Maybe this could be the answer to the carp problems. In the past I ran a Carp fishing comp on Lake Eildon over 7 days and was wrapped to get around 300 kgs weighed in this is a more effective approach to the same problem.
https://youtu.be/CQYJd-7iQb8

Great video David, it sure makes you think about a number of thing that can go wrong with such a sensitive environment, i went on to watch a few following videos

Read a study somewhere on the effectiveness of sports carp comps on population. By memory number caught was a very small % of total amount and within a short period of time population was back to normal. Main environmental issue was dealing with all the carcasses landed. Seems you just cant overfish a carp population, remaining carp just get bigger and breed more.