Eel research in the Thames
ZSL is monitoring eel migrations in the Thames and its tributaries as a result of the decline in the number of European eels returning to the UK.
The European eel (Anguilla anguilla) has long been associated with the River Thames. Recorded in the Domesday Book, eels continued to be a valuable fishery in London well into the 1800’s:
'London from one end to the other teems and steams with eels, alive and stewed; turn where you will hot eels are everywhere smoking away' (D. Badham, 1853).
With the eel-run an annual event of river life:
'The elvers came up in such tens of millions that they made a black margin to the river on either side of the bank' (C.J. Cornish, 1902)
However, recruitment of glass eels in estuarine and freshwaters has declined markedly since the early 1980s causing a major decline in the European fishery.
Concern that the current fishery is not sustainable was first raised by the International Council for the Exploration of the Sea (ICES) to the European Commission. The National Eel Management Plan is presently being assessed by the EU.
ZSL has been monitoring eel migrations since spring 2005 in several tributaries of the Thames in order to estimate recruitment and to identify potential restrictions to their movements and the data output from this on-going study has been utilised by the Environment Agency and ICES to inform management initiatives.
The study has also increased our knowledge of the species in the Thames catchment and raised awareness of the declining eel populations. By assessing the distribution of eels within the Thames catchment and identifying restrictions to eel migrations steps can be taken to ensure that the historic and infamous Thames eel remains a viable part of the ecology of the River Thames.