I fish a private pond and I am curious as to why the male bluegill are so thin, yet the females are thick. When I say thin I mean filleting them with an electric fillet knife is virtually impossible, so I keep the females and release the males. It's not just during the spawn either. They are thin all year long. I know certain things happen such as "stunting" when fish are over populated in a particular pond or lake, so is this sort of like that? Is there a scientific name for this?