Thank you. That's a good question.
One easy answer is that Asian carp produce a lot of waste. They're taking in 20% of their body weight in a day, in terms of food, and then they're excreting a lot that in an undigested form. What happens is that they make the water much more murky, and that also makes it harder for native fish to see in the water. Native fish need to be able to see to find their food. Where Asian carp have invaded rivers in the United States, they've had a direct impact on water quality in a negative way.