Theme representatives: J. Alheit, T. Baumgartner

The focus of Theme 1 is to explore how fish populations respond to ocean climate over time spans of hundreds to thousands of years. Long time series of data and modelling are used to determine how variation in the coupled ocean-atmosphere climate system affects the ecosystems in which small pelagic fish are important. It has a global and atmospheric perspective because climatic teleconnections are believed to be involved. The paleoecological component is driven by the fundamental discovery that anoxic sediments in regions with small, pelagic fish contain scales that can be used to reconstruct time series of abundance of those fish over thousands of years.
Three meetings related to Theme 1 were held over the last two years. “Major Turning Points in the Structure and Functioning of the Benguela Ecosystem” was the topic addressed by a GLOBEC-SPACC/IDYLE/BENEFIT meeting (Cape Town, South Africa, 12-16 February 2001). This meeting was the first of a series of similar workshops that will investigate turning points in other regions of the world that support large populations of sardine and anchovy. The Cape Town meeting was followed by a GLOBEC-SPACC/IAI workshop on "Comparative Studies of Long-Term Variability of Small Pelagic Fishes in the Humboldt and California Current Ecosystems" (Lima, Peru, 29 May-1 June 2001). Finally, a SPACC/GLOBEC Workshop on Paleoceanography (Munich, Germany, 10-13 October 2001) brought together research teams carrying out high resolution analyses of sediment cores from different anoxic sites in order to compare and cross-calibrate methodologies and co-ordinate future co-operation and comparisons. Overviews of the outputs of those three meetings were published in the April 2001 and April 2002 issues of the GLOBEC Newsletter.

A workshop, "SPACC in the Kuroshio System”, was held 9-10 December 2003 at the Ocean Research Institute, University of Tokyo, Japan). This workshop included presentations of time series concerning anchovy, sardine, and herring in the North Pacific, as well as other regions, and possible mechanisms for the observed fluctuations.