A deadly outbreak of avian botulism in Waikato’s Whangamarino Wetland has killed thousands of birds, including some rare native species.
Fish and Game New Zealand says it is “yet another wake-up call for urgent action” to be taken by the Waikato Regional Council.
“The latest outbreak of the deadly bacteria, which produces a toxin that can paralyze and kill birds, follows multiple and escalating outbreaks during summers in and around the Waikato area over the past decade,” said Fish and Game New Zealand in a press release on its website.
Poor water quality and changes in water flows resulting from human activities contribute to low oxygen levels, creating perfect growth conditions for this bacterium.
“This results in the death of fish, followed by birds before botulism spreads to other surrounding wetland environments,” Fish and Game New Zealand said, calling it “yet another red flag for a urgent action”.
The Whangamarino Wetland is the second largest freshwater wetland on the North Island, covering almost 7,000 hectares in Waikato, and has been chosen as one of three wetland sites of national significance in the Department of Conservation’s Arawai Kākāriki Wetlands Restoration Programme.
Fish and Game New Zealand chief executive Corina Jordan said the outbreak is an appalling situation and has had a massive impact on fish and bird populations in these wetlands.
“Parts of this wetland have been without oxygen for most of the three months leading to the mass death of aquatic species, even the hardiest freshwater species such as eels. This is not normal in healthy freshwater wetland systems,” Jordan said.
Corina Jordan, Chief Executive of Fish and Game New Zealand. Photo / Fish and game New Zealand
Jordan says the Waikato Regional Council needs to take a close look at how the system is managed and limit discharges into these waterways to help reduce the likelihood and severity of these incidents continuing to occur in the future.
“There have been long-term systemic failures in freshwater policies and a lack of implementation that have caused serious degradation of our freshwater ecosystems. Lake Waikare, one of the most polluted lakes in the Southern Hemisphere, has also been diverted to the wetland as part of the flood control program, which adds even more nutrients to the wetland,” a- she declared.
The degradation of waterways and associated environments, coupled with forecasts of longer, hotter summers, means these types of botulism outbreaks are likely to become more common, Jordan said.
Fish and Game Southern New Zealand game bird manager for the Auckland and Waikato region, David Klee, says the situation is grim.
“Botulism is symptomatic of severely degraded ecosystems and this area is impacted by human activity to the point where its resilience is severely compromised,” Klee said.
Thousands of wetland birds have been killed by the recent outbreak of botulism. Photo / Fish and game New Zealand
“Fish and Game, the Department of Conservation, Mana Whenua and volunteer hunters, working with contractors, have recovered nearly 1,500 dead birds and rescued hundreds of sick birds from the wetland, a significant step to try to minimize the size and scale of the outbreak.
Klee says Fish and Game NZ is doing all it can with the limited resources available, however many parts of the wetland, covering 7,000ha, are inaccessible.
“It’s an appalling situation both in terms of animal welfare and environmental impact,” he said.
Ngāti Naho Trust CEO Haydn Solomon has been involved in the cleanup operations and is concerned about the lack of action taken.
“Our whānau want answers from the authorities, not apologies. We are tired of today with consultants who lack follow-up, or hollow speeches from our leaders or mayors that lead nowhere. Our waterways are hammered,” Solomon said.
“Our wetlands, lakes, rivers and springs are at breaking point, but nothing substantial and meaningful is being done.”