I found the pyramid style traps are really handy. They are easy to toss in, have several openings around them and can allow anything from tiny crayfish to larger fish be sampled. If you get a mix of crayfish you may have burrowing and nonburrowing crayfish (papershells not commonly reported to burrow or stir up the bottom) But bullhead alone may be the problem.
I'm not sure how to target them at once in large quantities. For my goldfish I'm trying to get them to come to one end of the pond for floating feed every day (or every day i can get time to feed them) and then set up a seine net across that area. My naive plan is to condition them and then close the opening to that area. Perhaps the bullhead can be conditioned to come in the feeding area and feed off the pellets that make it to the bottom?
Unattended trot lines might work with a hook size targeted for larger BH and a stink bait that may not be attractive to YP or SMB?
I too have GSH whose size have grown over the past few years and the timing of my turbidity may also correlate with the size of the GSH. However, last fall, winter and spring when water temps were cool the water was fairly clear. Not sure what to make of that unless it relates to the slower metabolism of the fish in general, or the crayfish in particular.
It is strange though because others with lots of crays in their pond don't necessarily have turbidity issues, and lakes I go to that are overrun with rusty crays (aggressive) have crystal clear water. So either the silt settles more quickly in a larger BOW or, those BOW do NOT have fish that I have. (for example, I know those bodies of water do not have GSH in them...)
