kurt, if you don't subscribe to PB, you really should... Bill has a series of articles on SMB in it that has been spectacular. You can order back copies as well to get those that have already come out.
As far as YP, they need something to "hang" their eggs on. YP have long stringy eggs. They hang them on submerged tree limbs, aquatic vegetation and other structure. So if you are trying to promote YP reproduction in your pond, sink some branched trees, either natural or artificial ones.
Bill is the perch expert though, he may be able to give you ever better info...
