This study, undertaken by AZTI-Tecnalia, involved analysing the chain of marketing of the tuna fish, from the catch in the almadrabas to its freezing - the aim being to design a monitoring system adapted to this mode of fishing -, to its handling and processing and to the first stages of marketing the product. The end target is the design of an identifying label that enables the association of the product with the monitored information. Until now, most of the work has been concentrated on the FRIALBA frozen fish plant, in Barbate (Cádiz), recently built with the aim of improving the handling and preparation processes for red tuna for its subsequent marketing. The tuna arrives at the plant directly from the almadrabas and here classification, topping, gutting and cutting up takes place. The fillets are extracted and frozen at -60ºC for their subsequent marketings, both on the national market and on the Japanese one. Japan is the largest market in the world for tuna (it absorbs 30% of the world's production). The consumption there, basically aimed at the preparation of sashimi, has taken off in the past few years and, thus, imports as well. The sashimi market is, moreover, the most profitable in the world, given that the tuna can reach prices 30 times greater than that which will end up tinned. Monitoring systems are acquiring great importance in the food sector although it has to be pointed out the novelty of its introduction into the fish extract sector and the first stages of the marketing chain of the fish. To this is added the peculiarity of the application of the almadraba system for catching tuna. Currently five exist in Spain all of these in Andalusia.