I am 98% sure that an otter got into my pond and drastically reduced the fish population for me. I can still catch an occasional bluegill and even less often, a little LMB. I suspect that my pond was big enough and I had enough structure in it that not every fish was consumed.

The pond was stocked right at 2 years ago now, so the LMB are 6"8" and the bluegills are almost that long too. I haven't seen any sign of grass carp this spring, but I used to have some. I understand that otters will target catfish and grass carp first, since they are slower swimmers.

After consulting with the company that I bought my fish from 2 years ago, they recommend continuing to fish it now and try to make the best determination possible as to what fish I have left and then we will supplemental stock it this fall. (Meanwhile...I am devising a plan to kill every otter in Iowa! :))

I would like to target the catfish to see if I have any and also the black crappies. What would be the best way to sample the crappie population at this time? I assume that these fish would be about 5"-7" now and I would like to not catch more BG's and LMB's as I try to assess the crappie population.

Any good ideas? I have lots of structure in the pond, PVC apparatus', pallet beds, concrete reef, root balls from big trees, etc. TIA.

You get the ones in Iowa, I'll work on all of them here in MO, I'm in the same boat, went from a prolific fishing hole to a few small scarred up LMB and an occasional blue gill, didn't have any catfish but they started by cleaning out the trophy sized LMB, don't seem to have hurt the crappie as bad, still catch quite a few of them. Good Luck!

cloverleaf trap with dog food or fish pellets in it

otherwise - bobber and 4mm ice jig + red worm fished around weeds or brush. They're extremely easy to catch right now. I can usually pull 50+ in 2hrs out of my pond.

Catfish....run top lines (two or more pieces of 8' conduit with trottline tied between), with 18-24" dropper lines, use circle hooks and half crawlers. If you check the line daily it will cause 0 harm to the catfish.

A little bobber, split shot, size 6 light wire hook and a minnow. Crappie even those little ones have a hard time passing up a live minnow. I find minnows outfish worms and crickets when it comes to crappie. A small ( 1/16th ounce ) jig and a crappie slider works too.

Cloverleaf trap with a light stick hung in the center and float the trap or hang a few inches under the surface at night. Crappie will pile in.