To slip through the mirror-glass waters of New Zealand’s fiords is to enter a world of unusual creatures which divers rarely see elsewhere. Three factors combine to create the unique environment.
First, the Continental Shelf is very close to the Fiordland coast. As a result, the larvae of deep water organisms which live beyond the shelf have the opportunity to be carried by currents into shallower water in the nearby fiords. Their ability to grow in these new habitats is made possible by two other features. The very high rainfall in the area, coupled with the sheltered the surface of the sea. Frequently, this water is stained tea-brown as it trickles through the Fiordland forest, picking up chemicals from decaying vegetation.
The effect is to significantly reduce the amount of light penetration into the sea, and this allows normally light-shy creatures to live at shallower-than-usual depths. The most famous example is black coral. Typically, this type of coral is found at depths exceeding 40m, but the Fiordland species, Antipathes fiordensis, is found within snorkelling depth. Sea pens (shown here being photographed in Doubtful Sound) also inhabit shallow water only in Fiordland.
Black coral, once heavily exploited for use in jewellery, now enjoys legal protection, but it is one of only two invertebrate species which, by virtue of vulnerability, are safeguarded. Conservationists argue that, rather than protecting individual species, the Fiordland marine environment itself should be protected by means of a network of marine reserves.
At present, two small areas have been proposed as marine reserves: the northern side of Milford Sound and a channel near the entrance to Doubtful Sound known as The Gut.
It is likely that further sections of this unusual piece of coastline will be recommended as reserves or parks in the future.