The bluefin tuna (Thunnus thynnus, Linnaeus 1758) is a large pelagic fish in the family Scombridae . This species is widespread in all tropical waters, subtropical and temperate Atlantic Ocean including the Mediterranean Sea and the southern Black Sea, more frequent the waters off the coast and near the coast only at certain times (different from place to place) and at certain points, usually around islands and headlands. Spawning occurs in summer in waters slightly close to the coast than in other busy periods. The tuna pass by a wrong phase, during which they move in small groups very dense, consisting of fish of the same size, then get together in groups more dense during the gregarious phase, which coincides with the beginning of the breeding season. At this time the tuna migrate to spawning areas in many schools. The Atlantic bluefin tuna arrive for example in the Gulf of Mexico between January and June of each year, females of the species spawn in surface waters, which are then fertilized by the males mostly between April and May when its ten million liters of oil per day were discharged into the ocean, following the explosion of the oil rig 'Deepwater Horizon ", on 20 April. And 'the case to say that "it is raining in the wet" as the statistics tell us that spawning in this species has already declined by 82% over the last 30.
In the large Gulf of Mexico tuna eggs deposited mostly in two areas: one in the north west that seems to remain immune from the taint of oil spills and a north-east instead for the matches more with the black spot, causing a decrease of more than 20% in the small bluefin tuna. Most data come from the Envisat satellite and other satellites are able to develop European and international weekly maps that show location, shape and size of the black spot. Valuable data also required by the "Ocean Foundation, a nonprofit organization dedicated to protecting the ocean environment and its species to know exactly the places where the conditions for spawning may be more favorable.
E 'was used for this purpose an elaborate method that compares the maps of the oil with other maps for other reproductive indices (presence of plankton, water temperatures, ocean surface height) to see where and how the stain and habitats can be stacked in the period between April 20 and August 29.
Earth observation satellites have played a key role in assessing the magnitude of the disaster that is why the ESA is present with a stand at the 10th Conference of Parties of the UN Convention on Biological Diversity (COP 10), which held this week in Nagoya, Japan, and has as its theme the protection of natural habitats.
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