The effect of quota trading limitation in a fishery management through individual transferable quotas

Individual transferable quotas (ITQs) have been used in several countries worldwide to regulate access to marine fisheries. While ITQs can improve the economic efficiency of fisheries, in practice they are not a panacea and distribution and equity issues have been raised in many cases. To overcome those issues, ITQ systems have sometimes been designed with a set of regulations limiting the trade and capping ownership of quota units. In this study, we use an agent-based modelling approach to simulate the effects of introducing ITQs in the Tasmanian rock lobster fishery. Individual agent decisions regarding spatial and temporal fishing distribution are modelled at a monthly level taking into consideration the profitability they derive from fishing rock lobster. A quota trading model is integrated into the fisher decision making process allowing fishers the choice of leasing quota units in or out depending on economic performance and their catch expectations. The model is then used to investigate the consequences of setting a limit on quota trading. Preliminary results are presented on how the different harvesting patterns induced by a cap on trade and concentration of quota impact on the socio-economic performance of the fishery and the biological resource. The initial simulations show that allowing quota trade has been important in reducing capacity in the fishery. Simulations suggest that non tradeable individual quotas would not have led to the observed reduction in the active fleet. The model also allows to simulate the possible trajectory of quota leasing prices over the first decade of the ITQ system, and to assess its sensitiveness to external drivers such as the market crisis observed in the early 2000s.