Golden perch

The golden perch (Macquaria ambigua) is a medium-sized, yellow or gold-coloured species of Australian freshwater fish found primarily in the Murray-Darling River system. A subspecies is found in the Lake Eyre-Cooper Creek system, and another subspecies, suspected to be ancestral to all other populations, is found in the Fitzroy River system in Queensland. Other common names for golden perch are "goldens", "yellowbelly" and "callop", the last generally used only in South Australia.

Golden perch are not a true perch, which belongs to the genus Perca from the family Percidae, but a member of the Percichthyidae (temperate perch) family. This relatively widespread and widely stocked species is an important angling sport fish in Australia.

Distribution

Golden perch are native primarily to lowland reaches of the Murray–Darling River system, but also extend far into slope habitats and occasionally even lower upland reaches. In the Murray–Darling system golden perch are often found in sympatry with Murray cod.

The Macquaria perches, of which golden perch are one, continue the trend present in Murray–Darling native fish genera of diversification into more generalist lowland species and more specialist upland species. Golden perch, M. ambigua, represent the lowland species, while the closely related Macquarie perch, M. australasica, is the more specialised upland species which used to inhabit the upland reaches of the southern Murray–Darling basin, although this endangered species has now been almost wholly displaced by introduced trout species, dams, and associated effects such as cold-water pollution, and habitat degradation/modification.

Like many Murray–Darling native fish, golden perch have crossed river catchments through natural river capture/connection events. Golden perch are found naturally in the Fitzroy–Dawson River in central Queensland and the internal Lake Eyre–Cooper Creek drainage system of Central Australia. The fish has also been successfully introduced to other river systems in the Northern Territory, Queensland, and New South Wales, confusing studies of the natural range. Introductions into Western Australia have been unsuccessful.

Both of these separate populations are at least subspecies, possibly separate species, due to isolation from Murray–Darling populations, genetic drift, and natural selection. The taxonomy of golden perch has not been updated to reflect this, although the term Macquaria ambigua oriens, denoting subspecies status, has recently appeared in literature discussing the Fitzroy–Dawson population. Some research indicates the Fitzroy River population is the ancestral golden perch population.

Behaviour

Adult golden perch are carnivores, feeding on smaller fish and macrocrustaceans, including yabbies, shrimp, frogs, small fish, and aquatic invertebrates.