title: An extremely sensitive nested PCR-RFLP mitochondrial marker for detection and identification of salmonids in eDNA from water samples.
abstract: BACKGROUND
  Salmonids are native from the North Hemisphere but have been introduced for aquaculture and sport fishing in the South Hemisphere and inhabit most rivers and lakes in temperate and cold regions worldwide. Five species are included in the Global Invasive Species Database: rainbow troutOncorhynchus mykiss, Atlantic salmonSalmo salar, brown troutSalmo trutta, brook troutSalvelinus fontinalis, and lake troutSalvelinus namaycush. In contrast, other salmonids are endangered in their native settings.
  
  
  METHODS
  Here we have developed a method to identify salmonid species directly from water samples, focusing on the Iberian Peninsula as a case study. We have designed nested Salmonidae-specific primers within the 16S rDNA region. From these primers and a PCR-RFLP procedure the target species can be unequivocally identified from DNA extracted from water samples.
  
  
  RESULTS
  The method was validated in aquarium experiments and in the field with water from watersheds with known salmonid populations. Finally, the method was applied to obtain a global view of the Salmonidae community in Nalón River (north coast of Spain).
  
  
  CONCLUSIONS
  This new powerful, very sensitive (identifying the species down to 10 pg DNA/ml water) and economical tool can be applied for monitoring the presence of salmonids in a variety of situations, from checking upstream colonization after removal of river barriers to monitoring potential escapes from fish farms.
authors.affiliation: Department of Functional Biology, University of Oviedo , Oviedo , Asturias , Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Clusa
authors.affiliation: USR3278-CRIOBE-CNRS-EPHE-UPVD, Laboratoire d'Excellence "CORAIL", Université de Perpignan , Perpignan , France.
authors.forename: Alba
authors.initials: A
authors.lastname: Ardura
authors.affiliation: Department of Functional Biology, University of Oviedo , Oviedo , Asturias , Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Fernández
authors.affiliation: Department of Functional Biology, University of Oviedo , Oviedo , Asturias , Spain.
authors.forename: Agustín A
authors.initials: AA
authors.lastname: Roca
authors.affiliation: Department of Functional Biology, University of Oviedo , Oviedo , Asturias , Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: García-Vázquez
keywords: Family-specific primers; Salmonids; Species-specific RFLP; eDNA