Interactions between the near-coastal ocean and the San Francisco Estuary

• Fleishman, Erica

Abstract
The aim of this working group is to identify, analyze, and synthesize existing data on interactions between the near coastal ocean and the San Francisco Estuary with a non-exclusive focus on declining pelagic fishes. Substantial changes in the biological communities of San Francisco Bay may have occurred in response to a state change in the California Current system after 1998. The state change was characterized by increased upwelling, enhanced primary production, and strong southerly flow. These changes in the near coastal ocean were associated with increased biomass of phytoplankton, new seasonal phytoplankton blooms, declines in the distribution and abundance of bivalve mollusks, and high abundance of several predators of bivalves in San Francisco Bay. Processes in the near coastal ocean may have direct or indirect influences on abundance and survival of several fishes of management concern, including longfin smelt, striped bass, and possibly delta smelt. Changes in the near coastal ocean might also influence survival of outmigrating juvenile salmonids, including Chinook salmon and steelhead rainbow trout, as they enter the ocean. These results indicate that proper understanding and management of the San Francisco Estuary requires knowledge of ocean processes as well as riverine and internal estuarine processes. The working group will attempt to examine the relative influence of processes in the near coastal ocean on the fishes and other organisms in the San Francisco Estuary.