When I got back into fishing 6 years ago, smallmouth bass were abundant in the Thames River. I fished from Plover Mills to Komoka and every trip usually produced at least couple of small bass. Sometimes we'd get 10 or more on a trip. Sometimes was would get larger smallmouth upwards of 16 inches. Bass were abundant in both branches of the river. Excellent areas in town included Highbury Ave and the North Branch, the dog park on Hamilton Road and Thames Park downtown.
For the first couple of all areas of river produced bass. As time went on there were less and less bass to be had. Since 2010 I've only been able to catch less than 10 bass in the river and they were all small (8 inches or less). I fish the Thames River at minimum 50 times per year and usually more. I try a variety of locations, techniques and tackle. I've been successful in other locations where bass are present. There is a problem with the bass population in the Thames River within the London City limits.
To address my concerns I emailed one of the aquatic biologists at the Upper Thames River Conservation Authority. The person I emailed returned my email right way, acknowledged my concerns and shared with me that he has received additional concerns from other anglers. In addition he said he was going to start gathering some baseline data. He shared that water quality bethos sampling had remained stable and good for the last decade or so. It does not seem to be a water quality issue. Also they have not "noticed any significant habitat changes, which fish communities tend be more responsive to and indicative of."
When I receive more feed back I will post for everyone to see.