In 2017, we delivered the Wandle Eel Project in partnership with the Living Wandle Landscape Partnership, the Heritage Lottery Fund, Environment Agency, Zoological Society London (ZSL), National Trust, and Wandsworth Borough Council.
European eels (Anguilla anguilla) once thrived in London’s rivers but the number of young joining the adult populations have dropped by over 95% since the 1980s and the species has been classified as ‘Critically Endangered’ by the IUCN Red List of Threatened Species since 2008.
One of the major threats to eels in freshwater are barriers to upstream migration such as weirs and sluice gates that reduce the amount of habitat available for eels to grow and mature.
What’s been going on?
This project aimed to improve eel passage along the Wandle by installing eel passes at six locations where structures were a complete or partial barrier to migration. All installations were completed by Wandle Trust staff and assisted by local volunteers.
1. In June 2017, the existing eel pass at Morden Hall Park was repaired, extended and fitted with a monitoring trap. This site was then used by ZSL to train local volunteers, and National Trust staff to monitor elver migration along the Wandle.
2. The Topps Tiles tiles site in Earlsfield was delivered in December 2017 (in the snow), which included a row of lift out eel tiles with upstream deflector, and a section of low profile bed tiles on an adjacent channel. This site was testing the improved steel brackets which were fabricated by a local contractor/volunteer. These installations were designed as ‘easements’ to allow eels to navigate the fast flowing sections of the heavily modified concrete channels. Two old, defunct eel passes were disassembled and removed from site.
3. The Trewint Street easement was installed in December 2017, and consisted of a 30 m section of the new ‘low profile’ bed tiles that were commissioned for this project, with a short section of flexible bristles to navigate over a 300 mm wooden baulk at the upstream end. This has provided an additional route up the left hand channel which offers a less turbulent route than the fish pass in the right hand channel.
4. The eel pass at EDF was installed during Dec 2017/Jan 2018 with a 15 m section of ‘low profile’ bed tiles. As some high tides overtop the weir, these works were designed to increase the range of time/tides that this structure would be passable to elvers.
5. Improvements to an existing eel pass upstream of Ravensbury Park were installed in March 2018. An extension piece was added at the upstream end to prevent debris blockages. At the downstream end, a deflector plate was added to reduce turbulence, and four standard bed tiles were installed to direct eels towards the pass entrance.
6. This gravity fed eel pass was installed on a small side channel near Poulter Park in March 2018. This was a cheaper and more secure alternative to a pass that had previously been stolen.
We would like to give a huge thanks to all our volunteers who helped install these passes and those who are continuing to monitor eel numbers during the current season!