Elvering on the Severn Estuary

What are elvers?

They’re baby eels. Eels have a remarkable lifecycle which sees them travel thousands of miles across the Atlantic Ocean.

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Spawning (egg laying) has never been observed, but it is believed to take place in the spring, deep in the Sargasso Sea, between Bermuda and the Bahamas. Maturing females are thought to contain up to 10 million eggs. The eggs develop into a ‘leaf-like’ larva called a ‘leptocephalus’ It was originally thought that these larvae took three years to migrate from the Sargasso Sea to the European coast but, recent studies suggest that the journey may take as little as 12 months.

When the larvae reach shallower water they change into what is called the ‘glass eel’ stage before continuing with their migration into river estuaries.

eellifecycleThey use the tidal currents to push them into our river systems, going upstream on the flood tide. During the ebb tide they move out of the current towards the bank side to prevent being washed back out to sea. As the water warms during the late Spring, glass eels start to develop pigmentation and become strong swimmers. At this stage they look like miniature adult eels and are referred to as elvers.

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Male eel stay in freshwater for between 7 and 12 years, maturing at an average length of about 36cm. Females stay between 9 to 20 years and mature at a larger average size of about 50cm, though eel can grow larger reaching up to 1 metre in length and live as long as 40 years.

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When the fish mature they change to a blue/silvery colour and migrate seaward during the autumn, usually during dark stormy nights.

Population collapse

The European Eel is a critically endangered species. Since the 1970s, the numbers of eels reaching Europe is thought to have declined by over 90%. The exact reasons for the catastrophic decline are unknown but probably include: overfishing, parasites, barriers to migration such as weirs and natural changes in the North Atlantic currents

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Elver fishing

There is a very long history of fishing for elvers in the Severn Estuary. It’s important to the local culture and also makes a contribution to the local economy. The wholesale value of elvers has risen dramatically from around 50p a kilo in the 1980’s to anything up to £500 a kilo now. There are about 3000 elvers in a kilo. Prices fluctuate greatly depending on demand and the number of elvers about.

CaptureFishermen sell their catch to elver traders in the UK, who then sell them on for restocking fish farms and fisheries across Europe. Under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) regulations, it is now illegal to export European elver outside the Continent.

Regulating elver fishing

If you want to fish for elvers you need a special permit from us.

Details here http://bit.ly/11a4Dux

Last year we sold over 200 elver dip net licences on the Severn Estuary.
Because eels are so endangered and due to the potential financial benefits of catching large numbers of elvers we try to strike a balance between allowing fishing and protecting the vulnerable population.

Our permits put restrictions on the equipment you are allowed to use and how and where they are used. This limits the numbers of elvers it’s possible to catch while allowing fishing to continue.

Most elver fishermen are law abiding. Some are not! During the elver season ( from February to May) we devote a lot of effort to detecting and tackling illegal fishing activity. We have a dedicated team of fisheries enforcement staff who are fully warranted and equipped to carry this out.

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We also have some sophisticated kit, such as night vision headsets and cameras, sonar equipment and high- powered boats, to help us track down the guilty. Last year we successfully prosecuted 10 people at magistrates courts for illegal elver fishing on the Severn Estuary.

We also have the power to seize equipment that we suspect to be illegal or being used to carry out illegal activity. In the past, in addition to fishing equipment, we’ve seized and impounded boats, cars and vans!

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The elver season is now well underway and we’re out and about most nights.

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Chasing fish in the middle Severn

Last week, as part of a major survey of coarse fish in the mid Severn (from Shrewsbury to Worcester), we used a special piece of monitoring kit we borrowed from our friends in the South East region of the Environment Agency.

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It’s called an electrofishing boom boat and has been specifically designed to sample larger rivers. Catching fish in a big river presents lots of problems. It’s too deep and wide to net effectively, too big and deep for normal hand held electrofishing gear, and debris, obstructions and depth changes make sonar equipment unreliable. The boom boat is effective as it greatly increases the effective size of the electric capture field. The two large multiple rings arrangements on the front of the boat with metal prongs dipping into the water are the anodes and electricity passes between them and the cathodes (metal plates situated under the boat). This electric field then attracts fish towards the anodes and then immobilises them. The fish are caught by two people with nets on either side of the boat, and placed into an aerated storage tank on board the boat.

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Last week we fished between the County Showground and English Bridge in Shrewsbury. At various locations along this section fish caught were unloaded to colleagues on the bank.

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The team on the bank identify and count the fish, measure their tail fork length and take samples of scales which are sent for analysis. This tells us how old the fish are and how quickly they are growing. They are then released back into the water.

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We caught good numbers and a wide selection of fish including some large pike and perch, a shoal of roach, dace, chub, ruffe, gudgeon, European eel and juvenile Atlantic salmon as well as plenty of bullheads and minnows. A large adult Atlantic salmon was also seen but not caught.

The results from this investigation will be combined with match catch data from anglers and fry surveys to get a better appreciation of the fish population of this important fishery. We hope to produce a report on our findings later this year.

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Getting ship-shape for Shrewsbury Regatta

Everyone’s been pulling together, ready for the regatta

This weekend is Shrewsbury Regatta. We have been working hard to get a tree out of the River on behalf of the Town Council. It has been caught up on a high voltage electric cable running under the river by Porthill Bridge in the middle of Shrewsbury. This meant it wasn’t just a case of yanking it out!

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Our guys have done a lot of work behind the scenes to safely remove the tree. Firstly they liaised with the power company who agreed to have the cable potted and made safe. They also needed to talk to Severn Trent Water who have two large high pressure mains running under the river here and a sewer which runs under where we needed to put our heavy winching kit.

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All the talking and pre-planning paid off and the tree was removed yesterday without any disruption to power or water supplies, or anyone getting hurt.

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Our teams regularly remove trees and blockages to reduce flood risk in main rivers but it’s good to be able use our specialised kit to help the regatta go on in full swing. If you have time pop along to the rowing regatta this weekend at The Quarry park. For more information go to http://www.pengwernbc.co.uk . They have got a packed schedule of mens, womens, junior and novice races

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Dead fish in the Droitwich Canal

Over the last week we’ve had a number of reports of dead fish in the Droitwich canal around Vines Park.

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We have visited on a number of occasions and have found a total of about 30 fish in varying states of decomposition. Every time we’ve been out oxygen levels in the water have been good and there’s no apparent pollutant present.

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All the fish we’ve found so far have been mature bream and our fishery officers are confident that they’re victims of spawning stress. Spawning requires a lot of energy, both through egg production and through chasing potential mates. Fish can get scrapes and lose scales when thrashing against sunken tree roots, rocks and each other. These wounds give bacteria a point of entry. Secondary infections can overtake and eventually kill weakened fish. While signs of bacterial infections can vary, many fish will develop open sores, ulcers with white coloured fungus.

While it’s a shame to see dead fish this is an entirely natural phenomenon and hopefully the results of the spawning frenzy will more than compensate for the losses!

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We have taken additional water samples from the canal to make sure that there really is no pollution and we will continue to monitor the area.

If you see any dead fish or fish in distress please call our incident reporting line on 0800 80 70 60. All reports we received are passed on to our local officers.

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