With major law changes underway for the management of natural resources, what does this mean for a migration dating back 23 million years?
Ruku, a 100% te reo Māori current affairs and observational documentary series, joins two whānau doing their part to support eel migration and protect their freshwater habitats.
Richard Niania has lived at Te Reinga, in the Ruakituri Valley north-west of Wairoa, for more than 60 of his 70 years. He was born there during a flood, when the road across the river had washed out, and his mother could not get to hospital.
Kūmara and eel skin were among his first solid foods.
A river guardian and tribal historian, Richard is working to preserve the history, cultural and environmental practices of Te Reinga, including its once-thriving eel culture.
The names given to eels, knowledge of their behaviour, and when and how they were harvested are all part of that history. Land loss, farming and regulation have since changed the rivers, while many eeling practices have long faded away.
His evidence now forms part of Te Rūnanga o Ngāi Tahu’s High Court challenge over freshwater rights. The case comes as the Government begins a major overhaul of resource management law.
New legislation replacing the Resource Management Act will change how land, freshwater and development are managed across Aotearoa.
Richard’s affidavit draws on generations of knowledge passed down at Te Reinga, tracing the relationship between tangata whenua, their rivers and waterways, and the longfin eels that inhabit them.
The taniwha of Te Reinga
Richard’s affidavit records the history of Hinekorako and Ruamano. Their race to the sea carved the Ruakituri and Hangaroa rivers, which meet at Te Reinga to form the Wairoa River.
Hinekorako remains at Te Reinga. Richard identifies her as their matriarch, a force of nature.
“He putanga wai, he nohoanga tangata. He nohoanga tangata, he putanga kōrero.”
Richard remembers his grandfather could name 25 different kinds of eels at Te Reinga.
By the next generation, nine names remained. Richard remembers only one - ‘matemoe’. Matemoe is the longfin eel.
A prized catch reserved for special guests and pregnant women. Its name comes from what happens after a good feed. You sleep.
Richard says fat eels indicate clean water and stable riverbanks. Erosion occurs when the riverbanks collapse, and sediment enters the river. The ecosystem is disturbed.
Richard says “ko ngā mana o rō te wai” is Hinekorako, and paramount to every freshwater waterway’s ecosystem.
“Ko ngā makawe o Hinekorako he kohuwai.”
Kohuwai is a green aquatic moss that sways in gentle waterways, the hair of Hinekorako, a sign of clean water.
When the kohuwai disappears, Richard knows the water is in trouble. Hinekorako is warning them.
Successive cyclones over centuries have made the damage harder to ignore.
“I tēnei wā, nā runga i te kaha o tēnei mea te āwhā, pēnei i a Bola i tērā rautau, i a Gabrielle i tēnei rautau, kua silted katoa ngā kāinga o ngā mana o roto wai.”
Richard says some of the trees planted on regional council advice to control erosion have been uprooted, flung into the river and swept out to sea.
He is now researching other ways to hold the banks together. Harakeke is one of them.
“Inā ka haramai te waipuke, ka takoto te harakeke. Haere atu te waipuke, ka tū anō te harakeke.”
A break in the migration
At Tongariro, Ahurei Winitana and his boys are working with the longfin eels at the beginning of their freshwater lives.
Pua tuna, or baby longfin eels, arrive after a 5,000-kilometre odyssey across the Pacific, then make their way up the Whanganui River through swamps, streams and creeks towards the cold, fresh waters of Tongariro.
Kei te neke, kei te nuku te wai.
Hydro development changed the natural flow of those waterways, and the lagoon they once migrated to no longer exists. At the Ōtamangākau dam outlet, their upstream migration comes to a halt.
By law, hydro companies must trap the baby longfins and transfer them upstream.
Ahurei is contracted by Genesis Energy and the Department of Conservation to manage and monitor the migration.
During the pua tuna season, Ahurei and his sons check the trap each day, scoop and count the baby eels, then transfer them to Lake Ōtamangākau.
The whānau are direct descendants of Paramount Chief Horonuku Te Heuheu Tukino IV, who gifted the Tongariro National Park to the nation.
Ahurei says the responsibility comes naturally.
As they grow older, his sons will understand why their whānau does this work.
This season, 2026, there are fewer pua tuna.
“Kāore i te nui. Āhua ā-mano nei. Engari kāre e rau mano nei.”
Ahurei doesn’t know why.
“I runga i te hē o ngā hau pea, i runga i te hē o ngā wai. Kua āhua heke ngā nama o ngā tuna.”
The monitoring may reveal answers; meanwhile, the pua tuna must adapt to the dangers of their new home.
At Ōtamangākau, longfin eels are confined in the lake. Ahurei and his team monitor the eels, from the babies to the 70-year-old mature eels ready to migrate back to the Pacific to spawn.
He has found eels shredded after being sucked into turbines.
Ahurei knows what changes he’d like to see.
“Mehemea he ture me uru mai, koirā tētahi ture, me kaua koe e patu i ngā māmā.”
A single female can carry one to two million eggs.
“Ka patua e koe tēnā tuna, koinā te mutunga o tēnā rangai whakapapa.”
The final time he helps the migration is by truck. When the eyes of mature eels turn blue, they’re ready to migrate.
They are released downstream, over an Intake, and follow the Whanganui River to the west coast, and cross into the Pacific.
At Te Reinga, Richard continues watching, monitoring, recording and remembering practices to restore ‘te mana o rō te wai’. ‘Our footsteps are on the land and our handprints on the water.
We therefore have a duty of care for the water full in the knowledge that these obligations will pass to our children on behalf of their children when we are gone’. (Affidavit of Richard Niania, in support of the Ngai Tahu freshwater High Court case).
