THE STATE OF THE CALIFORNIA CURRENT IN 1995-1996 - CONTINUING DECLINES IN MACROZOOPLANKTON BIOMASS DURING A PERIOD OF NEARLY NORMAL CIRCULATION

The large suite of environmental data collected routinely in the coast al region of California provides the basis to make timely assessments of environmental structure that can be updated continuously Here we de scribe and interpret data collected during the previous 18 months. The emphasis is upon data collected on CalCOFI time-series monitoring cru ises and at coastal shore stations. Spatial pattern is described, and the data are interpreted in the context of anomalies from long-term me ans. The pattern of circulation in the California Current uas similar to the long-term mean during most of 1995. Circulation in early 1996 w as anomalous in that February was marked by a strong mesoscale structu re and a lack of the normal coastal countercurrent in the Southern Cal ifornia Eight. April 1996 was also a period of strong mesoscale struct ure, and the California Current was displaced farther offshore than no rmal. The springs of 1995 and 1996 were periods where the surface wate rs of the coastal region were enriched with cool, high-nutrient water, and the chlorophyll concentration and primary production were high. I ndices of environmental structure based upon coastal shore station dat a provided contradictory signals of the forcing processes causing this biological structure. Sea-surface temperatures at coastal shore stati ons were warm, and the upwelling index was anomalously low during the springs of 1995 and 1996, suggesting a pattern of low nutrient inputs and primary production. However, direct measurements on the CalCOFI su rvey cruises showed strong upwelling-favorable wind, and that cool, hi gh-nutrient, and high-production water was present over a large area o f the coastal region. It appears that structure during the study perio d in the coastal waters of central and northern California was similar to that in the CalCOFI study region. In spite of strong forcing and h igh primary production, macrozooplankton biomass continued the long-te rm trend of large decline which began in the mid-1970s.