Stewart Island might aptly be described as a detached piece of the South Island south-west, separated from the mainland by the shallow Foveaux Strait. The width of the strait varies from 17 to 30 miles and its depth is less than 20 fathoms. Within it is a string of rocky islets; the largest of these is Ruapuke.
The main island is roughly triangular in shape with its longest side facing west and the two shorter facing north-east and south-east respectively. The total land area, lying between 46° 40' and 47° 18' S and between 167° and 168° 20' E, is approximately 670 sq. miles. Coastlines are very ragged, deeply penetrated by the branching Paterson Inlet in the north and Port Pegasus in the south, and are fringed by rocky offshore islets.
From the head of Paterson Inlet, the Freshwater valley occupies a fault-bounded trough that divides the island into two quite distinct parts. In the north is the complex rugged highland containing Mt. Anglem (3,214 ft) and made of coarse basic igneous rocks. Almost all the rest of the island is made of granites with some schists in the neighbourhood of Pegasus. In 1888 special interest in this granite and schist country about Pegasus was aroused by the discovery of tin which has been mined sporadically with very little success. The only extensive flat alluvial lowland is in the swampy valley of the Freshwater River. This lowland reaches almost right across the island to within 2 miles of the west coast from which it is separated by a belt of low hills.
The south-west arm of Paterson Inlet reaches 6 miles inland and passes into the valley of the Rakeahua River. Aligned more or less parallel to this valley is a rugged axis with a steep face to north-west and a more gentle slope to the south-east coast. This axis reaches from Paterson Inlet to Pegasus Bay and in this south-eastern sector of the island are bare granite ridges and rounded tops (exfoliated domes). The highest point is Mt. Allen (2,459 ft). This rugged area resembles a tilted granite plateau, its surface deeply dissected and scoured by ice and its margin drowned to produce the intricate coastline about Port Pegasus.
Climatic data for Stewart Island is scanty but records from Halfmoon Bay show the average rainfall there to be 57 in. per annum, evenly distributed through the year. Summer temperatures seldom rise to 70°F but winter temperatures rarely fall below freezing point. Mean January temperatures are around 54°F, and mean July temperatures 39°F. Strong winds are frequent, especially from the west, and calm days are as rare as heavy frosts and prolonged snowfalls.
The frequent strong cold winds with driving rain seem to have conditioned the kind of indigenous vegetation. These main types of cover may be recognised according to local conditions of climate, exposure, and soil: lowland swamp and heath; lowland scrub; rain forest; tall subalpine scrub; and short scrub and boggy meadowland of the “tops”. The scrub is mainly manuka, but the rain forest of limited sheltered areas, notably in the vicinity of Paterson Inlet, once contained useful timber trees, notably rimu with some totara. Most of the tall timber has been cut out and deer are hampering regeneration as well as damaging such patches of uncut forest as remain.
Captain Cook sighted Stewart Island though he did not sail around it to find Foveaux Strait. It is after William Stewart that the island is named; he set up a short-lived colony of Europeans at Port Pegasus in 1826. European settlements and contacts have been concerned mainly with sealing (1801–50); whaling (1830–80); timber felling and milling (1865–1930); gold (1866–80); and tin (1888–1912). Settlement that has lasted to the present day is associated with fishing, farming, oysters, and mutton birds. The residential and holiday township is Oban, on Half-moon Bay.
Mining for gold and tin was soon found unprofitable, and farming has had only meagre success. Climate and topography have made it difficult to clear the land and keep it grassed for livestock, and the resources of accessible millable timber were always limited. So Stewart Island and the seas and islets about it have become best known for their fish, oysters, and mutton birds, and for the residential and holiday resort at Halfmoon Bay. The Fiordland -Foveaux Strait – Stewart Island area is New Zealand's chief source of crayfish and blue cod, and the fishing industry, directly or indirectly, supports most of the population of Stewart Island. The main Foveaux Strait oyster beds lie between Bluff and the north coast of the island, but this industry is mainly based on Bluff. Mutton birds have long been an important food for the southern Maoris who have control of the mutton birding rights. The birds taken are the young of the sooty petrel (Puffinus griseus) that nests in burrows on headlands and offshore islands of the south-west coast. Through April and May the young birds are killed and preserved for sale.
Most of the permanent residents of Stewart Island live in the township area about Halfmoon Bay. Of the 350 people there in 1962, about 15 per cent are retired men and women and some 36 per cent school children. As some 40 per cent of the residential buildings are holiday houses or cottages, this resident population is much increased during the summer. Halfmoon Bay is the chief holiday base.
Stewart Island was known to the Maoris as Rakiura, “The Island of the Glowing Sky”. It received its present name from William Stewart who was first officer of the brig Pegasus which called there in 1809.
by George Jobberns, C.B.E., M.A., D.SC., Emeritus Professor of Geography, University of Canterbury.
- Report on botanical survey of Stewart Island, parliamentary paper, Department of Lands, Cockayne, L. (1909), (gives much information on topography)
- Rakiura (a detailed history of all aspects of the Island), Howard, B. (1940)
- Geographical Journal, 87