It doesn't really matter how many eagles they are stating at one dam or another. The most critical factor is how close can you get to them while they are fishing. I believe L&D 14 is in the top 5 in the US for places to get good captures of eagles fishing. There are tons of examples on this thread I started some years ago: https://photography-on-the.net/forum/showthread.php?t=820444
I've been to L&D 13, 14, and 15, and I'd rather go to 14. I started going there in 2009 and I've been skunked a number of times, but if you go on a sunny day with the winds mostly out of the west and spend an afternoon there until around 4:00 pm, you are likely to get some good shots.