With few big snapper or crayfish left to eat them, the kina population had exploded. They were like "seaweed mowers," eating everything in their paths and leaving bare rock where there had once been thriving ecosystems.
As a dive instructor, Mr Rutene spent a lot of time under water, so saw first-hand what was happening.
Maitai Bay was not the only place with kina barrens, he said, but it was ideal for a rahui because it was sheltered, water depth ranged to almost 100m, and it could be easily monitored.
Reaction so far had been "very respectful," he said. Before the rahui there had been spear fishers and kayak fishers in the bay almost every day; now there were almost none.
The emphasis was on education, not enforcement, hapu members taking turns to hand out pamphlets and talk to boaties. Signs had been erected at beach access points, and the Department of Conservation, which supported the initiative, was giving pamphlets to everyone at its campsite.
"People have respected it. They understand what we're trying to achieve. They agree, and they support it," Mr Rutene added.
Unlike the rahui at Deep Water Cove, in the Bay of Islands — a hapu initiative now enforced by the Ministry for Primary Industries — the Maitai Bay declaration did not have legal status, so anyone who broke it could not be prosecuted, but Mr Rutene believed the rahui was effective even if it couldn't be legally enforced.
It was respected by most people, and made them think about their effect on marine life.
"It's embedded in people's minds now.
"They take what they need, not necessarily what they are allowed," he said.
A Haititaimarangai Marae subcommittee had been mandated to lead the rahui project, which took just over a year, including consultation, fundraising and pou carving, to launch.
Marine ecologist Vince Kerr had committed to monitoring the bay for any changes during the rahui.
The no-take zone's furthest point is currently a GPS location only, but the hapu plan to install a buoy, as well as markers on the land boundaries.
More than 60 people, including members of other iwi, kuia and kaumatua, and master waka builder Hekenukumai Busby, turned out for the December 20 dawn ceremony and unveiling of two pou carved by Darren Pivac.
The pou represent Kahutianui and her husband Te Parata, tupuna of Te Whanau Moana and Te Rorohuri.
The other side of the pou, facing the water, represent Hinemoana and Tangaroa, the female and male atua (gods) of the sea.
A small area of Waikato Bay, where local families have traditionally gathered food, is not included in the rahui.