The state of the California Current in 1998-1999: Transition to cool-waterconditions

This report reviews and provides a preliminary interpretation of recent obs ervations made by CalCOFI (California Cooperative Oceanic Fisheries Investi gations) and other programs sampling the coastal waters of the Californias, Since this is a continuation of a series of annual reports, the emphasis h ere is upon observations made during the past 18 months, but longer-term tr ends must also be considered. The major change in oceanographic structure i n the past year was the transition from strong El Nino conditions in early 1998 to cool-water, La Nina conditions in early 1999. Ecosystem structure a lso showed large changes during this period. Phytoplankton abundance during 1998, as indicated by chlorophyll concentration, was typical of the values seen during the last decade, but it appeared to be increasing in early 199 9 in association with the transition to cool-water conditions. Macrozooplan kton biomass during 1998 continued the long-term trend of low values which have been seen since the mid-1970s regime shift, and El Nino-related change s were superimposed upon this trend, The 1999 macrozooplankton data are not yet available to assess whether biomass is increasing. Observations made a t coastal shore stations, in southern California kelp forest communities, i n central and northern California, and in Baja California, Mexico, are cons ider-ed in order to place the CalCOFI observations in a larger regional con text. Because this year marks the fiftieth anniversary of the CalCOFI progr am, we use the discussion to consider future directions for the time-series program and how the CalCOFI data can be put to greater use at the regional , state, and national level.