Gazetted in 1993, the Te Whanganui A Hei (Cathedral Cove) Marine Reserve covers a total of 9 square kilometers
and became New Zealands sixth official Marine Reserve.

The Reserve is administered by the Department of Conservation in partnership with the Te Whanganui-A-Hei Marine Reserve Commitee, whose vision is of a well managed reserve, bountiful in marine life and respected and enjoyed by the public for generations to come.

It was chosen for a Marine Reserve because of the vast array of habitats and inhabitants associated with the coastline and outlying islands. Reefs, caves, archways and soft sediments provide the ideal playground for a variety of plants, fish, moluscs and crustacea. the Reserve is sheltered from the worst of the southerly winds and so provides visitors with a safe haven to enjoy an unspoilt marine enviroment.