The bass do look on the thin side. It is the end of winter, bass are at their lowest weight for the year now though. Buy a scale and start measuring and weighing each bass and keep records. Then this time next year you can compare the relative weights and see if your management work is making a difference. In all likelihood, you have a classic situation of a pond that has little to no management for many years. Many small stunted bass with not many sunfish which are bigger in size.
