Studying the relationships between men, seas and climate
The oceans provide cheap food to many people in the world. Thus, the economic weight of fisheries is considerable. Or there is, for several years, a stagnation of this manna that seemed inexhaustible, and a decline in the size of fish. This does result of overexploitation of marine species of global warming or the combination of these two factors? What changes can we predict today?
Scientists now have the means to answer these questions. To this end, the Eur-Oceans program, supported by the European Union, has just been launched in Paris. Its scientific director is two Frenchmen: Paul Tréguer, director of the European University Institute of the Sea (Brest, France). Finistère) and Louis Legendre, head of the oceanographic laboratory at Villefranche-sur-Mer (Alpes-Maritimes). But "to understand what will happen in the next fifty years, it is necessary to know what has happened in the last fifty years," said Mr. Tréguer at the conference Eur-Oceans which was held in Paris the 14 and 15 April, and which was opened by François d'Aubert, Minister Delegate for Research.
Indeed, marine ecosystems are proving much more complex to understand than their terrestrial counterparts, especially as they interact. Their response to the hydro-climate change will also be more brutal than on land. To understand them, it is necessary to gather technical means (satellites, ships, buoys, models) and today dissociated skills: marine physicists and chemists, marine biologists experts and specialists with a modern approach to fisheries .
Studying the interactions between climate, oceans and marine ecosystems at the global level, Eur-Oceans will focus on key regions: the North Atlantic, coastal systems and the Southern Ocean. 160 scientists belonging to 66 25 Marine Institutes country should work for this program. France participates through the CNRS, Ifremer, IRD, CEA and CNES. The project budget amounts to 40 million over four years, of which 30 is provided by research organizations and 10 by the European Union. Eur-Oceans has the status of "network of excellence" whose main objective is to remedy the fragmentation of European research. It is also associated with the international Imber program (Integrated Marine Biogeochemistry and Ecosystem Research), headquartered in Brest. Collaborations are also planned with the United States, Canada, Australia, Japan and Namibia.
The loss of cod off the coast of Canada has touched many minds and raised awareness. After a period of stability, the results of the cod fishery experienced, in 1992, a sudden collapse. Canadian authorities have banned the fishery for 10 years, but it is still expected to return to the area. At the root of the problem, a modification of a component of the ecosystem due to humans. By a phenomenon of trophic cascades, we now find in the region many shrimps and crabs. Seals, predators of cod, have increased their catches, decreasing the number and size of cod, and thus the amount of eggs. However, "when we are small, we are eaten by everyone because the size of the mouth is linked to predation," says Philippe Cury, director of the Mediterranean and Tropical Fisheries Research Center (Ifremer, Sète, Hérault). "Now," he says, "we need to develop an ecosystem approach to marine resources, whereas in the past we looked at the problem in a sectoral way. "
Suite and source: Christiane Galus, Le Monde, 15 / 04 / 05 bbc