ive done that as well.
12 gauge while duck hunting the Mississippi.
When I was in the army (light years ago) we sometimes went fishing in a wild way. We would throw a piece a bread in the water and wait for the fish to come to the surface to start feeding on the bread. Then we put a bullet right through the middle of the bread. The impact of the bullet on the water would stun the fish and we would take some and leave the rest. Those would swim away a few minutes later. It worked best with M14, SKS and AK47 all high speed with fairly large caliber bullets. It would not work with UZI. The bullets were to slow. M16 would not work either, in spite of the high velocity 5.56 was not large enough of a caliber.
I have been involved in Lamprey treatment and we always try to treat the lamprey spawning streams when the spawning happens. Sometimes a freak rain will flush the treatment chemicals or the overall creek levels are at flood stage in which case we cannot treat the streams.Do not kill off the lamprey at their breeding sites. Too cheap. Feed them more fish. Most expensive solution.
I posted it but did not understand your reply, but I'm a southern redneck so there's that.
I went over it just now and I see where your idea comes from. 50 years ago there was a lamprey problem, but that was not the reason why lake trout populations collapsed. It was pollution and also an over fishing (commercial) problem. With all the DDT and other poisons settling on the bottom where the lake trout live the amounts of DDT that accumulated in the Lake trout became the main reason why they stopped reproducing. Lake trout does not reproduce in the first few years of their life and by the time they were ready to spawn they had absorbed so much DDT that they no longer reproduced and their overall health was poor.
