Abstract:
Since 1961, the tuna catches off the south coast of Portugal with tuna pound nets (madrague type) have decreased progressively. After 1965, this decrease has reached such proportions, that the canning industry has become seriously affected. However, the lack of data prevented an oceanographic interpretation of this situation. By decision of His Excellency the Minister of the Navy, the Instuto Hidrográfico organized, after 1971, several cruises off the south coast of Portugal, MALAC, to measure temperature distributions along with the transparencies of the surface layers of the ocean, physical characteristics believed to be related to the tuna environment (habitat)
