Correct answer: Intentional release
Asian carp are known to be an invasive species, they feed on snails and mussels. These grass carp alter the food web by altering the communities of plants, fish and invertebrates.
It is known to be the most damaging aquatic invasive species which causes a severe damage to wetlands and shallow lakes.
The carp is introduced to aquaculture facilities in Arkansas and Alabama to control the vegetation in a pond. They were widely stocked and their range was expanded by intentional releases.