The northern snakehead is native to east Asia but has been brought in as a live food-trade fish. It may have been brought in as well for the aquarium trade. The smaller animals are attractive there.
They are currently established in areas of the midwestern United States and in various spots otherwise. We have reports from places such as Pennsylvania, Maryland, and New York State. The issue there may be that they are independent releases of fish rather than a spread. However, there does seem to be an area now, in the centre of the midwestern United States, where there have been escapes, and they have become established and are breeding in an area.
We have a risk assessment that has been completed on the northern snakehead. I think we have some sense of how they may move. I believe that the most visible threat would be the live trade—the live food and movement vector. That is what we would be most worried about in the case of the snakehead.
Michelle, did you have anything to add to that?