By Michiel Oliemans (the Netherlands)
Shrimp farming in the Mekong Delta in Vietnam has been growing extensively the past few decades. This caused environmental problems like pollution, salination and overharvesting. Due to higher demands on the shrimp sector, even bigger growth is expected in the future. Research on farmers’ behaviour can contribute to solve the problems in the Mekong Delta by gaining more knowledge about developments and choices of farmers. This research focussed on four types of shrimp farming: intensive, improved intensive, extensive and Integrated Mangrove Shrimp (IMS). IMS is considered to be the most sustainable option.
The purpose of this study is to create an Agent Based Model (ABM) that can determine social processes between farmers in the Mekong Delta, Vietnam. It is part of the ALEGAMS project and contributes to a bigger research about shrimp farming. It is based on previous research that resulted in an ABM about shrimp farming. Social processes are important to determine the choice for shrimp farming types. This was shown in earlier fieldwork and many other researches. The ABM is lacking these social processes, therefore new research was needed.
This study consists of a literature study about the current developments in shrimp farming and a research about social processes between agents in ABM’s. Resulting from the literature study, the consumat theory was used to develop a survey for data collection conducted in Vietnam in the Tra Vinh province. This theory was used to define behaviours and parameters to create a new model, called the consumat model. Inquiring, optimizing, imitating, and repetition behaviour influenced the choice of farming type by farmers. Collected data was used to create the consumat model in GAMA, representing the reality in a simplified version. The fieldwork showed correlations between satisfaction, uncertainty, hectare and income. These are used as a base for the development of the ABM. Probabilities measured in the field showed that farmers shifted to intensive shrimp farming in 90% of the cases. Scenarios were compared to a basemodel to validate the parameters used in the model. It showed that the probabilities were barely influenced by the parameters.
The developed consumat model can be used to show the influence of social processes in decision making by farmers in Vietnam. It shows that farmers have a preference to change towards intensive farming, this was always the same in the outcome of the model. But the behaviour types of the farmers were affected by changes in the parameters. For instance, it changed the timeframe to reach the equilibrium where most of the farmers had changed to intensive farming. Showing that social processes do have influence on the decisions of farmers. The consumat model can contribute in a better insight in the social processes between shrimp farming in the Mekong Delta.
Keywords: Agent Based Model; consumat theory; social behaviour; Mekong Delta; Complex Adaptive Systems; mangrove.