[1][2] In the fiords, heavy rainfall runs off from the surrounding mountains creates a permanent freshwater layer to about 5 centimetres (2.0 in) to 10 metres (33 ft) below the surface.

A final layer of seawater, too darkened by tannins from vegetation run-off to support most marine life, extends to depths of up to 400 metres (1,300 ft).

[1] The eastern side of the reserve has an extensive rock wall, mostly facing south and shaded from direct sunlight, with vertical drops of 59–60 metres (194–197 ft).

[4] The reserve was part of a conservation strategy the Fiordland Marine Guardians launched in 2002 and presented to the Ministry for the Environment Marian Hobbs and Minister of Fisheries Pete Hodgson in 2003.

However, members of Ngāi Tahu may remove pounamu provided they have the right authorisation, only collect by hand, keep disturbance to the site to a minimum, and only carry as much as they can in one trip.