The social benefits and constraints of stockings are difficult to quantify in monetary terms. The number of employed persons (construction of ponds and hatcheries, hatchery and pond management, fisheries management, fishing, etc. and sometimes also their social value) can be estimated. In addition there are other benefits, e.g. fish as food and recreational values are difficult to evaluate in financial terms. All these social effects can be accounted for imprecisely by lowering the target cost/benefit ratio. There are some constraints on stocking as well as benefits. There may be conflicts between different water users connected directly with the stocking programmes. In these cases the effects regarded as benefits by one user-group may be regarded as negative by the other, e.g., cases are known in Poland in which whitefish stocking in some lakes attracted large numbers of anglers. These not only fished out the whitefish, but also destroyed (due to simple curiosity) nets set by commercial fishermen. As a result, commercial fisheries which had borne the costs of stocking incurred economic losses, but the anglers considered these lakes to be highly attractive. From the socio economic point of view, the stocking programme resulted in benefits for anglers, but the fishermen regarded it as harmful and unprofitable.
