There are ponds, particularly in the northwestern part of the state, where there are no fish in some very desirable habitat. Maintenance stocking is a program of routine, continuous stocking intended to supplement or substitute for natural reproduction. Hatchery fish are released, survive, and grow to an acceptable size, and then they are caught by anglers. Maintenance stocking is done where there is suitable habitat, limited natural reproduction, and sufficient potential fishing pressure to ensure that the fish will be harvested. Southern and central Maine possess the bulk of these waters.
Experimental stocking is used in special situations.
It is sometimes difficult to predict the success of a proposed stocking program where complex biological interactions exist. In such cases, the department may undertake stocking on an experimental or tentative basis. Fish stocked on an experimental basis may be marked by fin clipping or tagging to allow analysis of the program, which may then be changed to a routine maintenance stocking, or it may be discontinued, depending upon the results. A good example of experimental stocking is the rainbow trout program that is underway. We will be stocking a handful of waters with rainbow trout along with brown or brook trout.