Invasive mussels

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A brief overview of UDWR's testing protocol for mussels

DWR's current protocol for determining a status of an affected water requires two steps:

  1. Visual observation of the mussel, which can include a flowcam or cross-polarized and light microscopy for veligers; followed by positive findings; via
  2. Tissue analysis through two independent PCR methods:
    • Ribozomal DNA method, assessing the ITS I region; and
    • Mitochrondrial DNA method, assessing the COX I region.

Case example

Pelican Lake's status is "Inconclusive." Veligers (microscopic larvae of a Dreissenid mussel—quagga or zebra) were observed via microscopy of a plankton sample during 2008 as a preliminary finding. But, a polymerase chain reaction test (PCR, which is a molecular assessment in a lab of the deoxyribonucleic acid (DNA) in the mussels' tissue) could not confirm that observation. The ribosomal ITS 1 region of the DNA, which is believed to be the most sensitive area for a PCR test, failed to show a positive find. Therefore, the mitochondrial COX 1 region of the DNA was not tested. Thus, more testing is needed, so plankton samples must be collected once per month during at least the next three breeding seasons for microscopic and PCR assessment.

If microscopic and two independent PCR tests of ribosomal and mitochondrial DNA each agree upon a positive finding from the same sample, the status would be changed to "Detected." And, if juvenile or adult quagga or zebra mussels were to be found, the status would be changed to "Infested." If either microscopic detection or a PCR positive find were not to occur for three consecutive breeding seasons, then the water body would be returned to the "Negative" status.

See status definitions

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