I sometimes stop and talk to anglers about what they hope to catch or what they have caught. None has ever mentioned eels. Though apparently it’s possible to hope to catch an eel.  Or to hope not to: ‘To many anglers, it is an unwelcome catch, since its strength means the experience is closer to wrestling than fishing.’

The Canal and River Trust tell you how to catch an eel with a hook and line  ‘Early evening or during the night is the best time to target and catch eels. They are not shy feeders and due to a powerful mouth they can bite through fine lines. The best baits are small dead baits or a bunch of lobworms or maggots on the bottom, often close in the margins or around weed beds. Small dead baits, such as roach, rudd or gudgeon, are a favourite and can be fished with a single large hook, such as a size two or size four.’ However, they caution that ‘removal of eels for any purpose is no longer permitted. All eels caught on rod and line must be returned to the waterway, either immediately or in a competition after the weigh in has taken place.’

Historically, though, eels were among the chief fish harvested from the Thames, often being caught in wicker traps or ‘bucks’ — made from willows, so from material conveniently close to hand. There’s a picture of such a trap in the Luttrell Psalter, from the thirteenth century.

Evidence that eels were plentiful — and valued– is provided by medieval requirements that rent be paid in eels. A historian who’s studied medieval practical and symbolic uses of eels has tried to map places recording eel rents. A number of these were round about Oxford, thus Swinford and Thrupp (Thrupp near Abingdon) both owed eel rents in the twelfth century to the Abbot of Abingdon, whose records are the source for the information. Swinford had to pay 325 eels, Thrupp a mere 175. Presumably the abbey had fishponds in which to keep them fresh. Eels were less important after the Black Death, it’s suggested, when more animals were kept, so there was more choice of protein. Still, Mary Prior tells us in her book on Fisher Row that when Cranmer was in prison in Oxford he was served eel broth for dinner almost every day. The need to avoid meat-eating during Lent enhanced the importance of fish.

The nineteenth-century artist William Turner of Oxford in at least two paintings depicted a man ferrying eel bucks in a punt — perhaps for use by mill weirs (one of the paintings is by King’s Mill on the Cherwell) but not necessarily: baited bucks could be placed elsewhere in the river. The other painting is by Hythe Bridge, where the Castle Mill stream runs alongside the canal. George Townsend, noting that the latter painting was completed before the demolition of this bridge (in this form) in 1861, suggests that the figure ‘seems to be shorthand for the city’s less celebrated, traditional ways of life, the days of which – like the ramshackle medieval mill and the doomed bridge – Turner perhaps thought were numbered.’

Though not the only fishers of eels, millers were particularly well placed to catch them, enduringly over many centuries, since they could place traps on their weirs, and even regulate the flow of water to maximise their chances of getting a good haul. A painting showing bucks on a frame by a weir at Iffley in 1782 is reproduced on the Thames Sweet Waters website.

In the 1866 parliamentary enquiry into the extension of the Thames Conservators’ jurisdiction from the lower to the upper river (discussed in my Techno-fix post), there were several exchanges about this practice (There were more mills in the upper than the lower rivers, so how the Conservators would approach the new challenge of dealing with them loomed quite large in discussion). Some who appeared before the committee accused millers of intensifying flooding, or of draining off water overnight at such a rate as to leave the river less fit for navigation, all just to catch a few hundredweight of eels (it was said, dismissively). The hundredweight – 112 lbs, approx. 50kg — seems to have been the unit in which eel catches were generally measured. Eel catches seem to weigh in at about one to ten lbs. So 112lb probably implies dozens rather than hundreds of eels – and only then given that the eels coming down river would be mature eels, coming down to spawn, as opposed to young glass eels, which would weigh in at tens of thousands to the hundredweight. If as claimed at this time the price never fell below 10d a lb, this was (in the prices of the day) not to be sneezed at. No one expressed any concern about the effect on the eels. It was taken as read that they were abundant.

Most eel species live in the sea, burrowing into the silt and coming out to predate at night. ‘European’ eels by contrast spend parts of their lives in rivers – they’re euryhaline fish: they can tolerate both salt and freshwater. They start life as small larvae, become slender elvers, then tougher mature fish, then mate, spawn and die.

Scientists say there’s much they don’t know about these eels. Supposedly they originate in the Sargasso Sea, some way east of Florida, as transparent spores. Atlantic currents then carry them to Europe, in the course of a few years, during which they become more clearly baby eels: ‘glass eels’ or elvers. They can be found all over Europe, though they’re not known on Africa’s Saharan coast, probably a function of currents. While too small to swim, they rely on currents to carry them, and tend not to penetrate much beyond the tidal reaches of rivers. Later they may swim up rivers, though hugging the edge. If they survive, they mature and become ‘yellow eels’, ‘rarely more than a meter long’. They may then live for a several decades, but ultimately, as ‘silver eels’ swim back across the Atlantic to spawn.

They’re predatory fish, and scavengers, liking dead meat. Gunther Grass’s novel, The Tin Drum, about interwar Germany, includes a memorable episode in which a severed horse’s head isn dipped into a river to catch eels. They mainly feed at night, when they may also crawl across land from one body of water to another. Someone who grew p on a lock island on the Thames at Maidenhead remembers encountering them there: ‘It was pretty common to find them slithering across the lawn. Very unpleasant to accidentally step on in the dark.’

The Zoological Society of London’s ‘Eel barrier assessment tool’ provides more information about the mid-life behaviour of eels than I’ve found elsewhere. They say that ‘After the first year or two, two behavioural strategies are apparent: home-range dwellers (establish in a given area for a number of months or years) and nomads (shift within and between water bodies, including fresh and saline environments).‘

Eel migrations are seasonal, and temperature driven. The assessment tool again notes, citing a scientific study, that ‘A threshold for enhanced migratory behaviour peaks at 14-16°C, no or little migration occurs beneath 10-11°C’. Young eels ascend rivers from April or May through to September or October . Downstream migration of silver eels takes place from August to December, peaking between September and November. In winter they dig into river banks and hibernate.

In  recent times, within Britain, eels have been especially numerous in the Severn estuary and tributaries of the Severn, and perhaps that was the case historically too. But there were also lots  in the Thames, especially around the estuary and up past London, a source of cheap but tasty food, much eaten until the last century the form of ‘jellied eels’. By the seventeenth century, London’s appetite had outstripped local supply, so eels had to be imported from Holland   

The recent ZSL study found striking variability in elver numbers between different tributaries of the Thames, and thought that interesting and hard to explain – but couldn’t be sure that it wasn’t due to the different efficiency of the traps set from place to place.

Eels disappeared from the Thames as it became increasingly polluted, but returned from the 1960s against a background of attempts to reduce pollution. Systematic monitoring of numbers seems to have taken place only since the 1980s, so previous longer term trends are unclear.. What is clear is that numbers have fallen cataclysmically during the early twenty-first century: most estimates suggest falls of more than 90%,  decline being  most marked among glass eels, though also notable among yellow eels (it seems possible that decline in numbers of young will keep feeding through to affect older numbers.

The Financial Times, in an informative article of 2010,  summarised speculations about the causes of decline: ‘The ocean currents of the Gulf Stream and North Atlantic Drift that carry their larvae back to land from their place of birth out in the Atlantic are shifting direction as sea temperatures rise, and so many of the larvae are missing European shores altogether. In addition, our rivers are increasingly blocked by manmade structures and punctuated by hydro power intakes whose turbines act as mincing machines. Commercial trawlers take millions of glass eels a year from the Bay of Biscay, wetland habitat has decreased dramatically, and a parasite introduced from Asia has infected the European population. Or perhaps something else entirely could be causing the population crash. No one knows for sure.’ The Pisces Conservation website carries a still more detailed and thorough discussion of the challenges.

One might worry about this for general ecological reasons. Eels fill a particular niche in the freshwater food chain, both as scavengers and as prey. The forces responsible for their decline affect other fish too. In July 2020, the World Wide Fund for Nature reported that migratory freshwater fish species declined by 76% on average over the previous four decades; in Europe alone, by 93%.

There’s also a commercial angle — which has concerned the EU, and helped to spark reportage in the Financial Times. In Britain in recent decades, there’s been onlyone industrial-scale eel company, Glasseel UK. And taste for eels seems to have declined, so conosumers mainly don’t mourn their loss. But on the continent, they’ve been caught annd eaten on a larger scale, and also exported in huge quantities to Asia, especially to Japan.

Hitsumabushi, a Nagoya specialty: eel eaten three ways, first straight, then with some relish, then with a kind of gravy. Initially servants’ food, eaten thus for variety because they got tired of eating eel all the time. Nagoya, 2004.

In 2009, the EU instituted an Eel Recovery Programme, which was implemented in member countries, including the UK. The European Council Regulation set targets for the recovery of European eel stocks and required the development of management plans to improve stocks; the Eels (England and Wales) Regulations gave the Environment Agency powerr to act.

Broadly, responses have taken three forms:

  • attempts to gather more data, to understand what’s been happening;
  • attempts to tackle sources of decline that are readily susceptible to human action,
  • attempts to sustain numbers artificially, through breeding programmes (the first task here is to work out whether eels can be bred and raised on fish farms – not achieved yet; there are eel farms, but they’re restocked from the wild).

Under the first head, the Zoological Society of London established a ‘citizen science’ monitoring programme, focussing its efforts on the tidal Thames and its tributaries.

Under the second head, energy has been directed into the construction of fish and eel passes, to help them bypass weirs and other such obstacles. Of course, neither weirs nor indeed fish passes are new. In John Blair’s collection on Waterways and canal-building in medieval England, it’s suggested that some historic channels around mills may have been constructed in the first instance to let fish pass. Still — it’s suggested — old weirs were wooden and imperfect; modern barriers pose a new order of challenge. So more and better passes are needed. Because young eels are poor swimmers, passes that are going to help them need to have special characteristics, like brush-covered surfaces they can wiggle their way up (this has been determined by giving eels a choice of different kinds of pass, and observing which they choose).

There have also been experiments with high-tech approaches, for example, tagging certain eels so that their movements can trigger suspension of power-station operations during the relatively brief periods in which eels are on the move.

In terms of the redirection of commercial effort, the British company Glasseel UK explain on their website the changes they have gone through in trying to find a niche for themselves in a rapidly changing environment over fifty years, to 2012: ‘In the late 1960’s [there was] a non sustainable rush of exports to Japan, followed by a strong demand for glass eels for aquaculture in Europe. Then in the 1990’s there was an unprecedented demand for glass eels from Asia. … In 1983/1984 there was a very marked stepped reduction (60% in one season) in glass eel recruitment. By the late 1980’s … we lost a substantial market share to … French suppliers….[but then] in the early 1990’s new customers appeared from China. Then fortunately for the eel, in 2010, the Eel Management Plan for the UK had been implemented and all exports outside of the EU was made illegal. In 2012 we moved to our current site supported by the European Fisheries Fund on the banks of the River Severn and we have continued to introduce sustainable fishery practices and solutions. [We aimed] to reduce capacity from 15,000kg to 1,500kg… not only to protect the fishery for future generations but also to maintain the economic, cultural and social values for the local community. The majority of our eels are now sold to Europe for restocking projects. With a proportion for sustainable aquaculture.’

Redirection of commercial effort only works up to a point, though – not least since there’s a large eel smuggling sector.

From C.J Cornish, The Naturalist on the Thames. Henry Taunt photo of eel bucks, ? Hurley, Great Marlow.
Reproduced from the Project Gutenberg copy of the book see also note at the end of this post

Knowing something about the life-cycle and habits of the eel helps to make sense of the millers’ strategies in deploying their bucks — which, when elevated in the photo above, were not in use. They were lowered into the water for use.

What millers were well-placed to catch was eels heading down river, that is migrating silver eel. So presumably their efforts will have been concentrated in the autumn – except (someone who fished for eel in Somerset in recent decades has said) in flood time, because ‘the fish will migrate at any time of year if the river is in flood’. Hence particular worries about the millers’ self-interested conduct in times of flood. Since eels are normally nocturnal, millers’ activities were concentrated at night – their habit was to pull up the mill sails and leave bucks attached to one weir at night, while other weirs were stopped up, to canalise traffic.

Eel bucks have given their names to various places in Oxford’s neighbourhood. Wikipedia instances as sites on the Thames, Buck Ait and Handbuck Eyot. At Dorchester-on-Thames there’s a ‘Buck Mead’ and a ‘Buck Pool’ on the Thame at the millstream, beside the abbey. As we have seen, abbeys took a lively interest in eels,as a food source for their monks.

Buck Pond from the weir, Dorchester-on-Thames

‘The floodgate near Flights Mill [Kirtlington] has an eel trap incorporated in its structure’ to this day. Elsewhere memories of such fishing endure. According to the VCH, at Islip, the fisheries continued to be valuable until the late 19th century and gave rise to the local industry of making osier cages or ‘weels’ for catching eels’.  ‘The famous Islip eels,,,at one time were sent to London pubs’

Traps continued in use until recently, even if not attached to mill weirs. In 2010, the FT talked to a Somerset eel fisher, who ‘under cover of darkness [because that’s when eels move, not because he was hiding anything], [the fisher] operates his rack, which throws eels up from the water on to its wooden staging and allows them to be kept alive within the structure’s submerged baskets. Early in the morning he checks the success of his fyke nets, often braving icy floodwaters to bring them in. “It’s cold, wet and uncomfortable,” he says, “but it is very exciting.’

When I crowd-sourced memories of eel-fishing around Oxford recently, some remembered eel trapping – around Wytham and Godstow (by family report) and at the north end of Hinksey Lake in the 1960s. One can trap without blocking off the whole stream, if bait, such as meat, is put in the baskets.

Other local memories of eel fishing, mostly from childhoods or early lives, involved hook and line:  ‘My father used to catch them, He used to cast the line from the Port meadow side towards lock island [Godstow]; they used to take shelter by the island.’ ‘We lived on Osney and [my Mum] would always tell the story of [my Dad] taking her fishing just around the corner near Osney lock and catching eels, one of which wound itself around her arm when my Dad was trying to take the hook out of it]. ‘I remember as a small child [living in Granfpont House, by Folly Bridge] being intrigued by the eels which the fisherman hung on the wrought iron fence on the towpath.’ ‘Being an angler I caught a couple of eels at Port Meadow by the old bathing huts area around the mid 70s’. They’re remembered as formidable: ‘I lived in Buckingham Street as a boy and fished in the river. Eels could be caught under Folly Bridge, the towpath side, if we caught one we took it home threw it in the bath and our dad sorted it for eating after he came home from work.

Mid 70s is as recent as most of the memories get. One man wrote: ‘I’m .. a fisherman and have been aware of the enormous decline in eel numbers just over the past three decades. I have not caught or seen anyone catch an eel for many years on the Thames. They used to be a pest’. But one man who responded to me – exceptionally, it seems — catches eels still: ‘I catch some lovely eels at a couple of nice hidden spot in Oxford . Nice light running gear. Air injected lob worms hair-rigged popped up from the bottom about 2 inches. I then bait up with a mixture of pure black mole hill soil and a very fist groundbait with dead maggots and worm amino additives. Last year we had 17 in total. And every single one was treated with utter care and RELEASED!!’

Oxford eel-fishing memories, and sites of modern fish passes

Now the area is a site for recovery efforts. The Environment Agency has been associated with several fish-pass projects around Oxford in recent years, thus at Godstow, Tumbling Bay (in association with Low Carbon West) and Hinksey Weir (in association with the River Restoration Centre). The issue has also arisen in relation to hydro plants at Osney and Sandford. In write-ups about these projects, only the account of the projected pass at Godstow specifically mentions eels among beneficiaries: :it’s said that the projected fish pass ‘will allow fish and eels to make their way up river.’  

Tumbling Bay fish bypass Google Earth view, imagery CNS/Airbus/

Concern about the cataclysmic fall in eel populations in the early twenty-first century led to lots of writing on the subject, so there’s an embarassment of material, including articles in the Financial Times and The New Yorker. All the sources I’ve used are linked somewhere in the post.

Thanks also to followers of the History of Oxford facebook group, who gave me useful links and shared their memories.

CJ Cornish, The Naturalist on the Thames can be accessed on the Thames Smooth Waters website or via Project Gutenberg. It’s a condition of use of Project Gutenberg books that this statement is reproduced This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at

The Historic England website also includes several other photos of eelbucks, including one that possibly gives a different perspective on that shown above.

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