Long-Term Seasonal Trends in the Prey Community of Delta Smelt (Hypomesus transpacificus) Within the Sacramento-San Joaquin Delta, California

JOSEPH E. MERZ, PAUL S. BERGMAN, JOSEPH L. SIMONIS, DAVID DELANEY,
JAMES PIERSON and PAUL ANDERS

The authors examined zooplankton community dynamics in the San Francisco Estuary, California. They present the first evidence of a shift in zooplankton species that are key prey items of delta smelt, which may have exacerbated well-documented food limitations of delta smelt since the invasion of the overbite clam. Future conservation efforts in the estuary should consider measures designed to restore the timing and magnitude of pre-invasion phytoplankton blooms.