Rod, you may or may not "see" active BG on the beds every time. And yeah, the word "definitely" is sometimes dangerous because to me, it signifies a measure of certainty. For me to say "you definitely have a lack of spawning habitat" would be an assumption on my part and assumptions get me in trouble.
Fish are amazing critters.. they seem to get off a spawn of some sort even in the worst conditions (more accurately-what WE see as worst conditions) yet spawns may not be as good as we would expect with great conditions for the same reason.
I don't think it's bad advise, I just think based on my experience it's a bold assumption. 50/50 chance either way. This falls into the "it depends" category.
My point is the BG are going to dish out bottom and try to spawn even if substrate isn't perfect. I think hatch rates and survival are results of better areas and materials, and really didn't mean there is right and wrong, just good, bad and better.
I seen no activity this year after the TP ran the BG out early..have no clue where the BG nested but very obvious they made it happen.
I don't know what the OP's capabilities are but I can also say if yoy aren't showing up in a trap-doesn't mean they ain't there but I didn't see any young until mid Aug in the traps. I trap when the WT hits 60 until it drops to 50. I remove every BG I catch because I have no LMB, so I grow the BG and sell'em.
As the water goes down this fall, I'll see where they made nests but I haven't found them yet.