Eurofisch: hyper-mobility, cosmopolitanism and the European eel’s appeal

Unlike the Atlantic salmon, the snake-like European eel (Anguilla anguilla) is widely perceived as devoid of charisma. An epic reproductive journey is integral to the salmon’s appeal. But an equally spectacular migration, if in reverse, defines the European eel. The sea-dwelling salmon returns to its freshwater origins. The freshwater-inhabiting eel goes back to its oceanic birthplace. Natural distribution represents another key point of similarity and difference. The salmon spans the North Atlantic, its European breeding grounds confined to more northerly freshwaters. The European eel, with its broader temperature tolerance, populates a wider latitude. Its habitat ranges from southern Iceland and Russia’s Kola Peninsula to the southern Mediterranean – despite the name, North Africa’s rivers and lagoons contain this eel species – and, on the Atlantic coast, as far down as the Canaries. From west to east, they are distributed from the Azores to Georgia.

Figure 1: ‘Artisanal’ dipnet fishing for elvers from the bank of the River Severn at Wainlode, Gloucestershire, on a spring evening in 2017 (Image: Environment Agency. Reproduced by permission of the Sustainable Eel Group). 

The eel’s Europeanness is most vividly demonstrated by its genes. Whereas the salmon displays high genetic diversity and reproductively discrete local populations, European eels all belong to the same breeding population. This singular, panmictic identity is rooted in a shared birthplace: the West Central Atlantic’s Sargasso Sea is a melting pot where every eel of the opposite sex is a potential breeding partner. And the place the next generation calls home could be anywhere within the species’ European range. Lacking the salmon’s homing instinct, the offspring of eel parents that spent their adult lives in Norwegian and Tunisian waterbodies respectively might settle in Wales. Alternatively, this progeny could end up in Portuguese freshwaters, or wherever the currents carry the tiny larvae (leptocephali) during their up-to-three-year odyssey. The European eel is the only truly pan-European fish: a paragon of cosmopolitanism I call ‘Eurofisch’.

On reaching western Europe, leptocephali metamorphose into glass eels. Shoals of these transparent mini-eels – also known as elvers in the UK – start entering southern Europe’s estuaries in December. But in 2012, fisheries scientists reported that ‘recruitment’ had fallen by up to 95 per cent since 1970. An Extinction Rebellion event in Yeovil, Somerset, in the summer of 2019, underscored the species’ critically endangered status. Protestors dressed as eels participated in a ‘drown in’ and a ‘European eel’ addressed South Somerset District Council.

I’ve recently examined the reasons for this drastic decline; tracked the emergence of concern; considered the remedies; looked at trafficking in glass eels for East Asia’s ‘grow-out’ farms that a Plymouth University project has characterized as an ‘unnatural migration’; and reflected on the prospects of eel appeal spreading. Mobilising popular support for eels is more difficult than drumming up enthusiasm for mammals, either terrestrial and marine (for example, ‘T-shirt’ animals such as pandas, polar bears, whales and dolphins). Few who have seen the 1979 movie version of Günter Grass’ novel, The Tin Drum (1959), will forget the stomach-churning scene on the Baltic beach near Danzig (Gdansk) where a fisherman hauls in a horse’s head writhing with eels that he pulls from ears, nostrils and throat.

Figure 2: Elvers wriggling upstream at Bradford on Tone, Somerset Levels, UK in April 2014. (Image: Andrew Kerr. Reproduced by permission of the Sustainable Eel Group). 

What I’d like to convey here is the richness of Europe’s eel heritage and how Eurofisch illuminates what it means to be European. The silver eel (the final, Sargasso-ready life stage) has the highest calorific value of any European fish. A venerable and varied culture of consumption unites Europe, from Spain to Sweden and from Ireland to Italy. Since early Christianity, roast eel has been the dish customarily served at midnight on Christmas Eve in Rome and Naples. The epicentre of Italian eel gastronomy, though, is Comacchio. Since the 1300s, this town in the Po Delta has hosted a silver eel fishery based on lagoons stocked with glass eels entering from the Adriatic. Eels are skewered and roasted, marinated in barrels, then canned. La Donna del Fiume (1955) starred Sophia Loren as an impossibly glamorous worker in a Comacchio cannery that’s now a museum.

In the early 1900s, glass eels were swept up hyper-tidal estuaries such as the Severn, Loire, Gironde, Minho and Tagus in tremendous quantities: surpluses were fed to pigs, fertilised vegetable plots and made into glue. In France, glass eels were boiled and served cold (‘spaghetti with eyes’). Meanwhile, in Severn estuary villages, super-abundant elvers were fried in butter or bacon fat, scrambled with eggs, or boiled and pressed into gelatinous, fried cakes. In Victorian London’s East End, whose labouring population could not afford salmon or meat, itinerant vendors of stewed and jellied eel and the ‘eel and pie’ shop were odoriferous fixtures of the cityscape. Dutch traders were supplying London by 1400 and in the late 1600s schuyts – ships fitted with wells for live export – established a mooring near Billingsgate fish market. Squirming cargos arrived almost daily until the early 1900s; the last schuyt docked in 1938.

In Frampton-on-Severn, the Easter Monday elver eating competition was woven deeply into village life. Male contestants gobbled down a pound of fried elvers. A contest for women (only required to consume half a pound) was founded in 1973. With steeply declining numbers and sharply rising prices, the contest was cancelled in 1990. Revival followed in 2015 – with ersatz elvers known as gulas, produced in Spain’s Basque country. Dubbed ‘elvers’ locally, gulas consist of surimi, blocks of fish paste from Alaskan pollack and Pacific whiting.

In June 2019, the Sustainable Eel Group, a science-led, Europe-wide campaign organisation, marked its tenth anniversary with a two-day meeting at the Natural History Museum and a week-long eel celebration. A highlight was the arrival at ‘Dutch Mooring’ of a reconstructed schuyt, absent from London’s riverscape for over 80 years. My visit coincided with that of Pieter Hak, proprietor of the Noted Eel & Pie House, Leytonstone. Hak told the Dutch crew that his great grandfather, a schuyt captain, sent his youngest son to London to learn the eel pie business in the 1890s. After he met and married the daughter of an English eel and pie shop owner, they opened their own place in Bow in 1926. Hak gave the crew a copy of Stuart Freedman’s paean to this hallowed Cockney institution, The Englishman and the Eel (2017); Hak appears on the cover, grasping a live eel. (Note, however, that an Italian immigrant established London’s oldest surviving eel and pie shops in 1902.)

Two years after leaving the EU, this sort of fishy connection can help, in a small way, to conserve a sense of Britain’s Europeanness. Britain’s eels belong to a wider European family, biologically and culturally. Our migratory eel also has a resounding message in an age of mass trans-border movements, reminding us that where we call home is not always where we, or our parents, were born.

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This blog is written by Cabot Institute for the Environment member Peter Coates, an Emeritus Professor of Environmental History at the University of Bristol as part of a joint Migration, Mobility and the Environment blog series with Migration, Mobilities Bristol. Some of the material in this post appeared in ‘Protecting Eurofisch: An Environmental History of the European Eel and its Europeanness’ in Greening Europe: Environmental Protection in the Long Twentieth Century – A Handbook (2022). Peter wrote a book on Salmon (2006) in Reaktion’s ‘Animal’ series and is currently writing a squirrel history of the UK.

Is extreme heat an underestimated risk in Bristol?

Evidence that the Earth is warming at an alarming rate is indisputable, having almost doubled per decade since 1981 (relative to 1880-1981). In many countries, this warming has been accompanied by more frequent and severe heatwaves – prolonged periods of significantly above-average temperatures – especially during summer months.

Heatwaves pose significant threats to human health including discomfort, heatstroke and in extreme cases, death. In the summer of 2003 (one that I am sure many remember for its tropical temperatures), these threats were clear. A European heatwave event killed over 70,000 people across the continent – over 2,000 of these deaths were in England alone. As if these statistics weren’t alarming enough, projections suggest that by 2050, such summers could occur every other year and by 2080, a similar heatwave could kill three times as many people.

Cities face heightened risks

Heat-health risks are not equally distributed. Cities face heightened risks due to the urban heat island (UHI) effect, where urban areas exhibit warmer temperatures than surrounding rural areas. This is primarily due to the concentration of dark, impervious surfaces. In the event of a heatwave, cities are therefore not only threatened by even warmer temperatures, but also by high population densities which creates greater exposure to such extreme heat.

UHIs have been observed and modelled across several of the UK’s largest cities. For example, in Birmingham an UHI intensity (the difference between urban and rural temperatures) of 9°C has been recorded. Some estimates for Manchester and London reach 10°C. However, little research has been conducted into the UK’s smaller cities, including Bristol, despite their rapidly growing populations.

Heat vulnerability

In the UK an ageing population implies that heat vulnerability will increase, especially in light of warming projections. Several other contributors to heat vulnerability are also well-established, including underlying health conditions and income. However, the relative influence of different factors is extremely context specific. What drives heat vulnerability in one city may play an insignificant role in another, making the development of tailored risk mitigation policies particularly difficult without location-specific research.

Climate resilience in Bristol

In 2018, Bristol declared ambitious intentions to be climate resilient by 2030. To achieve this, several specific targets have been put in place, including:

  • The adaptation of infrastructure to cope with extreme heat
  • The avoidance of heat-related deaths

Yet, the same report that outlines these goals also highlights an insufficient understanding of hotspots and heat risk in Bristol. This poses the question – how will Bristol achieve these targets without knowing where to target resources?

Bristol’s urban heat island

Considering the above, over the summer I worked on my MSc dissertation with two broad aims:

  1. Quantify Bristol’s urban heat island
  2. Map heat vulnerability across Bristol wards

Using a cloud-free Landsat image from a heatwave day in June 2018, I produced one of the first high-resolution maps of Bristol’s UHI (see below). The results were alarming, with several hotspots of 7-9°C in the central wards of Lawrence Hill, Easton and Southville. Maximum UHI intensity was almost 12°C, recorded at a warehouse in Avonmouth and Lawrence Weston. Though this magnitude may be amplified by the heatwave event, these findings still suggest Bristol exhibits an UHI similar to that of much larger cities including London, Birmingham and even Paris.

Image credit: Vicky Norton

Heat vulnerability in Bristol

Exploratory statistics revealed two principal determinants of an individual’s vulnerability to extreme heat in Bristol:

  1. Their socioeconomic status
  2. The combined effects of isolation, minority status and housing type.

These determinants were scored for each ward and compiled to create a heat vulnerability index (HVI). Even more concerning than Bristol’s surprising UHI intensity is that wards exhibiting the greatest heat vulnerability coincide with areas of greatest UHI intensity – Lawrence Hill and Easton (see below).

What’s also interesting about these findings is the composition of heat vulnerability in Bristol. Whilst socioeconomic status is a common determinant in many studies, the influential role of minority status and housing type appears particularly specific to Bristol. Unlike general UK projections, old age was also deemed an insignificant contributor to heat vulnerability in Bristol. Instead, the prevalence of a younger population suggests those under five years of age are of greater concern.

Image credit: Vicky Norton

Implications

But what do these findings mean for Bristol’s climate resilience endeavours? Firstly, they suggest Bristol’s UHI may be a much greater concern than previously thought, necessitating more immediate, effective mitigation efforts. Secondly, they reiterate the context specific nature of heat vulnerability and the importance of conducting location specific research. Considering UHI intensity and ward-level heat vulnerability, these findings provide a starting point for guiding adaptive and mitigative resource allocation. If Bristol is to achieve climate resilience by 2030, initial action may be best targeted towards areas most at risk – Lawrence Hill and Easton – and tailored to those most vulnerable.

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This blog is written by Vicky Norton, who has recently completed an MSc in Environmental Policy and Management run by Caboteer Dr Sean Fox.

Vicky Norton

 

 

Is Europe heading for a more drought prone future?

Parched landscape of Europe during the 2018 drought. Image credit: NASA, CC0

In 2018, Europe was hit with one of the worst droughts so far in the 21st century in terms of its extent, severity and duration. This had large-scale effects on the vegetation, both agricultural and natural. Harvest yields were substantially reduced, by up to 40% in some regions, and widescale browning of vegetation occurred.

A consortium of international researchers, including members of the Atmospheric Chemistry Research Group (ACRG) at the University of Bristol, asked the question: given the major impacts on vegetation, which plays an essential role in removing carbon dioxide (CO2) from the air, was there an observable change in the amount of carbon uptake across Europe during this event?

There are at least two ways to quantify the impact that the drought had on the terrestrial carbon sink: a bottom-up or top-down approach. Our plans and timelines to mitigate climate change rely on using these methods to predict how much of anthropogenic greenhouse gas emissions can be taken up by the natural biosphere. Currently, the terrestrial carbon sink (i.e. vegetation and soils) takes up approximately a third of manmade emissions. The oceans take up about a similar amount. But this important carbon sink is subject to variation brought about by naturally occurring variation in the climate and manmade climate change.

To investigate the impact of the drought on the European terrestrial carbon sink, modellers can predict how individual processes that contribute to the terrestrial sink would respond to the climate during that period – a bottom-up approach. For example, a study by Bastos et al. (2019) compared the estimates of net ecosystem exchange during the drought period from 11 vegetation models. Net ecosystem exchange quantifies the amount of CO2 that is either taken up or released from the ecosystem and is usually quantified as a flux of CO2 to the atmosphere. This value is negative if the ecosystem is a sink and positive if it is a source of CO2 to the atmosphere. The consensus from previous studies was that an unusually sunny spring led to early vegetation growth, which depleted soil moisture, which intensified the drought during the summer period. Although more CO2 was taken up by the biosphere in spring, in some European regions, like Central Europe, the lack of rain during the summer months meant that the soils, already depleted in water, could not maintain the vegetation, and this led to CO2 losses from the ecosystem.

At the ACRG we use measurements of gases in the atmosphere, like CO2, to improve estimates of emissions and uptake of these gases using a top-down approach called inverse modelling. Measurements are obtained from carefully calibrated instruments that are part of global networks of measurement sites like AGAGE (Advanced Global Atmospheric Gases Experiment) and ICOS (Integrated Carbon Observation System). We also require initial estimates of the fluxes, which we obtain from several sources, including vegetation models and bottom-up inventories, and a model that describes atmospheric transport of the gas (a model that describes how a pocket of air will travel in the atmosphere). Using a statistical approach, we can then improve on those initial estimates to get better agreement between the modelled and observed concentrations at the measurement sites. With this method, we have to account for all sources of a gas, both anthropogenic and natural, as the concentration that is recorded at a measurement site is the sum of all contributions from all sources.

In a recent publication by Thompson et al. (2020), we compared the CO2 flux estimates for regions in Europe over the last ten years using the ACRG modelling method, along with four other approaches. The combined estimate from these five modelling systems indicated that the temperate region of Europe (i.e. Central Europe) was a small source of CO2 during 2018. This means that when carbon losses due to plant and soil respiration are compared with the carbon uptake by photosynthesis, then a small positive amount was emitted to the atmosphere on balance. This is described by a positive net flux of 0.09 ± 0.06 PgC y-1 (mean ± SD) to the atmosphere, compared with the mean of the last 10 years of -0.08 ± 0.17 PgC y-1, which is a net sink of carbon, meaning that over the last 10 years more carbon was taken up by photosynthesis than emitted through ecosystem respiration. Northern Europe was also found to be a small source in 2018. This publication was part of a special issue on the impacts of the 2018 drought on Europe.

So what does this tell us about how carbon uptake might change in the future? A 2018 study by Samaniego et al. considered future projections from climate models under different scenarios ranging from 1°C to 3°C global temperature rise. They concluded that soil moisture droughts were set to become 40% more likely by the end of the 21st century under the current 3°C future compared with 1.5°C set out in the Paris Climate Agreement. Droughts like the previous “Lucifer” event in 2003, where as many as 35,000 people lost their lives due to the effects of the drought, are expected to become twice as likely. Failing to reduce greenhouse gas emissions so that we mitigate the global temperature rise will impact on our ability to grow food and make killer drought events more likely. Our study shows that more frequent droughts will reduce the biosphere’s ability to take up our CO2 emissions due to the impact of a warmer climate on the soil and vegetation of key natural sinks, and lead to fundamental changes in the structure and species composition of these systems into the future. Unfortunately, this will further exacerbate the effects of climate change.

Bibliography

A. Bastos, P. Ciais, P. Friedlingstein, S. Sitch, J. Pongratz, L. Fan, J. P. Wigneron, U. Weber, M. Reichstein, Z. Fu, P. Anthoni, A. Arneth, V. Haverd, A. K. Jain, E. Joetzjer, J. Knauer, S. Lienert, T. Loughran, P. C. McGuire, H. Tian, N. Viovy, S. Zaehle. Direct and seasonal legacy effects of the 2018 heat wave and drought on European ecosystem productivity. Science Advances, 2020; 6 (24): eaba2724 DOI: 10.1126/sciadv.aba2724

M. Reuter, M. Buchwitz, M. Hilker, J. Heymann, H. Bovensmann, J.P. Burrows, S. Houweling, Y.Y. Liu, R. Nassar, F. Chevallier, P. Ciais, J. Marshall, M. Reichstein. How much CO2 is taken up by the European Terrestrial Biosphere? Bulletin of the American Meteorological Society, 2017; 98 (4): 665-671 DOI: 10.1175/BAMS-D-15-00310.1

L. Samaniego, S. Thober, R. Kumar, N. Wanders, O. Rakovec, M. Pan, M. Zink, J. Sheffield, E.F. Wood, A. Marx. Anthropogenic warming exacerbates European soil moisture droughts. Nature Climate Change, 2018; 8, 421-426 DOI: 10.1038/s41558-018-0138-5

R.L. Thompson, G. Broquet, C. Gerbig, T. Kock, M. Lang, G. Monteil, S. Munassar, A. Nickless, M. Scholze, M. Ramonet, U. Karstens, E. van Schaik, Z. Wu, C. Rödenbeck. Changes in net ecosystem exchange over Europe during the 2018 drought based on atmospheric observations. Philosophical Transactions of the Royal Society B, 2020; 375 (1810): 20190512 DOI: 10.1098/rstb.2019.0512

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This blog is written by Cabot Institute member Dr Alecia Nickless, a research associate in the School of Chemistry at the University of Bristol.

Bristol Geographers appear in The Times and condemn divisive Brexit rhetoric

The following text comprises a longer version of a Letter to the Editor that appears in print and online in The Times. The letter, signed by over 85 members from of the School of Geographical Sciences expresses our dismay and disillusionment with the recent divisive rhetoric from the government regarding foreign workers and an inclusive society.

Further, we are concerned that this rhetoric is already acting as a detriment to our university’s values, and the research and teaching we do.

The letter starts here:

“As a nationally and internationally recognised research and teaching department, we echo Lord Rees’ recent comments to express our deep concern at the divisive and ‘deplorable’ rhetoric during discussions about Brexit and immigration at the recent Conservative party conference. This rhetoric does not reflect the values we aim to uphold in our university and discipline, nor the diversity of feelings in the country. We are dismayed, further, that our Prime Minister, a former student of geography, seems to have forgotten our subject’s core teachings and values.

We are ‘citizens of the world’. Our department’s research, teaching, and study ranges across diverse fields: from financial institutions to flooding; from philosophy to parliamentary boundary reform; from colonialism and biogeochemistry, and all the planetary processes in between. We come from over 19 different countries, and virtually every populated continent. We come from everywhere. And we contribute to numerous global and local initiatives that seek to make our world a better, healthier, happier place.

What unites our diverse scholarly work is the recognition that how we make sense of the Earth – how we ‘geo-graph’ it – matters. How we understand our relationships to the Earth and each other matters for addressing issues affecting our shared planet, equitably and honestly. For this reason, we highlight our responsibility to one another and the many complex forces that make life possible; we recognise and value the many who make us, always, more than one.

Thus, we stand behind all of our staff and students who come from all corners of the world, and who contribute, as international citizens, to the strength of our department and its impacts locally, nationally, and globally. International staff and students now feel very insecure about their futures here. While we will do everything we can to protect their work and contributions, we hope the government will make clear that their futures – and those of our colleagues across the UK – are under no threat.

The School of Geographical Sciences

University of Bristol”

In order of signing:

Prof Paul Bates, Head of School

Prof Ron Johnston, OBE, FAcSS, FBA (former-VC, University of Essex)

Prof Clive Sabel

Prof Richard Harris

Prof Jemma Wadham

Prof Tony Payne

Prof Alexandre Anesio

Prof Sharon Collard

Dr T Davies-Barnard

Dr Merle Patchett

Dr Alex Farnsworth

Dr Sarah Greene

Prof Kelvyn Jones, FBA, FLSW, FAcSS

Dr Jon Hawkings

Dr Gemma Coxon

Dr Chris Williams

Dr Malcolm Fairbrother

Dr Fotis Sgouridis

Mr Earl Harper

Dr Niall Quinn

Dr Chris Yates

Ms Laura De Vito

Mr Matt Trevers

Dr Fiachra O’Loughlin

Dr Twila Moon

Mr Edward Armstrong

Mr Julien Bodart

Mr Rory Burford

Mr Erik Mackie

Dr Peter Hopcroft

Mr Gwilym Owen

Mr Michael A. Cooper

Mr Tim Morris

Mr Gregory J. L. Tourte

Dr Julie MacLeavy

Dr David Manley

Dr Patricia Sanchez-Baracaldo

Dr Winnie Wang

Dr Mark Jackson

Dr Sandra Arndt

Dr Sean Fox

Mr Nathan Chrismas

Mr Thomas Keating

Ms Catherine Midwood

Dr Luke Ridley

Dr Andrew Tedstone

Ms Jeni Milsom

Dr Dewi Owen

Mr John Hargreaves

Ms Claire Donnelly

Dr Victoria Lee

Ms Natalie Lord

Ms Ciara Merrick

Dr Ros Smith

Dr Rosalyn M. Death

Ms Amy Waterson

Dr Jamie Wilson

Ms Nina Williams

Ms Iskra Mejia Estrada

Dr J-D Dewsbury

Ms Sara Davies

Mr George Burdon

Mr Sam Berlin

Ms Emily Eyles

Prof Jonathan Bamber

Mr Stephen Chuter

Mr Alistair Anderson

Mr Jethro Brice

Mr Matthew Marshall

Mr Oliver Wing

Mr James Crosby

Dr Katerina Michaelides

Dr Jo House

Dr Fran Bragg

Mr Dominik Hülse

Dr Alba Martin

Dr Jeff Neal

Dr Julie MacLeavy

Mr Edward Thomas

Prof Paul Valdes

Dr Franklin Ginn

Mr Samuel Rogers

Mr Alan Kennedy

Dr David Richards

Prof Penny Johnes

Prof Dan Lunt

Mr David Hayes

Mr Mat Keel

List of countries people are from:

United Kingdom

Spain

Brazil

Sweden

Denmark

United States of America

Canada

Greece

Italy

Ireland

The Netherlands

Belgium

France

Colombia

China

Germany

Mexico

Israel-Palestine

Cyprus