Boom and bust cycles in seafood prices

A great number of public/private founded researches have analyzed the causal relationship among different potential drivers for prices, such as demand and supply growth, changes in prices of raw materials and other inputs as well as the policy about stocking. Some analysts suggest that recent price developments are mainly explicable by market fundamentals i.e. supply and demand; however, other phenomena are important such as weather conditions, volatility in exchange rates, the increasing finance activities, etc in agricultural commodity markets. According to collected secondary information, price differences have been identified over; (i) several market levels (first sale, retailers price and marketing strategies/margins); (ii) price differences over geographical area (regionally and internationally import price); (iii) by quality attributes (source of raw material, the size, level of processing); (iv) the period of time (seasonal and cycle variations, trends, and random behavior). Moreover, some prices show different trends according to place of wholesale markets, fish size and seasonality. In order to find the features of the prices development without the impact of seasonality, a "boom and bust" model has been developed for seafood products. This model is based on a "law" in the temporal evolution of the events and it is composed by three components not directly observable: (i) trend is the underlying structure of the phenomena considered, often expressed by a polynomial function of degree not too high; (ii) cycle is the fluctuations around the trend; (iii) seasonality consists of the changes that occur with similar intensity in the same periods every year.