Lake Aroarotamahine, also known as Green Lake, is one of two small crater lakes on Mayor Island / Tuhua in the Bay of Plenty, New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

. Its outlet is a wetland leading to the smaller Lake Te Paritu

Lake Te Paritu

Lake Te Paritu, also known as Black Lake, is one of two small crater lakes on Mayor Island / Tuhua in the Bay of Plenty, New Zealand. It is connected to the larger Lake Aroarotamahine or Green Lake by a wetland, but there is no surface outlet to the sea as both lakes are in a depression.The lake...

 or Black lake.

The lake has a green colour due to algae. According to Māori legend, the green is the blood of Pounamu (greenstone) which fought a battle with Tuhua (obsidian), and, defeated, fled to the South Island.