Visited a lake in New York last week. Maybe 100 acres. 2 loons have been on the lake for about 6 years I believe. In that span, the bass fishing has really gone downhill. Some are saying the loons are eating so many fish a day, that it's affecting the fishing. The hope seems to be that the loons will move on soon-and find a different lake once they see there aren't many fish left on this one.
Another lake I know of, in northern Wi., has always had 2 loons as far as I know. On that lake, the bass fishing seems to be pretty consistent from one year to the next. Maybe a bit down, but not as noticeable as the lake in New York and there could be other factors in play such as harvest. (The New York lake has very limited harvest)
Have you noticed any effects from fishing where loons inhabit small to mid sized waters? (BTW-I am not saying "get rid of the loons"-just curious about the connection to fishing).