Trout or salmon at Lake Taupo, New Zealand?

Trout cookery in New Zealand has largely been pursued by anglers and amateurs instead of professional chefs since the trout is not a commercial item, it not being sold in the shops. This has come about by the Government banning the development of trout farms in order to protect the sport fisheries from the spread of disease. A compromise was made by allowing the development of salmon farming which is now a thriving business operating in sheltered coastal sea waters of the Marlborough Sounds in the South Island and the Firth of Thames in the North Island.

Rainbow trout were introduced into Lake Taupo about 1889. They are the migratory steelhead variety of rainbows from the Russian River, California. The fish now consider Lake Taupo as their personal sea in which to live, from which they migrate up the inlet rivers to spawn in the highlands. Also about this time salmon were introduced into the rivers with success limited to some rivers in the Canterbury Province of the South Island, particularly the Waitaki and Rakaia Rivers. Each year anglers await the return of these salmon from the Tasman Sea to spawn in the rivers. Anglers fish the river mouths and lower reaches for the King salmon, or Chinook aka Quinnat variety (Oncorhynchus tshawytscha) known to grow to 150 cm length and up to 60 kg, although 15 kg is huge for a NZ fish. This is the species of salmon that is farmed in floating cages in New Zealand, unlike in Norway and Chile where Atlantic salmon is farmed and is of a different Genus (Salmo salar). The Atlantic salmon is frequently landlocked in Chilean and Argentine lakes.

The Taupo rainbow trout was originally classified as a trout (Salmo gairdnerii) and brown trout as (Salmo trutta). Further study by biologists has reclassified the rainbow trout as a salmon of the Genus Oncorhynchus of which there are a dozen species in the northern Pacific region, the better known being the Coho, Sockeye, Chum, Pink salmon and now Steelhead salmon. I wonder whether the NZ Government has to check their legislative ban on trout farming, but to allow salmon farming, to see whether it does exclude the Taupo Steelhead Salmon (Oncorhynchus mykiss) aka rainbow trout?