Rex, take a look at the post by Eric showing his minnow cage he built. I explained in that post a method I've seen used by minnow growers to encourage spawning and egg hatching while deterring birds. I've seen it done but never tried it myself. I would think it would work good for you. You won't need a cage in a forage only pond but the black plastic would work for you I think. You just pull the plastic out when it's time to sein. The guy I saw used eight foot wide plastic and layed it in the shallows all around his pond. The fish hide underneath and lay eggs underneath.
