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Our eels are on a slippery slope

With eel populations down to less than 10% of their 1970 levels, we needed to take decisive action.

The dramatic reduction in the eel population has caused concern all over the world, and EU member states have drawn up plans to help. We have developed a national eel management plan. Part of the plan recommends elvers caught commercially from the Severn Fishery (where the elver run is still relatively good) are released into waters where eel populations are low.

One such area is the River Witham in Lincolnshire, which used to have lots of eels and supported a thriving commercial fishery. The staff here have restocked elvers in the Witham Delphs – a series of side-drains that connect to the fenland part of the river. The delphs provide a very good nursery habitat as the water is shallow, warm and sheltered. There is also plenty of the invertebrate food elvers need to grow and, importantly, there’s a connection to the main river – essential for the seaward journey the fish must eventually take to spawn.

We transport the elvers in insulated polystyrene trays filled with iced water. These tiny fish can absorb oxygen through their skin and travel well at this stage of their lives. We stocked four kilos of elvers into the Witham Delphs in 2008 and 2009, taking great care to introduce the fish gradually, as a sudden change in temperature could prove fatal. They are also very expensive – the current price is £400 a kilo.

We will continue to monitor eel numbers to establish just how successful this exercise has been. We hope it will reverse the downward trend of the eel population – in the River Witham at least.