Lochaber Eel Survey

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Lochaber Eel Survey

Final report 2010

Lochaber Fisheries Trust Ltd.

Biologists: Diane Baum, Lucy Smith

Torlundy Training Centre, Torlundy

Fort William

PH33 6SW

01397 703728

Funded through grants from Scottish Natural Heritage and Marine Scotland

Summary

This study is the first systematic survey of eel populations in Lochaber. Electrofishing was used to collect data on eel distribution and density across Lochaber between 2008 and 2010, and this was compared to incidental eel records from historical surveys (1996-2004). We found no evidence for a contraction in the distribution of eels across Lochaber. Eels were recorded in all the catchments surveyed with the exception of Morar. Eels are known to be present in Loch Morar and may simply prefer the loch habitat to tributary burns covered by this survey. Young eels were present on most catchments and estimates of eel age suggest recruitment of young eels has occurred on all but one of the catchments surveyed within the last 4 years. The oldest eel caught was estimated to be at least 28 years old, and could be over 40 years old if growth rates are low on our rivers.

Eel densities tended to be higher on rivers entering the west coast (Moidart, Shiel, Inverie) than those draining into upper Loch Linnhe. This could reflect the relative ease of migration of elver to the west coast as opposed to the head of a long sea loch. We found no relationship between eel density or mean eel size and survey site characteristics, altitude and distance form the sea.

Overall we found no evidence for a decline in eel distribution or abundance in Lochaber, but potential threats to the region’s eel population are discussed.

Introduction

The European eel Anguilla anguilla is native to much of northern Europe including Scotland. Eels breed in the Sargasso Sea in the mid Atlantic and drift back to the European coast as planktonic larvae. In the later stages of this largely passive migration, they transform into glass eels and then elvers as they enter river estuaries. Recent research suggests that many eels may remain in estuarine and coastal waters and never enter freshwater. However, most are thought to migrate upstream into river systems and may spend up to 50 years in fresh water before making the seaward migration to spawn in the Sargasso.

Eel numbers have declined dramatically in recent years. In 2007 the ICES eel working group stated that “the global European eel stock has declined in most of the distribution area and is outside safe biological limits,” and that “given the depleted state of the stock, urgent management actions are required to protect and restore the spawning stock, in order to restore natural recruitment” (ICES 2008). ICES estimates that the number of elvers returning to European rivers is currently just 10% of the level seen in the 1980s. Some of this decline is attributed to fishing pressure. Significant commercial elver and adult eel fisheries operate in many European countries. Changes in ocean currents are also identified as a causal factor for the decline in eels as this species is dependent on currents to transport larvae across the Atlantic. Eel fisheries in Scotland are few and small. There is no commercial exploitation of eels on the northwest coast of Scotland and little recreational fishing for this species. Eel populations in Lochaber should, therefore, not have suffered as the result of overfishing, but may demonstrate the negative effect of large scale changes in ocean systems.

Until now there has been no systematic survey of eel populations in Lochaber. Electrofishing surveys of juvenile salmonids for the purpose of managing salmon and trout fisheries are also effective at catching eels and the Lochaber Fisheries Trust holds historical records of incidental eel captures collected in this way from across Lochaber.

Methods

During past electrofishing surveys of juvenile salmonid populations carried out by the Lochaber Fisheries Trust (1996-2004), incidental eel captures were recorded (referred to as historical data throughout the report). This dataset is probably the best information currently available and provides some indication of the past distribution of eels in Lochaber. All past electrofishing data held by the trust were re-examined to produce a spreadsheet of eel records. This was used to identify sites to be surveyed during the current project and to allow a comparison of the historical and present distribution of eels in Lochaber.

One pass semi-quantitative electrofishing surveys targeted at eels were carried out at 5 sites in each of ten major catchments in the Lochaber region (Figure 1). The historical data described above was used to identify four sites within each catchment where eels were previously known to be present and one site where no eels had been caught. The sites fished covered a variety of different habitat types from small tributary burns to the mainstems of large rivers. These fifty sites are referred to as the original eel survey sites throughout the report.

The LFT has also carried out juvenile salmonid surveys in 2009 and 2010 for fishery management purposes. These surveys use the same electrofishing method and the LFT has collected data on eel numbers and lengths during these salmonid surveys increasing the number of sites surveyed and expanding the project to include other catchments. These sites are referred to as additional survey sites throughout the report. A total of 44 sites were surveyed in 2008, 96 in 2009 and 78 in 2010 (Figure 1). Some of the additional sites were on the mainstem of the Rivers Lochy and Shiel. These rivers are too deep and fast flowing to electrofish the entire width, so only the marginal areas on one bank were surveyed.

All surveys were carried out according to SFCC electrofishing protocols. Each eel caught was anaesthetised on capture and measured in the field. Local river managers, anglers and bailiffs assisted with the electrofishing on a number of the rivers surveyed. Ailort

Aline

Coe

Cona & Scaddle

Grigadale

Inverie

Leven

Lochy

Moidart

Morar

Nevis

Shiel

Strontian

Figure 1. Electrofishing sites surveyed 2008-2010. Square symbols represent original eel sites, circles represent additional sites fished for salmonid stock assessment Results

Eel distribution

A total of 803 eels were caught over the three years of the survey. Eels were caught in all catchments except Morar. The presence of eels recorded during the current survey is presented in Figure 2. Eels were caught in 62.4% of surveys carried out across the three years and were present at 88% of the original survey sites in at least one year between 2008 and 2010. However, eel distribution varied between the survey years and of the 50 original sites, eels were only present at 22 (44%) in all years they were surveyed.

Sites where eels recorded 2008-2010

Sites where eels were not recorded 2008-2010

Figure 2. The presence of eels recorded during the current survey (2008-2010 data pooled). Square symbols represent original eel sites, circles represent additional sites fished for salmonid stock assessment

Pooling results from 2008, 2009 and 2010 allows a comparison of the current distribution of eels with that recorded in historical surveys between 1996 and 2004 (Figure 3) at 80 sites for which these data are available. Eels were present in both the current and historical surveys at 50 sites, and consistently absent from 16 sites. The presence of eels at 14 sites had changed between the historical and current surveys: eels were absent in 2008-2010 in five sites where they had been recorded historically, but were recorded for the first time at 9 sites during the current survey. The sites where eel presence had changed were distributed throughout the region.

Sites where eels recorded in current and historical surveys

Sites where eels were not recorded historically but are present in current survey Sites where eels were recorded historically, but were not present in the current survey

Sites where eels have never been recorded

Figure 3. Comparison of eel presence recorded in the current survey (2008-2010) and that recorded in historical surveys (1996-2004). Square symbols represent original eel sites, circles represent additional sites fished for salmonid stock assessment.

Eel density

Eel density varied greatly between sites and between catchments (Table 1, Figure 4, Appendix). The Moidart catchment had the highest overall density of eels across the three survey years, but the highest density at an individual site (77.3 per 100m2) was recorded on the River Polloch (Shiel catchment).

There was considerable variation in eel density between sites and catchments. Generally rivers draining into Loch Linnhe (Lochy, Nevis, Cona and Scaddle and Leven) had lower densities of eels than those entering the west coast, Sound of Mull or Loch Sunart.

Figure 4. Relative density of eels recorded each year during the current survey. Red dots indicate sites where eels were not recorded. The size of green dots is proportional to the eels density recorded

a) Densities recorded in 2008

b) Densities recorded in 2009

c) Densities recorded in 2010

Table 1a. Summary of eel survey results by catchment including only original eel survey sites. Site-specific data is presented in the appendix.

Catchment Mean eel density (eels per 100m2) Length range of eels (mm) Mean eel length (mm) 2008 2009 2010 Total 2008 2009 2010 Total 2008 2009 2010 Total Ailort 1.64 2.77 0.42 1.82 164-321 174-372 196 164-372 231.7 232.4 196 230.2 Aline 2.41 1.10 1.40 1.61 116-334 189-332 210-354 116-354 206.4 248.8 282.7 240.3 Cona & Scaddle 0.97 0.82 0.68 0.83 117-332 182-439 106-285 106-439 240.9 284.0 176.8 235.1 Inverie - 5.00 6.25 5.60 - 60-340 92-248 60-340 - 181.7 134.5 156.5 Leven 1.57 2.92 3.79 2.43 120-300 144-262 112-296 112-300 198.5 195.1 176.4 188.9 Lochy 1.04 0.40 0.60 0.69 152-281 149-210 141-284 141-284 204.3 179.5 201.7 199.1 Moidart 7.21 9.53 5.74 7.75 91-358 71-335 109-276 71-358 173.3 154.1 136.4 158.7 Nevis 0.45 0.49 0.12 0.36 213-286 220-280 320 213-320 251.5 237.5 320 252.9 Shiel 5.78 2.40 13.86 6.96 105-421 90-241 87-268 87-421 190.8 162.7 137.5 157.6 Strontian 3.30 2.83 1.24 2.39 82-343 74-209 170-280 74-343 180.7 137.3 210 173.2

Table 1b. Summary of eel data from catchments where extra sites were surveyed in 2009 & 2010. Data includes original eel sites and additional sites.

Mean eel density (eels per 100m2) Length range of eels (mm) Mean eel length (mm) Catchment 2009 2010 2009 2010 2009 2010 Ailort 6.17 0.42 94-430 196 191.8 196 Inverie 3.46 6.25 60-340 92-248 165.8 134.5 Lochy 1.23 1.38 90-400 102-320 190.4 143.3 Morar 0 * * * * * Shiel 8.23 10.4 80-294 64-268 119.7 132.7

Population structure

Eels caught varied in size from 60 to 439mm and the size range showed a skewed normal distribution with a greater frequency of smaller eels, particularly in 2010 (Figure 5).

15 2008 F requency 2009 10 2010

25 45 65 85

105 125 145 165 185 205 225 245 265 285 305 325 345 365 385 405 425 445 465 485

Length (mm)

Figure 5. Length –frequency distribution of eels caught 2008-2010.

Large eels (>210mm, the upper quartile limit) were found on all catchments. Small eels (<120mm, the lower quartile limit) were not present on the Nevis catchment. Large numbers of small eels were recorded from sites on the Shiel, Lochy, Moidart and Inverie catchments, suggesting recent recruitment had occurred. Sites where small eels recorded 2008-2010

Sites where small eels were not recorded 2008-2010

Figure 6. The presence of small eels (<120mm) at a survey sites (2008-2010 data pooled).

Only one silver eel (adult eel preparing for marine spawning migration) was caught during the survey on the Allt Grigadale, Ardnamurchan.

We were not able to age eels during this study. Recapture studies and analysis of otoliths on Scottish eels have suggested a mean growth rate of around 13mm per year, with individuals varying from 9 to 17mm per year (Chadwick unpublished data; Wilkinson 1976). Using these data the age of eels caught during this study was estimated (Figure 7). Based on this it is estimated the majority of eels had entered freshwater within the last ten years. The largest eel recorded was estimated to be 28 years old based on medium growth rates or up to 41 years old if slow growth conditions are assumed. 140

120

100

low growth rate

F requency 60 Mean growth rate High growth rate

0 2 4 6 8

10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Estimated age (years)

Figure 7. Estimated age distribution of eels caught during the survey. Low, medium and high growth relate to fish growing at 9mm, 13mm and 17mm per year respectively.

Evidence of habitat choice

Eels were found in a variety of watercourses from small burns to large rivers, still pools to fast-flowing torrents. There was no relationship between the width of the watercourse and eel density (Figure 8) or mean eel size (Figure 9). There was also no association between eel size or density and the type of water flow or substrate at a survey site.

The LFT is also aware of eels existing in high numbers in loch and canal habitats in Lochaber as well as more unusual locations such as water storage tanks and water pipes.

80 )

2 70

2008 50 2009 40 2010

30 E el density (fish per 100m 20

0 0.0 5.0 10.0 15.0 20.0 25.0 30.0

River width (m)

Figure 8. Relationship between river width and eel density.

400 350 300 250 2008

200 2009 150 2010 100

Mean eel length (mm) 50 0 0.0 5.0 10.0 15.0 20.0 25.0 30.0

River width (m)

Figure 9.Relationship between river width and mean eel size across sites surveyed 2008- 2010.

There was a slight trend towards lower eel densities with increasing altitude (Figure 10) and distance from the sea (Figure 11), but neither relationship was significant. Similarly there was no significant trend in mean eel size with survey site altitude (Figure 12) or distance from the sea (Figure 13). However, within a catchment, eel densities tended to be higher at the lower end of the system and no eels were recorded at sites above 70m in altitude.

80 )

2 70

50 2008 2009 40 2010

Eel density (fish Eel per 100m (fish density 20

0 0 50 100 150 200 Altitude (m)

Figure 10. Relationship between survey site altitude and eel density.

Figure 11. Relationship betwen distance of survey site from sea and eel density. 400

350

300

250 2008 200 2009 2010 150

Mean Mean eel length (mm) 100

0 0 20 40 60 80 100 Altitude (m)

Figure 12. Relationship between survey site altitude and mean eel length.

400

350

300

250 2008 200 2009 2010 150

Mean Mean eel length (mm) 100

0 0 5000 10000 15000 20000 25000 30000 35000 40000 Distance to sea (m)

Figure 13. Relationship between distance of survey site from seal and mean eel length.

Natural or man-made barriers may limit the upstream migration of eels and affect their distribution. Eels were not recorded above significant falls on the River Nevis or the Allt Coire na Ba (Leven catchment). However, eels were found above a large natural fall on the River Slatach (Figure 14) and a man-made weir on the Allt Grigadale (Figure 15) both of which are impassable to adult salmonids.

Figure 14. Waterfall on the River Slatach that is impassable to salmonids but above which eels were recorded.

Figure 15. 1.8m high dam on the Allt Grigadale. The dam is impassable to salmonids, but eels were found in the upper Allt Grigadale and have been recorded from Loch Grigadale above the dam.

Discussion

Eel distribution in Lochaber

Eels were widespread in Lochaber and present in 10 out of the 11 catchment surveyed. No eels were caught in the Morar catchment survey, but eels are known to be present in Loch Morar and seem to prefer this to the tributary burns surveyed for this project. Other netting work carried out by the LFT and reports of incidental catches and sightings from members of the public suggest eels are present in many lochs in Lochaber and that man-made waterbodies such as canals, storage tanks and water pipes may also provide important habitats for eels.

Eels were not recorded at 12% of the original eel sites surveyed. An analysis of electrofishing data for the Scotland River Basin District Eel Management Plan 2009 (SEMP) found a slightly higher absence rate of 20% for sites in the northwest of Scotland. Across Scotland as a whole, eels were absent from 55% of sites, suggesting a more widespread distribution of eels on the west coast compared to other areas of the country.

Eel density was not related to altitude or distance from the sea in this study. This differs from the analysis carried out on Scotland-wide data for the SEMP, which found that eel density decreased with altitude and that eels were less likely to be present with increasing distance from the sea. Intuitively areas of river close to the sea and at low altitudes should be more accessible to ascending elvers. The absence of a relationship between altitude and eel density in this study could be explained by the relatively small range of altitudes surveyed and indeed eels were not present at the highest altitude sites included in this study. Given the convoluted coastline of Lochaber, distance from the sea may not reflect the difficulty of access for migrating elver. Glass eels drifting on oceanic currents are more likely to encounter the west coast of Lochaber rather than the rivers at the top of Loch Linnhe. This was generally borne out by this study since higher densities of eels were found on the Moidart, Shiel, Sunart, Inverie and Grigadale catchments compared to rivers draining into Loch Linnhe.

There are many natural and man-made obstacles to migrating fish on Lochaber’s rivers. Whilst guidance exists for determining whether barriers are passable for migratory salmonids, it is more difficult to assess what constitutes an impassable barrier for eels. Ascending eels are unable to leap, and elvers cannot swim against high current speeds. However, if suitable damp vegetation is available along the riverbank, elvers are able to migrate over land. The records of eels above waterfalls and dams in this survey clearly demonstrate the ability of eels to ascend barriers impassable to salmonids.

Trends in eel distribution

The presence of eels at a site was not consistent over the three years of this study. Whilst eels were present at 88% of the original survey sites in at least one year, only 44% of sites had eels in all years that they were surveyed. Clearly eels are a mobile species and their distribution is dynamic. This is an important consideration for future population studies.

Overall eels were present at slightly more sites in the 2008-2010 survey compared to historical surveys conducted between 1996 and 2004 (59 compared to 55 of the 80 sites for which data are available). This suggests a slight expansion in the distribution of eels, and provides no evidence for any population decline. Sites where the status of eels differed between historical and current surveys were spread throughout the region and there was no evidence of loss or recolonisation of eels on a particular river. Unfortunately eel density was not consistently recorded in historical surveys, but where the data do exist, densities appear similar to those found in the current survey.

Eel population structure

Eels caught in this study varied greatly in size. Direct measurements of eel age could not be made during this survey, but age can be estimated from previous studies on the growth rates of Scottish eels. These calculations suggest eels recorded in this survey ranged from those that had just entered freshwater, to individuals up to 28 years in age. Given the nutrient poor conditions of the West Highland rivers, slow growth rates may be more typical in this region and the largest eels caught in the survey may be over forty years old.

The majority of eels caught were below 200mm and estimated to be less than 10 years old. A greater proportion of young eels would be expected in a healthy population and clearly recruitment of young eels is occurring in Lochaber’s rivers. Poor recruitment has been cited as the major reason for declining eel populations in Europe. If this was the case in Lochaber, then small eels would be less frequent and larger eels would be disproportionately represented in the population. Small eels were only absent from the Nevis catchment, where the youngest eel was estimated to be 11 years old. In all other river systems eels less than 4 years old were found. High densities of young eels were recorded on the Shiel, Lochy, Moidart and Inverie catchments and were probably part of recent waves of migrating elver.

Habitat use of eels

This study found no evidence of habitat preference in eels or that eel populations were limited by suitable habitat. The habitats used by eels were very variable in terms of the size of the watercourse, flow rate and substrate type. Clearly eels are catholic in their habitat requirements and can colonise a greater range of environments than salmonids. The results from Morar suggest that in some cases eels may prefer loch habitats to tributary burns. However, eels were found in rivers flowing into Loch Shiel, which is a similar large oligotrophic loch. Eels have also been reported in many artificial habitats from canals and ponds to storage tanks and water pipes.

Status and current threats to Lochaber’s eel population

There is little evidence for a contraction in the distribution or poor eel recruitment over the timeframe of this study. However, anecdotal reports suggest the large overland elver migrations witnessed in the region in the past no longer take place. It would be complacent to assume the eel population is healthy and this current study should act as a baseline against which future trends can be measured. Electrofishing is an effective means of surveying shallow riparian habitats, but such surveys will inevitably exclude many of the habitats used by eels. However, since electrofishing is a commonly used method for assessing other fish stocks it is the most likely technique to be used in the future and has been adopted by the SEMP as the major means of assessing eel stocks.

No commercial eel fisheries operate on the west coast of Scotland and recreational fishing for eels is not common. The overexploitation of eel stocks cited as a major cause of the European decline is unlikely to be a problem in Lochaber. Water quality is also generally high in the region. Point-source pollution events are rare and localised and diffuse pollution is not thought to be a major threat to Lochaber’s fish populations generally. In common with all European stocks, Lochaber’s eel population is vulnerable to changing patterns in ocean currents. Eel larvae drift passively from the Sargasso Sea to the European coast, and any change in current patterns could affect their colonisation of Scottish rivers. Clearly this impact is hard to predict or quantify. Young eels are present on most of the rivers surveyed in recent years suggesting recent recruitment has occurred in the region. However, this should continue to be monitored in the future.

Silver eels migrating downstream to the sea may face obstacles on some of Lochaber’s rivers. Eels are known to be present above the hydroelectric dams on the Rivers Lochy and Morar. Though these dams make provision for the passage of migratory salmonids, these measures may not be adequate for eels. Dead eels are regularly found on the River Lochy and their injuries suggest they were killed by passing through the turbine at Mucomir. It is not known how many eels are killed in this way or what impact the other large hydro schemes or the many micro-hydro schemes that have recently been built or are being planned in Lochaber will have on local eel populations.

The parasite Anguillicoloides crassus was introduced to European eels from Japan through the export of fish. It is now widespread in England and Wales, but has only been reported from one location on the Tay catchment in Scotland. The parasite infects the swimbladder of eels and affects their swimming performance. It is not lethal (Gollock et al. 2005), but could affect the spawning migration of silver eels and thus reduce the overall health of the population (Kirk 2003). Whilst the parasite has not been recorded from Lochaber or surrounding regions, it is important to be vigilant as the parasite is able to spread quickly. Lochaber is connected by canals and hydro scheme pipes to other catchments in Scotland, and the propensity of eels to use such habitats could allow the parasite to spread into the region.

This study has found no evidence that Lochaber’s eel population is declining, and eel recruitment is thought to have occurred on most of the region’s rivers in the last four years. However, there are many potential threats to eels and it is hoped this study will form a baseline against which future trends can be measured. References

Gollock, M., Kennedy, C.R. & Brown, J.A. (2005)

ICES (2008). Report of the 2007 session of the Joint EIFAC/ICES Working Group on Eels. ICES CM 2007/ACFM:23.

Kirk, R.S. (2003). The impact of Anguillicola crassus on European eels. Fisheries Management and Ecology. 10: 385-394.

Scotland River Basin Eel Management Plan (2009). Scottish Government.

Wilkinson, G.R. (1976) Eels in the Scottish Highlands. Highlands and Islands Development Board. Commissioned Report 1976/15. Acknowledgements

The Lochaber Fisheries Trust would like to thank Scottish Natural Heritage, The Scottish Government and Fisheries Proprietors in Lochaber for funding this project. Jim McKinlay, Pete Madden, Jon Gibb, John Veitch, Alan Douglas and Alasdair Boulton kindly assisted with the fieldwork. Matt Gollock laid the groundwork for this project and encouraged a love of eels in us all.

APPENDIX

Results of eel survey presented by individual fishing sites.

Mean size Eel density Wet width Catchment River Site 2008 2009 2010 2008 2009 2010 2008 2009 2010 Original survey sites Ailort Allt lon a Mhuidhe Ail2 * 232.0 * 0.0 5.8 0.0 2.9 3.7 3.6 Ailort Allt Choire Bhuidhe Ail3 302.5 * * 2.3 0.0 * 5.3 4.8 * Ailort Essan Ail5 164.0 239.0 * 0.7 3.6 * 6.5 5.3 * Ailort Allt Raineachan Ail12 213.3 249.0 196.0 7.0 5.9 1.6 4.6 3.3 3.9 Ailort Roti Burn Ail10 * 198.0 * 0.0 2.1 0.0 6.1 11.2 9.1 Aline Allt a Choire Ali14 162.0 * * 1.5 0.0 0.0 4.5 4.2 3.15 Aline Strath Uladail, Wjitewater Ali1 270.5 280.5 231.5 3.2 2.0 1.4 11.9 14.7 13.3 Aline Aline, Eas Ruadh, Crosben Ali 6d 188.0 214.5 * 5.7 2.3 0.0 6.8 8.6 8.3 Aline Allt Buidhe Mor: Uileann Ali2a * 254.0 303.2 0.0 0.7 4.9 18.4 18.1 3.9 Aline Aline, Beach, Alt Beitheach Ali5 * * * * 0.0 0.0 * 4.6 5.2 Cona & Scaddle Cona Sca 10 * 0.0 * 0.0 0.0 0.0 20.1 14.9 18.9 Cona & Scaddle Cona Sca 9 * 196.0 143.0 0.0 2.4 2.4 18.1 9.3 9.6 Cona & Scaddle Scaddle Sca 3 214.0 342.7 246.0 3.8 1.7 1.4 17.0 11.4 17.7 Cona & Scaddle Scaddle Sca 4 268.0 0.0 106.0 1.3 0.0 0.6 22.8 7.3 8.5 Cona & Scaddle Scaddle Sca 6 321.0 0.0 * 0.5 0.0 0.0 18.9 10.2 15.8 Inverie Inverie In a * 155.5 127.9 * 9.2 17.4 * 14.4 17.3 Inverie Abhainn Ghrugaig In 3 * 60.0 * * 14.9 0.0 * 15.0 6.2 Inverie Abhainn Ghrugaig In 6 * 252.8 176.7 * 9.2 3.7 * 2.3 2.9 Inverie Abhainn nan Eildean In 8 * 268.0 206.0 * 0.8 0.8 * 4.4 6.5 Inverie Allt Gleann Meadail In 12 * 78.0 * * 1.2 * * 7.0 * Leven Leven Lev 1 192.5 166.0 0.6 * 5.3 22.1 * 8.1 Leven Allt Coire na Ba Lev 3 158.0 179.8 * 1.6 5.3 0.0 12.8 8.3 12 Leven Allt Coire na Ba Lev 5 * * 133.0 0 0.0 2.7 9.9 7.6 11.9 Leven Allt Nathrach Lev 28a 252.5 182.0 177.6 2.5 1.2 6.4 6.0 6.0 12.2 Leven Tributary of Allt Coire na Ba Lev 4 192.5 * 236.5 11.5 * 3.5 2.7 * 2.8 Lochy Allt Achaidh na Dalach Loc 28 * 217.5 141.0 0.0 6.1 0.9 4.0 3.1 4.4 Lochy Roy Loc 35 * 149 * 0.0 1.3 0.0 15.3 4.4 20.1 Lochy Loy Loc 19 * * 180.0 0.0 0.0 1.2 10.1 20.8 9.5 Lochy Loy Loc 17a 222.8 * * 4.6 0.0 0.0 10.4 13.1 11.1 Lochy Lundy Loc 23 167.5 * 284.0 2.4 0.0 1.3 5.4 10.4 5.8 Moidart Moidart Moi4 290.0 210.0 120.0 0.9 1.4 4.0 15.9 5.7 14.8 Moidart Moidart Moi 2 144.7 140.3 124.2 22.1 8.0 15.9 16.8 15.9 15.5 Moidart Moidart tributary Moi 1 190.9 148.5 * 18.8 27.7 0.0 2.0 16.6 2.2 Moidart Moidart Tributary Moi 6 162.5 186.5 * 2.7 7.9 0.0 1.2 2.4 1.95 Moidart Moidart Moi 7 194.5 * 259.0 2.3 0.0 1.5 14.2 1.9 12.9 Nevis Nevis Nev 1 252.3 212.3 * 1.7 3.2 0.0 23.9 13.6 31.7 Nevis Nevis Nev 2 * 220.0 * 0.0 0.6 0.0 26.4 11.1 28.7 Nevis Nevis Nev 3 * 243.3 * 0.0 2.0 0.0 18.3 8.6 19.8 Nevis Nevis Nev 4 249.0 * 320.0 0.5 0.0 0.8 19.5 15.3 23 Nevis Nevis Nev 5 * * * 0.0 0.0 0.0 18.7 16.3 18.3 Shiel Slatach Shi 10 227.3 * * 8.1 0.0 0.0 7.5 24.3 7.7 Shiel Callop Shi 11 196.0 173.3 211.0 4.0 2.5 1.7 7.3 9.5 8.8 Shiel Polloch Shi 21 160.9 166.0 127.1 17.3 2.2 77.3 9.2 6.5 8.1 Shiel Finnan Shi 13 199.0 133.8 * 3.5 4.9 0.0 14.8 9.9 16.4 Shiel Hurich Shi 16 * 220.0 * 0.0 0.9 0.0 9.8 14.8 9.2 Strontian Strontian Str 1 190.5 241.0 207.2 5.4 1.2 2.0 18.8 10.2 14.3 Strontian Strontian Str a 181.1 117.0 231.0 4.2 1.7 0.8 12.6 9.6 8.8 Strontian Strontian Str 2 131.3 88.0 208.6 3.3 3.9 2.0 12.0 10.3 11.9 Strontian Strontian Str 3 168.6 166.4 * 2.7 4.3 0.0 17.3 13.3 9.1 Strontian Strontian Str 5a 343.0 165.6 * 0.6 3.0 0 12.4 9.1 3.9 Additional Sites Ailort Allt lon a Mhuidhe Ail 1 * * * * 0.0 * * 3.4 * Ailort Essan Ail 6 * 256.7 * * 4.6 * * 4.1 * Ailort Lochan Dubh trib Ail 7 * 151.2 * * 7.8 * * 2.4 * Ailort Ailort Ail 8 * 117.5 * * 2.7 * * 8.2 * Ailort Ailort Ail 9 * 199.5 * * 30.8 * * 5.5 * Ailort Roti Burn AIL 11 * * * * 0.0 * * 11.9 * Ailort Ailort AilJW1 * 189.7 * * 12.3 * * 15.8 * Ailort Ailort AilJW2 * 137.3 * * 3.6 * * 12.8 * Ailort Ailort AilJW3 * 254 * * 2.1 * * 12.2 * Ailort Ailort AilJW4 * 164.4 * * 12.0 * * 12.6 * Inverie Inverie In b * 131 * * 4.8 * * 12.8 * Inverie Inverie In c * 135.6 * * 4.3 * * 8.3 * Inverie Allt Chluainidh In 2 * * * * 0.0 * * 2.9 * Inverie Abhainn nan Eildean In 10a * 140 * * 1.1 * * 5.8 * Inverie Allt Gleann Meadail In 11 * 165 * * 1.3 * * 12.3 * Lochy Lundy Loc 23a * 226.3 * * 6.0 * * 6 * Lochy Lundy Loc 22 * 217.1 123.0 * 8.5 0.9 * 9.8 17.4 Lochy Lochy Loc 2.5 * * 114.2 * 0.0 4.0 * * 6 Lochy Lochy Loc 1.1 * 121.8 142.0 * 5.8 9.0 * * 22 Lochy Lochy Loc 2.4 * 320 117.5 * 1.5 5.5 * * 9 Lochy Lochy Loc 3.2 * * * * 0.0 0.0 * * 10 Lochy Lochy Loc 3.4 * 156.5 * * 1.4 0.0 * * 13.0 Lochy Allt na Caillich Loc 24 * 242.7 236.0 * 3.1 1.5 * 4.8 3.5 Lochy Loy Loc 18 * 0 * * 0.0 0.0 * 12.2 9.4 Lochy Loy Loc 20 * * * * 0.0 0.0 * 11.5 9.8 Lochy Roy Loc 36 * * * * 0.0 0.0 * 26.9 22.4 Lochy Roy Loc 38 * * * * 0.0 * * 13.1 * Lochy Roy Loc 41 * 140 * * 0.9 0.0 * 7.4 8.5 Lochy Spean Loc 50 * * * * 0.0 0.0 * 20 16.5 Lochy Spean Loc 51 * * * * 0.0 0.0 * * 21.1 Shiel Polloch Shi 41 * 104.5 169.1 * 2.0 6.7 * 11.7 11.2 Shiel Polloch Shi 42 * 148.3 156.5 * 3.0 3.3 * 6.7 6.1 Shiel Shiel Shi 22 * 114.9 143.0 * 18.5 3.2 * * 4 Shiel Shiel Shi 26 * 145.9 150.4 * 10.3 5.3 * * 6 Shiel Shiel Shi 29 * 140 160.7 * 1.4 2.6 * * 10.6 Shiel Shiel Shi 39 * 225.1 * * 10.4 * * * * Shiel Shiel Shi 40 * 80 75.0 * 58.0 3.9 * * 6.4 Morar Allt an Loin Mor 1 * * * * 0.0 * * 4.4 * Morar Allt an Loin Mor 2 * * * * 0.0 * * 4.1 * Morar Allt an Loin Mor 3b * * * * 0.0 * * 6.9 * Morar Scamodale Mor 50 * * * * 0.0 * * 2.2 * Morar Bracorina Mor 5 * * * * 0.0 * * 3.1 * Morar Kinlochmorar Mor 9a * * * * 0.0 * * 10.3 * Morar Oban Mor 11 * * * * 0.0 * * 5.2 * Morar Oban Mor 12 * * * * 0.0 * * 4.6 * Morar Meoble Mor 22 * * * * 0.0 * * 20.3 * Morar Meoble Mor 27 * * * * 0.0 * * 20.4 * Lochy Lundy Loc 23b * * * * * 0.0 * * 6.3 Lochy Lundy Loc 23c * * * * * 0.0 * * 5.2 Coe Coe Coe 1 * * 235.5 * * 1.4 * * 12.3 Coe Coe Coe 3 * * * * * 0.0 * * 12.9 Grigadale Grigadale Grig 3a * * 148.0 * * 7.2 * * 3.2 Grigadale Grigadale Grig 4 * * 311.0 * * 0.9 * * 3.2 Grigadale Grigadale Grig 2a * * 112.5 * * 14.9 * * 4.9 Grigadale Grigadale Grig 2 * * * * * 0.0 * * 2 Grigadale Grigadale Grig1 * * 171.4 * * 8.7 * * 2.35 Shiel Allt Camas Drollaman Shi 1 * * * * * 48.4 * * 2.1 Shiel Allt Chamas Bhlathain Shi 5 * * * * * 7.7 * * 3.2

Predominant flow Predominant Catchment River Site Easting Northing type substrate Original survey site Ailort Allt lon a Mhuidhe Ail2 184900 781650 run cobble Ailort Allt Choire Bhuidhe Ail3 183525 781650 riffle cobble Ailort Essan Ail5 181800 781700 run cobble Ailort Allt Raineachan Ail12 182120 782160 run boulder Ailort Roti Burn Ail10 177900 781900 run cobble Aline Allt a Choire Ali14 168350 750100 run cobble Aline Strath Uladail, Wjitewater Ali1 171250 750450 run boulder Aline Aline, Eas Ruadh, Crosben Ali 6d 172050 754250 riffle boulder Aline Allt Buidhe Mor: Uileann Ali2a 174800 750700 run cobble Aline Aline, Beach, Alt Beitheach Ali5 176450 753400 run cobble Cona & Scaddle Cona Sca 10 197875 771600 riffle cobble Cona & Scaddle Cona Sca 9 200000 770360 riffle boulder Cona & Scaddle Scaddle Sca 3 200850 768950 run cobble Cona & Scaddle Scaddle Sca 4 200200 768800 run cobble Cona & Scaddle Scaddle Sca 6 198200 768240 run cobble Inverie Inverie In a 183100 800750 run cobble Inverie Abhainn Ghrugaig In 3 183200 800650 run cobble Inverie Abhainn Ghrugaig In 6 183500 800870 run cobble Inverie Abhainn nan Eildean In 8 180650 798800 riffle cobble Inverie Allt Gleann Meadail In 12 177800 799200 run cobble Leven Leven Lev 1 219050 761920 run boulder Leven Allt Coire na Ba Lev 3 218420 762270 run cobble Leven Allt Coire na Ba Lev 5 219139 763351 riffle boulder Leven Allt Nathrach Lev 28a 216535 761981 riffle boulder Leven Tributary of Allt Coire na Ba Lev 4 218770 762500 run cobble Lochy Allt Achaidh na Dalach Loc 28 217200 779850 run cobble Lochy Roy Loc 35 231350 789320 run boulder Lochy Loy Loc 19 212400 783300 run cobble Lochy Loy Loc 17a 214750 781900 run boulder Lochy Lundy Loc 23 214650 777050 riffle cobble Moidart Moidart Moi4 173500 772100 run cobble Moidart Moidart Moi 2 172700 771800 run cobble Moidart Moidart tributary Moi 1 171800 772200 run sand Moidart Moidart Tributary Moi 6 175080 772800 shallow glide pebble Moidart Moidart Moi 7 175450 773700 run cobble Nevis Nevis Nev 1 212350 773000 run cobble Nevis Nevis Nev 2 213150 771250 run cobble Nevis Nevis Nev 3 213600 770250 run cobble Nevis Nevis Nev 4 213900 769100 riffle boulder Nevis Nevis Nev 5 214600 768400 run boulder Shiel Slatach Shi 10 189900 780600 run boulder Shiel Callop Shi 11 192400 779250 run cobble Shiel Polloch Shi 21 179250 768200 riffle cobble Shiel Finnan Shi 13 191100 781400 run boulder Shiel Hurich Shi 16 183698 768171 run boulder Strontian Strontian Str 1 183450 763700 run cobble Strontian Strontian Str a 181750 762800 riffle cobble Strontian Strontian Str 2 184200 764100 run cobble Strontian Strontian Str 3 184750 764400 run cobble Strontian Strontian Str 5a 185470 765205 run boulder Additional sites Ailort Allt lon a Mhuidhe Ail 1 185200 781700 run cobble Ailort Essan Ail 6 181700 781700 run cobble Ailort Lochan Dubh trib Ail 7 178600 783100 run cobble Ailort Ailort Ail 8 178500 783200 run cobble Ailort Ailort Ail 9 178600 782900 run cobble Ailort Roti Burn AIL 11 177250 782200 run cobble Ailort Ailort AilJW1 176600 781900 run boulder Ailort Ailort AilJW2 176900 782300 run boulder Ailort Ailort AilJW3 177250 782500 run cobble Ailort Ailort AilJW4 177800 783000 run cobble Inverie Inverie In b 179250 798850 riffle cobble Inverie Inverie In c 180125 798900 run pebble Inverie Allt Chluainidh In 2 181350 800350 riffle cobble Inverie Abhainn nan Eildean In 10a 183570 800770 run cobble Inverie Allt Gleann Meadail In 11 180400 798750 riffle cobble Lochy Lundy Loc 23a 214000 777380 run cobble Lochy Lundy Loc 22 212900 776500 run cobble Lochy Lochy Loc 2.5 215900 781900 run cobble Lochy Lochy Loc 1.1 217639 783921 run pebble Lochy Lochy Loc 2.4 214202 780290 run cobble Lochy Lochy Loc 3.2 212814 777960 run pebble Lochy Lochy Loc 3.4 212181 777273 run cobble Lochy Allt na Caillich Loc 24 213500 776400 run cobble Lochy Loy Loc 18 213300 783100 run cobble Lochy Loy Loc 20 210700 784400 run cobble Lochy Roy Loc 36 233300 791030 run cobble Lochy Roy Loc 38 237925 792575 run cobble Lochy Roy Loc 41 233900 791950 run cobble Lochy Spean Loc 50 227000 780450 run cobble Lochy Spean Loc 51 226350 780700 run boulder Shiel Polloch Shi 41 179050 768380 run cobble Shiel Polloch Shi 42 178971 768682 run cobble Shiel Shiel Shi 22 166600 769300 run cobble Shiel Shiel Shi 26 166450 770300 run cobble Shiel Shiel Shi 29 167550 769000 shallow glide cobble Shiel Shiel Shi 39 167951 768378 deep glide pebble Shiel Shiel Shi 40 167830 768781 deep glide sand Morar Allt an Loin Mor 1 169900 794400 run cobble Morar Allt an Loin Mor 2 169750 794400 run cobble Morar Allt an Loin Mor 3b 169850 793400 riffle cobble Morar Scamodale Mor 50 169900 790100 run boulder Morar Bracorina Mor 5 172600 792600 run boulder Morar Kinlochmorar Mor 9a 186600 791010 run cobble Morar Oban Mor 11 187400 789700 run cobble Morar Oban Mor 12 187900 789600 run cobble Morar Meoble Mor 22 179750 787300 run cobble Morar Meoble Mor 27 179100 787900 run cobble Lochy Lundy Loc 23b 215431 777216 riffle cobble Lochy Lundy Loc 23c 216960 777315 run boulder Coe Coe Coe 1 210765 758315 run cobble Coe Coe Coe 3 213935 756675 run cobble Grigadale Grigadale Grig 3a 143605 766598 riffle boulder Grigadale Grigadale Grig 4 144363 766134 riffle boulder Grigadale Grigadale Grig 2a 142964 766990 run cobble Grigadale Grigadale Grig 2 142787 767104 run cobble Grigadale Grigadale Grig1 142520 767253 run cobble Shiel Allt Camas Drollaman Shi 1 176650 769650 run cobble Shiel Allt Chamas Bhlathain Shi 5 176700 768200 run cobble