The first shipment of Mackinaw trout – Salvelinus namaycush (also known as lake char or lake trout) arrived in New Zealand in 1906. They were released into two small Canterbury high country lakes near Arthur’s Pass, lakes Grasmere and Pearson – about 125km from Christchurch city.
The original plan was to release them into Lake Kaniere on the West Coast but due to transport problems, it was decided to release them into these small lakes on the way to lake Kaniere! They became established in these lakes which is quite surprising because the conditions are far from ideal. This species prefers very cold water and these lakes heat up too much during high summer.
Although the Mackinaw released into the smaller Lake Grasmere died out they have survived in Lake Pearson. However, the fish are small and in poor condition weighing less than a kilogram.
Some years ago an attempt was made by the then North Canterbury Society and the Southern Lakes Wildlife Conservancy to restore the stocks in Lake Pearson. Mackinaw were caught from Lake Pearson and taken to the hatchery in Wanaka where their condition was restored, and offspring were later returned to Lake Pearson to reinforce the stock. This brought only temporary respite for Mackinaw trout in Lake Pearson as the species in this alpine lake is still in poor condition with only small fish. In summer when the water gets too hot the Mackinaw retreat to the deepest part of the lake but it is only 17m at its maximum depth.
Your best chance of catching a Mackinaw in Lake Pearson is early in the season when the lake opens to fishing on the first Saturday in November. At that time of year the water is still very cold and the fish more active. Unfortunately, as the fish are so small and thin they are disappointing to catch. There has been interest in this species in the past because it grows to an enormous 46kg in its native North America.
Mackinaw trout are most unusual in that they don’t dig redds in the stream-bed. Adults fish use their tails to move mud and silt from the stone on the lake-bed and then the eggs are released over the clean gravels where they sink in among the stones and rocks. Like other salmonids, spawning occurs in April and May.