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Pacific Southwest Research Station


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Pacific Southwest
Research Station

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Emerald Bay control and management: stressors and mechanisms controlling Asian clam populations in Emerald Bay

Principal Investigators:
Allison Gamble, John Reuter, and Geoff Schladow, University of California-Davis
Sudeep Chandra, University of Nevada-Reno

Proposal [pdf]

Final Report [pdf]

Project Summary

The Asian clam (Corbicula fluminea) is identified as an aquatic invasive species that is well established in Lake Tahoe. First recorded in Lake Tahoe in 2002, Asian clam densities of up to 5,000 individuals-m-2 have since been reported, and its range has expanded substantially throughout much of the Lake’s southeastern area. The Asian clam often dominates the benthos where it occurs in Lake Tahoe. It is associated, but not necessarily the cause of, filamentous algal blooms, and deposition of clam shells in the nearshore is considered a degradation of aesthetic conditions in Lake Tahoe.

Emerald Bay is a special management area, and there is strong interest from resource and regulatory agencies in preserving its natural character. The clam population discovered in 2009 was considered localized in extent, and of low density; thus, it was thought to have the potential for treatment in its entirety. However, the special designations of Lake Tahoe and Emerald Bay limit the methods available to control clam populations to mechanical treatments. In 2010, Agency personnel decided to pursue a large-scale clam control project in Emerald Bay using benthic barriers supplemented with organic material. Implementation of this project occurred between 2012 and 2014.

Benthic barrier and organic material deployment (and in-progress redeployment) to treat the Asian clam population in Emerald Bay occurred under the direction of agency personnel. Science investigations associated with benthic barrier deployment occurred under the direction of University of California, Davis, and University of Nevada, Reno personnel, and focused on:

  1. Assessing the effects of a large-scale benthic barrier deployment on the Asian clam population in Emerald Bay. Results of this assessment are reported in Appendix A.
  2. Investigating how dissolved oxygen, nutrients, and food supply may influence the survival, and reproduction of the Emerald Bay clam population under the barrier treatments. Results from dissolved oxygen and nutrient investigations are reported in Appendix B. Results from food supply investigations are reported in Appendix A.
  3. Determining whether augmenting benthic barriers with organic material can further influence the survival or reproduction of the Emerald Bay Asian clam population. Results of this assessment are reported in Appendix B.

This document presents key findings from the investigations described in Appendixes A and B, with the aim of answering the question of how to optimize the effectiveness of benthic barriers to treat the Asian clam population in Emerald Bay.

Last Modified: Aug 29, 2016 09:50:06 AM