Stocking policies have developed and changed as fishery biologists and fish culturists have gained more knowledge of their complex fields. A lot of different factors are weighed before any fish is stocked into a body of water in Maine. Although these written guidelines are brief, it should be recognized that they result from thousands of days of research on the survival. And of course, above all, public access must be provided to all waters being stocked. Minimum access acceptable for stocking purposes is the right or privilege to reach a body of water without trespass.
Stocking is discontinued when the species has become established.
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.