As part of their ongoing commitment to deliver alternative measures under the National Environment Programme, Bristol Water have teamed up with Westcountry Rivers Trust (WRT) and Bristol Avon Rivers Trust (BART) to trial a unique glass eel monitoring programme.

The eel is a red list critically endangered species, more endangered than the snow leopard and the tiger. Bristol is one of the leading European forces in saving the eel, which through its life cycle it migrates across the Atlantic to live in UK rivers and lakes, where it grows for decades before making the return journey to spawn.

The aim of the study is to trial a new monitoring methodology samples glass eels (eels that have just reached UK coastal waters and have yet to develop pigmentation) at coastal “pinch points”.

The pinch point sites are areas where the eels will gather to ascend a barrier or tidal confluence, such as tidal flood gates, weirs, etc.  The young eels are attracted to the fresh water outputs and big tides bring them up the rivers searching out a home where they develop for many years.

The new methods involve a vertical drop net, known as the ballerina Skirt net, which provides refuge for eels while they wait out the tide to access their new habitats.  The net bundle is lowered into position and checked regularly through a tidal period, and once high tide is reached the eels will continue upstream and leave the refuge of the nets. The equipment was used for the first time last week.

The monitoring has a number of aims, including:

• to gather data on an important life but little-known history stage;
• to help provide information for rivers where eels are known to access but don’t have the data on numbers;
• to “re-stock” the captured eels over the nearest barrier as a conservation effort and;
• to unite volunteers in a large scale citizen science programme.

The first stage is focused on trialling the sample efforts and will be undertaken on the Rivers Axe and Pill (Bristol Avon) in Somerset with the expectation that what is learnt can be applied to other rivers and tributaries in the Bristol water catchment area.

Sophie Edwards, Environment Strategy Manager, from Bristol Water said:

“Our commitment to deliver alternative measures under the National Environment Programme means we can back innovative schemes, such as the Glass Eel Citizen Science project. This project engages volunteers to collect meaningful data on elver migration, to improve understanding of the pressures facing the European Eel. It is fantastic to partner with Westcountry Rivers Trust and Bristol & Avon Rivers Trust, who have outstanding expertise in this field of work. We also have support from local elvermen, whose knowledge, enthusiasm and experience is fundamental to the success of this project.”

The project has also become part of the “World Fish Migration day” and will be showcased as a UK conservation effort alongside other important projects.