Carp was originally found widely in Asia ,but there is some evidence it originated in Vietnam. It is believed to be a naturally invasive fish. It is one of the most widely distributed fresh water fish. Carp was introduced to the United States in the early 1800's from Germany. It was loaded in to special railroad tank carts and then ladled in to every creek, river or lake from east to west. Shipments were made to Idaho in 1882 and continued until the 1890's. By that time, carp were having a huge impact on native fish. Now carp are widely spread throughout Idaho. As a result it has created a carp control problem which now costs millions each year to partially control.

Carp were introduced to Australia as early as 1908 in Melbourne and Sydney. Asian carp was deliberately introduced to the Murrimbidgee Irrigation Area to "control" aquatic vegetation, but this plan didn't succeed because the carp did not thrive. It was in the 1960's when illegally introduced carp species gained access to the Murray in Victoria due to farms being flooded in the vicinity of Boolara where they were being grown. This subspecies literally exploded across the basin becoming a dominant part of the South Australian fisheries in the early 1970's. Carp can weigh from 15 to 20 pounds and one was recorded at 25 pounds.Carp grow up to 60kg overseas and, so far in Australia, the largest one recorded was 17kg.

Carp feeding on the surface of water.

Carp are one of the main causes for native fish to decline in numbers, flow alternation and habitat changes. It has been demonstrated that carp cloud still-water systems. For example, the Botanic Gardens in Adelaide, Australia, had carp in it about 5 years ago and visibility was about 5cm. Then it was cleared out and for the first time in a long time it was clear and vegetation flourished. Carp are also thought to be responsible for bank erosion in up-stream places of the Murray in black soil regions.

During the summer in backwaters you can often see the carp up- rooting aquatic plants. By getting rid of some aquatic plants carp numbers can be decreased. However, as weedbeds are important places for native fish , waterfowl and zooplankton, it is not the best solution.

Carp are responsible for creating many problems, including carrying and bringing in diseases, re-suspending nutrients from the bottom into the water, and out-competing other fish for space.

The most serious problem attributed to carp is that they secrete chemicals which reduce the desire of native fish to reproduce.

The size of young carp.

1) Governments need to make it illegal to transport live carp to river areas. South Australia, Australia has already done this.

2) Areas where carp breed need to be cleared.This may sometimes be difficult because areas they are in, may need water flowing all the time for irrigation purposes.

3) Parasite, viruses, and bacteria could be used to reduce the carp, but before this can be used, tests need to be taken out on the fresh water fish to find out if they harm them in any way. An exotic virus known as "spring viraemia of carp virus" is under consideration for this use in Australia.

4)The South Australian inland fishing industry, with help of the Australian Government has proceeded a fair way towards adding to the value of carp. This has increased the amount fishers are willing to harvest.

5)Reasearch undertaken by the SARDI Aquatic Sciences has already demonstrated ways of more efficently harvesting carp without impacting key native species. This technology has been exported overseas to the United States where it has been used for the past three and a half years.

6)Recreational and commercial sectors have agreed that commercial fishers will, as a matter of course, process carp taken by recreational fishers during fishing competitions. This means that instead of ending up in a landfill or spoiling the river bank, they can add value to South Australia.

7)The River Research Fishery in South Australia is only allowing bait-only access to most backwaters of the River Murray in South Australia. Doing this will mean that carp will have few refuges available in future.