The Fish

Brown Trout - Salmo trutta

Brown trout originated in Europe and have been distributed to many other parts of the world including USA, South America, Australia and of course, New Zealand. After several abortive attempts, brown trout ova were imported from Tasmania in 1867. These trout had been originally brought in from England. They were initially distributed in Canterbury, Nelson and Otago. Further shipments were later obtained from Tasmania and also from England, Scotland, Germany and Italy. They went to Auckland, Dunedin and Invercargill and then to anywhere that acclimatisation societies had been established. Most of these organisations had their own hatcheries so the ova were soon hatched and the fingerlings placed in local streams. Huge efforts went into transporting the ova to remote rivers and it is interesting to speculate just what drove these pioneers to take so much time and trouble to distribute the trout far and wide. By 1916, 50 million brown trout had been released into New Zealand rivers and streams. There was a huge variety in the sources of the original ova stocks. Some were river fish, others lake trout and a few from sea-run strains. It is now considered that all these types have been so intermingled and interbred that the brown trout of today is a mixture of all its forebears. Some trout still seem to display the original sea-running traits of that European sea-trout, especially in the South Island. These sea-run browns have a distinctive silver colour and so are quite different in appearance to their river-dwelling cousins.

Flaxy Lake Brown Trout Click for full view

This stocking of waterways by the various acclimatisation societies continued up until the 1980's by when most of the societies no longer maintained a hatchery. The last one in operation was the Hawkes Bay hatchery and that closed down in 2000. Basically the reason for these closures was a change in belief about the success of the earlier policy of stocking rivers. Over the past 20 years, NZ fish scientists have reached the conclusion that improving the trout habitat is much more productive than stocking rivers with hatchery fish. If the rivers are in poor condition, then stocking will not help as the river just cannot support a reasonable trout population.

Rainbow Trout (Oncorhynchus mykiss)

The rainbow trout originated in the mountain rivers of western North America from the Aleutian Islands in the north down to northern Mexico. They are now widely distributed throughout the world, having been first introduced to New Zealand in 1883. Originally it was believed that the first shipment came from the Russian River in California. Subsequent evidence has cast doubt on this assertion and it is now considered that the first shipments came from a hatchery on Sonoma Creek near San Francisco. Later shipments came from McCloud and Shasta Rivers, both of these being steelhead trout rivers. There is some considerable debate whether sea-run rainbows, commonly known as steelhead, are a separate genus or not. It is now considered that all rainbows belong to the same species and have now been given the name Oncorhynchus mykiss, replacing the previously used, Salmo gairdneri.

Waipunga Rainbow Click for full view

Most rainbows display a tendency to run up a river or tributary of a river to spawn. Many are lake-based and run up the rivers feeding the lake to spawn. The best example of this in the South Island is Lake Te Anau. This particular spawning tendency may be due to the nature of the strains of trout originally imported or it may be just a natural tendency of rainbow trout. It is also believed that there were imports of ova from Kootenay Lake in British Columbia. These `Gerard' strain trout are known for their rapid growth rate, similar to that of many trout in New Zealand lakes.

Food & Flies

The most common aquatic insects found in mountain rivers are as follows:

Common Name Scientific Name Nymph Adult

Brown Mayfly Deleatidium myzobranchia Pheasant Tail March Brown
Brown Mayfly Deleatidium vernale Furry PT Dad's Favourite
Mayfly Coloburiscus humeralis Tonga Kakahi Queen
Mayfly Nesameletus spp. Grey Darter Kakahi Queen
Mayfly Orniscigaster spp. Speckled Twilight Beauty
Horn Caddis Olinga feredayi Horn Sedge
Cased Caddis Pycnocentrodes Cased Caddis Sedge
Woolly Caddis Aoteapsyche Woolly Caddis Sedge
Green Stonefly Stenoperla prasina Green Stonefly
Brown Stonefly Aucklandobius Brown Stonefly
Black Stonefly Austroperla cyrene Black Stonefly
Green Beetle Pyronota festiva Green Beetle
Dobsonfly Archichauliodes diversus Creedons Creeper
Cicada Hemiptera Cicada
Willow Grub Pontania proxima Willow Grub
Midge Pupa Chironomus spp. Midge Pupa
Green Beetle Pyronota festiva Green Beetle