Auckland's Big Blue: Te Moana-nui-a-Toi

The ocean connects us all. On World Ocean Day, we celebrate the moana and reflect on our role in protecting it. Inspired by Ngā Huhua: Abundance, this article explores Te Moana-nui-a-Toi, Auckland's Big Blue Backyard, and what abundance means for the future of our oceans.

By Kate Waterhouse | 8 June 2026

If you travel by boat to the islands of the outer Hauraki Gulf, you may notice the sea changing colour—from the green waters of the inner Gulf to a deep, oceanic blue. If you're lucky, you'll be joined by a pod of irrepressible, stripey aihe (common dolphins) riding the pressure wave at the bow of your vessel, while gannets and shearwaters gather overhead, waiting for dinner to appear. Below the surface lies another world entirely.

This is Te Moana-nui-a-Toi—world-famous water, just beyond the horizon of Auckland, Aotearoa New Zealand's largest city. More than a quarter of the world's dolphin and whale species have been sighted here. It is a global hotspot for seabirds, with more than 28 breeding species. The area is also recognised as an Important Shark and Ray Area (ISRA), known for encounters with oceanic manta rays, as well as sunfish, seals, turtles and whale sharks.

It is extraordinary water and renowned among marine scientists. Te Moana-nui-a-Toi is named for Toi Te Huatahi, who according was among the earliest navigators to sail these waters around 1250 AD. Following the paths of seabirds and whales from the Pacific Islands, Toi and his people arrived in one of the world's most productive marine environments. For these first arrivals, the sight and sound of countless birds, waters teeming with fish and seals, and large gatherings of whales and dolphins must have been overwhelming.

Today, this place still contains all the ingredients for abundance. The combination of islands, seasonal winds, and warm currents mixing with cooler continental shelf waters creates ideal conditions for life to flourish. From microscopic phytoplankton and krill to pygmy blue whales, the food web here supports an extraordinary diversity of species. Fish range from small schooling pilchards to mako sharks, among the fastest sharks in the world.

At the base of this abundance are the smallest organisms. Phytoplankton feed zooplankton such as krill and copepods, which in turn feed fish, seabirds and larger predators. Before long, a feeding frenzy erupts. These spectacular events—known as workups—are one of the defining features of Te Moana-nui-a-Toi.

It is no surprise, then, that Te Moana-nui-a-Toi encompasses the deepest waters of the Hauraki Gulf Marine Park, often described as New Zealand's national park of the sea. Established in 2000, the Marine Park recognised the Gulf's ecological significance. More recently, parts of the area have received stronger protection through the establishment of High Protection Areas, where fishing is no longer permitted.

Yet these protections alone may not be enough to restore the abundance that once characterised Auckland's Big Blue Backyard. Decades of fishing pressure, habitat disturbance, warming seas, ocean acidification, and other human impacts have placed increasing strain on the ecosystem.

The tohu, or signs, are already visible. Workups are less frequent than they once were. Seabirds such as kororā (little penguins) and northern pākahā (grey-faced petrels) face growing challenges in finding food. The moana may still appear as blue as ever, but many who know it best say it needs time and space to recover.

To understand what abundance truly means, we must look to the memories and knowledge of those who have lived alongside this moana for generations. Opo Ngawaka, a kaumātua of Ngāti Rehua and kaitiaki of these waters, remembers a Gulf filled with migrating whales, vast flocks of seabirds, constant workups, and crayfish in every crevice of the reef. Reflecting on the changes he has witnessed, he wonders how future generations can understand what has been lost if they have never seen it for themselves.

Will our children's children know abundance as something real, rather than a story told by their grandparents? That is the question being asked by kaitiaki, scientists, conservationists, and communities who care deeply for Te Moana-nui-a-Toi. The decisions we make today will shape the future of this moana. Protecting its mauri—its life force—means ensuring that future generations inherit a thriving ocean, rich in life and possibility.