In this paper we examine the price transmission of fresh megrin in the Spanish market of fresh fish products at three different levels of the marketing chain: source, wholesaler and retail, using weekly price series for the period 1993-2001. We carry out a cointegration analysis of the system formed by the three prices in logs. Our results show the existence of two cointegration relations. We also study the causality in the short and the long run, and the results reflect two strong prices; the wholesaler price and the retail price, and a weak price at source. From the cointegration study and the map of causalities, two price transmission relations are derived, a perfect one (from the wholesaler price to the price at source) and an imperfect or partial one (from the wholesaler price to the retail price). Finally, a sensitivity analysis is performed with respect to the time period considered. As we consider more recent data to construct the time period analysed, we detect that the former partial transmission approaches a perfect price transmission, and the retail price becomes the only strong price.

Key words: fishing markets, price transmission, marketing margins, cointegration, error correction model, Granger-causality.
JEL classification: Q13, D12.