Freshwater Fishes

Rainbow Trout – Oncorhynchus mykiss – Identification Guide New Zealand

Rainbow trout were introduced into New Zealand as early as April 1883

Oncorhynchus mykiss

A brightly coloured magnificient rainbow jack trout in spawning colours. Photograph courtesy of Lance Gill and Fish The Drift NZ.

According to the late Bob McDowall in his book Gamekeepers for the Nation, early Auckland rainbow trout released probably came from Sonoma Creek, a small stream flowing into San Francisco Bay, in the United States of America. Once these fish were established in various Auckland waterways and at the Auckland hatchery, efforts were made to spread them around the country. Liberations of rainbow trout fry were made soon after in Lake Rotorua in 1892.

The first rainbow trout releases in Lake Taupo possibly occurred by 1897 when 5000 fish were liberated into the lake by the Wellington Society. Further releases were made into Lake Taupo by the Auckland Society in 1899, 1901, and 1902.

Rainbow trout from a Canterbury high country lake.

In 1888 Alec Johnson received 1000 rainbow trout ova from the Auckland Society in exchange for a similar number of brook trout. Johnson owned his hatchery in Opawa, Christchurch. It was from Johnson’s Troutdale Farm hatchery that other South Island Societies obtained stocks for release.

It is interesting to note that the records of where in the United States the ova came from for liberations in New Zealand, and exactly where and when liberations took place in this country are not as well recorded as one might expect.

Rainbow trout are the dominant species in the very successful, world-famous, central North Island trout fisheries. In the central North Island, the rainbow trout are landlocked. They spawn in lake tributaries and some smaller lakes. They also spawn along beach areas in Lake Rotoma, which lacks significant in-flowing or outflowing streams.

Allan Burgess with a typical rainbow hen trout from Canterbury’s Lake Selfe.

In the South Island, rainbows are mostly found in the high country lakes bordering the Southern Alps. The only other areas in the South Island where rainbow trout liberations have been successful are Wanaka, Hawea and Wakatipu, and some of the rivers adjacent to them.

Lake Benmore also has good numbers of rainbow trout.

The upper reaches of the big braided rivers like the Waimakariri, Rakaia, and others also offer high-quality rainbow trout fishing. Rainbow trout are generally absent from the lower reaches of these big rivers where brown trout tend to dominate. Rainbow trout are caught well downstream closer to the sea during wintertime.

Rainbows are often found in the same lakes and streams as brown trout. However, many fishing waters in the South Island hold brown trout only.

Dan Sweeney with a fat-looking rainbow trout taken near Lake Brunner. It seems this well-conditioned rainbow hen fish was taken in one of the rivers flowing into Lake Brunner: the Orangipuku, Hohonu or Crooked River. Possibly the water might also have been the outflowing Arnold River! Photograph courtesy of Brent Beadle’s Moana Trout Fishing Safaris.

Rainbow trout, in New Zealand, do not go to sea. Consequently, unlike brown trout, they have not spread naturally to inhabit waters where they have not otherwise been introduced. Hence, rainbow trout are less widespread than brown trout.

Interestingly despite numerous liberations of rainbow trout into New Zealand rivers, many of these releases have proven unsuccessful. It seems that rainbow trout prefer spawning rivers that flow into lakes.

In the central North Island, some of the best rainbow trout fishing occurs over winter when the trout run upstream from Lake Taupo to spawn in tributaries such as the famous Tongariro, Waitahanui, and Tauranga-Taupo Rivers

Rainbow trout grown from ova in New Zealand are the same strain of rainbow trout that are sea-running (known as “steelhead”) in their native North America.

For some reason, rainbow trout raised in New Zealand do not go to sea. Rainbow trout can tolerate higher water temperatures than brown trout. You must have a fishing license to fish for salmon, brown trout and rainbow trout in New Zealand.

Here is a little reading about rainbow trout on the Fish & Game website.

According to Wikipedia, the longest recorded lifespan of a rainbow trout is 11 years.

A brace of rainbow trout caught in Canterbury’s Lake Selfe. The top fish is a jack in spawning colours. The second is a much less colourful henfish. Note that these fish have spots on their tails while brown trout and quinnat salmon generally do not.
This is a rainbow hen fish weighing 4kg. It was caught in the Upper Clutha River, Central Otago.
Rainbow trout. A brood fish held at the Wanaka hatchery, Central Otago.
Warren Kemp caught this huge 8kg (17lb 8oz) rainbow trout in one of the Twizel Canals in May 2015. Click the picture to enlarge.

Rainbow Trout Coloration

The upper back is darkish green fading gradually to silver under the belly. There is a broad pink/reddish stripe along the full length of each side. There are many small dark spots on the whole of the upper half of the body, including the tail and dorsal fins.

Kelvin Derry with a Lake Coleridge Monster. It is an 11.2-pound rainbow jackfish taken while trolling with a blue Rapala. It was caught at 6.05 am January 2009. Rainbows from Lake Coleridge often appear bright silver coloured. Photograph courtesy of Kelvin Derry.

There is some variation between the sexes with adult males appearing bright red on the flanks, darker coloured overall, and heavier in the head and lower jaw. Rainbow trout in the South Island high country can be dark blue on the upper body, silver on the flanks, and sometimes difficult to distinguish from landlocked quinnat salmon.

Juvenile rainbows showing parr marks caught and gently released in the Hinemaiaia River, near Lake Taupo. Photograph courtesy of Dick Marquand.
All three rainbow trout in this photograph were caught in Canterbury’s Lake Coleridge. Read more about the identification of rainbows and landlocked salmon.
Blue rainbow trout from Lake Coleridge, Canterbury high country.

Like all salmonids rainbow trout can grow very large quite quickly if a plentiful food supply is available, conversely, rainbow trout can appear small and thin for their age if food is hard to come by.

Sean Konrad of Saskatoon, Saskatchewan, Canada, landed a 15.65 kg (34 lb 8 oz) rainbow trout (Oncorhynchus mykiss) in 20 minutes while fishing Lake Diefenbaker, Saskatchewan.

Rainbow Trout – A Pending World Record

Using a 4 kg (8 lb) class line, Sean Konrad of Saskatoon, Saskatchewan, Canada, landed a 15.65 kg (34 lb 8 oz) rainbow trout Oncorhynchus mykiss in 20 minutes while fishing Lake Diefenbaker, Saskatchewan. The current record is 28 lb 8 oz caught on April 20, 2003, from the Zymagotiz River in British Columbia. Several other rainbow trout records have come from Lake Diefenbaker.

This post was last modified on 26/06/2024 4:31 pm

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