Bio-economic analysis of the response of a fishery to changes in access regulation: the case of Individual Transferable Quotas in the Tasmanian rock lobster fishery

In the past three decades, there has been a move towards rights-based management of access to marine fisheries, especially individual transferable quotas (ITQs). Although it is generally agreed that ITQs improve the economic efficiency of fisheries, few empirical studies examined how stakeholders respond to the incentives set in an ITQ fishery, determining the actual economic, social and ecological outcomes of such a management system. This thesis addresses the question of how fishers and quota owners make decisions regarding their fishing activities in the context of an ITQ system. The study focuses on the Tasmanian rock lobster fishery. In 1998, ITQs were introduced in the fishery in an attempt to decrease fishing effort, while the total allowed catch (TAC) would restore the stock at a sustainable level. The thesis investigates the dynamics of the fishery as it evolved during the decade after introduction of ITQs. The study is based on an empirical analysis of the changes that occurred in the fleet and its activity, and on a bio-economic simulation model. To understand the complex dynamics of the fishery, fishing activity of the fleet was categorised as metiers that account for the spatial and seasonal heterogeneity of biological characteristics, infrastructure and weather encountered in the fishery. These metiers were used to inform an agent based model of fishing behaviour. The model combines individual decisions on allocation of fishing effort with a quota trading market where quota owners can lease in/out quota according to their expected economic performances. Empirical analysis shows that ITQs reduced the overcapacity in the fishery and that the TAC allowed the stock to rebuild. The impacts of ITQs on the fishery were the results of both structural changes of the fishing fleet and of the change of fishers behaviour. Fishers responded to the management change by modifying their fishing strategies in space and time to increase profit. In addition, the ownership of the fishing rights changed toward a higher proportion of quota owned by non-fishers, although concentration of quota has been limited in the fishery. The bio-economic model was used to investigate the key drivers that underpin fishing and quota-trading decisions by the fishers and profit-maximising decision process predicted well the observed fishing behaviour. The limitation of quota aggregation is believed to have facilitate the reduction of excess capacity of the fleet but could constrain economic efficiency of fishing firms. The model was also used to assess the future of the fishery and test scenarios on the potential impacts of changes in the economic and ecological environment in which the fishery operates. Although the future of the fishery remain uncertain, integrating dynamic fishing behaviour in projection models reduce the uncertainty and the use of economic drivers to simulate decision process allows to explore a wide range of scenarios regarding economic predictions and their outcomes including social and economic considerations