Diving Milford Sound

Diving Fiordland / Milford Sound

Few visitors to Fiordland are aware that below the tide line there is another world with its own fauna and flora. Much of the uniqueness is caused by the light-absorbing fresh water layer that restricts algal growth and allows deep water or light avoiding species to become established in shallow water. Below this freshwater layer the sea water is calm, very clear and relatively warm, with annual temperatures of 12-16°C (54-61 °F). This narrow temperature range throughout the year permits subtropical forms to exist. 

Black coral is known to occur at a few offshore islands of New Zealand, usually in depths greater than 45 metres (150 feet), but has been found in abundance in the waters of Fiordland from a depth of 5 metres (16 feet). Red hydro-corals are found from a depth of 15 metres (50 feet). The saucer sponge and the large tube anemone, usually considered to be a deep water species (100-200m or 330 to 650f deep), are common in water less than 20 metres (65 feet) deep in the fiords.

Approximately 160 species of fish have so far been recorded by divers within the surface 45 metres (150 feet) of the fiords. Warm water species include splendid perch and blue-dot triplefin. Cool water species include copper moki, trumpeter, banded wrasse and pigfish. Species usually confined to deep water (100m or 328f plus) include sandpaper fish and spiny sea dragons.

SPECIAL NOTE: Milford Sound has a post dive altitude consideration. For safety requirements we recommend planning to stay overnight following diving to reduce nitrogen levels before travelling to altitude on the Milford highway at 945m (3,100f).