Trout, Rainbow

Native to the west coast of North America and the pacific coast of North Africa, this fish has been introduced into many countries around the world.  It was first introduced into Tasmania via New Zealand in 1898.  Occurs commonly around most of the state, but tends to be more successful in lakes than rivers.  Self-maintaining populations are not common, and consequently many lakes and private farm dams are stocked for angling purposes.  They are considered by many anglers to have better fighting qualities than brown trout.  They also make up an important part of Tasmania’s fin fish aquaculture industry.

Similar in general appearance to brown trout, although rainbows have a tendency to be deeper in the body.  They also differ from brown trout in colouring and they have spots on the tail.  Dorsal fin is high on the back and further forward than the pelvic fins.  They have an adipose fin, a lateral line and small scales.  The mouth extends back below the eyes.

The colour is variable, but often has a rosy, pink flush along the sides and on the gill cover.  Lake populations are generally silvery, with a dark greeny back, with many small spots.  Breeding fish tend to be more intensely coloured, as do those fish found in rivers.  Can reach weights of over 20 kg and over 1120 mm in length.  The record for the biggest fish caught in Australia is a 7.8 kg fish caught in the Ouse River, Tasmania.

Breeding

Spawning occurs in spring when spawning fish migrate upstream to gravel bottom stretches of river.  Fish pair up and eggs and milt are deposited into a depression dug by the female.  These are then covered up by dislodging upstream gravel.  The eggs generally hatch after 4-7 weeks depending on water temperature, and hatchlings then stay in the gravel feeding off their yolk sacs until they emerge as fry.  They initially may form schools, but over the next year or two become solitary and territorial, as they move into deeper water.  Maturity is reached after 3 years.

Behaviour

Requires cool well oxygenated water, with adequate cover and shelter.

Diet

They feed on a wide variety of animals including crustaceans, molluscs, both aquatic and terrestrial insects and small fishes.

Status

An IFS Recreational Angling licence is needed to take rainbow trout.  Specific fishing regulations for bag and size limits, and fishing technique (bait, lure or fly) may vary between waters.

AquaticsLuke