Nga Rauru people on their annual river journey are learning how to monitor freshwater quality.
Scotty Moore and fellow Conservation Department (DoC) ranger Laurance Williamson are with a group of 60 as they travel the Waitotara River. It's the fifth Waitotara Awa Hikoi undertaken by the South Taranaki iwi.
Usually the trip starts further upriver at Trains Hut in the Waitotara Conservation Area. This year they couldn't get there, because the track was damaged in June's heavy rain.
Instead they're extending the downriver end to stay at Waikaramihi, a tribal fishing spot on the coast between Waiinu Beach and Snapper Rock.
There are 60 people registered for the trip, camp co-ordinator Ruta Broughton said, with some travelling in canoes and others driving to overnight stops.
"We all acknowledge this awa here as ours as Nga Rauru, and that's why we're here."
The cost is paid by the Te Kahui o Rauru board, which she is a member of.
The DoC rangers provide a vehicle and trailer and some canoes and safety gear. They paddle along, ensuring safety, and also offer workshops. This year people will be asked to think about why they value the river, what threatens it and how to protect it.
It's the second time Mr Moore has been on the trip.
"I feel really honoured to be invited back to join the hikoi. We really value our relationship with Nga Rauru Kiitahi," he said.
Trip co-ordinator Mark Pirikahu said DoC was important to the iwi. Its people used to live along the river. Some still owned land there but many had gone.
"They (DoC) have been looking after our assets for quite some time. Since (our Treaty of Waitangi) settlement they have been a great source for us on keeping us up to date with how things are happening in the environment."
The group started its journey at Takirau Marae further upriver on Saturday. Its members had an introduction and safety talks there, and spent two nights. Last night was spent at Puao, camping at the Belton homestead.
"We have heard this is a significant site," Mr Pirikahu said. A "cultural advisor" was due to arrive that evening, to tell the site's story. After that it was down to Waipapa Marae and then the Waitotara township, past Kaipo Marae, the river mouth at Tapuarau and the coast at Waikaramihi.
Mr Pirikahu also co-ordinates the annual river journey of Nga Wairiki/Ngati Apa on the Whangaehu. It starts at Tukino Skifield with four days in the Ruapehu District.
"You can talk until the cows come home, but taking our people to see these places is of more benefit," he said.