Molecular Method Applications to Support Entrainment Study Evaluations

The final EPA §316(b) rule requires the development of facility-specific, entrainment characterization report which estimates annual mortality of fish and shellfish eggs, larvae and juvenile life stages.  Taxonomic resolution is critical for distinguishing introduced, invasive, and economically less important fish species from state or federally listed, recreationally or commercially valuable species. Facilities must characterize and enumerate organisms to “the lowest taxon possible”, which is generally understood as species-level resolution, although the rule identifies no methods for attaining this level of resolution.

Early-life, fish and shellfish identification is limited to a few distinguishing, descriptive characteristics (color, shape, counts, and measurements). Limited features and similarities at this life-stage can limit descriptions to a coarser scale (family or genera level) of resolution. Additionally, the detection of rare species within the volume of eggs and larvae found in some ecosystems makes traditional sample processing time-consuming and costly. The Electric Power Research Institute funded this pilot study to assess the utility of barcoding and PCR techniques to support entrainment sample processing. This study validated the utility of barcoding and PCR methods to provide species level identifications on target taxa, and demonstrated the potential for PCR assays to be both quantitative in a mixed species environment.