Overview

Project Highlights

  • Ex-situ laboratory flume experiments to investigate the impacts of water control structures on eel movements, and how effects vary as functions of fish and flow characteristics;
  • Development of a spatially-explicit understanding of Eel movements, population health and habitat conditions across the Somerset Levels;
  • Development of a monitoring system for determining numbers and characteristics of Eels entering and exiting the River Parrett, at a seasonal resolution.

 

Overview:

The European Eel Anguilla anguilla is a critically endangered catadromous fish species with a poorly understood lifecycle. Newly hatched larvae (leptocephali) are transported on ocean currents from the Sargasso Sea to intertidal areas of Europe. It is believed eels pass through the leptocephalus stage in the open ocean, reaching European waters as juvenile “glass” eels, having undergone metamorphosis at sea. On arrival in shallow coastal habitats, Eels are washed into the mouths of rivers before continuing their journeys upstream. As Elvers between 7 and 8 cm in length, fish search for nursery habitats, often located significant distances inland. It is within these nursery habitats the eels remain and reach maturity over 7-12 years, before undertaking their seaward journey back to the Sargasso to spawn.

Eels face a variety of dangers and challenges throughout their life cycles. The species is targeted at sea by commercial fishing operations and inland fisheries activities, hydropower schemes and pumping stations can deplete populations. Further, river fragmentation and the presence of engineered structures can reduce habitat suitability and availability. Against this backdrop, estimates of the glass eel life-stage suggests recruitment across Europe has recently fallen below five percent of historic levels such that eels are critically endangered and at high risk of extinction. A range of management measures have therefore been implemented to increase and/or protect eel production. In the UK, measures include restrictions on fisheries, stocking of glass eels, removal or modification of barriers to upstream migration, and implementation of entrainment reduction measures. However, conservation efforts are hampered by poor understanding of how eel movements and distributions within systems are affected by different types of in-river structure and eels’ ability to negotiate these barriers when moving in an upstream or downstream direction. Furthermore, knowledge of eel immigration and migration which define populations within catchments, remains limited, and is largely based on modelling not empirical data collection. This project aims to improve our ability to conserve and manage inland UK Eel populations by developing a comprehensive understanding of their distributions and movements, and how these are influenced by anthropogenic activities.

Figure 1A Newbridge sluice, an example of an engineered barrier to migration, which may be influencing fish movements and so, B populations in the River Parrett Catchment. Average abundance per species data derived from electric fishing at three sites in the tidal Parrett are presented in B (n = 2; ± STDEV).

Methodology

The research programme will involve the acquisition of experimental data under field and laboratory settings and detailed examination of historical data to determine changes in population characteristics over time. It will use the River Parrett (Somerset Levels) as a model system. The project requires an interdisciplinary approach and will include the following elements: (1) flume and/or field experiments involving fish tracking to investigate the impact of water control structures on eel movements, how the effects vary with fish and flow characteristics and what modifications can be made to improve fish movements; (2) development of a spatially explicit understanding of Eel movements, population health and habitat conditions across the Somerset Levels, using contemporary mapping and tracking of eels, to identify key barriers to movement; (3) development of a monitoring system involving innovative fish sampling techniques for determining numbers and characteristics of Eels immigrating within and emigrating from the River Parrett.

 

Training and Skills

Students will develop a conceptual and theoretical understanding of both lentic and lotic ecosystems and develop skills in dealing with fish population and life history data and large hydrological/ ecological datasets. Students will undertake training to gain an understanding of data requirements to analyse the internal dynamics and external stressors within freshwater ecosystems. In addition, the student will develop skills in field sampling, data management, statistical analysis and physical modelling. The student will interact and collaborate within an interdisciplinary network of scientists and will have the opportunity to present his/her research at international conferences.

Timeline

Year 1: Orientation with partner organisations and collaborators. Training in research methods, time management and experimental design. Review of literature on eel ecology and fish passage. Examination of available fisheries datasets for the River Parrett catchment. Training in fish sampling techniques and modelling approaches, including the identification of data requirements and interpreting data structures and patterns. Development of an Eel monitoring network and associated methods.

Year 2: Field / experimental data collection from the study system, potentially including experiments utilising experimental flumes at the River Science Laboratory, Loughborough University. Initiation of data analysis of secondary data sources.  

Year 3: Data analysis. Writing of PhD thesis chapters, draft journal papers and conference presentations to academics and practitioners.

 

Partners and collaboration (including CASE)

This project will utilise and nurture long-standing and productive relationships with the Somerset Drainage Boards Consortium, Environment Agency (Somerset area) and Fishtrack Ltd., who are working with the supervisory team on a range of river management projects. The project aims to establish new and exciting relationships with the Sustainable Eel Group who work at the forefront of European Eel conservation, and the River Anglers Conservation Group who will be directly involved in helping to disseminate research findings to the wider public.

Further Details

For further information about this project, please contact Professor Stephen Rice (Associate Dean (Research) School of Social Sciences, Geography and Environment, Loughborough University – s.rice@lboro.ac.uk). For enquiries about the application process, please contact SocSciResearch@lboro.ac.uk. Please quote CENTA18-LU6 when completing your online application form: http://www.lboro.ac.uk/study/apply/research/.