Aquaculture of Triploid

Crassostrea ariakensis
in Chesapeake Bay

A Symposium Report

Concluding Discussion: Summary of Key Issues
Concerning Crassostrea ariakensis

In the wide-ranging discussion following the group reports, a number of key themes emerged on the potential benefits and risks, and on appropriate future actions regarding the aquaculture of C. ariakensis in the Chesapeake Bay.

Key Potential Benefits of C. ariakensis

• Expansion of employment and income with a restored shellfish industry.
  
  
• Increased state revenues from a vigorous industry.
  
  
• Improved ecological function in the Chesapeake Bay with increased numbers of filter-feeding bivalves.

Key Potential Hazards of C. ariakensis

• Hazard of unsanctioned "hooligan" introduction of C. ariakensis. These oysters would not be quarantined, posing the potential of introducing pathogens, parasites and other organisms. These oysters would be fertile diploids, lacking reproductive confinement.
  
  
• Hazard of changed ecosystem state, for example, of changing the current situation where most production is pelagic to one where most production is benthic. Such changes could reduce the productivity of certain valued fisheries.
  
  
• Any introduction of a non-native species poses unknown hazards.
  
  
• Hazard of not realizing the benefits posed should C. ariakensis not be commercially produced.
  
  
• Trojan oyster potential: Published reports establish the inviability of larvae produced by mating C. virginica and C. ariakensis (fertilization is relatively successful). Given that reproductive populations of the two species would be juxtaposed and spawn simultaneously, the newly formed embryos would serve as a gamete sink (for both species). In the case of C. virginica, this could represent an impediment to native restoration efforts.

Key Research and Development Needs

• Continue efforts to produce commercially viable numbers of tetraploid individuals.
  
  
• Continue research with the triploid in confined environments, especially to understand hazard pathways and probabilities.
  
  
• Give serious consideration to the possibility of introducing reproductively capable diploid C. ariakensis: it may be appropriate to initiate opportunity and risk assessments soon.
  
  
• Continue development of selectively bred eastern oyster stocks, although we must recognize that it would be genetically altered compared to a wild native oyster.