I perch fish a lot and see how bad the gobies are. I also work at a water treatment facility that takes water off the bottom of Lake Ontario. I see thousands a year. Do I think the gobies are eating the salmon fry, not really. The gobies have been here since the 90's and we have not had an issue with the salmon population. The last couple of seasons have been screwy but I do not believe it is due to Gobies. As for the smallmouth, there was a big die off due to VHS disease a while ago that caused the crash in the population.