Integrated and collaborative ecological and socio-economic modelling for sustainable razor clam management at Don Hoi Lord Ramsar site, Thailand

Worrapimphong Kobchai. 2010. Integrated and collaborative ecological and socio-economic modelling for sustainable razor clam management at Don Hoi Lord Ramsar site, Thailand. Bangkok : Chulalongkorn University, 255 p. Thesis Ph. D. : Agricultural Technology : Chulalongkorn University

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Encadrement : Le Page, Christophe ; Gajaseni, Nantana

Résumé : Don Hoi Lord wetland located near Mae Klong river mouth in the area of Samut Songkhram province, upper the Gulf of Thailand. The wetland was registered as the 1099th Ramsar site. Razor clam (Solen spp.) is an important species in the sandbars which are a part of this wetland. Fisherman has harvested razor clam for generating income more than 2 generations. Due to the previous studies, razor clam population has decreased through the time. The objective of this study aims to explore possible sustainable management policies for Don Hoi Lord by using Companion Modelling approach (ComMod). The approach mainly consists of Agent-based simulation model (ABM) and participatory simulation workshop with stakeholders involvement. To achieve the aim of the study, there are 3 parts including: 1) ecological study of razor clam population and its environmental factors especially sediment and particulate organic carbon (POC) between June 2008 - May 2009; 2) socio-economic study to understand fisherman harvesting behavior and razor clam market mechanism; and 3) ABM development from field study finding and test the management scenarios with the ABM. Moreover, the ABM was used in participatory simulation workshop to validate the ABM and to exchange and discuss on razor clam sustainable management.The results from ecological study showed that razor clam population was in crisis due to the decreasing of population. Mean density of razor clam was 0.51±0.30 clam/m2 which has been the lowest record among previous scientific studies since 1982. In addition, razor clam density had negative correlation with %organic matter in soil sediment and particulate sediment in water column (p < 0.05) but it was not correlated with POC. Razor clam market is being driven by a trader who buys all razor clam from a fisherman and processed razor clam as clam meat before distributing to market. The trader set razor clam buying price from fisherman independently based on their razor clam stock and a current market demand. Razor clam demand usually was increased during weekend and, presently the trader distributing processed razor clam to a restaurant and a merchant in fresh market. Regarding fisherman, there were 2 factors affected fisherman's decision to harvest razor clam, firstly the density of razor clam and secondly razor clam price. Due to the low razor clam density, fisherman had to harvest on other species instead of razor clam but razor clam is still the first priority. The ABM development was done by added i-stage distribution model and re-calibrated until the simulation model represented system behavior. Then, the management scenarios were tested with the ABM and it was found that reserved zoning accompany with quota system was the best scenario for sustaining razor clam population. Next, spatial interface of the ABM was upgraded based on socio-economic finding and the upgraded ABM was used in participatory simulation workshop with stakeholders. The workshop can be a forum for discussion among stakeholders by using ABM as mediator and stakeholders in the workshop which could share their representations for collective agreement to achieve the goal. Finally, the whole process of ComMod at Don Hoi Lord by communicating and coworking between researcher and stakeholders in the field study could help them instituted the group to working on sustainable management by implementing a reserved or forbidden zone on the sandbar at Don Hoi Lord.

Mots-clés Agrovoc : Solen

Mots-clés géographiques Agrovoc : Thaïlande

Mots-clés complémentaires : Solen regularis

Classification Agris : M11 - Production de la pêche
L20 - Écologie animale
U10 - Informatique, mathématiques et statistiques
P01 - Conservation de la nature et ressources foncières
E16 - Économie de la production

Champ stratégique Cirad : Axe 6 (2005-2013) - Agriculture, environnement, nature et sociétés

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