Game theory was used to analyze the extraction behavior of fishermen around the Southern  Sonkhla Lake in Southern Thailand. The field experiments were designed based on the concept of non-cooperative game theory for investigating fishermen’s behavior in response to four management policy  options: external regulations with individual transferable quotas (ITQs) and with individual quotas (IQ), and  co-management with ITQs and with IQ.

The analysis examined fishermen’s responses under high and low fish stocks that arose due to  seasonal salinity in the Lake. Higher fish stocks encouraged fishermen to increase their extraction. A co-management policy led to better results than imposed external regulation in terms of reducing extraction  and ensuring resource sustainability. There were no significant differences between ‘with ITQ’ and ‘without  ITQ’ in terms of reduction of extraction and sustainability of resource use. However, there were significantly  less violation behaviors when ITQs were used rather than with IQ. The ITQs provided more flexibility for  fishermen who wanted to increase their extraction while still following conservation guidelines. Therefore,  implementation of ITQ is recommended but with appropriate penalties.