372
16. Management of the Commons
equilibrium-exploits the resource faster than a setting in which all the fishermen cooperate.
16.5. Discussion and Conclusions
The results of this model show that the social structure of the fishing community, measured by the fractional shares that belong to each strategy, can
reach an equilibrium level. But clearly the three strategies-cooperation,
defection, enforcement-eannot coexist in the long run . The only possible
stable equilibrium levels-where each strategy earns equal payoff-are the
ones that either contain only defectors, or a mix of cooperators and enforcers. This result confirms that a social norm that sets cooperative catch
guidelines can be successful in ensuring the sustainability of a resourcegiven that the cooperative catch is small enough to ensure maintenance of
the fish population. However, that equilibrium seems to be quite vulnerable to changes in the system.
The results also suggest that the cooperative catch guidelines must be
supplemented with some kind of a punishment to render the cooperative
strategies competitive. As the case studies indicate, such mechanisms seem
to be an essential part of real life situations where a fishery is managed as a
communal resource.
Because the initial number of fishermen who choose each strategy matters, this confirms the necessity for the fishing community to be able to
clearly define the boundaries of the fishery, i.e. where and how much the
community is allowed to catch. Given that in many cases the method of
punishment is mainly some kind of a social incentive, and only supplemented with a nominal monetary incentive, it is unlikely that newcomers
would be willing to adhere to the social norm . This observation rests on the
assumption that newcomers do not belong to the culture they are entering
and , hence, they may not feel bound by the cooperative norm-since social
exclusion would not affect them . Therefore , newcomers likely become defectors and tip the scale towards a social equilibrium of defectors only. A
shift to a community of only defectors may lead to resource degradation,
and in tum to a decline in social welfare (Sethi and Somanathan 1993). In
addition, the model indicates the persistence of an equilibrium level of only
defectors. This implies that, if defectors manage to dominate a fishing community, it is unlikely that the community can re-establish the cooperative
behavior by recourse to social norms alone.
The results also demonstrate that long-term behavioral patterns seem to
be persistent. This suggests that cooperation today is likely to be followed
by cooperation tomorrow. However, this conclusion is only true if economic conditions remain stable . The cooperative equilibrium is vulnerable
and can easily be rendered unstable, as shown in scenarios 3 through 5. A
shift to an equilibrium level of defectors may be caused by increases in the
16. Management of the Commons
equilibrium-exploits the resource faster than a setting in which all the fishermen cooperate.
16.5. Discussion and Conclusions
The results of this model show that the social structure of the fishing community, measured by the fractional shares that belong to each strategy, can
reach an equilibrium level. But clearly the three strategies-cooperation,
defection, enforcement-eannot coexist in the long run . The only possible
stable equilibrium levels-where each strategy earns equal payoff-are the
ones that either contain only defectors, or a mix of cooperators and enforcers. This result confirms that a social norm that sets cooperative catch
guidelines can be successful in ensuring the sustainability of a resourcegiven that the cooperative catch is small enough to ensure maintenance of
the fish population. However, that equilibrium seems to be quite vulnerable to changes in the system.
The results also suggest that the cooperative catch guidelines must be
supplemented with some kind of a punishment to render the cooperative
strategies competitive. As the case studies indicate, such mechanisms seem
to be an essential part of real life situations where a fishery is managed as a
communal resource.
Because the initial number of fishermen who choose each strategy matters, this confirms the necessity for the fishing community to be able to
clearly define the boundaries of the fishery, i.e. where and how much the
community is allowed to catch. Given that in many cases the method of
punishment is mainly some kind of a social incentive, and only supplemented with a nominal monetary incentive, it is unlikely that newcomers
would be willing to adhere to the social norm . This observation rests on the
assumption that newcomers do not belong to the culture they are entering
and , hence, they may not feel bound by the cooperative norm-since social
exclusion would not affect them . Therefore , newcomers likely become defectors and tip the scale towards a social equilibrium of defectors only. A
shift to a community of only defectors may lead to resource degradation,
and in tum to a decline in social welfare (Sethi and Somanathan 1993). In
addition, the model indicates the persistence of an equilibrium level of only
defectors. This implies that, if defectors manage to dominate a fishing community, it is unlikely that the community can re-establish the cooperative
behavior by recourse to social norms alone.
The results also demonstrate that long-term behavioral patterns seem to
be persistent. This suggests that cooperation today is likely to be followed
by cooperation tomorrow. However, this conclusion is only true if economic conditions remain stable . The cooperative equilibrium is vulnerable
and can easily be rendered unstable, as shown in scenarios 3 through 5. A
shift to an equilibrium level of defectors may be caused by increases in the