Potential Transport of Harmful Algae through Relocation of Bivalve Molluscs

EPA Grant Number: R831704
Title: Potential Transport of Harmful Algae through Relocation of Bivalve Molluscs
Investigators: Shumway, Sandra E.
Current Investigators: Shumway, Sandra E. , Gary H, Wikfors , Joann, Burkholder
Institution: University of Connecticut
Current Institution: University of Connecticut , NOAA-NMFS , North Carolina State University
EPA Project Officer: Hiscock, Michael
Project Period: September 1, 2003 through September 1, 2007 (Extended to December 31, 2008)
Project Amount: $477,526
RFA: Ecology and Oceanography of Harmful Algal Blooms (2004) RFA Text |  Recipients Lists
Research Category: Aquatic Ecosystems , Ecosystems , Water


Published records and other data clearly indicate that cells and cysts of many HAB species can pass intact and viable through the digestive tracts of bivalve molluscs. These cells and cysts are capable of establishing new cell cultures under laboratory conditions. Shellfish are routinely transplanted between areas during normal aquaculture, shellfishing, and shellfish restoration practices. While the potential role of bivalves as vectors of HAB species has been recognized by many authors, their actual role in this process has not been examined. We propose a three-year study to assess potential pathways of introduction and consequences of shellfish transfer (commercial or personal) on HAB distribution, i.e. to determine the risk of transferring toxic algal cells/cysts during transport of live bivalves between sites, and to establish and evaluate mechanisms to minimize these risks using best management practices (BMPs). In addition to establishing means of mitigation and control, we have also included a strong outreach education component because we believe that education will play a major role in stemming or slowing the transfer of HAB species by way of shellfish movement.


Our major objectives are to: (1) determine which algal species pass intact and viable through the digestive tract of commercially important bivalve molluscs; (2) determine the extent to which washing and purging shellfish intended for transfer can slow or eradicate the potential transfer of HABs; (3) determine when bivalves are safe to transport following exposure to HAB species; (4) assess field populations in areas of known HAB outbreaks for the presence of viable cells/cysts in resident shellfish populations during non-bloom periods; and (5) provide information to the user groups through presentations, management agencies, trade publications, pamphlets, and web pages.


We will address these questions using standard laboratory techniques and well-established experimental protocols to determine rates of uptake, retention, and elimination of toxic cells/cysts, as well as excystment and release from fecal strands and the subsequent culture of viable cells. In collaboration with industry we will design, apply, and evaluate management strategies and BMPs.

Expected Results:

This research will be valuable to aquaculturists, watermen, processors, and managers for public health, and will assist in both habitat management and preservation of habitat integrity. Understanding the vectors for transfer of HAB species is critical to responsible environmental stewardship. This study specifically addresses special emphasis areas 1 and 4(b)–prevention and mitigation strategies, and the sources, fates, and consequences of HABs in food webs and fisheries. Results from this study will ensure that the user groups are provided the most current information available, in a useable format, to control and mitigate impacts of HABs on public health, shellfish aquaculture, and the environment.

Publications and Presentations:

Publications have been submitted on this project: View all 39 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 6 journal articles for this project

Supplemental Keywords:

human health, aquatic habitat, decision making, public good, global, RFA, Scientific Discipline, Water, Ecosystem Protection/Environmental Exposure & Risk, Health Risk Assessment, Oceanography, algal blooms, Environmental Monitoring, Ecological Risk Assessment, marine ecosystem, shellfish transport, bloom dynamics, human health

Progress and Final Reports:

  • 2004
  • 2005 Progress Report
  • 2006
  • 2007 Progress Report
  • 2008
  • Final Report