**ABSTRACT NOT
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For a copy of the full completion report, please contact the author via
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Detection and identification of
lampreys in streams using environmental DNA
1 University of Manitoba,
Winnipeg, MB
2Sea Lamprey Control Centre,
Sault Ste. Marie, ON
3Michigan State University,
East Lansing, MI
February 2014
ABSTRACT:
Control of sea lampreys in the Great Lakes requires
accurate assessment of the distribution of this species in natal tributaries
and the ability to distinguish sea lampreys from the four lamprey species that
are native to the Great Lakes; two of these native species are of conservation
concern. Environmental DNA (eDNA) has been used to assess the diversity
and abundance of aquatic species by detecting the DNA of an organism in the
water instead of locating the organism itself. We developed PCR-based assays to
distinguish among the four ‘species’ of Great Lakes lampreys (sea, American
brook, chestnut, and silver/northern brook lampreys), and employed these in the
development of efficient and cost-effective environmental DNA (eDNA)
methods. This included developing rigorous quality control protocols (e.g., to
guard against false positives), performing initial laboratory testing of the
assays to refine and calibrate the methodology, and demonstrating in the
field—for the first time—that both spawning and larval sea lamprey populations
can be detected in streams using eDNA techniques.
In 10L aquaria in the lab, we found that higher larval
densities had a positive effect on eDNA amplification success, while both
lower temperatures and higher flow rates had a negative effect on amplification
success. In the field, we were able to detect an increase in eDNA in the Little Thessalon River during the spawning run in May;
this elevated eDNA signal
persisted for approx.1 month after all adults had died but had attenuated by
late July. Our eDNA assay was also able to detect larval
lampreys in natural stream systems, but only in one of three high density
streams and in one medium density stream.
Given the success of detecting both spawning and
larval populations of sea lamprey, the developed sea lamprey eDNA detection methods could potentially
reduce cost and increase efficiency of current management strategies by serving
as a “red-flag” system, identifying streams with spawning adults as well as
streams with large larval populations that require more thorough assessment.
However, to minimize the occurrence of false negatives, further refinements
will be necessary to improve assay sensitivity.