Asking similar questions as to what one can expect natural mortality to be, Eric introduced me to paper by TPWD of a 17 year study. After attaining lengths >12", the mortality was much lower when in most years ranged between 5 and 10 percent. Eventually, as the fish aged, mortality rates trended higher. It depends entirely on what you want, but natural mortality will be insufficient to produce trophy fish over time. You plan to cull LMB and that will be crucial to success.

On the subject of condition. There were two years in which the average weight of LMB in the study declined. These years were also associated with spikes in mortality. So getting enough to eat is essential for good health and survival.

It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers