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Effect of the Emergency Drought Barrier on the Distribution, Biomass, and Grazing Rate of the Bivalves Corbicula fluminea and Potamocorbula amurensis, False River, California

Open-File Report 2021-1088
Prepared in cooperation with the Bureau of Reclamation
By: , , and 
https://doi.org/10.3133/ofr20211088

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Executive Summary

Benthic samples were collected from the Sacramento–San Joaquin Delta of northern California to examine the effect of the changing hydrologic flow on the bivalves Potamocorbula and Corbicula before, during, and after the False River Barrier (hereafter, barrier) was in operation (May–November 2015). Potamocorbula moved upstream in the Sacramento River as the salinity intruded. Given the lower electrical conductivity of the San Joaquin River, Potamocorbula did not move as far upriver as it did in the Sacramento River. Potamocorbula recruits settled in the Sacramento and False Rivers, whereas Corbicula recruits were mostly found in the San Joaquin River. When the grazing rates for the two bivalves were combined, new populations of Potamocorbula plus existing Corbicula likely reduced the net growth rate of the phytoplankton in and just upstream from the Sacramento and San Joaquin River confluence region when the barrier was in place. Prior to the barrier installation, a very dry period assumably aided the success of Potamocorbula in the confluence region; nonetheless, they also responded to the increasing salinity in the Sacramento River and their population spatially expanded. Potamocorbula’s upriver incursion was stopped owing to the return of freshwater flow due to the removal of the barrier, but the adults of the species were still present at the upstream end of Decker Island in January 2016. Corbicula adults did not seem to respond to the increased salinity caused by the barrier and maintained their biomass at all locations compared to what was recorded before the barrier.

Suggested Citation

Parchaso, F., Zierdt Smith, E.L., and Thompson, J.K., 2021, Effect of the emergency drought barrier on the distribution, biomass, and grazing rate of the bivalves Corbicula fluminea and Potamocorbula amurensis, False River, California: U.S. Geological Survey Open-File Report 2021–1088, 22 p., https://doi.org/10.3133/ofr20211088.

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Executive Summary
  • Hypotheses of Bivalve Response
  • Study Rationale
  • Results
  • Conclusions
  • Referenced Cited
  • Appendix 1
Publication type Report
Publication Subtype USGS Numbered Series
Title Effect of the emergency drought barrier on the distribution, biomass, and grazing rate of the bivalves Corbicula fluminea and Potamocorbula amurensis, False River, California
Series title Open-File Report
Series number 2021-1088
DOI 10.3133/ofr20211088
Year Published 2021
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) WMA - Earth System Processes Division
Description vii, 22 p.
Country United States
State California
Other Geospatial False River
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details