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Redfin Perch
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Percidae
Genus: Perca
Species: P. fluviatilis
Also known as European Perch, English Perch or Reddies.
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 Vic 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 Queensland. It survives in water temperatures of up to about 31°C, which largely explains its distribution.
It seems that the Taswegians are making efforts to stop the spread of Redfin, as they are with trout, but I'm unsure how successful they've been.
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 (see below) 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 Victoria.
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 Western carp gudgeon, 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.
Fun Fact:
Because of their similar appearance and ability to cross-breed, the yellow perch has sometimes been classified as a subspecies of the European perch, however, it is unclear whether or not hybrids are viable, and most classifications treat the two fish as separate species.
Primary Source:
Murray-Darling Basin Authority