Various species of European and American game fish have been introduced into New Zealand with a view to establishing sport fisheries, because indigenous fish, except for the grayling (Prototroctes oxyrhynchus), which disappeared soon after settlement, were not suitable as sport fish. Today brown and rainbow trout (Salmo trutta and Salmo gairdnerii) and quinnat salmon (Onchorhynchus tschawytcha) provide most of the angling, but some perch (Perca fluvitalis) and a few Atlantic salmon (S. salar) are also taken.
Brown and rainbow trout have been introduced into rivers or lakes throughout New Zealand and are established in most waters suitable for them. Trout require hard gravels in which to spawn. In many lakes, where spawning conditions are lacking or inadequate in tributary systems, stocks of trout, usually rainbow, are maintained by releasing finger-lings either annually or every second year. Releases are made in certain of the Rotorua lakes and the coastal dune lakes of the North Island, and some of the back-country lakes of the South Island.
Trout have not established satisfactorily north of a line from East Cape through Thames and Huntly, probably due to the high winter temperatures. Between this line and another from North Taranaki to Hawke's Bay, rainbow are the principal sport fish, and south of this line, except for the Rangitikei River, and the back-country lakes of the South Island, brown are dominant. Browns are present in the Rotorua lakes and Lake Taupo, but they are more difficult to catch and therefore not really sought after by anglers. Suitable spawning conditions are not present in the papa areas of the east coast of the North Island, or from Wanganui through to Waitara, nor in the dune areas of the west coast of the North Island. Papa streams, if stocked, could carry limited stocks of trout.
Rainbow trout average 2–3 Ib in weight, and brown taken from the Rotorua lakes and Lake Taupo about 6 Ib. Browns from the North Island rivers average 2–3 Ib, but those taken in the more rugged country of the South Island, west of a line from Cape Campbell to Te Waewae Bay, where they are less numerous but larger, average 3–4 Ib. East of this line numerous, but small, browns are taken averaging 1–2 Ib in weight.
Most waters give catches of one to three fish per day (or 0.25 to 1.0 fish per hour), or the weight of fish taken is usually between 0.5 and 2 Ib per hour.
Quinnat salmon are taken between January and April from the rivers of the east coast of the South Island between the Waiau and the Clutha, but the Rakaia, Rangitata, and Waitaki Rivers are the principal salmon waters. The quinnat are taken by anglers as they run in from the sea and up the rivers on their way to the spawning grounds near the foothills of these snow-fed rivers. Perch are available in the south-east of the South Island, and the south and west of the North Island principally. They are taken during the normal angling season, but lakes on the west coast of the North Island have been opened for perch fishing over the winter period, when they can be more readily caught.
The fishing pressure is greatest in the south-west of the South Island and the centre of the North Island, being light in the extreme north and west of the South Island and negligible in North Auckland. The total amount of angling done in the South Island (about 660,000 hours per season) is about three-quarters of that of the North Island but three-quarters of the North Island effort is concentrated in the Taupo and Rotorua districts.
New Zealand's sport fisheries are managed by acclimatisation societies, and the Department of Internal Affairs acts as an acclimatisation society in the Rotorua, Taupo, and Southern Lakes districts. An angling licence is required and the fees are payable to the local society. During the 1962–63 angling season about 32,300 men's whole-season licences were issued; women's, boys', and short-term licences were also available, and the total angling revenue was about £181,800.
The angling season is usually from October to April where brown predominate, and November to April or later for rainbow waters, with the closed season occurring when trout and salmon spawn, i.e., usually from May to September. Lure restrictions, bag, and size limits may be varied in each acclimatisation district. As research work is completed, if local game-fish populations can stand increased exploitation, restrictions are relaxed and/or the season extended, e.g., Lakes Taupo and Rotorua are open all the year and certain other waters in the Rotorua and Southern Lakes Districts are open for angling for more than seven months.
Basic research on game-fish populations, mainly brown and rainbow trout, is carried out by scientists of the Marine Department on behalf of the acclimatisation societies and the Department of Internal Affairs. Departmental advisory officers assist with the implementation of research findings and undertake, where necessary, local investigations on angling populations to assist the particular society manage its fisheries efficiently.