation that has caused severe degradation in our freshwater ecosystems. Lake Waikare, one of the Southern Hemisphere’s most polluted lakes, has also been diverted into the wetland as part of the flood control scheme, which is adding even more nutrients to the wetland.

"While there’s no quick fix, 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 these incidents continuing to occur in the future."

Degradation of waterways and associated environments, coupled with predictions of longer hotter summers, means these types of botulism outbreaks are likely to become more common, says Ms Jordan.

David Klee, Fish & Game’s southern game bird manager for the Auckland/Waikato region, says 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.

"Fish & Game, the Department of Conservation, Mana Whenua, and hunter volunteers, in conjunction with contractors, have recovered close to 1,500 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.

"We are doing what we can with the limited resources available but it’s a 7,000 ha wetland area, many parts of which are inaccessible. A massive thanks goes out to those volunteers who have assisted us. It is an appalling situation both in terms of animal welfare and the environmental impact.

"It also affects the wellbeing of everyone involved in the response. This is an internationally significant wetland supporting an array of habitats and life, but it’s been soul-destroying to be surrounded by death and decay.

"It really is ambulance at the bottom of the cliff stuff. Until we see a huge paradigm shift in how we treat our freshwater environments, these situations will continue to occur.

"Whilst the flood events this summer have exacerbated the issues in Whangamarino, this is not an isolated incident and they are increasing in ferocity."

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. Our wetlands, lakes, rivers and springs are at breaking point, yet nothing substantive and meaningful is done ."