Get some WR measurements and report back. Per Kenny underperforming LMB typically due to lack of appropriate forage size - you can help the forage base by installing some dense shallow cover to help escape predation or cull low WR LMB or both.
This helped me year before last when my pond was two yrs old. An E survey in March showed few bg in the 2 to 3" range. It was suggested to me to add shoreline cover because I did not have any vegetation and we added 25 lbs of fhm's tp take some of the pressure off the cnbg fry. And then the first of June I had lots and lots of cnbg in the desired size. I am planning on replicating the same thing this year.
