The meat of the Atlantic Bluefin Tuna (also known as Red Tuna in Spain) has long been a prized item in the gastronomy of Spain and the western Mediterranean. These majestic fish, weighing up to 200 kg (and definitely not a small round fish that fits neatly into a tin), normally live in the cold waters of the Atlantic, but every spring they migrate along the west coast of Spain and through the Strait of Gibraltar to lay their eggs in the warm waters of the Mediterranean. And it’s along the southwest coast of Spain, in the fishing towns of Zahara de los Atunes, Conil, Barbate and Tarifa, that they are trapped using the traditional method of the Almadraba.
The season is brief, starting following the full moon in late April or May. The Almadraba is a system of nets that drive the tuna into a central pond, where they are forced to the surface and are hauled into the fishing boats to be slaughtered. This allows the fisherman to select the best fish, the rest being released to continue their journey, making it a sustainable way of harvesting the bounty of the sea. The fish are normally flash frozen to be sold at auction. The local bars and restaurants in Seville will often buy a tuna, which will last them through the year, being taken from storage to be used as required.
The filleting of a tuna, in which the head, tail and fins are removed, and the different cuts separated from the backbone is called the ronqueo (literally, snoring, after the sound of the knife running along the spine of the fish), and an expert can complete the job in about twenty minutes.
The tenderest cuts, especially the ventresca (belly), are of often served raw or marinated. Other parts are usually grilled. Almost all the fish is consumed, including organs and cheeks (considered by many as a great delicacy). Many of the minor cuts, such as Morrillo (collar), were once the food of the poor, retained by the fisherman when the bulk of the fish was sold, but have since become gourmet items.
There are also various Rutas de Atún (Tuna Routes) this time of year, where you can see the fish being caught and prepared.