I wouldn't toss in LMB quite yet. Large mouth (to me), anal fin white (or light colored) margin says to me that there is some GSF in the mix. Now, a GSF is half of a HBG, so I wouldn't panic just yet.
Think about HSB and SMB. If they don't control them, then you can always add LMB, but if you drop in LMB from the get-go, you can never turn back.
Trap all you can, even see about running a seine thru there once or twice. Or, get a small Fyke Net. You'd be amazed at how many fish you can remove with one.
