Ōnuku Rūnanga turns invasive seaweed into sustainable export to protect Akaroa Harbour

In a significant move for both the local economy and marine conservation, Ōnuku Rūnanga has launched a commercial harvest of invasive undaria seaweed from Akaroa Harbour. As reported by the NZ Herald in October 2026, the partnership between mana whenua, Premium Seas, and Ceres Organics aims to turn an ecological threat into a high-value export commodity known globally as wakame. Undaria pinnatifida, an invasive species present in the harbour since the 1990s, has long threatened the local ecosystem by outcompeting indigenous macrocystis (giant kelp). Ōnuku Rūnanga chairman Rik Tainui explained that the seaweed acts like gorse, swamping areas traditionally used for mahinga kai. Because the seaweed releases spores when disturbed, traditional removal methods are often ineffective and prohibitively expensive. This new initiative creates a circular economy where the commercial sale of wakame funds its own removal, allowing native ecosystems to recover. The project reached a milestone in 2026 with its first commercial harvest. Lucas Evans, chief executive of 50/50 venture partner Premium Seas, oversaw the processing of mature undaria, which is valued for its savoury umami flavour and mineral content. The collaboration began after Tainui and Carmelle Hine-Mārama of Ngāti Tūwharetoa met Hayley Fraser-Mackenzie of Ceres Organics at a national seaweed conference. For Tainui, the project is about more than business; it is about restoring the health of Te Pātaka o Rākaihautū—the great food storehouse of Rākaihautū. He noted a significant decline in fish numbers since his childhood at Ōnuku in the 1950s. By harvesting the invasive undaria, the rūnanga (Ngāi Tarewa) hopes to create space for the fast-growing indigenous macrocystis to flourish, ultimately supporting the return of a thriving marine environment for future generations.