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Decline of the European Eel

December 9 2008

The European Eel (Anguilla anguilla) is an incredibly important, but often under-valued fish species in the Atlantic Area. It is essential to the economic viability of many small-scale coastal fishing communities in Europe as well forming part of the traditional fishing economy in the UK.

The eel, like the salmon, lives alternately in freshwater and seawater, but unlike the salmon, the eel spends its adult life (yellow eel stage) in freshwater then swims down river where it is thought to migrate out to the Sargasso Sea to breed (silver eel stage). This mass spawning produces vast numbers of larvae, which drift/swim with the ocean currents across the Atlantic. These larvae eventually reach the European coastline where they metamorphose and move up into rivers during the spring (elver stage).

Recently a massive decline in the number of eels arriving at European Rivers has been noted. ICES/EIFAC working groups recently defined eel populations as 'outside safe biological limits' with critical levels reached mainly in Northern Europe. This decline has been linked to factors in the freshwater environment including changing land use and increased numbers of impassable barriers, as well as factors in the marine environment such as long-term alteration of the currents that young eels rely on to make their journey from the Sargasso Sea.

In an effort to address this decline or enlighten managers to its origins, the Trust has joined a European partnership research project called INDICANG. The project is focusing on gathering all available information on European eels to permit a better European scale understanding of the factors leading to the declines.

The Trust is gathering information on eels themselves such as male:female ratios, age and parasite loading. The Trust will also investigate changes in other indirect factors that have paralleled the decline, like changing land use over time, fishing pressure and changes in the numbers of migration barriers. The collected information from across Europe will subsequently be collated, assessed and disseminated to those involved in the management of eels and perhaps potential causes might be identified.

INDICANG was launched in April 2004, and the UK partnership is managed by Toby Russell who will be working closely with our European partners to create a conservation strategy for the eel. The Trust has also joined forces with the Environment Agency for sample collection and with the Eel Research Group based at Kings College, London who are providing expert advice and practical support.

Since the start of the project we have gathered data on eel populations for a number of South-West Rivers. This data has been used to target various eel sampling strategies looking at the three life history stages of the eel; elver, yellow and silver eels. We have established an elver monitoring trap and conducted eel sampling at Slapton Ley and the surrounding catchment; this has only been possible with the support and assistance of the local officers from the Field Studies Council and National Nature Reserve. We are also gathering data and samples from the Tamar, Camel and Fowey catchments in Cornwall.

To examine all possible issues we need to capture examples of eels at all life stages; this is not straightforward and variety of different methods for their capture have been deployed: we have used elver traps, fyke netting and electric fishing!. Captured eels are processed carefully and information on length, weight and abundance is recorded; this gives an indication of the health of the population within the river. Anglers are also providing this sort of information for the project, which has proven very helpful.

How you can help?

The elver is just one life stage of the eel. We are also collecting information on the adult population of eels across Devon and Cornwall. If you are a fisherman who catches eels regularly, intentionally or not, you can contribute to the project by filling out an eel recording form available from our web site at:

There are also other ways in which you can contribute, either through time or financial contribution. If you would like to know more about this project including how to contribute, please contact Toby Russell at the address below or on 08707 740696 or [email protected]

Toby Russell
The Westcountry Rivers Trust
10 Exeter Street
PL15 9EQ