Newsletter Autumn 2018

bove is a copy taken from a section duce a long term management plan for few pails a day. Using a lot of water brings of Bryant’s 1826 Map of and the additional water resource required to with it how is it used and what is in the Ayou might want to ponder what you meet forecast demand. The plan runs for waste water, apart from the obvious. It take from this before reading further. The 25 years with a rolling five year review by has to be treated at a sewage treatment flow through the articles in this Newslet- OFWAT. Anglian Water is working on their works and the effluent discharged into a ter is ‘water’, how we sourced and used it plan running from 2020-2045. There are river. The ‘raw’ water abstracted by a wa- in the past, and how we source, use and several factors involved and a significant ter company from aquifers and rivers has dispose of it now. The article content is all degree of uncertainty. The forecast is that long been recognised as containing nitrate, ‘local’ but reflects the wider situation in to avoid a water deficit at 2045 there is phosphate, and pesticides. Anglian Water East Anglia, and much nationally. A very an additional need for water resource of describes this as ‘an ongoing challenge’. wet spring followed by a very hot and dry between 307 and 472 million litres per A recent spillage from the water sew- summer raised media and public inter- DAY. The two largest factors are house- age network in the centre of Blakeney il- est. This focussed on first flooding and hold growth and climate change; the only lustrates a not unusual occurrence. The then a drought which in some parts of the factor ‘fixed’ is household growth, deter- main cause was a blockage in the pipe- country saw water shortages and hosepipe mined by Government and derived from work and unseating a manhole cover. The bans. There were also reports of pollution ONS forecasts on population increase. blockage was mainly due to a build-up of incidents. Much less recognised is that For North Norfolk this means 10,300 new fat. But everywhere there is an increasing some farmers had abstraction restric- houses from 2016 to 2036; of which Holt range of more insidious pollutants, which tions placed on them by the Environment will have 400. will enter our aquifers and rivers, and Agency as aquifer and river levels fell; a In East Anglia each person, as an av- the food chain. Recent research indicates drier than average winter would bring the erage, uses 133 litres of water per day, micro-plastics may enter the human body risk of restrictions to more water company the vast majority for purposes other than through the gut, with an unknown impact. customers. drinking. Even up to the mid-1950s, the People and wildlife share a common inter- Water companies are required to pro- water used per person might have been a est in our water resource and quality. Eel Migration Disrupted

he European Eel is now a criti- Left: an epic battle in progress. heron; and each time the heron re- cally endangered species. For turned to the attack. This took place Tmillennia there was an abundant Right: a pond drying out. at a large pond next to the supply and a mainstay in the human Photographs and observations by at West Acre on the 15th September, diet. Much still remains to be known Richard Brooks. some two months before the normal about the life cycle, but satellite tag- migration time. Further, two fellow ging is beginning to provide some in- called “silver eels”. Typically silver photographers had seen three large formation on the ocean return to the eels have at least 15% of body weight eels from the same hide a few days spawning grounds, in the depths of as fat; they do not feed during the earlier. So what was happening? the Sargasso Sea in the Caribbean. journey. The eyes get much wider The pond had been full some time We now know the 4,000 km to 6,000 and can adjust to moving at ocean previously, but when the photograph km journey takes from three to six depth or near the surface. This re- was taken it was clearly drying out, years. The elvers that first arrived in turn migration behaviour was part and by end October the whole pond Europe in a Spring ‘run’, and have of the mystery of the eel that had was dry. There would have been some matured in rivers and wetlands are, fascinated the Greeks and Romans, evaporation, but more importantly after twenty or more years, ready and nations right through to modern the reputed blocked pipe that feeds to return. This happens in late Au- times and the new research. the pond, or an agricultural abstrac- tumn, after a wait for a wet and dark A recent incident witnessed by tion. Whatever the cause the outcome night. wildlife photographer Richard Brooks is clear; a hot summer, drought and Males typically migrate at a length was most dramatic and unexpected; water stress on wildlife was the rea- between 35 and 45cm, whereas few a heron had caught an eel of a size son for the eel moving ahead of time females migrate before they are at he had not seen since the 1970s, per- and in broad daylight. There were no least 45cm long. Just before leav- haps some 60cm long. It was an epic winners here; the eel died from re- ing for the open sea, eels change in battle between the heron and a sil- peated stabbing, and the heron did appearance to a darker blue on the ver eel, which lasted for more than not eat the eel; perhaps it was just back and paler and even white on 45 minutes. The eel kept wriggling too big. the belly, and at this stage they are slipping away from the beak of the Ian Shepherd

2 RGCG Newsletter Summer Low Flows

ow flows in a river create problems spokesman said “distressed and dead sett Ford. The great concern was that for several species, and in this hot fish have been reported across East An- the cause of death might well be due to Land dry summer the Eastern Daily glia and more than 6,000 fish have been crayfish plague, arising from the spore Press (EDP) has reported incidents of affected. Our fisheries officers are react- of the mould carried by the non-native dead fish in rivers and in ponds. This ing to an average of two incidents per signal crayfish. After consulting the is the most obvious of indicators that day which is involving a lot of resource”. Environment Agency, samples of the nature is in trouble. Fish will die due to The Environment Agency had re- dead crayfish were sent for analysis lowered oxygen content in a water body. moved 400 dead fish from a lake in to the Centre for Environment, Fish- There can be algal blooms on a pond or Clare Castle Country Park in Suffolk eries and Aquatic Science (CEFAS) in lake which the affects aquatic plant life on the 26 July. The Agency was quoted Lowestoft. A walk upstream on the and oxygen content, as well as evapo- as saying “you get a build-up of duck- day indicated that no more crayfish ration losses; chemical contaminants weed and pond-like plants that start to had died. This visit was followed by in rivers become more concentrated; dominate – while these plants produce inspections at the ford site, but again loss of fish reduces the food supply of oxygen during the day, during the no more casualties; however the pres- their predators; water voles may have night they suck it out”. In another in- ence of duckweed was noted. less vegetation to feed on, and become cident on the 30 July EDP another EA To our great relief the CEFAS analy- more vulnerable to their predators. If statement on a burst sewage pipe inci- sis subsequently showed the crayfish the summer heat is broken by a heavy dent; “thunder storms caused surface kill was not due to the plague. Low flows rain event which leads to arable topsoil water to run off into the river resulting and changes in aquatic plant growth run-off into rivers, the resulting silt can in oxygen levels falling to 11%, causing combine to create areas where there is drop oxygen levels further and kill fish. a hundred fish to die”. To help the dis- a critical reduction of oxygen level, and A fish kill of 28/29 July on the River tressed fish remaining, hydrogen per- fish suffocate and die. The Letheringsett Thet led a resident to report that “the riv- oxide was dosed to raise the oxygen. Watermill ‘mill pond’ in fact stretches as er is usually full of life with bream, roach In late July Ursula Juta of the Nor- far as the footbridge, and with low flows and perch”. The photograph showed the folk Rivers Trust found half a dozen meeting the ‘rising’, this will create the fish were lying in a large surface area dead white-clawed crayfish in the condition of ‘still water’. of duckweed. An Environment Agency Glaven by the footbridge at Lethering- Ian Shepherd

Autumn 2018 3 A Whole Lot of Planning Going On

n 11 January the Prime Minister the 2012 NPPF, and so are key state- and Michael Gove launched the ments on having the highest level of O25-year Environment Plan, and protection and the intrinsic value of on the 24 July the revised National character and beauty. Proposals in Planning Policy Framework (NPPF) the consultation draft would have was published. For those interested weakened the wording; and omitted in the natural environment both are Country Wildlife Sites. On biodiver- worth a read (NPPF from section 15). sity there are new proposals for Na- The NPPF covers all aspects of plan- ture Recovery Networks and the need ning, and councils have to conform for river basin management. There is to this for their Local Plan for plan- a major emphasis on the ecological making and decision-taking. The En- network and the ‘stepping stones’, vironment Plan can be recommended the annex definition being: “Pockets as mandatory reading, irrespective of habitat that, while not necessarily of any party politics or politicians. It connected, facilitate the movement of comes with a complete range of en- species across otherwise inhospitable vironmental issues in a single docu- landscapes”. ment, something never attempted What better than the restoration before; and takes a 25 year view, of farmland ponds and the award not 25 weeks. Through the chapters Top: restored pond in Briston on made in 2016 to a pioneering Bris- there is a great deal of cross-linking Richard Waddingham’s farm. ton farmer Richard Waddingham, between the themes. The language is and the inspiration he gave to others, plain English and well-written and Above: RW at the 2016 award cer- particularly Carl Sayer of UCL and illustrated, clearly with an empathy emony. Photo courtesy WWT. the RGCG. The award came from the for the topics. It does set out aims, Wildfowl and Wetlands Trust. Very targets and timescales. These provide the general presumption in favour aptly the WWT was founded by Peter a framework for a future towards im- of development. However this pre- Scott, Richard’s boyhood hero with plementation. sumption does NOT apply to National his early childhood interest in wild- The NPPF is much dominated by Parks and AONBs. Some protection life. large scale housing delivery, and from development is retained from Ian Shepherd

4 RGCG Newsletter Holt Spout Hills: the Past

his article may be viewed as a A 1909 watercolour of Spout Hills. clearly shown. The course of the river brief history of Holt Parish, which Perhaps Sunday Best, and note the marks the boundaries with five other Tlies in the catchment of the River grazing animals – some artistic parishes. Glaven; but it is from the perspective of licence, but the ‘wet valley’ stream Some points to note are the sig- the source of the water that the town layout is the same today. nificance of Holt in the area shown. has always been dependent upon. We The thick black line running south look at three ‘break’ periods for wa- cerpt taken from Bryant’s 1826 Map from Holt signifies a Turnpike or Mail ter supply in shortening time scales – of Norfolk. It shows the middle and Road. It does as now continue through the Domesday Book right through to upper regions of the Glaven, with our Saxthorpe and Corpusty and then on the late Victorian times; from then to marking HW to show the headwaters to Norwich – the B1149. The lake at the mid-1950s; and from there to the of the river at Bodham and Bacon- Bayfield is shown as a ‘broadwater’, a current situation and on to 2045 (see sthorpe. The course of the river in go- widened river, and it was later extend- front page). These may seem rather ing upstream from Bayfield is shown ed to a lake over a number of decades. odd time intervals to look at, but if you by a wriggly line with dots alongside; Sir Alfred Jodrell under-grounded the are interested in water resource, and the line gets thinner, and the dots re- river with a brick tunnel in the period the future of the human race, it makes moved, as we approach the headwa- 1890-94 (but the river was re-instated sense. And for the RGCG what pros- ters. The depth of the valley sides is to the surface, to run alongside the pects for wildlife. We take the history illustrated by the shading, and takes lake in 2014, the New River project). of Holt as an illustration of the wider us through to Letheringsett and on to Keith Entwistle in his book An Il- East Anglian and national situation in Hunworth, then past Holt Heath (Low- lustrated History of Holt (published terms of water resource and usage. es) to Selbrigg. The main tributaries in 2004) very aptly makes Spout Hills On the front page we have an ex- Thornage, Stody and Pond Hills, are his first point of call in describing the

Autumn 2018 5 long history of the town. “We start in Photograph of the Pump House in in the surface pond, to be replaced by the west and we start with water. In our 1885 at Spout Hills, when newly an underground abstraction from the current age we live in ignorance of the built. water table. precise origin of water, but for centuries The Water Tower was 56ft high and the people of Holt knew exactly where Hempstead in neglect. Five sizable mills held 15,000 gallons of water. The their water gushed – the Hills. It flowed is a lot for a small river, but cutting maintenance contract for the two build- from a natural spring they’d christened through the western end of the Cromer ings was with CT Bakers. An appren- the Spout. The very name reveals their Ridge, it has a relatively steep gradient tice who went on to spend his working confidence in its power – not the drib- and water flow for a lowland river. life with the buildings and their opera- ble, not the spring, but the Spout”. As regards the demand for water sup- tion described them in much detail to Entwisle goes on to explain that the ply and use, there would have been little Entwistle – he had recorded conver- Hills were more than the source of wa- change over many centuries. Entwis- sations with many residents who had ter. They were common land set aside tle quotes from William White’s History lived in Holt all their lives, as well as to the townspeople for grazing, a right Gazetteer and Directory of Norfolk, 1883: much archive research, and sourcing of instituted in the Enclosure Act of 1810. “On Spout common, on the south-west old photographs. And more than this, they were available of the town, a copious spring issues out The Pump House was fuelled by the for recreation. The Parish Council of of the gravel hill, and affords an ample nearby gas works. Inside the building the Parish of Holt published these bye- supply of pure soft water, which is car- were two huge engines, one larger than laws on February 1st, 1898: “Through- ried in carts to the town, where there the other; each had a massive flywheel. out these byelaws the expression The are also three public pumps. The spring To your right was the well, about six Council means the Parish Council of head is walled round, and is visited by feet in diameter, with a steel liner. This the Parish of Holt, and the expression many as a natural curiosity, and for the had a depth of about ninety feet down The Pleasure Ground means the plea- prospect of enjoying the fine prospect to a platform. To climb down, there was sure ground known as Spout Hills”. (sic) which it commands over the ro- a steel ladder bolted to the side. The In this article we trace the history mantic valley of the Glaven”. platform was not the bottom of the well of that most fundamental of human Two years after this publication there as such; it was possible to open it up needs, water; also here, but also in our was a huge step-change. A Pump House and descend further into the bore – to next newsletter, we look at aspects of was built on Spout Hills in 1885, and a depth of 120 to 130 feet. The larger the word ‘pleasure’. Like most Norfolk with it a Water Tower in Shirehall Plain. engine was used to draw water from towns Holt has a long history. In the Horse and cart were replaced, but not the full depth of the bore, the smaller 1086 Domesday Book it is described as entirely. Even after this development, one from the well. The huge pressure a market town with a port at the nearby water carts from outside the town still caused the rods to break from time to port of Cley (then an important trad- continued to bring fresh water to the time. It was a difficult process to re- ing port, one of four Glaven Ports). The town and sold it for a farthing per pail. move them. The considerable weight Parish had five water mills and twelve The pond that held the spring water was was borne on the shoulders of two men plough teams. The five mills in fact set on a slope, and left un-embanked at who carried them through the town to would be shared with other parishes. the high end for people and horse and the forge in Baker’s premises. The op- Letheringsett Mill is the only working carts to enter; remains to this day, al- eration to remove or insert the rods was mill in the county; those at Glandford, beit modified. We take 1885 as the first fraught with danger. Thornage and Hunworth are private break point. It marked the change from The Industrial Revolution had come houses, Edgefield just a remnant and water taken from spring, and collected to Holt. There was a supply and de-

6 RGCG Newsletter mand situation which is very different from that we have today. A balance had to be struck between rate of supply to the water tower and consumption, but the difficulties were not a lack of water resource, if anything the opposite. They centred on communications between pump house and water tower. The level of water in the tower could be gauged from the ground by a specially made piece of equipment. If too much were pumped the water tower would over- top, and a pipe ran the water down a drain in the street. If this was not be- ing noticed, then a child would run to tell the man who oversaw the opera- tion, the Waterworks Manager, whose role earned him a place on the Parish Council. In his house he had a big plate with pennies on it. The reward to the child would be a penny from the plate. Many of those interviewed had this as a childhood memory; but more so the fun and freedom of playing on Spout Hills. This including damming the stream which ran down to Letheringsett; and then remove the dam and watching the water flood across the Rectory lawn on Letheringsett Hill. Both the water tower and the pump house were in use until their demoli- tion in the mid-1950s, a time of a rapid acceleration of domestic demand for water and the need for a bigger wa- ter distribution network. We were now entering our third age, that of a mas- sive uplift in consumption and waste. The loss of the waterworks’ buildings was of some regret to Entwistle. He remarks that this was a decade that had little time, and even less sensitiv- ity, for Victorian architecture. He felt with good reason that the pump house and water tower were a lovely blend of function and grace; and the era of the car was going to make its mark. The site of the water tower is the small car park area opposite Byfords. With the coming of more water comes more waste water. The stream leaving from Spout Hills on its way to the Glaven is the recipient of the effluent from Holt Sewage Treatment Works. If a stream could feel, then after millennia of great service, it would surely think this a great indignity. Clearly we owe much to the heroic work of Keith Entwisle. Keith and the Holt History Project started by a general appeal through the press for materials of all kind – documents, photographs, Photograph of the Water Tower, Shirehall Plain; perhaps taken around diaries, newspaper cuttings, fam- the time of the watercolour. ily archives. Keith liked to use first- hand testimony wherever possible. there was an incredibly rich source cord Office. Holt is fortunate in having He recorded many conversations with of photographs for a visual record of Keith and colleagues to carry out this residents on the theme of a Holt child- Holt in the 20thC. Much of this came task; as Keith says: “throughout the hood. His interest and enthusiasm from one resident who collected pho- project my practice has been first to shines through the huge amount of tographs from childhood and whose look and listen, then think and link.” information he gained. He found that albums are now in the Norwich Re- Ian Shepherd

Autumn 2018 7 Cleaning up Chalk Streams: a new wetland creation to treat

waste water on the river Ingol

ollowing up the focus of our last Aerial view of completed project many pollutants from waste water as newsletter on pollutants that stress showing the series of wetland cells. is practicable and financially viable. Fthe wildlife in the Glaven, this ar- High phosphate levels encourage plant ticle summarises a recently completed Opposite page: new wetland show- growth but selectively encourage algae scheme at in West Nor- ing established planting. and rank growth on rivers that damages folk, with a thought about promoting a the ecological balance. It is expensive to similar project on our river. ents and also come from animal waste, strip out phosphates, and small WTWs Large towns have water treatment and efforts are made to avoid any run- are not obliged to remove phosphates – works (WTW) that are obliged to reduce off into watercourses. Their other main this includes all the WTWs discharging phosphate levels in the treated wa- source is from human waste, and in into the Glaven, including Holt. Some ter that enters rivers. Phosphates are recent decades from increased use of rivers have higher environmental sta- added to farmland as essential nutri- detergents. WTWs aim to remove as tus and protection which raises the bar

8 RGCG Newsletter on WTW effluent. This applies to Faken- or cells, requiring a new bypass for the out the wetland, and the Ingol site has a ham which discharges into the Wensum river and conduits to carefully regulate footpath close by, enabling the scheme SSSI. Holt, in terms of population size, flow. The planting of the wetlands was and its improved wildlife to be appre- is someway off being obliged to strip out with native plants selected by the NRT, ciated by the public. The hope is that phosphates from the effluent. However including iris, sedge, rushes, marsh such schemes will prove not only effec- this new scheme raises a hope that an marigold, watercress and purple loose- tive, but also economically viable. The environmentally friendly way of reduc- strife (perhaps for the colour and pleas- Glaven has more than one WTW that ing pollutants may become more wide- ing name!) All in all, it was a major task could benefit from such a scheme, and spread in the near future. costing about £500,000, and completed it would require a similar collaborative At Ingoldisthorpe, high ammonia and on time in the wet winter of 2017/18. approach to make this happen. It could phosphate levels going into the river This I understand, is comparable to the create real benefits to the water qual- from the WTW were the problem for An- costs of chemical stripping equipment. ity in the Glaven and hence its valuable gian Water (AW) and the Environment Such schemes have long been used wildlife. Agency (EA), who monitor such things. worldwide, and once established have Quoting Regan Harris from Anglian The river is a small and the attraction of being low tech, and Water: very vulnerable to these pollutants. requiring relatively low and infrequent “This is a really exciting project and a It enters the sea close to maintenance. Phosphates and nitrates first for any Water Company in England. RSPB reserve. A number of solutions will be taken up by the plants in the We need more natural ways to treat were considered, but creating a wetland cells, and turned into more vegetation. them (phosphates and ammonia) rather to soak up the problematic effluent, As vegetation increases, it may need than adding more and more chemicals came out top. A team consisting of AW, clearing out if the wetland fills up with in our treatment processes which is un- EA, the Norfolk Rivers Trust (NRT), the reeds etc. The expectation is that this sustainable. So the wetland is a great Landowner and expert contractors Wil- would be very infrequent, and in the solution. It’s excellent for biodiversity liam Morfoot, came together to plan the long term more carbon neutral than the and does this job for us naturally. We creation of a series of wetlands. These alternative treatment mechanisms. want this scheme to become more com- shallow excavations would be populated A previous smaller scheme on the monplace as a water treatment option in with plants that would filter the effluent at Northrepps was set up by the future as it’s an excellent example of leaving the WTW, leaving the cleaned NRT (as part of the 9 chalk rivers proj- how by working together we can provide up water to be fed back into the river. ect) and has been running successfully innovative solutions for our treatment The situation on the River Ingol was for several years. An important part of processes, ensure they are sustainable favoured by having a suitable and avail- these schemes is to monitor water qual- for future generations and protect the able site for the wetlands. The valley ity to ensure effectiveness. The EA have environment.” where the WCC is sited is naturally set low limits for ammonia of 1mg/ Many thanks to Jonah Tosney and wet and unsuitable for arable produc- litre and phosphorus of 4.5mg/litre at David Diggens from the NRT for lead- tion. The existing woodland besides the the Ingol, and early results are encour- ing the implementation of the project river was diseased with Ash dieback, aging. and providing photos, and to Tim Sis- and needed to be cleared. Consider- There is also the important aspect of son from William Morfoot for the aerial able work was undertaken to model community involvement. Children from shot. and landscape the series of four ponds the local primary school helped plant Henry Crawley

Autumn 2018 9 Habitats of the Glaven’s Majestic Bullhead Will Oliver, UCL MSc Study

t first glance, the bullhead or mill- Left: a Glaven bullhead in all its projects must not ignore the needs of ers thumb (Cottus gobio) might not glory. this lovely little fish. Aseem the most inspiring little fish. As a further aspect of my study I Their small size, dark mottled colour, Right: fish were surveyed by elec- aimed to map how the distribution of oversized pectoral fins and bulbous trofishing 200m stretches of the fish species changed across my elev- head gives them an overall ‘brut- . en Glaven sample sites. By calculat- ish’ appearance that, to many, does ing site “catch per unit effort” scores not stand up to the elegance of the MSc in Aquatic Science disserta- for each species it was shown that brown trout. This has resulted in the tion project, with the help of ECON eels and trout were present at higher bullhead being largely overlooked; Ecological Consultancy Ltd and Carl abundances at sites downstream of classed alongside minnows and stick- Sayer, I sampled eleven sites on the Hunworth Mill. Catches of these two lebacks in the ‘other fish’ category in River Glaven between Glandford Mill species were significantly lower above early fisheries surveys. The species is, and Selbrigg Pond, investigating the Hunworth Mill, with bullhead and however, far from boring. Males will micro-habitat preferences of both 3-spined stickleback instead making aggressively defend nests of eggs and the bullhead and the more widely up the majority of the catch. Reasons have been shown to produce a vocal researched brown trout. By compar- behind this apparent distribution knocking sound known as a ‘roar’ to ing the results, I was able to reveal pattern can only be hypothesised, attract females. Additionally, the spe- some key differences in the habitat with fish passage and habitat avail- cies lacks a functioning swim bladder likes of the two species. Bullhead ability both being potential factors. (the organ which provides most fish were shown to be most strongly as- The stretch of the Glaven directly species with buoyancy), meaning it is sociated with regions of the river below Selbrigg Pond seems still to be effectively anchored to the river bed, dominated by fast, shallow water that suffering the ill effects of recent fine such that even the smallest of weirs had an abundance of woody debris sediment pollution events, with ab- can function as an impassable barri- structures. In contrast, brown trout sence of any fish community except ers to its dispersal. avoided these areas, instead prefer- for a small population of stickleback. Bullhead are a keystone species ring deeper, slower sections domi- It seems likely that bullhead will within the chalk stream ecosystem nated by submerged aquatic plants. probably need to be re-introduced and therefore it is vitally important The results indicate the importance to this area. If you are interested in that these environments have plen- of having a range of habitat types in reading the full study please feel free tiful bullhead habitat. But what is chalk streams like the Glaven and to get in touch: williampearceoliver@ good bullhead habitat? For my UCL emphasise how future restoration gmail.com

10 RGCG Newsletter The Birthplace of Eels Ian Shepherd

he birthplace of eels was subject electro-fishing have been measured Sea. In all 714 thin-heads were to centuries of speculation and and weighed in surveys carried out caught at twenty four areas. As they T debate. By the 1800s there was across the Glaven catchment. Some reached the Sargasso Sea the num- much international popular and sci- of these eels were also tagged by bers caught increased and the size entific interest in solving this mys- Adam Piper of the Zoological Soci- decreased. tery. This was driven both by national ety. It will take some years before This confirmed his hypothesis – pride in scientific advances, equiva- results are known but he was not at the right place at lent to be the first to reach the South Finally the RGCG are putting on the right time, and spawning had Pole, and by commercial interests in hold the daily monitoring of the taken place several months before. fisheries, and importance of the eel in Spring run of elvers at Glandford With so much at stake Schmitt felt the human diet. The breeding ground Mill, running over a period of 3-4 he must get more evidence. Other was confirmed as the Sargasso Sea months. This was carried out by trawler ships sent back a trickle by a Danish scientist in the early Willie Brownlow, supported by Hen- of samples which did not take him 20th Century. But first with the end ry Crawley and Robin Combe. So we further in his search for more evi- of the Eel project we say something return to the discovery of where the dence. WW1 and German subma- to mark the final work on eel surveys elvers came from, starting as eggs rines interrupted. It was in 1920 and tagging, the results of which will deep in the Sargasso Sea. These turn that a Danish 550-ton schooner take some years to appear and be to larvae, and may reach a sea sur- sailed, and the captain was told to analysed. face as half larvae and half elever. just go where Schmitt requested. The Glaven Eel Project was HLF or the ‘thin-head’ in the account by On 8 June at the location 29°N funded and ran from February 2015 Tom Fort in his splendid The Book 60°W they landed 1,300 thin-head, to March 2018. The project was of Eels, copyright 2002. The thin- many of them between 7 and 10 managed by the Norfolk Coast Part- head had been noted in the Straits mm long, and at depths of between nership and reported in our editions of Messina, between Calabria and 50 to 100metres. On 27 June, a lit- of the Newsletters of Autumn 2015, Sicily, as early as 1850s, but not tle south west, they caught almost Spring 2016 and Autumn 2017. recognised for what they were. The 800 specimens with one haul of the One of the project objectives was to area is subject to the equinoctial net. Schmitt had again missed the increase the scientific knowledge of tides and great upsurging currents spawning time, and the thin-heads, eels, and an article by Alan Walker sweeping into the bottleneck to the while smaller than any previously of CEFAS in A15 on the life cycle north and south, regularly deposit- covered, were not at their viable includes the tagging of mature eels ing a host of deep sea fishes on the minimum. on their final journey and the use beaches. Not unreasonably an Ital- The ship sailed again in the next of satellite data storage tags on the ian scientist who studied this area year, 1921. Keeping a course cen- back. The use is limited by the cost claimed this as the source for all tred on 27°N 59°W, they came of a tag, but the technology will im- the eels found in Italian rivers and across larvae everywhere, the vast prove and become cheaper. lakes, to great acclaim. majority of them less than 20mm Further, prior to their return jour- The European eel has a distribu- long. The tiniest of all, at 5mm, ney, the movement of eels around tion all along the west coast from were retrieved in mid-April at loca- the river and ponds during the 20 Scandinavia south to Portugal, tions that had been without results years or more, is not well under- with big influxes of elvers in the three weeks previously. Given that stood; nor their reaction to vari- UK and France, particularly at the little is known about the earliest ous types of barrier, large or small. high tidal range of rivers like the stages of larvae life, it seems likely Eels are most active when feeding at Severn and Loire. So a Danish fish- that Schmitt missed the hatching by night, and lay low during the day, eries scientist set out to challenge a day or two at most, possibly only and can be filmed to study their the Italian ‘solution’. His name was a few hours. However Schmitt had behaviour. To carry out a study of Johannes Schmitt, and through his enough evidence to make his case, movement of a tagged eel in a lo- wife had good connections to Co- and on the 2 February presented his cal area over months or years, sci- penhagen shipping companies. His paper ‘The Breeding Places of Eels’ entists typically use Passive Inte- first searches in trawlers with fine at The Royal Society of London. His grated Transponders known as a nets to survey areas of sea took name became synonymous with the PIT-tag; the same microchips that place in 1904. He captured a larva discovery of the spawning ground. vets put inside dogs and cats and of 7.5cm long near the Faroes, more His work had brought great prestige provide the individual identity. Eels than 2,000 miles from the Mediter- to his country, and cemented his caught in rivers, ponds and coast- ranean. He went from there to the position as one of its outstanding al creeks by either fyke netting or Azores, and then to the Sargasso men of science.

Autumn 2018 11 Invasive species on the Glaven: an ongoing problem

f the many potential non-native rivers whose banks in places are species that can cause prob- overrun and severely damaged by O lems in river habitats, we cur- Balsam stands. There is always the rently have three well known trou- likelihood of new areas of growth ble-makers on our patch. Signal on riverbanks, if any seed gets into crayfish, Himalayan Balsam and the river and floats downstream. American Mink. These are probably Please let us know if you see any – well known to our members but the we may not know about it. What’s photos here may act as reminders, better, join us to pull some up next and we would welcome reports of July – please contact me if you’d any sightings. like to help. In the last newsletter I reported on a project to inoculate Signal Crayfish the balsam with a rust spore that It is unlikely you will see any in the has been shown to weaken and kill Glaven, because thanks to years of it. We helped to get this started on heroic effort, their presence on part the Glaven this year, and hope to of the lower river has been almost report success soon. The project is extinguished. They are nocturnal, run by the Centre for Agriculture but can be seen on riverbeds that and Bioscience International (CABI) are overrun elsewhere in Norfolk. and the Norfolk Non-native Species The threat is that they would breed Initiative (NNSI). up their numbers and then migrate upstream to outcompete the healthy Mink native white clawed crayfish (wcc) Mink numbers on rivers in East An- which remain in the upper river. glia are slowly declining after a high Signals also carry a plague deadly to point probably triggered by release WCC. We have barriers in place to from Mink Farms. They are incred- prevent the populations mixing, but ibly destructive predators who fa- we need to be alert to any crayfish vour rivers, are good swimmers and sightings which might indicate dis- prey on fish, birds, mammals and ease. If you see any crayfish dead or invertebrates. Moorhen and water dying on the riverbank please con- voles are particularly vulnerable. tact us. The important steps taken Gamekeepers hate them. We oc- to preventing the demise of WCC is casionally get reports of mink, but to outlaw any trapping of Signals for this summer there have been sever- culinary purposes, and encouraging al confirmed sightings up and down strict hygiene when taking boots or the river. The Norfolk Mink Project angling gear from one river area to is a volunteer group that has made another which could transfer the great efforts to control mink by re- plague fungus. porting and trapping. They provide advice and traps which we are cur- Himalayan Balsam rently deploying, so far without suc- We know where the hotspots of cess. It is thought that Otters will growth on the river catchment are, displace mink – let’s hope our local but despite many years of destroy- otters will up the anti. Again please ing the flowering plants before let us know if you see one. They are seed dispersal in late summer, we between the size of a stoat and an haven’t been able to eradicate it yet. otter, with dark but variable coat The Glaven is far better off in this colour. respect than many other Norfolk Henry Crawley

River Glaven Conservation Group We aim to work in Henry Crawley Chairman 01263 713306 friendly collaboration email: [email protected] with landowners and farmers, conservation Ian Shepherd Secretary 01263 713370 organisations and Anne Rolfe Treasurer & Membership Secretary relevant public bodies. Web site www.riverglaven.co.uk