I have been thinking about whether a almost 12 pound bass was even possible in Michigan in the past, so I have done a little digging, mainly on the alcona dam record. I have found that when they built the dam there was a steady population of trout that had inhabited that stretch of the Ausable.
The trout could have had a large impact on the record, in addition to the dam. My uncle's brother has talked about a guy that caught a 9 1/2 lbs largemouth caught out of Fletchers, but i've never confirmed it. I have also been looking into the lakes above, and below Sanford lake and I believe that once the river starts to fill up more and more we could see a influx of giants caught out of there often, but I guess time will tell.