HBG won't produce enough fry to feed the LMB. HBG are "large mouth" bluegills, but they come about by crossing GSF and BG. No LMB involved....

The largest fish die in an environment that is low on O2, that's why you saw the GC dead. I'll bet the largest HBG are dead as well.

www.hoosierpondpros.com

[Linked Image from lh6.ggpht.com]
http://www.pondboss.com/subscribe.asp?c=4
3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).