USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Natural and human limitations to Asian clam distribution and recolonization—factors that impact the management and control in Lake Tahoe

Principal Investigators:
Marion Wittmann, now at University of Notre Dame
Sudeep Chandra, University of Nevada-Reno
John Reuter, University of California-Davis
Geoff Schladow, University of California-Davis

Proposal [pdf]

Final Report [pdf]

Additional Reports:
Denton et al. 2012 [pdf]
Wittmann et al. 2012a [pdf]
Wittmann et al. 2012b [pdf]
Wittmann et al. 2013 book chapter (pdf not available for distribution due to copyright)

Please contact Dr. Sudeep Chandra with questions regarding the reports.

Project Summary

The invasive Asian clam (Corbicula fluminea) is established and shows signs of spreading in Lake Tahoe. In 2002, low density populations (2‐20 individuals per m2) were observed in the south eastern portion of the lake, and in 2009 densities up to 5000 individuals per m2 have been measured. Through extensive field collection and laboratory experimentation, the University of California-Davis (UCD) and University of Nevada-Reno (UNR) science teams have found that this expanding population comprises the majority of benthic community biomass in regions where it has established, is associated with filamentous algal blooms, and (through shell deposition) has negatively impacted the aesthetic value of the Lake Tahoe nearshore.

In response to this nearshore invasion, federal and state agencies collaborated with UCD and UNR to develop a short term Asian clam management plan and implement a series of studies to understand the distribution, life history and reproductive strategies of this species in relation to population control.

The major objectives of this research were to:

  1. Understand the life history (including reproduction and growth) of deepwater clam populations and their response to habitat, water currents and nearshore clam populations as a potential habitat for viable populations.
  2. Develop the relationship between treatment site selection (i.e., low population density site versus high density population center site) and rate of Asian clam recolonization rates.
  3. Estimate recolonization following a rubber bottom barrier application and perform a cost-efficiency analysis based on recolonization rate and site selection.