How did carp get here?
Carp have been introduced into Australia both deliberately, in an attempt to imitate the European environment, and accidentally, through the escape of ornamental or aquaculture fish.
In Victoria, the stocking of carp began as early as 1859, but early stocking attempts were not successful. In NSW, the earliest known introductions occurred near Sydney in 1865. In the early 1900s, fingerlings were used to establish several wild populations of carp around Sydney, including in Prospect Reservoir (where they still persist).
The timing and mode of carp introductions into the Murray-Darling river system is unclear, though there are early records of some carp being translocated from Sydney, and a distinctive orange-coloured ‘Yanco’ strain became established in the Murrumbidgee in the early part of the 20th century. Whatever the source(s), carp have been established in the Basin since at least the 1920s, although for some time they remained fairly uncommon.
In the early 1960s a new strain was imported for aquaculture and reared at a fish farm in Boolarra. These carp were stocked into farm dams near Mildura and soon spread up the Murray and Darling Rivers, assisted by widespread flooding in the mid 1970s.
Since then, carp have since gone on to radiate very successfully throughout the Murray-Darling system, including in Queensland and South Australia as well as NSW and Victoria. They have also been found in Lakes Crescent and Sorrell in Tasmania.
Many NSW coastal catchments now also contain carp, often koi which have escaped from backyard ponds or been deliberately released.
The spread of carp may also have been assisted by anglers illegally using them for live bait or illegally stocking them to create new carp fisheries. The fact that a distinct strain, unrelated to nearby populations, has been found in two dams in the Murray-Darling Basin (Wyangala and Burrinjuck Dams) suggests human introduction from a separate source.