This week we have a short blog for you from Harry the site manager for Greylake, Swell Wood and West Sedgemoor about how we are helping eels at Greylake.
Helping Eels at Greylake
European eels were once very common in Somerset’s wetlands (and across the whole of Western Europe) but some estimates have put their population decline in recent decades at 99% and they are now classed as critically endangered. If you talk to an old retired ditch cleaner, they will tell you how they used to pull them out by the hundreds, allowing them to slither back into the ditch once the machine had passed. Sadly nowadays they are a rare sight.
European Eels have an amazing lifecycle. They spend most of their life in fresh water as a “yellow eel” feeding and growing in places like the Somerset Levels. Between 6 and 20 years of age they mature and change colour into a “silver eel”. They then swim out to sea in the Autumn and travel about 3,000 miles to the Sargasso sea, on the other side of the Atlantic Ocean to breed the following spring. Apparently, they don’t all take a direct route, some meander around taking the scenic route arriving later to breed the following season. Here they breed and lay eggs. When these eggs hatch eel larvae are initially leaf shaped and they can take up to 3 years to find their way back across the Atlantic as tiny transparent “glass eels”, as they enter our rivers they become darker in colour and become “elvers”.
At Greylake we have recently installed a new ladder to help these elvers access the reserve’s fantastic ditches and pools where they can grow into mature eels. This new structure replaces and old rope and mesh netting solution that was effective but coming to the end of its days.
The elvers are constantly heading up stream and so detect the water flowing down through the green strands which you can see in the photos and wiggle up the gently slope into the reserve.
It is still not fully understood why eels are in dramatic decline, but barriers to the migration of the elvers is undoubtedly one of many likely reasons, so we hope this small project will help in some way.
Harry