Easy sliders - eel tiles clear way to end of epic trip

EELS which swim more than 3,000 miles from near the coast of North America only to get stuck in Yate can now carry on all the way to Chipping Sodbury at last.

For almost 50 years, the European eels found their extraordinary journey from the Sargasso Sea to South Gloucestershire blocked by concrete weirs installed by flood defence managers in the 1960s.

That stopped the new housing estates of Yate getting flooded, but wasn’t great news for the eels, which actually wanted to go further up the River Frome to Westerleigh and Chipping Sodbury.

The astonishing journeys of the European eels have long baffled scientists.

They are born, or spawn, in the Sargasso Sea in the western Atlantic which has currents going in a circle around it and is famed for its calm waters and huge seaweed.

As larva, they just drift around the Atlantic before reaching freshwater estuaries like the Bristol Channel, where they turn into elvers, and then swim upstream, becoming grown up eels and living their lives – up to 20 years – in the waters of the River Frome.

Then, when it’s their time, they swim back down the river and back to the Sargasso Sea, where they mate, lay their eggs and die – a phenomenon that hasn’t really been captured or understood that well by scientists.

But after the flood prevention work in Yate, the eels of the River Frome found getting to the lovely shallow waters of Chipping Sodbury much too hard.

So now the Environment Agency has given them a helping hand.

Four weirs on the stretch of the river running through Yate are about to be modified, with a small notch cut into three of the weirs, and eel tiles and baffles being fixed to the fourth weir.

The Environment Agency said it hopes this work will make it easier for the eels to pass the four weirs, and reach their habitat further upstream.

The work should open up around five miles of river upstream. It began last week and is due to be completed in the middle of the month.

“This work should see an increase in the number and variety of fish we find in the Frome, and generally make this a better place for people and wildlife,” said Heather Barker, Bristol Frome project manager at the Environment Agency.

“The work is part of a wider programme of projects through the Frome Reconnected Partnership to improve the River Frome. The weirs along this stretch of river are surrounded by public open space

and alongside the Frome Valley Walkway. We hope the local community will appreciate the work we are doing to improve the local environment and value the river and its habitat.”

To help eels travel upstream, eel tiles are being attached to the wall at the side of one of the weirs. The eel tile is a blank board on one side, but on the other side of the board facing the wall, are lots of little cones.

Because eels are long and thin, they are not very good swimmers, but they are very good at wriggling and crawling. Eels can use the gaps between the cones to wriggle through and this will help them to climb over the weir.

The baffles are long strips of recycled plastic attached to the front of the weir, and they help to concentrate flows of water by channelling the water through notches cut into the plastic.

This increases the depth of water and reduces the speed so that fish can swim through the notches and over the weir.

Four weirs on the River Frome will see measures put in place to help eels pass through

Work on improving the River Frome in Yate for eels includes ‘eel tiles’ like these