RESEARCH &
scientific
  mmm
Characterizing species assemblages and targeted screening for invasive
  species in ballast: DNA based species identification and enumeration


 Objectives:

 • Develop molecular techniques to
 characterize species assemblages in ballast
 samples
 •Develop molecular techniques to detect
 nonindigenous species (NIS) in ballast
 • Develop bioinformatic tools to mine
 molecular data sets to better characterize
 invasion events

 Rationale:

 Ballast (water and solid) exchange is one of the dominant avenues of introduction and spread
 of Non Indigenous Species (NIS) across the United States. Many ballast management
 programs currently mandate that ships execute open ocean ballast exchange to expel NIS
 carried in ballast taken up in coastal waters. Compliance with this requirement is difficult to
 assess from physical measurements such as salinity. An alternative approach now being
 considered is gauging compliance by characterizing species assemblages in ballast tanks- if
 tanks are completely purged during open ocean exchange, the species found in ballast tanks
 should be of oceanic, and not of coastal origin. However, the effectiveness of this compliance
 standard will be limited without accurate and efficient methods for characterizing species
 assemblages found in ballast.
 Besides determining compliance, a goal of many ballast water management programs is to
 detect or screen ballast for NIS that are regularly transported by commercial shipping traffic.
 "Hit lists" of NIS have already been generated that identify species posing the greatest threat
 to estuarine ecosystems. These lists include NIS already established in domestic waters that
 may be secondarily introduced to other areas through regional transport. Screening species
 assemblages for NIS may also help determine the "NIS load" being carried in ballast. "NIS
 load" in part reflects the frequency of introductions, as well as what is known as "propagule
 pressure", or the effective population size of incoming cohorts of NIS. Both factors may
 determine whether a species will become established after being introduced into a novel
 environment. Measuring "NIS load" for species transported in ballast would help characterize
 invasion dynamics and may therefore lead to more effective management strategies.

 Approach:

 Development and application of DNA-based methods for identifying organisms in ballast
 samples can provide accurate and  consistent species level identifications for all of the
 dominant taxonomic groups found in ballast (including species-level identification of
 organisms at all life stages). Unlike morphological data, molecular data sets developed for
 species inventories can also be mined for other purposes,  such as determining the effective
 population sizes of incoming NIS  cohorts and studying the temporal variability in NIS
 population demography. These data can also be mined to analyze the adaptive response of
 species to environmental change, and interspecific evolutionary relationships. By providing
 species level identifications and enumeration, DNA-based analyses can also be extended to
 assess ecological conditions and reference data on natural environmental variability.

 Participants: MERB/EERD(NERL), GLNPO, Region 5, Region 9, Region 10

                                     Contacts:

                  Michael Blum, Mark Bagley, Marc Tuchman, John
                          Perrecone, Joan  Cabreza, Allan Ota

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