16.3. The Model
363
feet from the cooperative catch guidelines. ElO corresponds to the cooperative catch guidelines that should be adhered to in order to ensure the sustainability of the resource. By definition,
E/O> ElO.
(7)
Following common practice (see e.g. Ostrom 1990 and Sethi and Somanathan 1993), fishermen who adopt high effort levels are called defectors. Those who adhere to the cooperative catch guidelines have the option
of sanctioning the defectors . As stated, such sanctioning can range from social disapproval to physical damage such as the destruction of fishing
equipment. Consequently, those who adhere to the cooperative catch
guidelines are of two types: enforcers who sanction the defectors, and cooperators who do not.
However, to carry out sanctions is not only costly for the fishermen being
punished, but also for the enforcer, since it may be risky to damage someone else's equipment. For instance, those who enforce the rules in the
Maine lobster fishery always risk getting caught, in addition to spending
valuable time to damage someone else's equipment. Hence, the cost of enforcing the user rules is low, but not absent.
For the model, an initial number of fishermen belonging to each category
is exogenously given. However, the number of fishermen that choose each
strategy changes over time. The fractional share that belongs to cooperators
is represented by F/O, the share of defectors by Fd' and the share of fishermen that choose to be enforcers by F/O.
Each fisher adopts exactly one of the three strategies at each time-period.
Since cooperators and enforcers use the same extraction level, the total
level of effort is given by (Sethi and Somanthan 1993):
(8)
where
(9)
The STELLA module corresponding to equations (8) and (9) is shown in
Figure 16.2.
What we are interested in examining is how each fisherman determines
whether he will cooperate and adhere to the cooperatively set catch guidelines, defect or enforce the rules. We assume that each individual fisherman
can change his strategy over the course of the game by responding to
changes in the payoff to each strategy.
The payoff to each strategy type (OP), where i= c,d,e) is given by equations 10 through 12 (following Sethi and Somanthan 1993).
363
feet from the cooperative catch guidelines. ElO corresponds to the cooperative catch guidelines that should be adhered to in order to ensure the sustainability of the resource. By definition,
E/O> ElO.
(7)
Following common practice (see e.g. Ostrom 1990 and Sethi and Somanathan 1993), fishermen who adopt high effort levels are called defectors. Those who adhere to the cooperative catch guidelines have the option
of sanctioning the defectors . As stated, such sanctioning can range from social disapproval to physical damage such as the destruction of fishing
equipment. Consequently, those who adhere to the cooperative catch
guidelines are of two types: enforcers who sanction the defectors, and cooperators who do not.
However, to carry out sanctions is not only costly for the fishermen being
punished, but also for the enforcer, since it may be risky to damage someone else's equipment. For instance, those who enforce the rules in the
Maine lobster fishery always risk getting caught, in addition to spending
valuable time to damage someone else's equipment. Hence, the cost of enforcing the user rules is low, but not absent.
For the model, an initial number of fishermen belonging to each category
is exogenously given. However, the number of fishermen that choose each
strategy changes over time. The fractional share that belongs to cooperators
is represented by F/O, the share of defectors by Fd' and the share of fishermen that choose to be enforcers by F/O.
Each fisher adopts exactly one of the three strategies at each time-period.
Since cooperators and enforcers use the same extraction level, the total
level of effort is given by (Sethi and Somanthan 1993):
(8)
where
(9)
The STELLA module corresponding to equations (8) and (9) is shown in
Figure 16.2.
What we are interested in examining is how each fisherman determines
whether he will cooperate and adhere to the cooperatively set catch guidelines, defect or enforce the rules. We assume that each individual fisherman
can change his strategy over the course of the game by responding to
changes in the payoff to each strategy.
The payoff to each strategy type (OP), where i= c,d,e) is given by equations 10 through 12 (following Sethi and Somanthan 1993).