Discovery of the Heartbreaking Scene

In the coastal landscape of Manawatū-Whanganui, nestled between the small townships of Himatangi and Tangimoana, lies Pukepuke Lagoon—a serene dune lake that has long been a vital part of the local ecosystem and cultural heritage. Just last week, around early April 2026, staff from Horizons Regional Council stumbled upon a grim sight during a routine check: the once-water-filled basin had transformed into a vast expanse of cracked mud, littered with the carcasses of thousands of eels and other aquatic creatures. Birds circled overhead, pecking at the remains, while survivors struggled weakly in shallow puddles. The air was thick with the stench of decay, painting a picture of ecological devastation that shocked even seasoned environmental workers.

This coastal dune lake, perched atop ancient sand dunes west of State Highway 1, is no stranger to fluctuations in water levels. However, the scale of this die-off was unprecedented, prompting immediate alerts to the Department of Conservation (DOC) and local iwi groups. What began as a low-water observation quickly escalated into a full-blown crisis, with reports of eels of all sizes—from tiny juveniles to massive adults over a meter long—stranded and suffocating in the drying sludge.

The Tireless Rescue Operation Unfolds

Word spread rapidly through the iwi networks, igniting a swift community response. By late last week, around 40 volunteers from Ngā Hapū o Himatangi—encompassing Ngāti Rākau, Ngāti Te Au, and Ngāti Tūranga—along with members from Rangitāne o Manawatū, Te Rūnanga o Ngā Wairiki Ngāti Apa, and Ngāti Raukawa, mobilized at the site. A rahui, a traditional Māori prohibition on access and activity, was promptly placed to protect the area spiritually and practically, accompanied by karakia (prayers) to honor the taonga species lost and those still fighting.

The rescue was hands-on and grueling. Volunteers waded into the thigh-deep mud, scanning for signs of life amid the desolation. Each live eel—often caked in thick sludge that stripped their protective slime layer—was carefully extracted, rinsed in rainwater puddles to revive them, and placed into buckets or containers. These resilient fighters were then transported to nearby healthy waterways, ensuring their survival in oxygen-rich environments. By mid-week, an estimated 3,000 longfin eels had been saved, a testament to the dedication amid challenging conditions exacerbated by recent rains that turned the bed into a slippery mire.

Justin Tamihana, a key volunteer from Ngā Hapū o Himatangi, captured the emotion: "Standing here looking around me right now there's probably 100 dead ones and it doesn't include what you can't see under the ground." The effort continues daily, with smaller teams persisting as the threat lingers.

Longfin Eels: Taonga of Tremendous Cultural Value

At the heart of this tragedy are the longfin eels, known as tuna kūwharuwharu in te reo Māori. These remarkable creatures, scientifically Anguilla dieffenbachii, are New Zealand's largest freshwater fish, capable of growing to 2 meters and living over 100 years. Endemic to Aotearoa, they migrate thousands of kilometers to tropical waters near Tonga to spawn, with larvae (leptocephali) drifting back on ocean currents—a lifecycle spanning decades that underscores their resilience and mystery.

For Māori, tuna are more than sustenance; they are taonga species, embodying whakapapa (genealogy) and the health of waterways. Historically caught using hinaki (eel traps), they featured in rituals, stories, and as indicators of environmental wellbeing. Pahia Turia, chairperson of Te Rūnanga o Ngā Wairiki Ngāti Apa, emphasized, "Nowhere in our history though did any of our ancestors ever talk about that lake drying up." Their decline nationwide—listed as endangered—amplifies the loss here, where breeding stock perished en masse.

Unpacking the Causes Behind the Drying

Why did Pukepuke Lagoon, a conservation-managed wetland, succumb so dramatically? Horizons Regional Council points to a "lack of water," linked to prolonged dry spells in coastal Manawatū. Recent summers have seen nearby lakes like Dudding and Herbert similarly stressed, but iwi leaders suspect deeper issues. Historical drainage for farming has shrunk the lagoon from 162 hectares pre-European settlement to just 15 hectares today, with groundwater extraction and altered hydrology playing roles.

Climate change looms large: New Zealand's dune lakes, rare globally, are hypersensitive to evaporation, reduced rainfall, and rising temperatures. A 2018 DOC report noted Pukepuke dries roughly once a decade, but this event's severity hints at compounded pressures. No tampering at the weir was found, ruling out sabotage, yet calls grow for holistic assessments including land-use intensification. For more on dune lake vulnerabilities, see this DOC overview.

Official Investigations and Agency Support

Horizons Regional Council, alongside DOC and Manawatu District Council, launched probes immediately. Chief executive Michael McCartney called the scenes "confronting," committing to historical data reviews. DOC provides logistical aid and technical expertise, with operations manager Moana Smith-Dunlop stressing partnership: "Our immediate collective priority is to protect and care for surviving tuna." An iwi-led investigation by Rangitāne o Manawatū Settlement Trust aims to "future-proof" the lagoon, blending mātauranga Māori with science.

Access remains restricted, prioritizing salvage and study. Early findings suggest no water quality issues like high nitrogen, focusing instead on inflow deficits.

A Glimpse into Pukepuke's Storied Past

Pukepuke Lagoon's story mirrors broader environmental shifts. Once a sprawling 162-hectare wetland teeming with life, European farming from the early 1900s fragmented it through drains and reclamation. By the 1940s, it stabilized at 15 hectares under DOC stewardship. Vegetation studies from the 1980s highlight macrophyte swamps dominated by raupo and sedges, supporting diverse birds and fish. Eels thrived here as top predators, but isolation as a perched lake made it prone to desiccation.

• Pre-1900: Expansive Māori mahinga kai (food gathering) site.
• 1910-1930s: Reduced to 49 hectares via drainage.
• Post-1940s: Current size, with periodic low levels.
• 2018: Natural heritage plan commissioned by DOC.

Ripple Effects on Local Ecosystems

Beyond eels, fish and invertebrates perished, disrupting food chains. Birds feasted on remains, potentially spreading disease, while nutrient release from decay risks algal blooms upon refilling. Coastal dune lakes like Pukepuke—among 57 in Manawatū-Whanganui—are biodiversity hotspots, hosting rare plants and hosting migratory species. Their loss signals wider wetland degradation, with groundwater reliant species hit hardest. Community members note frogs and insects also suffered, underscoring interconnectedness.

Echoes of Past Eel Crises Nationwide

New Zealand has witnessed similar heartbreaks. In 2021, 2,000 eels were rescued from a blocked Hauraki Plains drain; Northland hapū mourned thousands minced in Hikurangi Swamp pumps. Canterbury farms saw storm-stranded eels, while longfin declines plague dams and polluted rivers. NIWA data shows populations halved since 1980s, urging nationwide action.

Community Spirit Shines Through

The response embodied kotahitanga (unity). Whānau arrived with buckets and gumboots, children learning alongside kaumātua. Social media rallied support, with Facebook posts like "The tuna need us immediately" drawing dozens. Tiana Meroiti recalled a lucky find: "Luckily, it was still moving." Hayden Turoa praised the turnout: "All of our iwi had a strong response, and showed up in force."

Charting a Path Forward Amid Uncertainty

Refilling depends on rains, but prevention is key. Proposals include weir enhancements, riparian planting, and groundwater monitoring. Iwi advocate mana whenua leadership, integrating rāhui with policy. Climate models predict drier east coasts, demanding adaptive strategies. For eel conservation insights, explore DOC's Tuna page.

Debbie Te Puni of Rangitāne urged: "Put politics aside... acknowledge the mana of the whenua." As investigations unfold, this tragedy galvanizes hope for resilient wetlands.

Lessons for New Zealand's Waterways

Pukepuke's plight highlights vulnerabilities: balancing farming, conservation, and climate. Actionable steps emerge:

• Enhance early warning systems for dune lakes.
• Restore historical inflows via fencing and planting.
• Promote sustainable groundwater use.
• Empower iwi in management plans.
• Invest in eel passage tech at barriers.

Stakeholders from farmers to policymakers must collaborate, ensuring taonga like tuna endure for future generations. This event, though tragic, sparks momentum for change in Aotearoa's freshwater narrative.

Photo by Paolo Gregotti on Unsplash