Publication Abstract

Eels in the River Leadon – measures, models and management plans

Authors: Alan Walker & Jon Hateley

Management and conservation of European eel, Anguilla anguilla, across Europe is focussed by the EU Regulation 1100/2007 (the Eel Regulation). Eel management plans (EMP) detailing preliminary assessments of the UK eel stock and anthropogenic impacts along with management actions were implemented in 2010. The first official progress review is to be reported to the European Commission in June 2012, and requires estimates of past and present silver eel biomass, and estimates of mortality rates from fisheries and other human induced factors.

In the absence of historic data and few recent data on silver eel production across England and Wales, models applied to index rivers have been extrapolated to river basin districts. These applications need to be tuned to local characteristics of eel production, or data from similar habitats, and their extrapolation needs to be anchored to other indices of eel production such as yellow eel surveys and silver eel counts.

We use two seasons of silver eel ‘observations’ from a DIDSON multi-beam sonar, and modelling based on yellow eel surveys, to assess the eel stock of the River Leadon, a tributary of the River Severn. This present stock is compared against a model-based estimate of silver eel production from the 1980s based on yellow eel surveys. Finally, we examine the potential impacts of human factors, and the potential effects of management measures to address these impacts.