There was a guy doing demos at NYSTA convention this year who uses large rubber fishing lures shoved onto the trigger of 330 and placed so that the fish appears to be swimming upstream.
I've never done it, but seems simple enough.

When I trap otter I go blind sets also and like was stated narrow part of a stream or creek.Also cross over of some kind. I have caught them by just use beaver caster on a stick that was set for beaver and also fish for coon tie to a tree.I was told some get them in there rat sets also. One person in the past told me about they get them in there beaver set with snares under the ice. The otter think that the snare lock is a minnow flick in the current and it was shiny. If it is just a small narrow stream that can fit a 220 in I set it and with a dive pole over it. Or a larger one with a 330. Or a #3 coil for foot hold on some cross overs.They work for me.Also bottom edge set also with 330.

Goldfish or BTO have worked for some