Andrew Kerr of the Sustainable Eel Group gave one of our Tuesday Talks providing a fascinating insight into the life of eels and what is being done to protect them. Here’s a summary of his lecture:
The European Eel is one of the oldest species on Earth today. They were around millions of years before the ice age. In its life, this amazing animal moves from living in salt water to fresh water and back to salt. And they can move across land! It doesn’t decide its gender until it is several years old – and it lives for 25-30 years. And the eel is still quite a mystery; there’s much about its life we know little about.
Eels are born in the Sargasso Sea in the Western Atlantic Ocean. Many tens of billions of egg are laid every year that then float on currents towards Europe. On the way, the eggs hatch into tiny leaf-shaped babies called ‘leptocephalae’ that continue to drift through the ocean. This journey takes about 2 years and less than 1% survive. As they get near land, they turn into glass eels about 6cm long and finally start swimming. They wash into estuaries like the Severn and move into fresh water, their bodies changing as they go, their colour becomes darker and they become pigmented elvers. They like to move at night in big numbers and over the next 5-10 years they move about a river system finding food to grow.
As they get older they turn into ‘yellow’ eels and finally, when fully mature, into ‘silver’ eels, at which point they make the long journey back to the Sargasso Sea, swimming 4000 miles against currents to spawn and die. For nearly 100 years scientist have tried to track this journey and research how they spawn in the wild but so far no one has succeeded. Attempts to breed eels in captivity have also failed.
But eels are facing a massive problem. When elvers come into rivers and try and get upstream, the thousands of metal and concrete barriers (weirs, dams, turbines and flood defences) humans built over the last 50 years prevent them from reaching vital habitat. So organisations like the Severn Rivers Trust and the Sustainable Eel Group have been adapting or screening them to help eels and other fish to get past them. And the number of glass eels arriving in Europe has dropped so much since the 1980s that scientists listed it as ‘critically endangered’.
The Sustainable Eel Group was founded in 2009 to take action to support the recovery of the European Eel. Fishing in Europe is now strictly controlled and most glass eels that are caught in the UK go into conservation schemes. They’re transported past barriers and released into habitat that have been blocked by barriers. This is called ‘restocking’. In 2014, 35 million glass eels were caught on the River Severn and the River Parrett and the majority have gone to conservation schemes including in schools and wildlife centres. In 2014, over 90 million fish were moved like this in Europe – a record! Some fish from the UK were moved from rivers in the west to rivers in the east, and others were flown to new homes in countries like Germany, Sweden, Estonia, and Holland.
Scientists are trying to learn more about the eel to understand how to help them more effectively. Projects like the citizen science initiative with ZSL are counting eels and showing us where they are. Others are using satellites to follow silver eels as they swim back to the Sargasso Sea. In countries that eat eel, the Sustainable Eel Standard has been introduced to help people choose eel that is caught and grown in the most sustainable way. Throughout Europe, people involved in fishing, conservation and science have joined the Sustainable eel Group to help the eel population recover.
From the very earliest moments of the ‘sustainable eel agenda’ the Board of SEG has advocated science-based thinking, strategies and programmes – a recent important paper has been Dr Willem Dekker’s latest paper on the eel recovery published by ICES Journal of Marine Science June 2016 (ICES Journal of Marine Science (2016), doi:10.1093/icesjms/fsw094) .
Dr Dekker particularly emphasises
- Implementation has effectively come to a standstill
- The agreed goals have not been realised
- The required protection has not been achieved
- From 2012 – 2015 no further reduction in mortality has been achieved
These headlines are very serious for the eel and whilst some comfort can be taken from the reported improvements to the recruitment of glass eels, this needs to be seen in the context of starting from a very low base. Eel recovery has a long way to go.
The SEG provides leadership too to try and accelerate an EU-wide program of eel recovery, working and developing their ‘Theory of Change’. For more about their vision of eel recovery and the full document please visit their web site www.sustainableeelgroup.org.
Eel fishing was once an important part of making a living in the Lower Severn Vale Levels. You can read more about tradtional fishing on the Severn here.