Site navigation:

ECOFACT ECOFACT | European Eel Research and Management

The category page

European Eel Research

The European eel Anguilla anguilla is a fish of significant ecological importance. It is one of only 15 native fishes present in Ireland’s freshwater ecosystems and is perhaps the most recognisable of all our fauna. In recent decades, this species has undergone a dramatic decline throughout its range. The European Eel is a unique indicator of the environmental health and integrity of our oceans, estuaries and freshwaters, and its recent decline is seen as a serious environmental matter.

In response to the decline in European eel populations European Council Regulation 1100/2007 “Establishing measures for the recovery of the stock of European eel” has now been adopted in member states.

European eel European-eel European-eel

With funding from the ESB and in co-operation with the National University of Ireland, Galway, a major study on European eel in the Shannon estuary and Lower Shannon and Shannon estuary was undertaken by Dr. William O’Connor of ECOFACT during the period 1995-2003. This is largest juvenile eel research project to ever be undertaken in Ireland. This major research project included the following detailed studies:-

  • Immigration timing and activity rhythms of glass eel in the Shannon estuary in relation to temporal and environmental factors
  • Factors influencing the upstream riverine migration of juvenile European eel on the River Shannon and selected tributaries of its estuary
  • Size structure and development stages of migrant European eel populations, and the size selectivity of various trapping methods
  • Fish census results at the Ardnacrusha Borland fish-lift, with particular reference to European eel
  • Interactions of juvenile European eel, brown trout Salmo trutta and other predators, in the tidal section of the lower Shannon River
  • The assessment of European eel densities and population structures in the lower reaches of rivers in the Shannon estuary area using electrical fishing
  • Bycatch fish species recorded during the operation of a pilot scale glass eel fishery on the Shannon estuary
glass eels 2 European-eel-survey pull-net

During the study exceptional results were obtained in relation to catching glass eels and elvers. Indeed, over 20 million juvenile eels captured and transported upstream on the River Shannon, to above the Shannon hydroelectric scheme . The key finding of the study was that despite the global downturn in eel numbers hugely significant catches of both glass eels and elvers could be made with determined and focused effort. Indeed, the annual catches made during the study period (1997-1999) exceeded the catches of any the previous catches since 1980, and (temporarily) reversed the decline in eel catches recorded on the River Shannon.

The results of this study call into question the validity of many juvenile eel index sites in Ireland as it is clear that catch effort, and the quality of this effort, can have a highly significant influence on results obtained. It is also clear that an urgent best effort approach is needed now to maximise use of available glass eel and elver resources to save this species and restore its fisheries. Banning of all eel fishing, which is has occurred in Ireland, may not be the most prudent use of available glass eel and elver resources.

To access the report just click on this link: ‘Biology and Management of European Eel (Anguilla anguilla, L) in the Shannon Estuary, Ireland‘.

Current News Stories:

  • Filming a documentary on Sea Lampreys

    We were delighted to work recently with BBC Earth on a documentary on Sea Lampreys Petromyzon marinus. The filming took place during early-June 2017 on the old River Shannon at Castleconnell, Co Limerick. This is part of the Lower River Shannon Special Area of Conservation, and Sea Lampreys are a key conservation interest of this […]

    Continue Reading
  • Major new book – Wildlife and Wind Farms

    A major new book will be published in May 2017 entitled ‘Wildlife and Wind Farms: Conflicts and Solutions’. Volume 1 of this book includes a chapter prepared by Ecofact Principal Ecologist Dr. William O’Connor. The two-volume set provides a comprehensive overview of the interactions between wind farms and wildlife, each volume dedicated to one of the two […]

    Continue Reading
  • Surveying wintering birds in the Irish Midlands

    Our staff are currently undertaking a number of wintering bird surveys in the Irish Midlands. Here we have provided some photos and videos from bird surveys we undertook during December 2015. Our bird surveys are undertaken to inform both the Environmental Impact Statement (EIS) and Natura Impact Statement (NIS) reports being prepared for proposed wind energy […]

    Continue Reading
  • Marine and estuarine ecology surveys

    Marine and estuarine ecological surveys are a key service provided by ECOFACT. These surveys are undertaken for a number of purposes, including informing the Environmental Impact Assessments and Article 6 Appropriate Assessments of proposed developments affecting the marine / estuarine environment. These surveys are also to monitor the impact of industrial and municipal discharges and aquaculture […]

    Continue Reading
  • Freshwater Pearl Mussel surveys

    The Freshwater Pearl Mussel Margaritifera margaritifera is a (freshwater) bivalve listed under Annex II and V of the EU Habitats Directive. It is legally protected in Ireland under Schedule 1 of the Wildlife Act (1976 (Protection of Wild Animals) (Statutory Instrument No. 112, 1990) and the European Communities (Natural Habitats) Regulations (Statutory Instrument No. 94, 1997). Owing […]

    Continue Reading

Photo Gallery

View More >>

Site Search