The more obvious one might be that suspended burbot are up feeding on baitfish. The prey depends on the system you’re fishing. The couple of lakes I target ’em around here have tullibee/cisco. Don’t see a whole lot of them after dark, but the ones we do see usually tend to be suspended and slow moving. Yup, burbot will absolutely take one down. Same goes for a suspended rainbow trout or even smaller walleye.
Judging by the burbot I have cleaned in the past (and checked their stomach contents) they still seem to prefer eating crayfish and small perch, which of course are going to be tighter to the bottom.
Another thing I’ve noticed since getting LiveScope a couple seasons back, is that a lot of those suspended burbot are staying at the same depth as where they slid off the break. Can’t tell you how many times I have watched them swim OUT of a big weed flat on LiveScope, and stay right at the 14-18′ depth where they left the weeds. Then they swim off into the abyss – out over 30-50′ of water – but stay suspended at that 14-18′ depth until they’re no longer visible on LiveScope. Wild.
Maybe it’s a pressure thing? Not like angling pressure, but the pressure changes of going from shallow to deep water, and vice versa.
I’ve also watched numerous suspended fish “meet up” in the middle of the water column. Burbot that were hundreds of feet apart on LiveScope – both suspended – but then meet up somewhere in the middle and mosey off together.
Don’t know what it all means, but it’s interesting nonetheless. 🤷♂️ Or at least I think it is lol.