While I seriously doubt the long term success of many of these measures and to think a lot of other things were indeed killed that make a stream such an interesting eco system, I've not been made award of significance of genetic differences in the southern strain of brookies that live in park waters. There well may be genetic differences from stream to stream, but that hasn't been discussed.
If the poision killed off all the fish, I'm assuming it killed off crayfish, salamanders, aquatic incets and other native fish that lived in the stream and it wasn't selective to just rainbow and brown trout.
The biggest concern I had over the entire thing is killing off everything in the stream.
However, I do believe the fisheries biologists know a whole lot more about it than I do. I wouldn't expect them to tell me a lot about implementing computer systems in a Fortune 500 company and I wouldn't want to be telling them how to do their jobs.