Annex J Lamprey Baseline Report - archive.parliament.scot...Appropriate Assessment Lamprey Baseline Report For and on behalf of: Wallingford HydroSolutions Ltd. Approved by: Dr. Andy

Annex J

Lamprey Baseline Report

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��Wallingford HydroSolutions Ltd.

Waverley Railway (Scotland)

Appropriate Assessment

November 2005


Maclean Building

Crowmarsh Gifford

Wallingford

OX10 8BB

www.hydrosolutions.co.uk

Waverley Railway (Scotland)

Appropriate Assessment


For and on behalf of:

Wallingford HydroSolutions Ltd.

Approved by: Dr. Andy Young

Position: Director

Date: 25 November 2005

This report has been prepared by Wallingford HydroSolutions will all reasonable skill, care and diligence within the terms of the Contract with the client and taking account of the resources allocated to it by agreement with the client.

We disclaim any responsibility to the client and others in respect of any matters outside the scope of the above. This report is confidential to the client and we accept no responsibility of any nature to third parties to whom this report, or any part thereof, is made known. Any such party relies on the report at their own risk.

Contents

1 INTRODUCTION ...............................................................................................................................1

2 LIFE STAGES AND HABITAT REQUIREMENTS.......................................................................2 2.1 INTRODUCTION .............................................................................................................................2 2.2 SPAWNING HABITAT .....................................................................................................................3

2.2.1 Habitat Requirements ..............................................................................................................3 2.3 JUVENILE HABITAT .......................................................................................................................3

2.3.1 Habitat Requirements ..............................................................................................................3 2.4 ADULT HABITAT ...........................................................................................................................3

3 SENSITIVITY TO IMPACTS............................................................................................................4 3.1 LOSS OF HABITAT AND CHANNEL DIVERSITY.................................................................................4 3.2 DISRUPTION OF SUBSTRATE AND SILTATION .................................................................................4 3.3 LOSS OF RIPARIAN AND SUBMERGED VEGETATION........................................................................4 3.4 CHANGES IN WATER QUALITY AND TEMPERATURE........................................................................5 3.5 BARRIERS TO MIGRATION..............................................................................................................5

4 SURVEY METHODOLOGY .............................................................................................................7 4.1 HABITAT MAPPING SURVEY .........................................................................................................7

4.1.1 Survey Methodology ................................................................................................................7 4.1.2 Survey Analysis........................................................................................................................8

4.2 ELECTRIC-FISHING SURVEY ..........................................................................................................9 4.2.1 Preliminary Survey..................................................................................................................9 4.2.2 Electric-Fishing Survey Methodology .....................................................................................9 4.2.3 Species Identification.............................................................................................................10 4.2.4 Analysis of Survey results ......................................................................................................10

5 RESULTS ...........................................................................................................................................11 5.1 INTRODUCTION ...........................................................................................................................11 5.2 SPAWNING HABITAT ...................................................................................................................11 5.3 JUVENILE HABITAT .....................................................................................................................18

5.3.1 Locations of Potential Habitats .............................................................................................18 5.3.2 Juvenile Larval Abundances..................................................................................................20 5.3.3 Species identification.............................................................................................................20 5.3.4 Accuracy of Habitat Rating ...................................................................................................22 5.3.5 Accuracy of Sampling............................................................................................................22

5.4 BARRIERS TO MIGRATION ...........................................................................................................22 6 CONCLUSIONS ................................................................................................................................23

7 REFERENCES...................................................................................................................................24

ANNEX 1 – PHOTOGRAPHS OF JUVENILE HABITATS IDENTIFIED WITHIN THE HABITAT MAPPING SURVEY ..................................................................................................................................27

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1 Introduction

Wallingford HydroSolutions Ltd (WHS) working with the Tweed Foundation were commissioned by Environmental Resources Management (ERM) to conduct surveys on the Gala Water and River Tweed to assess the presence of and impacts of the Waverley Railway Project on river lamprey (Lampetra fluviatilis); brook lamprey (Lampetra planeri) and sea lamprey (Petromyzon marinus) within the catchment. ‘The Waverley Railway’ Project is an initiative with the ultimate aim of re-establishing a rail link to provide a passenger transport service from Edinburgh to the central Borders area in Scotland by 2008. The Project is seen as the first phase of reinstating the entire rail link between Edinburgh and Carlisle, which was closed in 1969 (Waverley Railway Project, 2005). The railway currently runs alongside the Gala Water for almost the entire length of the river, with the current infrastructure being 27 crossings (bridges and culverts) and 15 river bank protection measures (where the river has been reinforced or realigned). The majority of these structures are in various states of disrepair, and will therefore require engineering works in-stream or in the vicinity of the Gala Water.

The Gala Water is part of the River Tweed Special Area for Conservation (SAC) and all three species of lamprey, listed in Annexes IIa and Va of the European Union’s Habitats Directive are qualifying features of the SAC. The presence of lamprey within the Gala Water is not well known. Two possible juvenile sites within the Gala catchment were electric-fished by the Tweed Foundation whilst assessing the distribution and abundance of lamprey in the River Tweed cSAC / SSSI (Campbell and Corson, 2004). The first site to be electric-fished in August 2004 was located at Anderson’s Chambers, towards the bottom of the catchment in the centre of Galashiels. At this site only three very small lamprey ammocoetes were found, although the available physical habitat was identified as suitable for lamprey ammocoetes. Brook lamprey ammocoetes were identified in September 2004 at the second site near Haltree, towards the top of the catchment just downstream of the confluence with the Heriot Water.

The three species of lamprey have significantly different lifecycles. The major difference of relevance to the Appropriate Assessment is that river and sea lamprey mature and migrate downstream to the estuary or sea to feed before returning to their river of origin to spawn, whereas the brook lamprey is a purely freshwater species. There is evidence that brook lamprey will be the only species present above impassable weirs (Bond, 2003). Although the cauld at Galashiels has a fish pass for migratory salmon, it may act a migratory barrier for river and sea lamprey. Whilst adult sea lamprey have been found upstream of similar caulds within the Tweed catchment, their larvae have not yet been found more than 20km upstream of the estuary (Campbell and Corson, 2004). As will be discussed, the electric-fishing survey of juveniles conducted as part of this survey only yielded evidence of brook lamprey within the catchment.

To assess the presence and possible impact of the Project on lamprey two surveys were completed. A habitat survey of possible lamprey spawning and juvenile habitats was

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conducted by WHS within the regions of the proposed engineering works. This was followed by an electric-fishing survey of the possible juvenile habitats by the Tweed Foundation which assessed the presence of lamprey within the catchment and the utilisation of specific juvenile habitats.

The lifecycle and habitat requirements for lamprey are presented within Section 2 and the sensitivity of lamprey to potential impacts of the scheme is discussed for each life stage within Section 3. The survey methodology is presented within Section 4 and the results of the surveys are discussed within Section 5. The conclusions from the surveys are presented in the context of the proposed scheme within Section 6.

2 Life Stages and Habitat Requirements

2.1 Introduction

The lampreys are a family of primitive jawless vertebrates which are eel-like in shape with a skeletal structure made up of strong, flexible cartilage and a round, sucker-like disc mouth. Adult lampreys have two dorsal fins, which are continuous with elongated tail fins, and the predacious species develop strong, horny, rasping teeth as adults (Maitland, 2003). There are three species of lamprey in Britain; river lamprey (Lampetra fluviatilis); brook lamprey (Lampetra planeri) and sea lamprey (Petromyzon marinus). Electric-fishing found no evidence that river or sea lamprey are present within the Gala Water therefore only brook lamprey are considered in the following sections.

The brook lamprey is the most abundant and smallest of the British lamprey, with adults generally reaching lengths between 10 and 17 cm (Maitland, 2003). The lamprey life cycle is similar for all species, with adults migrating upstream to spawning grounds, where they spawn in pairs or groups laying eggs in crude nests. After hatching, the young elongated larvae, known as ammocoetes, swim or are washed downstream by the current to areas of sandy silt in still water, where they burrow and spend the next few years in burrows (Maitland, 2003).

The metamorphosis from ammocoetes to adult is dramatic, taking place in just a few weeks. The ammocoetes are semi-translucent and mainly dull grey-brown in colour and transform to have a much more silvery side and belly although the back remains dark grey-brown (Maitland, 2003). Their eyes are covered by opaque skin as ammocoetes which clears to reveal large and bright eyes giving the lamprey proper vision for the first time. The rim of the mouth develops into a full sucker with blunt teeth which are much less developed than those of the two predacious species (Maitland, 2003). As adults the brook lamprey never feed and they die shortly after spawning.

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2.2 Spawning Habitat

Lamprey create nests in shallow depressions by lifting away small stones with their suckers. These are then used to protect the eggs by surrounding and sometimes covering the nest. The nest itself may be under a large stone, log or clump of vegetation, however is frequently in open shallow water, where the spawning adults are vulnerable to predators (Maitland, 2003).

2.2.1 Habitat Requirements

Maitland (2003) likens lamprey spawning habitats to that of salmonids, such as trout. The size of habitat can vary, but ranges between 1 m2 and 10 m2. These spawning grounds are described as well-oxygenated gravel dominated substrate, overlain by a range of water depths (Bond, 2003), generally positioned at the tail end of pools (Maitland, 2003).

2.3 Juvenile Habitat

The juveniles (ammocoetes) live burrowed in suitable silt beds for up to seven years. They are mainly in running water, but they have been found in silt beds in lakes. Ammocoetes are blind, the suckers incomplete and teeth undeveloped. They feed by creating a current that draws organic particles and minute plants into the pharynx, where they become entwined in a slimy mucus string, which is constantly swallowed by the larvae (Maitland, 2003).

2.3.1 Habitat Requirements

Suitable juvenile habitat is defined as open-structured, aerated, silty and sand substrates, between 2 and 40 cm deep, typically overlain with less than 0.5 m of water (Bond, 2003). These habitats can be divided up into optimal and sub-optimal habitats; optimal defined as stable fine sediment or sand � 15 cm deep, low water velocity and the presence of organic detritus; whereas a sub-optimal is defined as shallow sediment, often patchy and interspersed among coarser substrate (APEM, 2002). These silty regions generally occur in slack waters, created either in the margins or behind an in-stream or marginal obstacle (e.g. riparian vegetation, boulders, fallen logs, etc.). These habitats can therefore be relatively permanent or temporary (i.e. could be washed out in the next spate). Shade was also considered important to juvenile habitats during an analysis of substrates used by brook lamprey in Sweden (Hardisty & Potter, 1971).

2.4 Adult Habitat

Juveniles metamorphose into adults between July and September (Bird & Potter, 1979) and from autumn onwards migrate upstream by night, usually continuing to burrow like juveniles or hide under rocks by day (Maitland, 2003). Once in the vicinity of the

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spawning gravels, they hide under stones or among vegetation until March or April (Hardisty & Potter, 1971). A clear migratory route in addition to suitable spawning and juvenile habitats is therefore critical.

3 Sensitivity to Impacts

The sensitivity of lamprey to possible impacts of the scheme are discussed in the following sections and listed within Table 1. Lamprey are susceptible to disturbance at any stage during their life cycle however they are most sensitive to disturbance during spawning and hatching which occurs between April and June (SNH, 2004). Given lamprey juveniles reside within marginal silt beds for up to seven years the direct disturbance of the juvenile habitats may have a very significant impact on the integrity of the Lamprey populations within the Gala Water.

3.1 Loss of habitat and channel diversity

A major possible impact of the scheme is the loss of suitable habitats resulting from either temporary disturbance during construction or permanent disruption of physical habitats.

3.2 Disruption of substrate and siltation

Gravel composition is of vital importance during spawning and incubation of eggs. Consequently, gravel extraction or disruption (due to in-stream works) may reduce the availability of spawning or juvenile habitats. Changes to the flow regime may alter the natural gravel composition downstream or remove a region of slack water resulting in the washing out of any suitable juvenile silt beds. Fines can smother incubating eggs by preventing intra-gravel currents and by clogging the interstices at the surface of the riverbed.

3.3 Loss of riparian and submerged vegetation

Aquatic and overhanging riparian vegetation is important as it provides cover for adult lamprey during migration and spawning, and shade for juvenile habitats. The loss of overhanging vegetation can leave fish susceptible to predation and reduce shade resulting in excessive warming (Bjorn & Reiser, 1991). Removal of riparian vegetation could result in increased siltation from overland runoff and increased instability of the river banks which could lead to increased rates of erosion and ultimate collapse into the river. Riparian vegetation can also be important in creating slack waters in the margins within which silt bed may build up and provide suitable juvenile habitat.

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3.4 Changes in water quality and temperature

Brook lamprey are regarded as being sensitive to pollution, but little specific literature is available (Maitland, 2003). Potter et al. (1970, 1986) have shown that oxygen tension is a major factor in the maintenance of the burrowing habitat of juvenile lamprey. Whilst they can survive almost anoxic conditions in their burrows for only a few hours, after which they must come out or die (Maitland, 2003), they can tolerate low oxygen tension, and may remain in their burrows for some time under these conditions (Hill & Potter, 1970). Reductions in oxygen concentration may occur as a result of a temporary pollution event but also may occur on a more permanent basis due to hydraulic manipulation, such as the deepening of the channel which would result in a reduction in oxygen levels at the bottom of the channel (WWF, 2001). Maitland (2003) notes that laboratory studies on the effect of temperature on the development of embryos have shown that incubation only occurs successfully within a relatively restricted range of 10ºC to 14ºC. Spawning and hatching is sensitive to temperature changes however temperature changes are not likely to be a consequence of the scheme.

3.5 Barriers to migration

Although brook lamprey do not undergo the long migration from the estuaries and sea, adults still migrate upstream to suitable spawning grounds. As well as significant physical obstacles (such as dams, weirs, rapids or waterfalls) and chemical obstacles (such as pollution events); any significant alteration or management of channel which removes too much cover or creates long stretches of very fast water (> 2 m/s) must be avoided along the migratory route (Maitland, 2003).

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Table 1 Sensitivity of lamprey to impacts

Impact Spawning Juveniles Migration

local removal of species

in-stream disturbance high medium medium

disturbance of banks low medium low

physical disturbance of habitats

loss / degradation of channel diversity high high high

disruption of river bed substrate high high low

loss of wetted perimeter medium high medium

loss of riparian vegetation (food source, cover and shade) medium medium medium

loss of submerged vegetation medium medium medium

changes in flow regime (large scale) high high high

changes in flow regime (local) medium medium medium

barriers to migration (physical and flow velocity) N/A N/A high

over deepening of channel (oxygen depletion) high medium low

Sediment pollution

deposition of fines high low [1] N/A

increased suspended solids high medium medium

Reduced water quality

acute - hydrocarbons high medium medium

acute – metals/paint/other high medium medium

chronic - herbicides high medium high

chronic - organic (nutrient enrichment, DO depletion) high medium high

Notes: [1] Increased deposition of fines could actually create more juvenile habitat thus benefiting the lamprey population. However, this would only be advantageous if spawning gravels were not smothered.

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4 Survey Methodology

The survey methodology assessed the presence and utilisation of spawning and juvenile habitats, in addition to the absence of any obstacles to upstream migration within the Gala Water. Physical habitat mapping was used as the survey methodology for assessing spawning habitats and migration potential whilst the habitat assessment for juveniles considered habitat mapping coupled to electric-fishing surveys of potential habitats. The methodologies are presented in further detail below:

• Spawning habitats and migration: survey reaches were mapped for the extent of meso-habitats, with average channel cross-section and dominant and sub-dominant substrate recorded for each meso-habitat. These were combined with information on anthropogenic and natural erosion/deposition features and significant riparian vegetation using the method presented within Section 4.1 to assess lamprey spawning and migration habitat availability at the reach scale.

• Juvenile habitats: The survey reaches were mapped for suitable juvenile lamprey habitats, which were subsequently prioritised in terms of suitability and sampled by the Tweed Foundation using electric-fishing surveys. This survey is presented within Section 4.2.

4.1 Habitat Mapping Survey

4.1.1 Survey Methodology

In-stream physical surveys of habitat indices were used to characterise the availability of suitable habitat for Atlantic salmon and lamprey. The survey methodology was broadly based on River Habitat Surveys (RHS, 2003) in which dominant meso-habitats extents are identified within the survey reach, together with the dominant and sub-dominant substrate and average channel cross-section. These were quantified together with anthropogenic and natural erosion/deposition features and significant riparian vegetation. The surveys also included a reference velocity and channel cross-section, hence flow measurements. 500m reaches were surveyed 100m upstream and 400m downstream of a point engineering works (i.e. bridges and culverts). For engineering works that extend over a length greater than 300m, the reach surveyed was extended to 100m downstream of the full length of the works, to ensure a sufficient distance downstream of the works was mapped. The details of the survey methodology are described within the Atlantic Salmon Baseline Report which forms an Annex to the Appropriate Assessment report (WHS, 2005).

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4.1.2 Survey Analysis

For each meso-habitat mapped the suitability for lamprey spawning was assessed using the average channel depth, dominant and sub-dominant substrates, and presence of overhanging riparian vegetation. The depth and substrate were assigned a score of optimal, sub-optional and marginal, and these scores were combined with the presence of overhanging vegetation, to give an overall score of optimal, sub-optional, marginal and unsuitable for each meso-habitat. This is presented as a percentage for each score for each surveyed reach. As spawning commonly occurs in the transitional period between pools and riffles the number of transitions between meso-habitats for each surveyed reach was calculated per unit length as a measure of the channel diversity.

Little is known about the precise nature of gravel beds used for spawning by lamprey, but the general requirements are detailed in Section 2.2. Most of the substrates at spawning sites identified in British rivers are described as gravels (Maitland, 2003), defined as 15 – 110 mm in size by Bond (2003). Maitland (2003) states that the preferences of lamprey spawning beds are likely to be similar to those of salmonids, which are described as gravels with a large proportion of smaller materials to consolidate the mass while leaving it permeable to water. Stones embedded in fine sands or silts which form a hard bed are avoided, as are uniform small gravels which move easily in a flood. There is limited knowledge about the type of substrate used by spawning lamprey hence the suitability of the surveyed dominant and sub-dominant substrates is more difficult to define than that for Atlantic salmon (WHS, 2005). The surveyed dominant and sub-dominant substrates were assigned a score of optimal and sub-optional as defined in Table 2.

Table 2 Lamprey Spawning Gravels

Dominant Substrate Sub-dominant Substrate Score Large gravel Small gravel Optimal Small gravel Large gravel Optimal Large gravel Sand Sub-optimal Small gravel Sand Sub-optimal

Suitable channel water depths for lamprey spawning are defined by Bond (2003) to vary between 20 – 150 cm, whereas Maitland (2003), based on previous studies, quotes depths of 3 – 30 cm (Hardisty, 1986) or less than 40 cm (Hardisty & Potter, 1971). The ranges of depths assigned scores of optimal, sub-optimal, and as marginal are shown in Table 3.

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Table 3 Lamprey spawning depths

Minimum Depth Maximum Depth Score 3 cm 19 cm Sub-optimal

20 cm 30 cm Optimal 31 cm 40 cm Sub-optimal 41 cm 100 cm Marginal

4.2 Electric-Fishing Survey

4.2.1 Preliminary Survey

Suitable juvenile lamprey habitats were mapped over reaches of various lengths all of which extended 100m upstream and downstream of the extent of the works. Every region that contained suitable open-structured, aerated, silty and sand substrates of greater than 10 cm depth was recorded as a possible habitat. This errs on the conservative side as optimal depths are generally regarded as being greater than 15 cm in depth. For each of these habitats the substrate type, depth and aerial extents were recorded, together with the water depth and a qualitative explanation of the reasons for the formation of the habitat. These details along with photographs were studied by the Tweed Foundation, and ranked in order of suitability for lamprey on a scale of one to ten, with ten being optimal. All areas scoring four and above were listed for survey, as were six control areas of rank less than four (two for each rank). The control areas were selected to test the success of the classification scheme in identifying suitable potential juvenile habitat. The control areas were chosen from locations that had no areas of any higher rank. These results are presented within Section 5.3.

4.2.2 Electric-Fishing Survey Methodology

The electric-fishing survey methodology, used within the SNH funded assessment of lamprey distribution and abundance in the River Tweed cSAC / SSSI in 2004 (Campbell and Corson, 2004), was a semi-quantitative method, which is recommended for use on “sub-optimal” lamprey habitat in SAC rivers (Harvey & Cowyx, 2003). The methodology recommended for “optimal” habitat is a quantitative method using 1m2 quadrats, which requires open, flat, areas of sediment of at least 1m2. Very few of these habitats exist within the Tweed catchment, therefore quantitative surveys would present a bias towards the densities observed within these rare habitats, as opposed to the actual distribution within a catchment.

The sampling methodology adopted within the Gala Water was therefore based on the semi-quantitative method presented in Harvey and Cowyx (2003). This methodology involved electric-fishing against the flow, moving a Pulsed DC current slowly over areas

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of sediment, and catching the lamprey larvae as they attempted to escape from their burrows. The time taken to cover an area, the length of bank fished and the average width of the area fished were all recorded, allowing data to be presented in four ways:

• Total catch • Numbers per square metre • Numbers per minute • Numbers per metre length of bank.

4.2.3 Species Identification

The larvae of river and brook lamprey can only be distinguished with confidence through dissected in the laboratory. However given all river lamprey larvae metamorphose at less than 125 mm, the assumption was made that any larvae larger than 130 mm can safely be identified as brook lamprey. Obviously, the absence of larvae over 130mm does not mean that brook lamprey are absent (Campbell & Corson, 2004). The larvae of the sea lamprey are identifiable in the field.

In addition, the width of the eyes of river lamprey macropthalmia (the late juvenile stage) are almost always more than 2.4% of their body length, so macropthalmia with eyes proportionally smaller than this can also be identified with certainty as brook lamprey. To aid identification the eye width and body length were measured for all macropthalmia found during the survey, using a Vernier Gauge Caliper. Using these criteria it is possible to positively identify the presence of brook lamprey at sites, although river lamprey can only be confirmed as present if their macropthalmia are found.

4.2.4 Analysis of Survey results

The abundance of lamprey found at each of the identified possible juvenile habitats, as stated in Section 4.2.2, were recorded as the number per minute, numbers per m2 and numbers per m length. The abundances of lamprey in SAC rivers are classified using two measures; the first a density estimate based on optimal habitat, and the second a density based on a catchment-wide survey that includes a diversity of habitats. The attributes for compliance with favourable status are defined within Harvey and Cowx (2003) as:

Optimal habitat • Population density river/brook lamprey ammocoetes > 10 /m2 • Population density river/brook lamprey ammocoetes (chalk streams) > 5 /m2 • Population density sea lamprey ammocoetes 0.2 /m2

Catchment perspective • Population density river/brook lamprey ammocoetes > 2 /m2 • Population density sea lamprey ammocoetes 0.1 /m2

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The above classification was used as a guide, where optimal was defined as those habitats with densities greater than 10 /m2, sub-optimal defined as habitats within the range of 2 – 10 /m2 and marginal defined as those with densities less than 2 /m2.

In the assessment of lamprey distribution and abundance in the River Tweed cSAC / SSSI in 2004 (Campbell and Corson, 2004) survey locations were chosen to give maximum geographical coverage. Three sampling sites within 100 m of the bank were selected at each location. This approach is an unbiased sampling approach that is not biased towards preferentially sampling areas of good or even suitable habitat.

The survey approach within this current study is significantly biased as, with the exception of the six control sites, only silt beds identified as potentially suitable for lamprey were selected for the electric-fishing sampling. The results, when classified using the method above are therefore significantly biased towards observing lamprey.

5 Results

5.1 Introduction

Using the habitat mapping surveys and electric-fishing surveys, described in Sections 4.1 and 4.2, the suitability of lamprey habitats was assessed for:

• spawning habitat (habitat mapping); • juvenile habitat (habitat mapping coupled to electric-fishing surveys); and • barriers to migration (habitat mapping).

The full results of the habitat mapping survey, detailing the meso-habitat extents and cross-sectional areas, the natural and anthropogenic features, and significant riparian vegetation recorded, can be found within the Atlantic Salmon Baseline Report, which forms an Annex to the Appropriate Assessment (WHS, 2005).

5.2 Spawning Habitat

Using the criteria described in Section 4.1.2 the percentages of optimal, sub-optimal and marginal lamprey spawning habitat were calculated for each surveyed reach within the

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catchment. These percentages are presented within

0

10

20

30

40

50

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50

51-8

(A-C

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51-8

(B-C

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51-8

(C-D

) 9 10 11 13 14 16 17 18 19 20 21 22 24 25 26 27 28 29 30 31 3334

-36 37 38 39 40 41 42 45 46 47 49

Reach ID

Perc

enta

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ngth

Missing data

Marginal

Sub-optimal

Optimal

Figure 2 Percentage length of optimal, sub-optimal and marginal lamprey spawning habitat within each surveyed reach

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Table 4 together with the percentage of missing data for each reach. The missing data accounts for meso-habitat for which the substrate or depth was not recorded during the survey, due to for example, the Tweed being too deep to safely wade therefore substrates and depths were not recorded.

The locations and extents of the surveyed reaches are shown on Figure 1, along with the engineering locations. The presence of each spawning habitat class is presented by site within Figure 2. This illustrates that the suitable lamprey spawning habitats are sporadically distributed throughout the Gala Water with many of reaches not containing any suitable spawning habitat. For all but one of the reaches containing optimal habitat the optimal habitat constitutes less than 20 % of the total reach.

The number of transitions between meso-habitats per 100 m is presented in

0

10

20

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-36 37 38 39 40 41 42 45 46 47 49

Reach ID

Perc

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ngth

Missing data

Marginal

Sub-optimal

Optimal


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Table 4 by site. This shows the catchment wide variance between channel diversity, as represented by the transition density between meso-habitats is low within the main channel downstream of the confluence with the Heriot Water (from reach 11). The transition density is 3.5 /100 m (standard deviation of ± 1.2 /100 m), on the main channel; and 7.0 /100 m (standard deviation of ± 5.9 /100 m) on the tributaries and upstream of reach 11. The transition density is higher within the tributaries and upstream of reach 11, which is a consequence of the smaller channels within these parts of the catchment.

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Figure 1 Map of surveyed reaches and engineering locations

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Table 4 Percentage length of optimal, sub-optimal and marginal lamprey spawning habitats found within surveyed reaches, including the percentage of missing data and the number of transitions of meso-habitat per 100 m (those not on the main Gala Water channel are shaded).

Reach ID Number of Meso-Habitats / 100m

Optimal / %

Sub-optimal / %

Marginal / %

Missing data / %

50 17.1 0.0 54.7 0.0 0.0 51-8 (A-C) 5.2 0.0 0.0 0.0 0.0 51-8 (B-C) 16.2 0.0 10.0 0.0 0.0 51-8 (C-D) 13.9 16.3 38.9 0.0 0.0

9 11.7 10.8 56.3 7.0 0.0 10 6.4 10.2 69.0 0.0 0.0 11 3.8 13.2 2.8 0.8 0.0 13 3.8 16.4 20.0 0.0 0.0 14 4.6 10.0 5.1 0.0 0.0 16 7.0 0.0 4.1 0.0 0.0 17 18.1 0.0 0.0 0.0 0.0 18 5.3 0.0 9.5 0.0 0.0 19 4.2 2.1 0.0 0.0 0.0 20 3.0 14.2 19.0 0.0 0.0 21 2.4 0.0 14.8 0.0 0.0 22 1.8 7.6 5.3 0.0 0.0 24 4.0 0.0 3.7 0.0 0.0 25 5.0 0.0 11.4 0.0 0.0 26 5.0 0.0 1.3 0.0 0.0 27 3.6 18.0 6.7 0.0 0.0 28 3.2 11.2 0.0 0.0 0.0 29 1.9 15.8 3.9 0.0 1.4 30 4.0 0.0 0.0 0.0 0.0 31 3.2 31.5 10.3 0.0 0.0 33 2.7 14.6 27.3 0.0 0.0

34-36 3.6 0.0 0.0 0.0 0.0 37 2.2 0.0 0.0 0.0 0.0 38 4.0 3.6 0.0 0.0 4.9 39 19.5 0.0 0.0 0.0 0.0 40 2.8 0.0 0.0 0.0 0.0 41 3.4 0.0 0.0 0.0 0.0 42 4.2 0.0 0.0 0.0 0.0 45 3.2 0.0 0.0 0.0 0.0 46 3.1 0.0 0.0 0.0 14.4 47 3.3 0.0 0.0 0.0 40.8 49 0.8 0.0 0.0 0.0 100.0

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5.3 Juvenile Habitat

5.3.1 Locations of Potential Habitats

The locations of all silt areas identified within the preliminary survey as possible juvenile lamprey habitats are presented within Table 5, together with the habitat suitability ranking scores assigned by the Tweed Foundation. This preliminary survey identified 47 potential juvenile habitats within the engineering works survey reaches of which 9 were on the River Tweed. The habitats that were sampled are identified within Table 5 differentiating between those rated four and above and those used as a control. In total 34 sites were electric-fished 6 of which were used as controls. The photographs for each of these sites are presented within Appendix 1.

The permanence of the silt beds (i.e. likelihood of being washed out in winter spates) was considered when assessing the baseline abundance of lamprey within the Gala Water as this will contribute to evaluating whether the potential loss of a habitat will significantly affect the integrity of the lamprey population within the Gala Water. The likely reasons for the occurrence of the silt beds were divided into 6 categories as presented in Table 5 under ‘occurrence’. These results show that 16 habitats occurred as a consequence of vegetation (either aquatic or riparian) creating localised slack water areas; 16 habitats occurred in the margins (due to an slack region of flow); 6 occurred in a poached bank; 6 formed part of a collapsed bank; 1 was in a side channel; and 2 were associated with the presence of an artificial structure (collapsed walls or riprap). This indicates that few of these habitats are permanent features and therefore could be lost through scour during winter spates.

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Table 5 Locations and ratings of all identified possible juvenile habitats within the Gala Water (Habitats sampled are denoted by *, and those used as a control are denoted by +)

Site ID Habitat ID Bank Easting Northing RATING Sampled Occurrence 51 51.1 Both 340284 654752 2 * poached 52 52.1 Left 340334 654517 1 vegetation

52.2 Left 340366 654513 1 + marginal 52.3 Right 340434 654355 1 marginal 52.4 Right 340557 654038 4 * poached 52.5 Right 340566 654010 2 vegetation

14 14.1 Right 342342 650820 6 * vegetation 14.2 Right 342292 650789 2 poached 14.3 Left 342297 650787 4 * poached

19 19.1 Right 344132 648339 5 * vegetation 21 21.1 Left 344440 647561 6 * collapsed bank

21.2 Right 344433 647540 3 marginal 21.3 Left 344442 647545 5 * side channel

26 26.1 Right 344319 645613 5 * vegetation 27 27.1 Left 344875 645288 3 * collapsed bank 28 28.1 Right 345100 645232 4 * vegetation

28.2 Right 345145 645180 8 * vegetation 28.3 Right 345230 645137 5 * artificial structure

29 29.1 Left 345326 643743 5 * collapsed bank 29.2 Right 345293 643578 no photo vegetation 29.3 Left 345341 643378 5 * collapsed bank

33 33.1 Left 345123 641405 1 collapsed bank 33.2 Right 345162 641385 2 collapsed bank 33.3 Left 345209 641390 4 * marginal

35 35.1 Left 345389 640795 5 * marginal 37 37.1 Right 345613 640048 5 * marginal

37.2 Left 345701 639965 1 + vegetation 37.3 Left 345725 639939 3 marginal 37.4 Left 345807 639853 6 * vegetation 37.5 Left 345998 639654 3 vegetation 38.1 Right 346510 639179 3 + poached

38 38.2 Right 346551 639188 1 vegetation 38.3 Right 346617 639114 7 * marginal 38.4 Right 346598 639045 6 * poached

40 40.1 Left 347058 638899 2 + vegetation 42 42.1 Right 347497 637871 5 * artificial structure

42.2 Right 347476 637861 2 + marginal 45 45.1 Left 347548 637486 6 * marginal 49 49.1 Right 351561 635153 4 * marginal

49.2 Right 351571 635164 5 * marginal 49.3 Right 351581 635199 8 * vegetation 49.4 Right 351588 635242 2 marginal 49.5 Right 351595 635286 4 * marginal 49.6 Left 351575 635344 4 * marginal 49.7 Left 351572 635338 1 vegetation 49.8 Left 351566 635322 3 + vegetation 49.9 Left 351568 635307 5 * marginal

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5.3.2 Juvenile Larval Abundances

The results of the electric-fishing surveys carried out in September 2004 in the Gala Water are presented within Table 6 as total catch, density per m2, numbers per minute and numbers per meter length. These results show that the majority of the samples produced only a few lamprey larvae. Each habitat was given a score, in terms of density per m2, of optimal density (> 10 /m2), sub-optimal (2 – 10 /m2) and marginal density (< 2 /m2). Based on the abundance classes 25 of the habitats were classed as marginal, of which 15 produced less than 1 /m2; 6 sub-optimal habitats were identified (half of which produced less than 5 /m2); and 3 habitats were identified as optimal, with a maximum of 16.6 /m2 recorded at the highest abundance habitat. Whilst it is important to consider the actual size of each habitat in addition to the density when assessing the impact of the engineering works, (as a large area of poor habitat with low densities can actually hold more larvae than a small area of high density), only one habitat would be over estimated by its density. This was habitat 37.2, which has a density of 5 /m2, but as it is only 2m in length, therefore its significance is less than its density suggests. All remaining habitats of densities greater than 5 /m2 were found in habitats of bank length greater than 5 m.

5.3.3 Species identification

The identification of species found within each habitat is also presented in Table 6. Brook lamprey were identified at 12 out of the 16 habitats on the Gala Water, identified by a combination of larvae size and presence of the macropthalmia. No evidence of river or sea lamprey was found in the Gala Water, although the difficulties in identifying river lamprey larvae mean that their presence or absence cannot be completely confirmed. The macropthalmia of river lamprey was identified within one of the surveyed habitats on the River Tweed, which is in agreement with the 2004 surveys were river lamprey were identified both upstream and downstream of this location. This does not mean that the larvae of this species would be present at this site as the macropthalmia are migratory.

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Table 6 Species identification and abundances of lamprey within surveyed habitats

Habitat ID

Bank Length (m)

Total No. Larvae

No. / minute

No. / m2

No. / m Length

Seen but missed

Larvae >130mm

Macropthalmia Brook River Score

51.1 23.3 15 0.76 0.64 0.64 + + Marginal 52.2 2.5 0 0 0 0 Marginal 52.4 16.2 17 1.39 1.4 1.05 + + Marginal 14.1 6 2 0.65 0.67 0.33 Marginal 14.3 4.7 31 6.2 13.19 6.6 + + Optimal 19.1 16.7 41 2.65 3.27 2.46 Sub-optimal 21.1 8.2 68 5.44 16.59 8.29 + + Optimal 21.3 24.5 161 5.46 6.57 6.57 + + Sub-optimal 26.1 8.4 5 0.63 1.19 0.6 Marginal 27.1 5.6 9 2.08 3.21 1.61 Sub-optimal 28.1 6.5 33 3.54 10.15 5.08 Optimal 28.2 12.6 17 2 1.8 1.35 + + Marginal 28.3 6.2 35 4.47 7.53 5.65 + + Sub-optimal 29.1 14.6 16 1.26 1.1 1.1 + Marginal 29.3 22.2 11 0.76 0.66 0.5 Marginal 33.3 19 32 2.37 1.35 1.68 + + Marginal 35.1 26.4 44 1.91 1.67 1.67 + + Marginal 37.1 8.8 17 2.43 1.93 1.93 + + Marginal 37.2 2 5 1.67 5 2.5 + + Sub-optimal 37.4 26.5 4 0.23 0.2 0.15 Marginal 38.1 27.5 2 0.17 0.15 0.07 Marginal 38.3 9.3 0 0 0 0 * Marginal 38.4 20 0 0 0 0 Marginal 40.1 3 2 0.67 1.33 0.67 Marginal 42.1 15 11 1.18 0.73 0.73 Marginal 42.2 12.5 0 0 0 0 Marginal 45.1 14.7 76 4.39 3.45 5.17 Sub-optimal 49.1 3.8 0 0 0 0 Marginal 49.2 4 1 0.57 0.33 0.25 Marginal 49.3 3.6 3 0.92 0.83 0.83 Marginal 49.5 5 1 0.25 0.27 0.2 Marginal 49.6 13.7 18 2.7 1.75 1.31 + + Marginal 49.8 7.4 3 0.56 0.54 0.41 Marginal 49.9 24 33 2.28 1.38 1.38 + + Marginal

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5.3.4 Accuracy of Habitat Rating

The rating of habitat suitability from the preliminary survey measurements and photographs is necessarily subjective. For the majority of the habitats the suitability was overestimated and there is a general trend of increasing abundance with increasing suitability ranking. There is the possibility that some of the potential juvenile habitats not electric-fished may have good lamprey abundances present, particularly if in close proximity to abundant habitats. The 13 remaining sites were re-assessed based on the survey results, Six were still ranked as poor as they of marginal extent (less than 2 m in length), two habitats, 21.2 and 49.7, due to their proximity to other habitats, may have good densities of larvae as they are located in proximity to habitats with good densities. The remaining five habitats retained their poor ranking.

5.3.5 Accuracy of Sampling

Two of the habitats were particularly difficult to sample, with significant under catch of larvae. Habitat 35.1 is on a very steep silty bank within slow flowing deep water within the margins. The habitat had to be sampled from the bankside and visibility was obscured by disturbed sediment. From within this habitat 17 lamprey larvae were missed, and the depth of the water towards the centre of the channel was too deep to sample, although larvae were disturbed from that area. The presented abundance is also underestimated for habitat 21.3, where 161 larvae were captured, but another 50-100 were missed. The depth of the sediment and high abundance of lamprey present resulted in high numbers escaping at a rate that could not be counted.

5.4 Barriers to Migration

The main potential barriers to migration observed within the catchment are the presence of weirs and other artificial structures. Three weirs were observed within the survey reaches; two small weirs within reaches 41 and 46, and the cauld at Galashiels which has a fish ladder. A fourth possible migratory barrier is present just downstream of engineering location 25, where a supporting structure for a ford blocks the channel during low flows. Brook lamprey have been found throughout the Gala Water catchment, therefore any current barriers to migration do not impede the movement of brook lamprey through the catchment above the cauld. The failure to positively identify river lamprey within the Gala Water and their presence within the Tweed near the mouth of the Gala Water suggests that the cauld in Galashiels does act as a migratory barrier to river lamprey. However, further sampling would be required to confirm their absence within the Gala Water.

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6 Conclusions The conclusions from the survey are:

• Brook lamprey were identified within the Gala Water. River lamprey were identified within one of the habitats on the Tweed but there is no evidence that river lamprey are present within the Gala Water.

• Potential lamprey spawning habitat occurs in small extents throughout the catchment, with optimal habitat found at only 15 of the surveyed reaches. This generally comprised less than 20 % of the reach extent.

• Almost all the juvenile habitats sampled had a few larvae but only a few habitats had them in abundance, a pattern matching the outcomes of the previous survey within the Tweed catchment.

• Two of the surveyed habitats on the Tweed produced samples with greater than one larvae per m2. These are of little significance in the context of the middle Tweed, where there are known to be much more productive sites both upstream and downstream, and a great deal of habitat similar to the area around the bridge.

• At the few habitats with high abundances habitat loss or damage could be significant within the Gala Water. It is possible that the high quality habitat sampled during the survey may be a very high proportion (or even all) of such habitat on this river. Key areas in terms of impacts on lamprey populations on the Gala Water would therefore appear to be Locations 21 (Pirn House), 28 (Killochyet), 35 (Bowshank) and 45 (Balnakeil) based on both abundance and amount of habitat (location bank length). Location 14 (Hazelbank) is of note but of lesser importance.

• The populations on the Gala Water appear to be non-migratory brook lamprey hence loss of high-quality habitat could damage locally restricted populations. However, it is thought that brook lamprey do migrate locally to spawn which would reduce their dependence on any one area.

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7 References

APEM, 2002. Distribution of sea, brook and river lampreys on the River Tay. Scottish Natural Heratage, Commisioned Report F01AC610 (Unpublished).

Bird, D.J. and I.C. Potter, 1979. Metamorphosis in the paired species of lamprey, Lampetra fluviatilis (L.) and Lampetra planeri (Bloch). 1. A description of the timing and stages. Zoological Journal of the Linnaean Society of London. 65, 127–143.

Bjorn, T.C. and D.W. Reiser, 1991. Habitat Requirements of Salmonids in Streams. Influences of forrest management on salmonid fishes and their habitats. Bethesda: American Fisheries Society.

Bond, L., 2003. The Endrick Water cSAC Conservation Strategy. Conserving Natura 2000 Rivers. English Nature, Peterborough.

Campbell, R.N.B. and P. Corson, 2004. The Assessment of Lamprey Distribution and Abundance in the River Tweed Candidate Special Area of Conservation / Site of Special Scientific Interest. Report Commissioned by SNH from The Tweed Foundation (unpublished)

Hardisty M.W. and I.C. Potter, 1971. The biology of Lampreys. Academic Press, London.

Hardisty M.W., 1986. Petromyzontiforma. The freshwater fishes of Europe. Aula-Verlag,Wiesbaden.

Harvey J.P. and I.G. Cowx, 2003. Monitoring the River, Brook and Sea Lamprey. Conserving Natura 2000 Rivers Ecology Series No. 7. English Nature, Peterborough.

Hill B.J. and I.C. Potter, 1970. Oxygen consumption in the ammocoetes of the lamprey Icthyomyzon hubbsi. Journal of Experimental Biology 53, 47–57.

Maitland, P.S.,2003 Ecology of the River, Brook and Sea Lamprey. Conserving Natura 2000 Rivers Ecology Series 5. English Nature, Peterborough.

Potter I.C., B.J. Hill and S. Gentleman, 1970. Survival and behaviour of ammocoetes at low oxygen tensions. Journal of Experimental Biology 53, 59–73.

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Potter I.C., R.W. Hilliard, J.S. Bradley and R.J. McKay, 1986. The influence of environmental variables on the density of larval lampreys in different seasons. Oecologia 70, 433–440.

RHS, 2003. River Habitat Survey in Britain and Ireland: Field Survey Guidance Manual (2003 Version).

SNH, 2004. Guidance for Competent Authorities when dealing with proposals affecting SAC freshwater sites. Scottish Natural Heritage.

Waverley Railway Project, 2005. Waverley Railway Project website [accessed October 2005]: www.waverleyrailwayproject.co.uk

WHS, 2005. Atlantic Salmon Baseline Report. The Waverley Railway Project. Wallingford HydroSolutions.

WWF, 2001. The Status of Wild Atlantic Salmon: A River by River Assessment

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Annex 1 – Photographs of Juvenile Habitats identified within the Habitat Mapping Survey

Figure 1. Habitat 51-1

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Documents

Annex J Lamprey Baseline Report - archive.parliament.scot...Appropriate Assessment Lamprey Baseline Report For and on behalf of: Wallingford HydroSolutions Ltd. Approved by: Dr. Andy