The Simulation of Drifting Dead Pigs in the Sea

In 2017, dead pigs infected with African swine fever were found on the beach of Tianpu, Kinmen, an offshore island of Taiwan. After the event, the Kinmen government carried out a thorough pig farm quarantine. However, none infected pig was found in any of the pig farms. This study aims to identify where the dead infected pig came from. Affected by ocean currents, marine drifts can often reach hundreds or thousands of kilometers away from their origins. During the winter, ocean currents across the north of the Taiwan Strait from west to east may transport the pigs from the coast of Fujian and Zhejiang, China, to the coast of north-central Taiwan. Another possible driven force is the near-shore current of western China. In order to analyze the possible drifting path of pigs, the hydrodynamic model and the particle tracking model were applied. Pigs were simulated as mass particles. The simulation domain includes sea area nearby Kinmen and China where pigs may originate. Considering the effect of the currents and wind from 2018/12/26 to 2019/1/3, three possible drift scenarios were set for analysis, including (S1): originated from Weitou Bay; (S2): originated from Jiulong River estuary; (S3) originated from the coast of Quanzhou. The results showed that the most possible scenario is S3.