Last year our pond had the outflow tube get plugged up in a big storm and totally filled to overflowing. We found out at the time that the emergency spillway had silted in and was actually higher than the middle of the dam even though it really didn't look like it. The water washed over much of the middle of the dam up to about 2" deep. The backside of the dam was covered with hundreds of tiny bluegill, I'd say less than 1 1/2" or so in length, most less than 3/4". Didn't see any other species but lots of these poor baby bluegill.

I know this is a different situation, but I'd think pretty much the same thing would likely happen with what you are talking about.