Distribution and seasonal differences in Pacific Lamprey and Lampetra spp eDNA across 18 Puget Sound watersheds
Summary
Lampreys have a worldwide distribution, are functionally important to ecological communities and serve significant roles in many cultures. In Pacific coast drainages of North America, lamprey populations have suffered large declines. However, lamprey population status and trends within many areas of this region are unknown and such information is needed for advancing conservation goals. We developed two quantitative PCR-based, aquatic environmental DNA (eDNA) assays for detection of Pacific Lamprey (Entosphenus tridentatus) and Lampetra spp, using locked nucleic acids (LNAs) in the probe design. We used these assays to characterize the spatial distribution of lamprey in 18 watersheds of Puget Sound, Washington, by collecting water [...]
Summary
Lampreys have a worldwide distribution, are functionally important to ecological
communities and serve significant roles in many cultures. In Pacific coast drainages of
North America, lamprey populations have suffered large declines. However, lamprey
population status and trends within many areas of this region are unknown and
such information is needed for advancing conservation goals. We developed two
quantitative PCR-based, aquatic environmental DNA (eDNA) assays for detection
of Pacific Lamprey (Entosphenus tridentatus) and Lampetra spp, using locked nucleic
acids (LNAs) in the probe design. We used these assays to characterize the spatial
distribution of lamprey in 18 watersheds of Puget Sound, Washington, by collecting
water samples in spring and fall. Pacific Lamprey and Lampetra spp were each detected
in 14 watersheds and co-occurred in 10 watersheds. Lamprey eDNA detection rates
were much higher in spring compared to fall. Specifically, the Pacific Lamprey eDNA
detection rate was 3.5 times higher in spring and the Lampetra spp eDNA detection
rate was 1.5 times higher in spring even though larval lamprey are present in streams
year-round. This significant finding highlights the importance of seasonality on eDNA
detection. Higher stream discharge in the fall likely contributed to reduced eDNA
detection rates, although seasonal life history events may have also contributed. These
eDNA assays differentiate Pacific Lamprey and Lampetra spp across much of their
range along the west coast of North America. Sequence analysis indicates the Pacific
Lamprey assay also targets other Entosphenus spp and indicates the Lampetra spp assay
may have limited or no capability of detecting Lampetra in some locations south of
the Columbia River Basin. Nevertheless, these assays will serve as a valuable tool for
resource managers and have direct application to lamprey conservation efforts, such
as mapping species distributions, occupancy modeling, and monitoring translocations
and reintroductions.
