Environmental Assessment of the Set-net Operation in Rayong Province, Thailand

Abstract

Environmental assessment of set-net operation in Mae Rumphueng Beach, Rayong Province was evaluated during 2013-2014. Field surveys around the set-net fishing ground were conducted in the beginning (October 2013), middle (January 2014), ending (April 2014) periods of the operation and six months after the operation ending (October 2014). The results of paired t-test showed that acid volatile sulfide (AVS) of the bottom sediments within set-net A, set-net B and the reference area from four periods were not significantly different (p>0.05). Additionally, average amount of AVS including set-net A, set-net B and the reference area in the beginning (0.0011±0.0018 mg/g dry), middle (0.0026±0.0029 mg/g dry) ending (0.0028±0.0028 mg/g dry) and after-ending (0.0053±0.0117) were much lower than the criteria value for critical farm (2.5 mg/g dry proposed by Yokoyama, 2003). The density of benthic macro-fauna during middle and ending periods in set-net area were significantly higher than those in other areas; whereas those during beginning and after-ending periods were not significantly different. These results indicated that set-net operation did not relevant to the polluted substance, AVS, but had an influence in the increasing of benthic macro-fauna density during the operation season, which was recovered to the initial condition after removal of gear construction.