Helping hand for eel life in Otamangakau

Students from Te Kura o Hirangi in Turangi had the opportunity weigh, measure and look at the eel before she was released to migrate to the sea.

Years ago a tiny elver, a baby eel, crossed the Pacific Ocean to the mouth of the Whanganui River.

From there, she made her way upriver, over obstacles and rapids, evading danger and predators at every turn. Finally, she arrived at a wetland lagoon in the Central Plateau. Here, she was safe.

Over the years she grew. Eventually, at the age of around 60, she reached sexual maturity and was seized by the urge to migrate, back to the sea, back to the place she was born to spawn, and then to die.

But in the intervening years something had changed. The swamp had become a lake, built to store water for the Tongariro Power Scheme. She was trapped.

Until recently. Lured by a tasty bait of cat food, she swam into a hinaki (net) and was trapped. The net was pulled in and there was a group of school children from Te Kura o Hirangi in Turangi, waiting to meet her and learn about eels.

On a patch of damp grass she was carefully lifted out, weighed (5kg) and measured (1.1m). Local eel expert Lena Morgan of Nga Puna Toi Ora Ki Tuwharetoa explained to the students that this eel is a long-fin female eel, estimated at between 60 and 70 years old and ready to migrate.

"Her eyes are glassy and blue which means she's migrating and her skin is wrinkly. She's probably got like two million babies in her, this beautiful girl."

Once the eel has been studied, she is taken on the five-minute drive to the Whanganui River headwaters and released, along with a karakia and the students' aroha.

This work of trapping and releasing migrating eels has become a crusade for local Ngati Hikairo couple John and Lena Morgan.

Lena Morgan shows a female migrating long-fin eel, estimated at around 60 years old, to students from Te Kura o Hirangi in Turangi.

For years, the people of Ngati Hikairo, a hapu of Ngati Tuwharetoa, would gather long-fin eels, known by their Maori name of tuna. The area between Mt Tongariro and the Whanganui River housed tuna in its waterways, and the flat land in between had swamps and lagoons inhabited by native fish such as long-fin eels, koaro and inanga. Eels would swim up the Otamangakau Creek to what was then the Otamangakau Lagoon. After the advent of the power scheme it became Lake Otamangakau. The lake had a fish screen area to prevent the eels migrating further upstream and the hapu continued its custom of gathering them, this time from the areas where the eels would collect when it rained. But over the 40 years since the scheme went in the numbers of eels dropped, from 50 or 60 eels every rain event, to only 20 or 30 annually.

In the past, little was known about eels. It was not until recent years that scientists discovered that the eels are long-lived and slow-growing, that they migrate to sea to spawn, and that they spawn only once. People began to realise the eels were in decline. Without the opportunity to migrate, they would eventually die out.

John Morgan of Ngati Hikairo saw the problem. With iwi and hapu support, he approached Genesis Energy and explained the eels were trapped in the lake and had no way of migrating back to sea. The company agreed to help fund a tuna restoration project to support the eel stocks and the culture of Ngati Hikairo; and John and Lena established Nga Puna Toi Ora Ki Tuwharetoa to support their passion for looking after and protecting the eels.

John Morgan of Nga Puna Koi Ora Ki Tuwharetoa with an eel. He is pictured with Te Moko Isherwood (left) and Manaariki Dunn-Albert from Te Kura o Hirangi.

They began by removing the mature migrating eels from the lake and transporting them a few kilometres away to the headwaters of the Whanganui River to be released.

Genesis put in an elver ramp at Lake Otamangakau which collects the baby eels migrating upstream in a tank. From there, John and Lena move them into the lake and rivers where they can continue their growth. Genesis is also putting in eel passes on structures on the larger rivers to allow the elvers to move upriver easily although on the smaller streams John and Lena will continue transferring them manually.

Cam Speedy of Genesis Energy says around 11,000 elvers have been transferred during the five years the project has been running and John and Lena's efforts have gradually restocked areas where the eels have been in decline. Genesis also funds eel expert Jacques Boubée to provide technical advice to the couple.

Jahkasha-Rose Graham-Warena (left) and Paekitawhiti Te Moho release a migrating eel into the Whanganui River headwaters. John Morgan is behind them in the high-vis vest.

Cam says it's interesting that elvers are less inclined to migrate up rivers where there are few eels and the scientific theory is that the adult eels release pheromones that the elvers follow, although more work is being done in this area.

"Matauranga Maori [Maori knowledge] probably knew this already, and the beauty of this project is we are matching modern ecological science of eels with the knowledge that John's family have developed over generations at that site. It's the power of two knowledge systems together and that's one of the real buzzes of this project."

As well as moving eels and elvers around, longer term, John and Lena have been undertaking eel surveys within the five waterways on the lower slopes of Mt Tongariro. With help of Turangi-based consultancy firm Poipoia Ltd, Ngati Tuwharetoa Fisheries Trust applied to the Ministry of Primary Industry's Customary Research Fund to fund a Pataka Tuna Project and the first stage is establishing a good data base of eel populations and migration.

The Morgans have also been running wananga [workshops] training rangatahi in eel monitoring and measurement and the Ngati Hikairo tikanga around eels.

Long term, the goal is to establish a traditional Pataka Tuna (eel population) in Lake Otamangakau for customary monitoring and tuna harvesting.

Lena says her whanau have always hunted and gathered kai and lived off the land, and restoring the eels will allow future generations to do the same.

"Now we're teaching the rangatahi the kaitiakitanga and they learn all the other stuff, the whakapapa and the whanau and their connection to it." She says with eels such a long-lived species, it will take years to see results but ultimately it will benefit the children and their children.

"We're not doing this for us, we're doing this for the eels and for the hapu ... it's about educating the kids."