Speaking of otters, we have had about 7" thick ice for several weeks, I seen where the otters were going up into the the bank and then out on top of the ice thru holes in the ground and leaving their fish scales and heads scattered on the ice, this was on the bluff side of the pond so the banks are pretty vertical, set some traps there but most were too small, just muskrat traps and a couple were tripped and they got out, just left a few hair.
So I was walking along the edge of he ice and actually seen the otter underneath the ice, he seen me at the same time and skedaddled into the den hole under the ice, so a light bulb went off in my thinker. I cut a hole right at the edge of the ice by his hole and dropped a snare with the loop right in front of the hole. had to take to other end of the snare and drilled a hole in the frozen ground at the correct elevation and drove in a piece of rebar, to have the noose right in the hole.
Bingo, worked like a million dollars, 12 hrs later we have a fisheater in custody. like shooting fish in a barrel.

I been trying to trap beavers and muskrats but don't have much, if any, luck on those steep banks with the conibear traps, no place to stake down a conibear.
Snares are not legal everywhere, but here in MO they can be used for some things when you have a trapping license and proper training.

All the really good ideas I've ever had came to me while I was milking a cow.