However along with this significant growth in aquaculture production, there is an increasing concern over the availability of adequate and suitable space for aquaculture expansion. In recent decades aquaculture has been in competition with different users both on land and in the water due to other competing economic developments such as agriculture, renewable energy and tourism. Furthermore, the potential impacts of climate change on aquaculture (e.g. increasing water temperature, evaporation and precipitation levels) and increasing constraints from ecological concerns (e.g. nutrient enrichment, disease outbreak, conflict of interest with other societal demands) have made the battle for space harder. In response to these limiting factors and the search for adequate and suitable space, aquaculture is now expanding into deeper offshore environments.
The attractiveness and potential benefits of moving aquaculture deeper offshore are many. For example, as a result of increased water flow and depth, offshore sites tend to be less susceptible to the effects of farms on the environment (e.g. nutrient enrichment, disease outbreak), to the effects of the environment on farms (e.g. land- based pollutants), or to the effects of climate change (e.g. water temperature). While offshore environment can play a major role in ensuring good environmental outcomes, reduce conflict between different users, and provide a better culture environment for some aquaculture species, the choice of farm location also plays a critical role in determining its productivity, environmental impact, and interactions with other services provided by the ocean. In other words most issues related to aquaculture development and administrative decision-making are driven by spatial considerations. Thus the tools developed in Geographic Information Systems (GIS) can be used for spatial planning purposes in offshore aquaculture development and administrative decision-making.
Spatial planning needs to include sustainability considerations, without this development and administrative decisions may run contrary to the environmental and social objectives. One way of achieving sustainable development is to define management objectives (e.g. physical, social, ecological, production) in terms of ‘carrying capacity’. These carrying capacities can be used to define the upper limits of aquaculture production, the ecological limits, and the social acceptability of aquaculture in a way that does not cause unacceptable change in any carrying capacities over an extended period. Since the interactions between the major carrying capacities over time characterises the behaviour of the ecosystem, it can then be explained through System Dynamics (SD) modelling.
Given the strength of SD modelling in representing temporal processes with restricted spatial modelling capabilities, and the competency of GIS for spatial modelling with limited representation of temporal aspects, the aim of this PhD project is to integrate GIS with SD to provide a powerful decision support tool that would minimise adverse environmental impacts, social conflicts, and maximise economic return.