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The Pacific lamprey (Entosphenus tridentatus) is an anadromous fish once abundant throughout coastal basins of western North America that has suffered dramatic declines in the last century due primarily to human activities. Here, we describe the development of an environmental DNA (eDNA) assay to detect Pacific lamprey in the Columbia River basin. The eDNA assay successfully amplified tissue derived DNA of Pacific lamprey collected from 12 locations throughout the Columbia River basin. The assay amplifies DNA from other Entosphenus species found outside of the Columbia River basin, but is species-specific within this basin. As a result, the assay presented here may be useful for detecting Entosphenus spp. in geographic...
Abstract: Lampreys (Petromyzontiformes) have persisted over millennia and now suffer a recent decline in abundance. Complex life histories may have factored in their persistence; anthropogenic perturbations in their demise. The complexity of life histories of lampreys is not understood, particularly for the anadromous Pacific lamprey, Entosphenus tridentatus Gairdner, 1836. Our goals were to describe the maturation timing and associated characteristics of adult Pacific lamprey, and to test the null hypothesis that different life histories do not exist. Females exhibited early vitellogenesis – early maturation stages; males exhibited spermatogonia – spermatozoa. Cluster analyses revealed an “immature” group and a...
Lampreys are endangered in Europe, and European states are legally required to take measures to ensure their protection. However, there is currently little information on the distribution of the three species present in Northern Ireland. Anecdotal records of adult lampreys were collated from anglers and other sources, and a systematic electrofishing survey was undertaken to establish the distribution of lamprey ammocoetes. Lampreys were found in seven of the nine Northern Irish river catchments. Brook lampreys (Lampetra planeri (Bloch)) were widely distributed, but the two anadromous species, sea lamprey (Petromyzon marinus L.) and river lamprey (Lampetra fluviatilis (L.)), were more limited in their distribution,...
This report contains 474 annotated citations that are relevant to fish passage through dams in large temperate floodplain rivers. Our goal was to survey the literature to help define the potential ecological consequences of restricted fish passage through dams in the Upper Mississippi River System and to identify alternative engineering solutions for increasing fish passage in large temperate floodplain rivers. Consequently, topic coverage is broad, including theoretical concepts in large river ecology, engineering design of fish passage structures, ecological responses to river impoundment, fish swimming performance, and relations between freshwater mussels and fish. This report is served in searchable electronic...
Abstract: Similar to other lampreys, Pacific Lamprey Entosphenus tridentatus is of cultural importance and increasing management concern. Larval lamprey naturally reside and burrow in fluvial sediments making them especially vulnerable to stranding and mortality during dam operations that dewater their nursery habitats, such as the drawdown of Leaburg Reservoir (McKenzie River, OR) in March 2018. Our study objectives were to: 1) identify changes in larval distribution, abundance, and density due to the drawdown; 2) evaluate techniques (excavation, liquefaction, and electrofishing) to sample and salvage larvae in dewatered habitats; and 3) examine larval emergence from burrows during dewatering. We assessed changes...
Studies using neutral loci suggest that Pacific lamprey, Entosphenus tridentatus, lack strong spatial genetic population structure. However, it is unknown whether temporal genetic population structure exists. We tested whether adult Pacific lamprey: (1) show temporal genetic population structure; and (2) migrate different distances between years. We non-lethally sampled lamprey for DNA in 2009 and 2010 and used eight microsatellite loci to test for genetic population structure. We used telemetry to record the migration behaviors of these fish. Lamprey were assignable to three moderately differentiated genetic clusters (FST = 0.16–0.24 for all pairwise comparisons): one cluster was composed of individuals from 2009,...
This pilot study presents an environmental DNA (eDNA) assay for sea lamprey Petromyzon marinus and brown trout Salmo trutta, two species of economic and conservation importance in the Republic of Ireland. The results demonstrate the effectiveness of eDNA for assessing presence of low-abundance taxa (here, P. marinus) for environmental managers, and they highlight the potential for assessing relative abundance of rare or invasive freshwater species.
Genetic identification of aqueous environmental DNA (eDNA) provides site occupancy inferences for rare aquatic macrofauna that are often easier to obtain than direct observations of organisms. This relative ease makes eDNA sampling a valuable tool for conservation biology. Research on the origin, state, transport, and fate of eDNA shed by aquatic macrofauna is needed to describe the spatiotemporal context for eDNA-based occupancy inferences and to guide eDNA sampling design. We tested the hypothesis that eDNA is more concentrated in surficial sediments than in surface water by measuring the concentration of aqueous and sedimentary eDNA from an invasive fish, bigheaded Asian carp (Hypophthalmichthys spp.), in experimental...
Elucidation of genetic mechanisms underpinning migratory behavior could help predict how changes in genetic diversity may affect future spatiotemporal distribution of a migratory species. This ability would benefit conservation of one such declining species, anadromous Pacific lamprey (Entosphenus tridentatus). Nonphilopatric migration of adult Pacific lamprey has homogenized population-level neutral variation but has maintained adaptive variation that differentiates groups based on geography, run-timing and adult body form. To investigate causes for this adaptive divergence, we examined 647 adult lamprey sampled at a fixed location on the Columbia River and radiotracked during their subsequent upstream migration....
The Pacific lamprey (Entosphenus tridentatus) is an anadromous fish that is of conservation concern in North America and Asia. Data on Pacific lamprey population structure are scarce and conflicting, impeding conservation efforts. We optimized 12 polymorphic microsatellite loci for the Pacific lamprey. Three to 13 alleles per locus were observed in a sample of 51 fish collected from the West Fork Illinois River, Oregon. Observed heterozygosity ranged from 0.235 to 0.902 and expected heterozygosity ranged from 0.214 to 0.750. Cross-species amplification produced 8 to 12 polymorphic loci in four other Entosphenus species and in the western brook lamprey (Lampetra richardsoni). Two loci appear to be diagnostic for...
Allozyme allele frequencies and mtDNA sequence data were used to differentiate seven populations of lamprey from the Columbia, Klamath, and Sacramento River basins as well as two coastal streams in California. Allozyme genotypic data from ten polymorphic enzymes were scored in 166 lamprey specimens and mtDNA control region nucleotide sequences were obtained from nine individuals. Of 31 comparisons of observed genotypic frequencies at polymorphic loci to those expected under Hardy- Weinberg equilibrium, 9 (29%) deviated significantly (p<0.05). Log likelihood statistics were used to test for heterogeneity of allele frequencies calculated from the ten polymorphic loci and there were significant allele frequency differences...
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