Eel Management plans for the United Kingdom - Eel Management Plan for the North West River Basin District Published: December 2008 www.defra.gov.uk
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www.defra.gov.uk Eel Management plans for the United Kingdom Eel Management Plan for the North West River Basin District Published: December 2008
Contents
1. Introduction
2. Description of the North West River Basin District
2.1 The North West River Basin District
2.2 Current eel population
2.3 The Fishery
2.4 Silver eel escapement
2.5 Eel mortality and available habitat
3. Restocking
3.1 Need for restocking
3.2 Past restocking
3.3 Compliance with restocking requirements in the Regulation
4. Monitoring
4.1 Assessment of silver eel escapement
4.2 Price Monitoring and reporting system
4.3 Catch and effort sampling system
4.4 Traceability of live imported and exported eels
5. Measures
5.1 Measures to improve confidence in escapement and meet Escapement Objective
5.2 Measures taken 2007 to 2009
5.3 Measures to be taken 2009 to 2012
5.4 Measures to be taken beyond 2012 to achieve Escapement Objective
6. Control and Enforcement
7. Modification of Eel Management Plans
Eel management plans for North West River Basin District1. Introduction
This Eel Management Plan for the North West River Basin District (RBD) aims to describe
the current status of eel populations, assess compliance with the target set out in Council
Regulation No 1100/2007 and detail management measures to increase silver eel
escapement. This will contribute to the recovery of the stock of European eel.
2 Description of the North West River Basin District
2.1 The North West River Basin District
The North West RBD covers an area of 13,140 km2, from Cheshire in the south to the
Lake District in the north. The landscape is varied – from mountains and lakes in Cumbria,
to the seaside at Blackpool and the industrial heritage of Manchester.
The numbers and areas of four main water body types, as defined by the Water
Framework Directive, are shown in Table 2.1 (Defra 2005).
Water body type Number present Length/Area
Rivers with catchments greater than
477 4,910 km
10 km2
Lakes with areas greater than 0.5
76 59 km2
km2
Transitional water bodies 14 279 km2
Coastal water bodies 8 1,509 km2
Table 2.1 Water bodies in the North West RBD.
The region has significant environmental problems, with a quarter of England’s derelict
land and a third of the poorest quality rivers in England and Wales. Agricultural land use
covers 80 percent of the district, and there are important habitat and wildlife areas,
including 25 Special Areas of Conservation and seven Special Protection Areas with water
dependent features.
To the south, where the population is concentrated, the River Mersey flows west towards
Liverpool and the Mersey Estuary. In the central and northern areas lie the counties of
Lancashire and Cumbria with a mix of rural landscape and urban heritage. The district has
numerous lakes and still waters, many of which are within the Lake District National park in
the north of the River Basin District.
Eel management plans for North West River Basin District
12/2008
Page 1 of 23Figure 2.1 The North West RBD.
Existing Environment Agency information on the obstructions to fish movement in the
North West River Basin District has been gathered. The most significant barriers are
shown in Figure 2.2. In general there are major man-made barriers to eel migration
throughout the RBD, but particularly in the south.
Eel management plans for North West River Basin District
12/2008
Page 2 of 23Passability
Unknown
Not passable
Restricted
Not restricted
Figure 2.2 Distribution of obstructions in the North West RBD.
2.2 Current eel population
2.2.1 Glass eel recruitment
There is one fishery-independent glass eel recruitment dataset for the North West RBD,
from the dykes that lead into the Leighton Moss Special Protection Area and Ramsar site
in Cumbria. This information was considered by Knights (2001). The wetland is important
for birds because it is the only breeding site for bittern, Botaurus stellaris outside of East
Anglia; eel are a favoured food of this species. A tidal flap gate controls water levels in the
reserve and eel passes and traps have been operated since 1997 to monitor recruitment.
Commercial fishing in the Red Barn Dyke and Quicksand pool that lead from the tidal flap
gate to Morecambe Bay has been licensed since 1996. In 2000 it was estimated that 50-
85% of the recruits were removed by this fishery.
Eel management plans for North West River Basin District
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Page 3 of 232.2.2 Yellow Eel Distribution
The Environment Agency samples yellow eel within the North West RBD at 345 sites on a
six year rolling programme (i.e. 57 are sampled each year). In addition 80 sites are
sampled annually and 57 sites are sampled as part of the Water Framework Directive
programme of monitoring. These 482 sites are multi-species surveys and may therefore
underestimate the true density of eel (Knights et al., 2001). To support these surveys there
is some high quality survey information for the River Ellen in Cumbria, gathered at 19 sites
in 2004 for a Defra project (B. Williams, Kings College London pers. comm.).
Figure 2.3 illustrates the distribution of eel from the Environment Agency river fish
sampling programme. This shows that eel are present at almost all of the sites surveyed
from the Ribble to the Derwent, except for the upper reaches of these rivers.
Further south and around the city of Liverpool, the eel distribution is much more patchy
with long stretches of the Rivers Mersey, Irwell, Tame, Goyt and Bollin without any eels
caught in surveys.
Eel management plans for North West River Basin District
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Page 4 of 23Figure 2.3 Distribution of eel in the North West RBD (2001-05 survey data
combined).
Eel management plans for North West River Basin District
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Page 5 of 232.2.3 Abundance and Biomass in the North West RBD
2.2.3.1 Glass eel data
Data are available from the combined trap and pass at the entrance to Leighton Moss.
Figure 2.4 shows the total number of elvers captured in the trap each year to 2008.
Figures for 2004-08 are combined totals for trap and pass. The pass was not operated as
a trap prior to 2004 and to estimate the number of elvers migrating up the pass a
calibration exercise was undertaken in 2005 and 2006. This compared the number of
elvers caught in the trap with those counted using the pass, this ratio was used to estimate
the number of elvers using the pass between 1997 and 2003.
45000
40000
Total number of elvers
35000
30000
25000
20000
15000
10000
5000
0
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008
Year
Figure 2.4. The number of glass eel trapped entering Leighton Moss,
1997 to 2008.
2.2.3.2 Semi-quantitative yellow eel data
There is very little information on eel stocks in the North West RBD. Prior to 2000 electric
fishing surveys undertaken as a part of the Environment Agency National Monitoring
Programme have not routinely recorded, numbers, lengths or weight of eels caught and
effectively only show presence and absence of eels.
There are some electric fishing data from the 1990s where the number of eels caught at
various electric fishing sites have been recorded. These data were generally collected by a
single pass of electric fishing, sometimes without an upstream stop net. This form of
electric fishing severely underestimates the actual site population (Knights et al., 2001).
Studies suggest that eel-specific surveys with stop nets and several slow runs of electric
fishing can provide population estimates ten times greater than those estimated by semi-
quantitative sampling (Knights et al., 2001).
Eel management plans for North West River Basin District
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Page 6 of 23On the River Lune, semi-quantitative electric fishing surveys were carried out in 1991 and
1997. 134 sites were surveyed in 1991, and 74 of these were sampled in 1997. Eels were
present in 70% of sites in 1991 and 64% in 1997. In 2002, 75 of the 1991 sites were
surveyed and eels caught at 32 of these, 43%. In 2007, 45 of the 1991 sites were
surveyed again and eels caught at 17 of them, 38%.
Similar surveys on tributaries of the River Ribble showed that eels were caught at 39 of the
70 sites (56%) surveyed on the River Hodder in 1993, 56% (Walsingham 1993). Repeat
surveys at 27 of these sites in 2004 found eels at 17 (63%). On the Skirden Beck tributary
of the River Ribble in Lancashire eels were caught at eight of the 15 sites surveyed in
1994 (53%) [Clifton-Dey et al. 1995] and repeat surveys in 2003 found eels at only four of
11 sites (36%).
These survey data appear to suggest a declining presence of eel at survey sites through
time. However catches were too variable to show any significant trends in eel density.
There is also some information contained within an Environment Agency internal report
(Watson & McCubbing 1997) based on 415 single-run electric fishing sites carried out
between 1992 and 1996. Eels were often found in high densities, including over 200 eels
for a single run of electric fishing at the bottom of the River Bela. Numbers decreased with
distance upstream and above migration barriers but eels were found in reasonable
numbers (one to 10 eels per 50 metre river stretch) in main rivers and larger upstream
tributaries above and below large online lakes:Windermere, Esthwaite, Rydal, Grasmere,
Coniston Water and Wastwater.
Electric fishing studies at Leighton Moss, in combination with the recruitment studies
mentioned earlier in this Plan, indicated average densities in open waters and reedbed
zones in 1998 were 3 and 15 eels per 100m-2, respectively, with biomasses of 65 and 327
g 100m-2 , respectively (Knights et al., 2001).
2.2.3.3 Eel specific survey data
Within the North West RBD eel-specific electric fishing surveys have been carried out on
the River Ellen in Cumbria, which was surveyed for a Defra project in 2004 (B Williams,
Kings College London, pers. comm.). Sixteen sites were surveyed for this work, from the
tidal limit to 31 kilometres upstream. The density in numbers and biomass, and the
average eel length from this study is shown in Figure 2.5.
Eel management plans for North West River Basin District
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Page 7 of 23120
100
Density (#/100m 2)
0.0903x-
y = 38.121e
80 2
R 0.6582 =
60
40
20
0
0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00
Distance to tidal limit (km)
1000 -0.0598x
y = 822.72e
2
Biomass (g/100m2)
800 R = 0.6145
600
400
200
0
0.00 10.00 20.00 30.00 40.00
Distance to tidal limit (km)
400
Average eel length (mm)
300
200
y = 2.6635x + 209.58
2
100 R = 0.3877
0
0.00 10.00 20.00 30.00 40.00
Distance to tidal limit (km)
Figure 2.5 Eel density and average length for surveys on the River Ellen,
2004
Eel management plans for North West River Basin District
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Page 8 of 232.2.4 Population size structure North West RBD
The number of eel less than 150 mm long (age 1 – 3 years), 151 to 450mm, and longer
than 450 mm (all assumed to be female) for the eel specific survey on the River Ellen are
shown in Figure 2.6. This suggests that the majority of the population in the River Ellen are
destined to migrate as males. Certainly evidence from the Severn suggests that few
females migrate at a length less than 45 cm (Aprahamian, 1988) and that the technique is
not biased against larger eel (Aprahamian, 1986).
1200
1000
Number of eels
800
600
400
200
0
450
Length category (mm)
Figure 2.6 Eel length categories for River Ellen 2004.
Age data for the eels in the North West RBD are available from two surveys. A sample of
54 yellow eels was taken from the Stanley Dock on the River Mersey in 1982 (M.
Aprahamian, Environment Agency, pers. com.). Age was determined from reading otoliths,
using the burning and cracking technique as described by Aprahamian (1987). Ages
varied from 2 to 13 years and sampled eels had an average growth rate of 59.8 mm/year
(SD ± 17.7 mm). A sample of 167 eels was also aged from the River Ellen in 2004, using
the same technique. The eels ranged from 2 to 26 years with a mean growth rate of 18.9
mm/year (SD ±7.0 mm). The difference is presumed to reflect the difference in productivity
between the two waters.
2.3 The Fishery
2.3.1 Introduction
Licences to fish for eels and glass eels commercially are issued by the Environment
Agency on a Regional basis. The North West RBD is located within the North West
Environment Agency Region.
Eel management plans for North West River Basin District
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Page 9 of 23The eel fishery in the North West RBD is quite small. The number of licenses issued from
2005 to 2007 for North West Region is shown in Table 2.2. It should be noted that the
number of licences issued is not the same as the number of fishermen. One fisherman is
able to set many traps and fykes. The only fishing gear operated by a single person in
North West RBD is the dip net for glass eel.
Fishing Method Licensed instruments
Year 2005 2006 2007
Elver Dip Nets 19 22 21
Gloucester Wing Nets 0 0 0
Small Wingless Traps 70 37 51
Winged Traps/Fykes 151 90 131
Fixed Traps 0 0 0
Table 2.2 Number of eel licences issued by the North West Environment
Agency Region, 2005 to 2007.
2.3.2 The elver (glass eel) fishery
Glass eel fishing in England and Wales is conducted mainly on the River Severn and, to a
lesser extent, on the Rivers Wye, Parrett and Usk (see section 1.2; Figure 2). There is
some glass eel fishing in the North West RBD with the principle fisheries on the Rivers
Bela, Lune, Wyre and Ribble; and Red Barn Dyke, downstream of Leighton Moss SSSI.
Since 2005, eel and glass eel fishermen have had to declare their weight of catches and
the river where they were taken at the end of each season. A total of 166 kg of glass eels
were declared as caught in the North West RBD in 2005, 116 kg in 2006 and 200 kg in
2007. The rivers where these were caught are shown in Table 2.3.
River Declared catch (kg)
2005 2006 2007
Lune 34 3 43
Wyre 53 50 46
Douglas 0 0 2
Ribble 34 25 49
Red Barn Dyke 23 16 19
Bela 16 12 20
Gilpin 0 0 2
Kent 0 0 1
Unknown 7 4 19
Table 2.3 Declared elver and glass eel catch in North West RBD rivers,
2005 to 2007
Around 95% of the licensed glass eel netsmen returned a satisfactory catch declaration in
2006 and 2007, although it is likely that the values in Table 2.3 are underestimates, they
do indicate the relative importance of the elver fisheries in the North West RBD rivers in
UK terms where the total declared catch over the period ranged from 0.2 to 2.0 tyr-1 . The
declared catches in each month for the whole North West RBD are shown in Figure 2.7.
Eel management plans for North West River Basin District
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Page 10 of 232005 2006 2007
200
Declared catch (kg)
150
100
50
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Figure 2.7 Declared monthly glass eel catch in North West RBD, 2005 to
2007
2.3.3 Yellow and silver eel fisheries
Recreational Fishery
The recreational fishery for eels within the North West RBD is small. The vast majority of
eel are captured whilst anglers are fishing for other coarse and game species and, in these
circumstances, eel are usually returned to the water.
In 2007 a total of 141,000 fishing licences were sold in the Environment Agency North
West Region. This encompasses the North West RBD. A survey of Anglers carried out in
the 1990s indicated that the average distance travelled to fish by a licence holder was 20
miles and that 35% fished predominantly on rivers (National Rivers Authority 1995).
Assuming that each angler catches one eel per season (Appendix 4) then approximately
50,000 eels are caught by recreational anglers each year. The level of post release
mortality has not been assessed.
Commercial Fishery
Commercial yellow and silver eel fisheries in the North West RBD are relatively small, less
than 5% of the declared annual catch for England and Wales. The principle fisheries for
yellow and silver eels operate in and around the River Weaver in Cheshire (90% of the
declared eel catch in 2005), with much smaller fisheries in rivers, lakes and marshes
throughout the RBD.
The declared catch data from 2005 to 2007 is shown in Table 2.4 for different rivers in the
RBD. The distribution of catches through the months in 2005 to 2007 is shown in Figure
2.8 and 2.9.
Eel management plans for North West River Basin District
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Page 11 of 23River Declared catch (kg)
Yellow eels Silver eels
2005 2006 2007 2005 2006 2007
Lune 30 - 30 2 - 10
Morecambe Bay 25 119 13 6 2 6
Ribble - 41 24 3 2 2
Gowy 35 24 18 3 4 5
Cocker 7 - 9 - - 8
Mersey 21 100 - - - -
Weaver 1280 445 - 160 70 -
River Brook - - - 4 - -
Wyre 2 - - - - -
Known stillwaters 140 35 84 24 6 38
Unknown stillwaters 78 487 33 - 1020 16
Total 1618 1251 211 202 1104 85
Table 2.4 Declared yellow and silver eel catches for rivers in North West RBD 2005-2007.
2005 2006 2007
500
Declared catch (kg)
400
300
200
100
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Figure 2.8 Declared monthly catches of yellow eels in the North West RBD, 2005 to 2007.
2005 2006 2007
300
Declared catch (kg)
250
200
150
100
50
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Figure 2.9 Declared monthly catches of silver eels in the North West RBD, 2005 to 2007.
Eel management plans for North West River Basin District
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Page 12 of 232.4 Estimates of silver eel escapement
There is some information on silver eel migration within the North West RBD from the
resistivity fish counter at Backbarrow on the River Leven, 3km downstream of
Windermere. The Leven catchment is dominated by Lake Windermere, which represents
97% of the wetted area available to eel. The resistivity fish counter was installed to record
the number of upstream and downstream moving salmon and sea trout in the river, but it
was noted in the 1990s that it was also counting downstream moving silver eels (Watson
and McCubbing, 1997).
The information from the 1990s was considered by Knights et al (2001) and compared with
data from the 1940s when large scale experimental traps were in operation in the same
area (Lowe, 1952). The trap was fished on a mill leet just downstream of Lake
Windermere. The reported escapement will thus depend on the proportion of flow diverted
down the mill leet and should be taken as a minimum estimate. More fish counter
information has been collected since 2001. All of these data are shown in Table 2.5.
Year Silver eel count Average
1942 793 1430
1943 1,487
1944 2,010
1994 369 1782
1995 3,194
2000 704 908 (mean of 2000, 2002, 2003
2001 No data & 2007)
2002 878
2003 1,090
2004* 98
2005* 181
2006* 358
2007 962
Table 2.5 Silver eel escapement in the River Leven (*Data incomplete counter not
working for part of the migration period)
The data vary greatly between years and recent silver eel estimates from resistivity
counter data have been affected by technical problems in 2004, 2005 and 2006 which
prevented a full years count from being made. The efficiency of the trapping work carried
out in the 1940s and of the resistivity counter in recent years is unknown, and therefore
any comparison of this data must be made with care.
It is possible to estimate silver eel escapement biomass from these data assuming a mean
weight of silver eel at 281g, based on silver eels sampled in the Severn (M. Aprahamian,
Environment Agency, pers. comm.) and an area of the Leven catchment at 1546 hectares
(wetted area available to eel), this is shown in Table 2.6
Sampling year Silver eel escapement (kg) Silver eel escapement
(kg/ha)
1942-1944 402 0.26
1994-1995 501 0.32
2000-2007 (2000, ’02, ’03, 171 0.16
’07)
Table 2.6 Silver eel escapement in the River Leven
Eel management plans for North West River Basin District
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Page 13 of 23Table 2.6 suggests that estimated silver eel escapement in the period 2000 to 2007 is 62%
of the 1942-44 data. Review of silver eel escapement data from other systems in Europe
suggests a silver eel escapement of 4.2kg/ha for lakes on the Shannon and 0-6.5kg/ha for
other UK rivers (both Moriarty and Dekker, 1997); 5kg/ha for the Eider (Germany) and 8
individuals per hectare for the German state of Brandenburg (both Wysujack pers. comm.).
The low levels of production from the Leven may relate to the oligotrophic nature of the
catchment and that is dominated by Lake Windermere, which represents 97% of the
wetted area available to eel. Thus, the estimated escapement from the River Leven
appears low when compared to other systems, and was low in the 1940s, when conditions
may be considered to have been closer to pristine. However, with unknown trap efficiency
in the 1940s or recent years, these results must be viewed with caution.
Data from the 2004 electric fishing surveys of the Ellen catchment were applied to the
Reference Condition Model (RCM: Appendix 3) to assess compliance with pristine
conditions (Figure 2.10). As this was an eel-specific survey the data reflect actual densities
found in the river. Comparison of the 2004 situation (area under the curve) with that
estimated by the RCM suggests that the potential production of silver eels from the Ellen in
2004 represents more than 100% of the reference (“pristine”) conditions. The conclusion
from this is that the Ellen meets the 40% escapement target, and using this river and the
silver eel data for the River Leven as surrogate rivers for the whole RBD, the North West
meets its escapement target.
45.0
40.0
35.0
Eel density (#/100m )
2
30.0
25.0
20.0 Observed y = 38.1e-0.0903x
2
r = 0.66
15.0
10.0
Predicted
5.0 y = 38.1e-0.129x
0.0
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Distance from tidal limit (km)
Figure 2.10 The predicted (dotted line) and observed rate of decline in eel density
for the River Ellen
2.5 Eel mortality and available habitat
2.5.1 Eel Habitat
We have no information on amount of habitat that was available for eel production in the
past, but it is likely due to the industrialisation in the South of the basin; with urbanisation,
land drainage and flood defence works, and the construction of weirs, the amount of eel
habitat has declined significantly. In the North of the basin, these pressures, whilst still
present, have probably been at a lower level. This may explain why the Leven and Ellen
appear to meet the escapement target.
Eel management plans for North West River Basin District
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Page 14 of 232.5.2 Barriers to migration
The legacy of an industrial history in the North West of England is that the natural
hydrology of many of the rivers in the RBD have been significantly changed by weirs,
sluices, bridges, mills and dams. These have created barriers to fish migration, including
the upstream movement of eels, that still persist in many places today. In the South of the
river basin, where most industrialisation occurred, centred around the cities of Manchester
and Liverpool there are at least 1,000 obstructions that are recorded on the Environment
Agency Flood Risk Management database.
In the North of the river basin, in Lancashire and Cumbria, there are fewer obstructions,
but the rivers are still not entirely open to eel migration; a recent investigation looked at the
passability of 203 obstructions in Lancashire and Cumbria for eel migration and concluded
that only 36 were freely passable to eels (Environment Agency, pers. comm.)
In the north of the river basin a report was produced in 2000 that considered and assessed
some of the barriers to eel and elver migration in the watercourses that drain into the Kent,
Leven and Duddon estuaries (Evoy & Martin 2000). This identified some of the major
barriers to migration: including tidal floodgates, weirs, flow gauging structures, and two
Environment Agency fish passes: only eight of the 46 structures investigated were
considered to be “no obstruction” to eel and elver migration.
2.5.3 Entrainment and Hydropower
There is currently no information on the level of eel entrainment within the North West
RBD. In the North West RBD there are at least 12 hydropower installations recorded by
the British Hydropower Association (www.british-hydro.org) or from the Environment
Agency’s permitting database. The extent of mortality of eel at these installations has not
been estimated. However, mortality of eel at one of these installations was observed as
having a significant impact on silver eel escapement (B. Bayliss, Environment Agency,
pers. comm.). The issue has since been resolved at this site.
2.5.4 Predation
The North West RBD comprises 12% of the freshwater and lake habitat in England and
Wales (A Walker, CEFAS, pers. com.), and may expect to constitute 12% of eel
consumption by cormorants: 3.5 to 5.2 tonnes (Appendix 6). With the average length of eel
taken at 40-55 cm (Carss and Marzano 2005) or 150-200g this suggests 18,000 to 35,000
eels consumed by cormorants within the North West RBD each year.
Predation of eel by other species is considered in Section 1.4.4 of the Overview.
2.5.5 Water quality and pollution
The General Quality Assessment of the rivers in the North West RBD, based on the
information on invertebrates, shows that the rivers in the north of the District are of very
good or good quality Figures 2.11 and 2.12. Those in the Mersey Basin tend to be of fair,
poor or even bad quality although over the past 20 years nutrient loading from point
sources such as industry and sewage treatment works has been greatly reduced. Diffuse
pollution is still an issue throughout the District and effluent from Combined Sewer Outfalls
are known to impact on fish stocks around population centres.
Eel management plans for North West River Basin District
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Page 15 of 23Figure 2.11 Biological GQA Grades for North West RBD
Eel management plans for North West River Basin District
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Page 16 of 23Figure 2.12 Chemical GQA Grades for North West RBD
2.5.6 Pathogens and parasites
There is no information on the prevalence of Anguillicoloides (Anguillicola) crassus
(Overview Section 1.4.6) in the North West RBD.
3 Restocking
3.1 Need for restocking
The European Eel Regulation allows for the use of captured eels and glass eels for
restocking areas of habitat in order to increase silver eel escapement and work towards
meeting the compliance target. The available evidence from silver eel monitoring on the
Leven and from using the RCM on data from the Ellen in 2004 suggests that the rivers in
the North West RBD are meeting the silver eel escapement target. It is likely that
Eel management plans for North West River Basin District
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Page 17 of 23populations in the South of the RBD, and in particular the Mersey Basin, are well below
their potential densities without human influence. These rivers are however recovering
from an historic industrial heritage, and the present day population is an improvement from
that in the 20th century.
This being the case, there is a need for consideration of eel restocking in the southern part
of the RBD, around the Mersey Basin. However, this will need to be assessed in relation to
the other issues mainly barriers and the impact of water quality on escapement from this
basin.
In the future, when more high quality data is available for the RBD, this may suggest that
the escapement target is not being met, in which case stocking does become a viable
management option.
3.2 Past restocking
There are no records of past restocking of eel into rivers in the North West RBD.
3.3 Compliance with restocking requirements in the Regulation.
This is addressed in Appendix 7.
4 Monitoring
At present there is no specific monitoring of yellow eel populations in the North West RBD.
It is proposed that, subject to funding, from 2009 the following sampling regime is initiated.
• Survey of the River Ellen: ten of the sites previously surveyed in 2004 sampled
biennially. This will allow a comparison with existing data in order to examine trends
in the eel populations
• Two other river systems in the RBD (Gowy and Lune) to be sampled biennially by
eel specific electric fishing at ten sites per catchment. Consideration of these data
and the application of the RCM or other models will generate better information on
compliance with the escapement target.
• Consider monitoring a ‘lake-fed’ system for eel, if resources permit.
• Routine electric fishing surveys at 482 sites in the RBD will generate
presence/absence, eel length and some population density data that will be
incorporated into future models and analysis of the rivers in the RBD.
• Monitoring of glass eel migration at Red Barn Dyke and on three other sites within
the RBD. This will generate information on the recruitment of glass eels to the North
West RBD.
• Continue monitoring silver eel escapement via the resistivity fish counter at
Backbarrow on the River Leven.
• The yellow, silver and glass eel fisheries will continue to be monitored through catch
returns and the consideration of import and export data. Further efforts will be made
to ensure complete and accurate reporting of catches by life stage
4.1 Monitoring of silver eel escapement
The North West RBD has one estimate of silver eel escapement from a river system: the
resistivity fish counter on the River Leven. The efficiency of this counter for recording eel
migrants is uncertain and more work is needed to improve the confidence in data
Eel management plans for North West River Basin District
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Page 18 of 23generated from it, but it is potentially an excellent monitoring tool. Resistivity counters are
also present on other rivers in the RBD and the potential of these to monitor silver eel
migration will also be considered.
Ongoing work to improve the assessment of compliance with the silver eel escapement
target is described in Section 1.6.1 of the Overview.
4.2. Price monitoring system
This is addressed in Appendix 8.
4.3 Catch and effort sampling system
This is addressed in Appendix 9.
4.4 Origin and traceability of live eels
This is addressed in Appendix 10
5 Measures
Data presented suggests that, using the RCM, the North West River Basin District is
meeting the 40% escapement target of eels required by Council Regulation No 1100/2007.
This assessment is based on limited data centred around a small and possibly
unrepresentative river in the north of the RBD. Other evidence suggests that populations
are declining with fewer sites having eels present in the central part of the River Basin
District. There is also a large industrial heritage in the south of the RBD, with a very large
number of barriers to migration. It is therefore suggested that measures, particularly those
to improve access, should focus around the Mersey catchment.
The Reference Condition Model (RCM) has been used to assess whether the North West
RBD meets the target of 40% of the silver eel escapement that would be produced under
undisturbed conditions. From the data available, it was not possible to determine the
biomass of silver eel migrating from the Ellen catchment, and surrogate data have been
used to assess compliance with the target. This is considered justified as the silver eel
fishery is currently small.
It is clear that the current compliance of the RBD has a low level of confidence attached to
it and more work is needed to determine the correct status of the basin. We are taking the
precautious approach to these assessments and implementing a series of measures to
enhance eel production in the RBD. Potential measures are discussed below, followed by
details of those measures that have been implemented recently, and those which will be
implemented from 2009, and remainder of the first phase, of this EMP
5.1 Measures to improve confidence in escapement target and meet Escapement
Objective
Monitoring
Eel population monitoring is needed in order to have greater confidence in the estimation
of silver eel escapement from the River Basin District. This includes glass eel recruitment
Eel management plans for North West River Basin District
12/2008
Page 19 of 23into the basin, yellow eel populations in freshwater and silver eel escapement. These will
be detailed below.
Reduction of the fishery pressure.
At the moment there is no evidence that the North West RBD is failing the escapement
target, and therefore no reason to restrict the eel fisheries. However, it is essential that
exploitation is sustainable and it is important that the Environment Agency works closely
with the industry to ensure awareness of the eel issue and the need to deliver the 40%
escapement target. The information from the eel fishery is of poor quality and, although a
new catch return system was imposed in 2005, there still remains a large proportion of the
catch that has not been allocated to a river. The quality of data gathered in future years
needs to be improved.
Whilst this information is being collected and a better assessment of the eel fishery is
made, the fishery should be kept within its existing limits by not allowing the number of
instruments to be increased or the range of where they are currently set. This would be as
a precaution until more detailed information is gathered on stocks and the fishery.
Improving access and habitat.
This is addressed in Section 1.4.2 of the Overview, and detailed below.
Stocking of glass eel
This is considered in detail in Section 1.4.5 of the Overview and in Appendix 7.
The requirement for stocking is a low priority.
Predator control
No action will be taken to control predators (see Overview Section 1.4.4).
5.2 Measures taken 2007 to 2009
Improving access and habitat
• Installation of eel pass at Woolston weir on River Mersey.
• Installation of elver pass at gauging station on River Leven.
• Ongoing fish pass works on Rivers Leven, Bela and Ehen and at Ennerdale Water
incorporate facilities for eel migration.
5.3 Measures to be taken 2009 to 2012
The following measures are planned to be implemented from July 2009:
Monitoring
• Continue to improve quality of data collected on eel populations from 482 multi-
species electric fishing survey sites.
Eel management plans for North West River Basin District
12/2008
Page 20 of 23• Establish a biennial programme of yellow eel monitoring at ten of the sites on the
River Ellen which were surveyed in 2004, at ten sites on the River Gowy and ten
sites on the Lune catchment. If resources permit, monitor one lake-fed system for
eel.
• Data on glass eel migration will continue to be collected at Red Barn Dyke by the
RSPB at Leighton Moss Special Protection Area. Glass eel trapping will be carried
out at two additional sites to assess recruitment.
• Investigate the feasibility of monitoring silver eel escapement from Leighton Moss
SPA.
• The resistivity counter at Backbarrow will be validated for monitoring silver eel
escapement, and other counter sites in the RBD considered.
• Investigate the status of pathogens and contaminants in eel populations across the
RBD, wherever practicable.
• Commercial eel fisheries will continue to be monitored through catch returns and
through the assessment of import and export data. Illegal exploitation of yellow eel
and glass eels will be targeted by enforcement teams
Improving access and habitat
• An assessment will be made of the major obstructions to glass eel migration in the
North West RBD. This will be translated into a regional GIS-based eel prioritisation
tool.
• Feasibility and design of eel passes at Eastham Lock, Dutton Lock, Saltersford
Locks, Hunts Lock and Vale Royal Locks on the Weaver catchment.
• Design of eel passes on the River Sankey, Ditton Brook, Spittle Brook and Whittle
Brook.
• Feasibility and design of eel passes at Irlam, Ashton and Northenden weirs on the
River Mersey
• Produce a prioritised action plan for eel passes in the rest of the Mersey catchment.
Review the study of barriers to fish movement on the Mersey catchment and
evaluate the passability for eel.
• Feasibility study for installation of eel passes at gauging weirs on the Lune
catchment.
• Fish passage improvements at Yearl weir on the River Derwent to ease eel
migration.
• Study of barriers to eel migration in south Cumbria to be expanded across the Lake
District rivers.
Eel management plans for North West River Basin District
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Page 21 of 23• Undertake works to improve eel passage on Churchtown weir on the River Wyre.
• The Programme of Measures for the Water Framework Directive will be a good
opportunity for improving habitat and access for eel populations. All opportunities
should be taken to influence waterbodies for the benefit of eel populations.
Stocking of glass eel
• Further consideration will be given to stocking within the North West RBD and a
stocking plan for the release of small numbers of glass eels will be produced. This
will include pre and post stocking surveys to identify the effectiveness of glass eel
releases on silver eel escapement
Reducing the impacts of entrainment
• All abstraction points in the RBD will be assessed for their likely impact on eel
populations and appropriate screening suggested.
• All hydropower installations in the RBD will be assessed for their likely impact on
eel populations and appropriate screening suggested.
Stakeholder engagement
• Eel Management Plan Implementation Group will be convened comprising
representatives of the Environment Agency Area Teams with responsibility for the
North West RBD. This will make decisions on bidding for limited resources.
• Close liaison with the Mersey Life Project will help to achieve improvements for eel
populations in the Mersey basin.
All of these actions will be subject to resources being available (see section 1.5). The
actions proposed in the period from 2009 to 2012 are detailed in Table 5.1. Measures
that will have a direct effect on silver eel escapement are qualified in terms of their
presumed benefit, where: short = 15
years. Note that only the shortest term is given and that the classification is for the time
to effect silver eel escapement and not the time for the measure to be implemented.
Issue Actions to be carried out (subject to resources being available) Timescale
Exploitation • Monitor commercial eel fisheries through catch returns and through the
assessment of import and export data.
• Illegal exploitation of yellow eel and glass eels will be targeted by • short
enforcement teams
• Initiate a price monitoring and reporting system for eels less than 12cm
long.
• Initiate a system to ensure the traceability of all live eels imported or
exported from the UK
• If necessary bring in byelaws to limit fisheries and protect stocks • short
Habitat • Produce maps of available & potentially available eel habitat within the
River basin district, identify significant areas for habitat restoration works
• Use the Environment Agency’s consenting of works on rivers and
stillwaters and their own works programme to improve eel producing • medium
habitat.
• Identify waterbodies within the Water Framework Directive Programme of
Eel management plans for North West River Basin District
12/2008
Page 22 of 23Measures with significant opportunities for improving eel habitat
• Identify all surface water abstraction points and hydropower installations
within the RBD and quantify their impact on eel populations
Passage • Produce plan of priority actions for easing passage taking into account
area of available upstream habitat and cost. Target Weaver, Mersey and
Lune catchments.
• All fish passage works are to incorporate facilities for eel passage • medium
• Identify waterbodies within the Water Framework Directive Programme of
Measures with significant opportunities for improving eel passage
Stocking • Identify areas for restocking within the RBD
• Undertake pilot study with effective pre and post stocking evaluation to
determine the contribution that stocking makes to the spawning stock
• If economically and scientifically justifiable produce plan for wider RBD
Monitoring • Continue to gather information on yellow eel density and biomass
throughout the RBD.
• Begin glass eel trapping at two sites to assess recruitment.
• Validate Backbarrow resistivity counter and investigate further sites for
silver eel monitoring.
• Further development of models to assess compliance with target (RCM
and SMEP)
• Monitor success of novel eel passage solutions
Resources • Obtain funding: through partnerships with other organisations; bids to the
Agency’s project pot (~£150k annually); from the European Fisheries Fund
and from Interreg.
Table 5.1 Proposed actions 2009-2012
5.4 Measures beyond 2012 to achieve the Escapement Objective
It is intended that, in the period 2009 to 2012, actions will be reviewed in response to
improved information on the effectiveness of the measures identified above.
6 Control and Enforcement
These are addressed in Appendix 12.
7 Modification of Eel Management Plans
EMPs will be updated as and when new data become available. New data will feed into
the ICES / EIFAC Eel Working Group country report for the UK and will be reviewed for the
next reporting round in 2012.
Eel management plans for North West River Basin District
12/2008
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