Redfin in Tasmania

by Carl Hyland on 28 Feb 2012 Like them or loathe them, Redfin perch are a species that can provide great sport or great eating qualities whilst other species such as trout or salmon are in shutdown mode.

Warm water temperatures are what this species thrives in and in most freshwater impoundments and brackish salt water, will often thrive where other species cannot.

The Redfin perch is native to the cool-temperate waters of the Northern Hemisphere. It was first introduced to Tasmania between 1858 and 1862 and to Victoria in 1861. The species is widely distributed throughout the temperate portion of the Murray-Darling Basin, but absent from the colder headwaters and the hotter reaches of the Darling drainage. It is not present in Qld. It survives in water temperatures of up to about 31°C, which largely explains its distribution.

Lowland impoundment waters such as Brushy Lagoon in the North of Tasmania and the North and South Esk rivers systems are inundated with the species and anglers can have an impact on their numbers. The Inland Fisheries Service became very concerned with the impact of their numbers in Brushy Lagoon in…2006 and launched a program to spot eradicate Redfin in places such as Miena in the Great lake with the application of poison Rotenone. This was successful; with the species being eradicated successfully from here but not so at Brushy Lagoon, where the lake was drained and Rotenone was applied in vast quantities. This species again flourished and remains a species that dominates this water during all seasons.

The species is occasionally moved illegally by anglers and, once established, can increase rapidly in numbers. In Lake Burley Griffin, Canberra, within six years of establishing it formed 58% of the total catch. However, these numbers declined dramatically after an outbreak of EHNV in the early to mid 1990s, and the species now comprises around 10–15% of the catch. The perch is a popular angling species, particularly in Vic and Tasmania.

Identification:

A medium sized and deep-bodied fish with a slightly forked tail, two separate dorsal fins and a large mouth which reaches to under the eye. Maximum length 600 mm and weight 10 kg; commonly 400 mm and 1–2 kg. The back is olive-green to grey, paling on the sides to white on the belly. There are usually around six black bands on the back, tapering on the sides. The pelvic and anal fins and margins of the tail are bright red or orange-red, which is the origin of the common name.

Redfin perch mainly occur in slow-flowing or still water habitats, such as lakes, billabongs and swamps, especially where freshwater plants are abundant. Individuals are generally mature after 2–3 years, but males may mature at the end of the first year. A characteristic of the species is the propensity to ‘stunt’ ’under conditions of poor food availability or overcrowding, when individuals can mature at a very small size (approx. 120 mm length).

Spawning occurs in spring when water temperature reaches 12°C. Thousands of eggs are laid as gelatinous ribbons amongst freshwater plants. The eggs are 2–3 mm in diameter and the larvae hatch in 1–2 weeks with juvenile fish forming large schools. Perversely, redfin eggs are not palatable to other fish species.

The Redfin perch is a pelagic carnivore with a diet that includes crustaceans (shrimps, yabbies and other freshwater crayfish), zooplankton and small fish such as, galaxiids and Eastern gambusia. It is known to prey heavily on newly stocked trout.

The Redfin perch is the main host for Epizootic Haematopoietic Necrosis Virus (EHNV). This virus, unique to Australia, was first isolated in 1985 on Redfin perch and is characterised by sudden high mortalities of fish. Laboratory trials have demonstrated that Macquarie perch, Silver perch, trout and Mountain galaxias are among several species found to be extremely susceptible to the disease, but the impacts in the wild are as yet unknown. EHNV has now been recorded from NSW, ACT, and Victoria.

The perch is a voracious predator, with large and small individuals consuming species such as trout and salmon.

The one good thing about perch, is that they are a half decent sports fish and do make for fine consumption and if the pearl white flesh is prepared correctly, rate highly amongst anglers who regularly target them I know of one angler who regularly smokes them and finds them quite comparable with Atlantic salmon.

Tackle:

Light rods ,2kg are suitable for the taking of perch and terminal tackle in the form of small hooks and split shots are all that are required to ensure a day’s fun on the water. Suckers for baits suspended under floats, redfin will also take lures such as small minnow types and celtas or Mepps.

Red and black matuka flies are favourite and watching schools of juvenile redfin attacking a presented wet such as a Matuka or Deceiver can be quite comical as it is the larger fish that usually takes the prize.



Here’s a great recipe: Perch Polonaise

In four cups of vegetable stock, cook 2lbs of perch fillets until done (only a few minutes). Remove cooked fillets from stock with slotted spoon to platter and keep warm in oven. In saucepan, melt three tablespoons of butter and switch off heat.

Add four to five finely chopped hard boiled eggs to the pan and toss to coat evenly with butter. Then add two or three tablespoons of finely chopped fresh dill - salt and pepper the mix generously. Toss the mix to blend everything together.

Sprinkle fish with lemon juice and top with the egg mixture you have in the pan.

Variation - A finely chopped onion may be added to the butter before you add the eggs for extra flavour. Serve immediately.