Decomposition of aquatic product price fluctuation based on X12-HP model

This article used X12 seasonal decomposition and H-P filtering method to decompose the wholesale price of China's four types，28 kinds of aquatic products into four fluctuation types，which were trend fluctuation， cycle fluctuation，seasonal fluctuation and stochastic fluctuation，and analyzed the fluctuation characteristics and variation law of different types of aquatic products price. The results showed that price of different types of aquatic products kept different trend fluctuation，and the difference also existed in the same type；the seasonal fluctuation of freshwater fish，marine fish，shrimp and crab’ price generally showed inverted“ V” shape，the seasonal fluctuation of shellfish price showed a linear decline from the beginning to the end of the year. The time span of freshwater fish， marine fish，shellfish’ cycle fluctuation was about 2 years，but shrimp and crab cycle fluctuation was just more than 10 months. The impact of stochastic fluctuation，seasonal fluctuation，cycle fluctuation on freshwater fish and marine fish’s price was relatively small and changed little during the inspection period，but the impact of stochastic fluctuation，seasonal fluctuation and periodic fluctuation was relatively larger and had a tend to weaken. Based on the analysis conclusion，we proposed some suggestions including adjusting the structure of aquatic production， strengthening market monitoring and early warning，building risk prevention system of industry.