Oral Presentation International Conference on River Connectivity (Fish Passage 2018)

eDNA as an efficient tool to assess the distribution of European eels upstream of pumping stations (#63)

Jon Bolland 1 , Leona Murphy 1 , Ros Wright 2 , Ian G Cowx 1 , Hayley Watson 3 , Robert Donnelly 3 , Bernd Haenfling 3
  1. University of Hull International Fisheries Institute (HIFI), Hull, YORKSHIRE, United Kingdom
  2. Environment Agency, Norwich, England
  3. Evolutionary Biology Group, University of Hull, Hull, England

Concern over the status of European eel stocks is so great that the EU has specific legislation (The EC Eel Regulation (1100/2007)) for eel conservation. This is enacted in the UK through the Eels (England and Wales) Regulations 2009 Statutory Instrument (the Eel SI), which requires pumping stations abstracting greater than 20 cubic metres a day to be screened to prevent fish/eel entrainment. This legislation applies to all pumping stations, unless exempted by the Environment Agency, partly due to a lack of knowledge of fish and eel populations in pumped catchments. To ensure Eel SI compliance is informed by real-world evidence, 36 years (1979-2015) of traditional fish survey data (nets, traps and electric fishing) from upstream of 124 high priority pumping stations in England were reviewed. At least one eel was caught upstream of 50 pumping stations and no eels were caught from upstream of two. No eel surveys were performed upstream of 72 of the 124 pumping stations investigated. Traditional fish survey techniques are time consuming, labour intensive and, in some instances, inefficient for eels, and thus represent an unfeasible solution for filling the large eel distribution knowledge gap. Therefore, the potential for using Environmental DNA (eDNA) to assess presence or absence of eels in pumped catchments was investigated in combination with traditional survey techniques. Eel eDNA was detected in all instances an eel was caught and at a number of sites where no eels were caught, presumably due to the low number of eels in the river and/or the ineffectiveness of the traditional sampling technique. There were also instances when eels were not caught and no eel eDNA was detected. Preliminary findings suggest eDNA is a viable technique to assess the presence or absence of eels in pumped catchments to inform management decisions for Eel Regulations compliance.