Paradigm or Paradox: Can We Attribute Species Changes to Global Climate Change in Light of Decreasing Water Temperatures in Central California?

Overall and since the late 1970s, there has been a warming of upper waters of the California Current off California, a decline in its biological productivity (i.e., phytoplankton abundance), and an increase in the number of warm-water species. Superimposed on this warming trend, waters off Central California have experienced a period of cooling since 2000. The goal of this project is to explore the effects of basin-scale climatic variability on pelagic species abundances in Central California. To date, scientists have collected nine datasets that describe relative fish abundances in the region and are in the process of comparing trends to a basin-scale climate index developed by the CeNCOOS (Central and Northern California Ocean Observing System) program. The index combines sea surface temperature, salinity and chlorophyll-a measurements to estimate ocean productivity. Preliminary results show high correlations between the index and fish abundances. In the final months of the project, researchers will finalize their analyses and present their findings at the 2012 Western Groundfish Conference.