The great stocks of sardines and anchovies, and other small pelagic fishes, account for about one third of the world's yield of marine fish and are of key economic importance in many nations. Production from these great stocks depends upon a delicate balance of physical ocean processes. Without a doubt, global heating will alter this triad of physical processes. The most immediate response to greenhouse warming would occur within the atmosphere rather than within the ocean, affecting the wind field over the ocean, and hence, patterns of upwelling. Thus global climate change could substantially alter these factors that determine favorable reproductive habitat long before ocean temperature changes due directly to greenhouse warming may be evident.
Some initial scenarios are already available.
One important result of this project was to establish the existence of recurrent patterns between the environment and the pelagic fish dynamics. The aim of the CEOS project was to enlarge this analysis through a comparative approach and to generalize previously obtained results. Upwelling ecosystems in the Pacific are dominated by large interyear variability whereas in the Atlantic they are characterized by a more seasonal variability. To compare the dynamics of two different functioning upwelling systems would help to understand the impact of environmental constraints on pelagic fish dynamics. Through the CEOS network it was possible to assemble and compare knowledge and data that were collected during several decades in the different upwelling areas.