Non-Native Fish Species Survey Using Boat Electro-fishing in the Spey and Dee Catchments
R. Laughton*, A. Hudson** and N. Sherwood***
Spey Research Report 03/06
*Spey Research Trust, 1 Nether Borlum Cottage, Knockando, Morayshire AB38 7SD. Tel 01340810841, Fax 01340 810842, email [email protected]
**Dee District Fishery Board, Mill of Dinnet, Dinnet, Aboyne, AB34 5LA. Tel 01339 885241
*** Stellar Environmental, 1 Main Street, Aystone, Oakham, Rutland, LE15 9AE. Tel 01572 821810
Prepared for
Cairngorms National Park Authority Grantown on Spey Morayshire
March 2006
CONTENTS Page
List of Tables 3
List of Figures 3
Summary 5
Objectives 6
1 Introduction 7
3 Method 7
3 Results 9
3.1 Skating Pond, Grantown 9 3.2 Nethy Pool - Frankies Corner, Mainstem Spey 13 3.3 Loch Beag and the Bogach 13 3.4 Loch Alvie Angling Record 17 3.5 Lochs Davan and Kinord 17 4 Conclusions and Recommendations 22
5 Summary of Recommendations 27
Acknowledgements 28
References 29
2 LIST OF TABLES
Table 1: The fish species caught and catch per unit effort (fish.min -1) in the Skating Pond Grantown, 29 th May 2005.
Table 2: The fish species caught and catch per unit effort (fish.min -1) in Loch Beag and the Bogach 30 th May 2005.
Table 3: The fish species caught and catch per unit effort (fish.min -1) in Lochs Davan and Kinord.
LIST OF FIGURES
Figure 1: Boat electro-fishing team from Stellar Environmental in action on Loch Beag, May 2005. (Photo R. Laughton)
Figure 2: Aerial view of the Skating Pond in Grantown on Spey showing proximity to the River Spey. (Photo R. Laughton)
Figure 3: Length (mm) frequency for trout caught in the Skating Pond, Grantown, 29 May 2005.
Figure 4: Length (mm) frequency distribution for eels caught in the Skating Pond, Grantown, May 2005.
Figure 5: Orfe in natural colours (above) and Golden Orfe (below) captured in Skating Pond, Grantown, 29 th May 2005. (Photo R. Laughton)
Figure 6: Juvenile Tench captured in Skating Pond, Grantown, 29 th May 2005. (Photo R. Laughton)
Figure 7: Map showing locations of Loch Beag and Bogach.
Figure 8: Large Tench (8lb) captured in Loch Beag, May 2005. (Photo R. Laughton)
Figure 9: Roach and Rudd fry captured from Loch Beag Survey May 2005. (Photo R. Laughton)
Figure 10a: Length (mm) frequency histogram for pike captured in Loch Beag and the Bogach, 30 th May 2005.
Figure 10b: Length (mm) frequency histogram for eels caught in Loch Beag and the Bogach, 30 th May 2005.
3
Figure 11: Orfe captured by an angler in Loch Alvie, 19th July 2005. (Photo K. Taylor)
Figure 12: Map showing location of Lochs Davan and Kinord on Deeside.
Figure 13a: Length frequency distribution for Perch in Loch Davan, 1st June 2005.
Figure 13b: Length frequency distribution for Pike in Loch Davan, 1st June 2005. Age classes are estimated using Treasurer and Owen (1991).
Figure 13c: Length frequency distribution for eels in Loch Davan, 1st June 2005.
Figure 14a: Length (mm) frequency distribution for Perch captured in Loch Kinord, 31st May 2005.
Figure 14b: Length (mm) frequency distribution for Pike captured in Loch Kinord, 31st May 2005. Age classes are estimated using Treasurer and Owen (1991).
Figure 14c: Length (mm) frequency distribution for Eels caught in Loch Kinord, 31st May 2005.
4 SUMMARY
A previous survey using gill nets, angling and fish traps of lochs in Speyside and Deeside (Redgewell, Laughton and Hudson 2004) indicated the presence of non native species at a number of locations. This survey builds on the 2004 one by testing boat electro-fishing as an approach to assess open water areas. The boat electrofishing was trialled at five stillwater locations, Skating Pond (Grantown), Loch Beag, the Bogach, on Speyside and Loch Davan and Loch Kinord on Deeside. A trial was also conducted on a slow flowing reach of the Spey near the confluence with the River Nethy.
In general the technique proved successful with a range of fish species captured and a range of age classes for the dominant fish species. Pike, eels, trout and perch were captured. Non native species including Orfe (Leuciscus idus ), (in Golden and natural forms) and tench (Tinca tinca) were captured in the Skating Pond, rudd ( Scardinius erythrophthalmus ) and roach ( Rutilus rutilus ) were captured in Loch Beag and an angler provided another Orfe from Loch Alvie. No non-natives were captured from the Bogach, Lochs Davan and Kinord.
Results from Loch Beag indicate that Roach and Rudd are establishing a spawning population and the juvenile tench captured in the Skating Pond may also indicate a spawning population. The benefits of the boat based electrofishing technique are discussed along with the implications of non natives on the native fish populations.
5 OBJECTIVES
The objectives for the non-native fish species survey were to:
• Test boat electro-fishing as a technique for surveying lochs, ponds and mainstem stretches within the Dee and Spey catchments.
• Produce baseline non-native fish species presence/absence data for key lochs within the Spey and Dee catchments.
6 1. INTRODUCTION
Redgewell, Laughton and Hudson (2004) carried out a survey of several lochs on Speyside and Deeside during 2004. A questionnaire survey was used to examine fishing pressures and techniques and gill netting was then used to examine if any non native fish species were present. Encouragingly most of the lochs contained only the expected range of species, typically, trout, pike, eels, and charr. However, non-native fish species were discovered in Loch Beag, Speyside, adult rudd ( Scardinius erythrophthalmus ) and roach (Rutilus rutilus ) were captured but no juveniles. A number of ponds were also examined and a variety of species were documented with breeding populations of Golden Orfe, Leuciscus idus , present in one.
A number of techniques were implemented during the survey including gill-netting, angling, minnow traps and electro-fishing along the margins. During the survey concern was raised regarding the gill netting as suitable means for surveys. NORDIC protocols were followed throughout and only small numbers of fish were caught however, the authors felt that it would be useful to try alternatives and this survey explores boat based electro-fishing.
2. METHODS
Stellar Environmental, Rutland, were contracted to conduct boat electro-fishing surveys. Electro-fishing equipment consisted of 13.4kVa generator linked to a transformer and control box (Electracatch Model WFC4-HV) with two anodes and cathode. The anodes were stainless steel rings (diameter 400mm) and were fitted with knotless mesh nets (mesh size 2mm). Voltages ranged from 200V to 600V and ampage from 8A to 30A.
Two boats strapped provided a stable working platform. The electrofishing equipment was placed in one boat and holding tanks in the other. Anode operators were stationed at the front of each boat, while the driver was located at the rear of the boat containing the electro-fishing gear. There was also room for an addition net handler. The paired boats were powered by an outboard motor.
7 A simple sampling strategy was devised for the ponds and lochs. Each habitat area i.e. reed beds, open water, shallow margins were fished and a note of the time fishing was recorded. In general and since the main purpose of this survey was to determine species present the data was then amalgamated from each habitat type. A fish finder was also used in the larger lochs to identify potential accumulations of fish.
Sampling was conducted while the boat was moving forward with the anode operators sweeping ahead of the bow. An additional crew member also caught any fish missed by the anode operator. Fish were captured by the anodes with nets, on capture the anode was switched off and the fish placed directly into the holding tanks. Fish were not removed by hand from the anode and net to minimise risks to operators.
Figure 1: Boat electro-fishing team from Stellar Environmental in action on Loch Beag, May 2005. (Photo R. Laughton)
After the survey was complete the fish were processed on shore. Fish were anaesthetized using benzocaine solution, identified, measured, scale were obtained from salmonids. All native species were returned and non-natives were retained and photographed.
Some additional data was also obtained form anglers fishing on Loch Alvie.
8
3. RESULTS
Four sampling locations were examined using the boat electro-fishing technique on Speyside, Loch Beag, the Bogach, the Skating Pond in Grantown and the mainstem near the confluence of the River Nethy. On Deeside two lochs, Davan and Kinord, were examined.
3.1 Skating Pond, Grantown
Figure 2: Aerial view of the Skating Pond in Grantown on Spey showing proximity to the River Spey. (Photo R. Laughton)
Located in Grantown on Spey (302983,827055) (Figure 1) the Skating Pond is a man- made feature which is fed by an input from the Kylintra Burn. Approximate area is 1.6ha and the pond is generally shallow in depth typically between 1 to 1.5m. As the name suggests the pond was created for skating and curling. However, as it has matured with reed beds and vegetation it has begun to support a range of wildlife and bird species. The pond is seldom fished and no data on the fish species present is available.
9
Initial observations gave little indication that there was many fish within this pond but members of the pubic had reported sightings of a large golden coloured fish while feeding the ducks. Redgewell, et al (2004) indicate that roach had already been observed in the Kylintra Burn after a pollution incident in a pond further upstream and it seemed likely that other fish species may also have escaped at that time from a privately owned pond and entered the burn which supplies the Skating Pond.
The pond was surveyed on the 29 th May 2005, three fishing runs covering both the reed beds and vegetated areas of the pond along with the area of open water were completed. The total time fished for the survey was 85 minutes. Table 1 indicates that four species were captured, trout, eels, orfe (natural and golden forms) and a tench.
Golden Trout Eel Orfe Tench Orfe No CPUE No CPUE No No No Caught (fish.min -1) Caught (fish.min -1) Caught Caught Caught
88 1.04 22 0.26 1 2 1
Table 1: The fish species caught and catch per unit effort (fish.min -1) in the Skating Pond Grantown, 29 th May 2005.
A substantial number of trout ( Salmo trutta ) were caught (n=88, CPUE 1.04fish.min -1). Figure 3 provides a length frequency histogram for the captured trout and for the entire catch lengths ranged from 160mm to 370mm and for brown trout. The ages ranged from 2+ to 4+ years. Although 2+ trout were the smallest and 4+ the largest there was considerable over lap amongst the age classes make mean lengths for each difficult to calculate. A number of scales indicated periods of rapid growth which reflects the better feeding opportunities in the pond than in the burn. In addition some of the trout were silvery in appearance indicating the onset of smolting.
Eels were the second most abundant species in the pond (N=22, CPUE 0.26fish.min -1).
10 Length frequency histogram for eels ( Anguilla anguilla ) is presented in Figure 4 and lengths ranged from 200mm to 590mm. There were no clear age-classes evident within the eel population.
18 16 14 12 10 8
Frequency 6 4 2 0
0 0 0 0 0 0 0 0 0 30 6 9 5 12 1 180 210 24 27 300 330 36 39 Length (mm)
Figure 3: Length (mm) frequency for trout caught in the Skating Pond, Grantown, 29 May 2005.
4
3
2 Frequency 1
0
0 0 0 0 0 0 0 0 0 5 0 0 100 150 20 25 300 350 40 45 5 550 600 65 7 Length (mm)
Figure 4: Length (mm) frequency distribution for eels caught in the Skating Pond, Grantown, May 2005.
11
Figure 5: Orfe in natural colours (above) and Golden Orfe (below) captured in Skating Pond, Grantown, 29 th May 2005. (Photo R. Laughton)
A large golden fish was captured and this was confirmed as a Golden Orfe ( Leuciscus idus ), (length 420mm) and an additional two natural coloured Orfe (Leuciscus idus ), (lengths 390mm and 400mm) were also caught (Figure 5). One juvenile tench ( Tinca tinca ) was also captured (Figure 6).
Figure 6: Juvenile Tench captured in Skating Pond, Grantown, 29 th May 2005. (Photo R. Laughton)
12 3.2 Nethy Pool-Frankies Corner, Mainstem Spey
A roach was caught by an angler in the Nethy Pool on the mainstem of the Spey near the confluence of the River Nethy during 2004 (Redgewell, et al 2004). Thus the boat electro-fishing technique was trialled in this slower flowing reach of the mainstem. Success was limited. A large adult salmon was disturbed by the technique but not captured and only one small pike (length 290mm; age 3+) was successfully captured.
3.3 Loch Beag and the Bogach
Loch Beag (286264, 809165) (Figure 7) covers an area of 10ha and has a maximum depth of 9m. It flows into Loch Alvie (286691, 809606), via a shallow channel. Fish could readily move between the two lochs. The outflow of Loch Alvie is also a narrow channel that flows through a marshy area known as the Bogach (288200, 809700) (Figure 7). The channel has been dredged in the past and fish have been known to migrate from the Spey to Loch Alvie via the Bogach, which drains into the R. Spey. Although the channels are silted and well vegetated fish would still be able to move between the Spey and Loch Alvie.
Two fishing runs were completed on Loch Beag covering the vegetated habitat and open water areas. A fish finder was also used to direct fishing activities. Total fishing time was 110minutes and the fish species captured and CPUE are presented in Table 2.
Roach/Rudd Pike Eel Tench Fry CPUE No CPUE No No Caught No Caught (fish.min -1) Caught (fish.min -1) Caught
L. Beag 16 0.15 18 0.16 50+ 1
Bogach 11 0.12 8 0.11
Table 2: The fish species caught and catch per unit effort (fish.min -1) in Loch Beag and the Bogach 30 th May 2005.
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Figure 7: Map showing locations of Loch Beag and Bogach.
The boat electro-fishing was quite successful. Pike (N=18, CPUE=0.16fish.min -1) and eels (N=16, CPUE=0.15fish.min -1) were captured. One large tench (length 480mm; weight 8lbs) was also captured from Loch Beag (Figure 8).
Figure 8: Large Tench (8lb) captured in Loch Beag, May 2005. (Photo R. Laughton)
14 Observations from the fish finder indicated a substantial shoal of small fish was present and a sample of 50+ roach and rudd fry was successfully collected using the electro- fisher (Figure 9).
Figure 9: Roach and Rudd fry captured from Loch Beag Survey May 2005. (Photo R. Laughton)
One fishing run of 90 minutes was completed on the Bogach. Two species were captured, pike (N=11, CPUE 0.12fish.min -1) and eels (N=8, CPUE 0.09fish.min -1) (Table 2).
Data on pike and eels were combined for Loch Beag and the Bogach and are presented in Figures 10a and 10b. Figure 10a suggests that four age classes of pike may have been captured. Scales were collected from a number of the pike and analysis confirmed that 2+ through to 4+ adults were present. Scales from the large 590mm pike were more difficult to determine but age was estimated at 5+ or 6+. Spawning marks were evident on several scales and indicated fish often spawned from age 3+ onwards. Scales also indicated a period of rapid growth from around age 3+.
15 5 2+ 3+ 4
3
2
Frequency 4+ 5+/6+ 1
0
0 0 0 0 0 0 0 0 50 0 0 100 150 20 25 300 350 40 45 5 550 600 65 7 Length (mm)
Figure 10a: Length (mm) frequency histogram for pike captured in Loch Beag and the Bogach, 30 th May 2005.
4
3
2 Frequency 1
0 0 40 80 120 160 200 240 280 320 360 400 440 480 520 560 600 640 680 Length (mm)
Figure 10b: Length (mm) frequency histogram for eels caught in Loch Beag and the Bogach, 30 th May 2005.
Figure 10b* indicates that eels ranged from 220mm to 550mm. The sample is likely to contain a range of ages but there are no clear indications of age classes.
16 3.4 Loch Alvie Angling Record
An additional report of an unusual fish (Figure 11) was provided by Ken Taylor, (Kinrara Estates) from a pike angler fishing Loch Alvie on the 19 th July 2005. The specimen was confirmed as an Orfe, ( Leuciscus idus ).
Figure 11: Orfe captured by an angler in Loch Alvie, 19th July 2005. (Photo K. Taylor)
3.5 Lochs Davan and Kinord
Figure 12: Map showing location of Lochs Davan and Kinord on Deeside.
17 Lochs Davan and Kinord are situated on Deeside near Dinnet and are within the Muir of Dinnet National Nature Reserve (NNR) (Figure 12). Two fishing runs were conducted on each loch encompassing a range of habitat types.
Table 3 indicates that three species were captured, perch, pike and eels in both lochs. Total fishing time was 117minutes for Loch Davan and 205minutes for Loch Kinord. Pike Eel Perch No CPUE No CPUE CPUE No Caught Caught (fish.min -1) Caught (fish.min -1) (fish.min -1) L. Davan 18 0.15 31 0.26 41 0.35 31/05/05
L. Kinord 24 0.12 53 0.26 37 0.18 01/06/05 Table 3: The fish species caught and catch per unit effort (fish.min -1) in Lochs Davan and Kinord.
Table 3 indicates that numbers of each species caught was very similar for both lochs. Catch per unit effort was very similar between the two lochs for pike and eels but was much higher for perch in Loch Davan.
14 12 10 8 6 4 Frequency 2 0
0 50 0 0 0 0 0 0 0 0 100 15 200 250 30 350 40 45 500 55 60 65 70 Length (mm)
Figure 13a: Length frequency distribution for Perch in Loch Davan, 1st June 2005.
18 5 2+ 4 3 2 4+ Frequency 1 0
0 40 80 0 0 0 0 0 0 0 12 16 200 240 280 320 36 40 44 480 520 560 600 64 68 Length (mm)
Figure 13b: Length frequency distribution for Pike in Loch Davan, 1st June 2005. Age classes are estimated using Treasurer and Owen (1991).
4
3
2
Frequency 1
0
0 40 80 0 0 0 0 0 0 0 0 0 12 16 20 240 280 320 36 40 44 48 520 560 600 64 68 Length (mm)
Figure 13c: Length frequency distribution for eels in Loch Davan, 1st June 2005.
Figure 13a indicates that at least two age classes of Perch were captured in Loch Davan. No scales or other material was collected for age determination. However, it seems likely that the first group of perch are 1 year olds with a gap then to the second larger group which are probably 3 years. It appears 2 years old are missing from the catch.
Figure 13b indicated that at least two age classes of pike were captured. No scales were taken and using data previously reported for Loch Davan by Treasurer and Owen (1991) it seems likely first group are 2 year olds and the second 3 year olds.
Figure 13c illustrates the length frequency distribution for eels in Loch Davan. Sizes range from 124mm to 576mm. No clear age structure pattern emerged.
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Figure 14a indicates that at least two age classes of Perch were captured in Loch Kinord. No scales or other material was collected for age determination. However, it seems likely that the first group of perch are 1 year olds with a gap then to the second larger group which are probably 3 years. It appears 2 years old are missing from the catch.
Figure 14b indicated that at least three age classes of pike were captured. Again no scales were taken and using Treasure and Owen (1991) as a guide it seems likely first group are 2 year olds and the subsequent group is 4 year olds. Three year olds appear to be absent from the catch.
Figure 14c illustrates the length frequency distribution for eels in Loch Davan. Sizes range from 254mm to 662mm. No clear age structure pattern emerged.
20 12 10 8 6 4 Frequency 2 0 0 40 80 120 160 200 240 280 320 360 400 440 480 520 560 600 640 680 Length (mm)
Figure 14a: Length (mm) frequency distribution for Perch captured in Loch Kinord, 31 st May 2005. 4 3+ 3 2+ 2 4+
Frequency 1
0
0 50 0 0 100 150 200 25 300 350 400 450 500 550 600 650 70 Length (mm)
Figure 14b: Length (mm) frequency distribution for Pike captured in Loch Kinord, 31st May 2005. Age classes are estimated using Treasurer and Owen (1991). 5 4 3 2
Frequency 1 0 0 40 80 120 160 200 240 280 320 360 400 440 480 520 560 600 640 680 Length (mm)
Figure 14c: Length (mm) frequency distribution for Eels caught in Loch Kinord, 31st May 2005.
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4. CONCLUSIONS AND RECOMMENDATIONS
4.1 Survey methodology
The previous non-native survey of the lochs in Speyside and Deeside have concentrated on gill netting as the primary sampling methodology (Redgewell, et al 2004) although angling, minnow traps and electrofishing were also utilised with limited success. The current survey utilised a boat based electro-fishing survey technique. In general the approach was very successful in the shallow Skating Pond and also proved effective in the deeper lochs such as Davan and Kinord, with a range of species captured.
There were a number of limitations, although a range of age classes were captured for species such as pike, perch and trout, the younger age classes (0+, 1+) were always missing. Equally the older larger fish may also be missed or evade capture.
The system operated with a large generator and the boats were powered by a petrol outboard motor hence the operation was very noisy. This may well scare the fish and reduce success. An electric outboard motor could be utilised but a large capacity generator will always be required to deliver suitable power to attract fish from depth.
The anodes used in the current survey were 3m or 5m long and provided a good operating range while remaining relatively easy to manipulate. Longer anodes would become difficult to operate so water bodies deeper than 5m would be difficult to sample with this technique. Fixed booms (Harvey and Cowx 1996) have also been used from boats and this could also be used in the future. The anodes were fitted with mesh nets to allow capture of the fish after it was attracted to the probe. This is technique is generally frowned upon (SFCC 1998) since it can put the fish into tetanus and lead to damage. Some damage to trout in the Skating Pond was recorded in the form of spinal injuries probably resulting from direct contact with the anode ring while in the net. However, it was limited to a few trout and no damage was observed amongst the non salmonid species. This approach does allow a considerable flexibility for the operator and reduces the number of staff required in the boats. However, further work is required to ensure there is no unseen internal damage to the fish.
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Timed fishings were carried out across a range of habitats in this survey. This proved successful in answering the survey objectives. All the fishings were timed allowing CPUE data to be generated however for future monitoring a more rigorous approach is required. Set areas or banks could be marked and fished allowing revisits in the future, fishing could be conducted in set patterns within or throughout a range of habitats. If baseline surveys are to be established for lochs within Speyside and Deeside particularly to meet the future demands of the Water Framework Directive then further though on the most suitable approach is required.
On its own boat electro-fishing does provide all the data required to fully manage a loch system. Fish finders were used in conjunction with the electro-fisher to guide the operators to a shoal of fish and this illustrates the benefits of combining technologies. Future surveys will require effective use of a range of techniques including acoustics, netting, catch data and electrofishing to provide robust data for management purposes.
The main aim of the current survey was simply to determine if the technique was suitable for determining if non-native species were present and providing further baseline data on existing native species. This was achieved and with some refinements boat electro-fishing should be considered as a useful technique for future census surveys.
4.2 Fish Populations
The key purpose of the survey was to establish if there were any other non- native species present which had not been detected by the netting survey in 2004. The findings are worrying. In Loch Beag it is clear that the adult roach and rudd found in 2004 have successfully spawned and fry are establishing. Fish fauna in Loch Beag is limited to pike and eels so the effect may be limited within the loch itself. However, Loch Beag is connected to Loch Alvie and eventually to the Spey, via the Bogach. The current survey found no non-natives in the Bogach but it seems likely that they will eventually progress through the lochs to the mainstem. The implications of a new species establishing within the Spey is not clear, there may well be competition for food and habitat and existing valuable stocks of trout and salmon may be affected.
23
Complete removal of the fish through poisoning is neither feasible in Loch Beag nor desirable from the perspective of other wildlife interests. The channel between L. Beag and L. Alvie is small and it may be possible to construct a barrier to contain the fish although some may still be transferred by other animals and floods. It is recommended that options to contain the roach and rudd be explored further. Further monitoring on the Loch Beag and Alvie system is also recommended.
Tench was also caught at two locations the Skating Pond and Loch Beag. The large individual caught in Loch Beag was capable of spawning but no juveniles were captured. However, juvenile tench tend to be bottom orientated and difficult to catch via electro- fishing so the result is not conclusive. The opposite was evident at the Skating Pond with a single tench fry captured. This may indicate that larger tench are present and have spawned in the pond. Suitable habitat exists for tench in both locations and given the right conditions the species could establish.
Orfe were captured in the Skating Pond and were estimated at 4 to 5 years old. No juveniles were captured but recent evidence form Redgewell et al (2004) indicates that spawning populations already exist in ponds elsewhere in Speyside. An additional record of an Orfe was also received from Loch Alvie in July 2005.
Lochs Beag and Alvie was stocked with non-native species in the past by the late Mr Peter Braun, who had hoped to offer a wider range of fishing opportunities. Clearly some of the introduced species are still present and worryingly the roach and rudd have begun to spawn.
The orfe and tench present the Skating Ponds are also likely to originate from the activities of the late Peter Braun. His own pond where he retained a range of fish species is upstream and drains in the Kylintra Burn so passage from the upper pond into the Skating pond would be relatively straight forward. There are tentative plans to drain the Skating Pond in Grantown and remove a substantial portion of the reed beds and vegetation. If this proceeds through simply draining the pond via the Kylintra Burn then the non-natives present, tench and orfe, will easily be washed into the Spey and may establish in the mainstem. It is recommended that measures are developed to collect the
24 fish from the pond prior to or during draining. This would provide some control on the spread of non natives and also further data on the trout and eel populations present.
It is clear that fish species stocked into ponds pose a threat to the native fish fauna and Redgewell, et al (2004) suggested mapping ponds within the Spey and Dee catchments and creating an inventory of the species present to provide better information on the extent of non-native species present. This should be coupled with a public awareness exercise aimed at communicating the potential problems caused by the escape of non- native fish, signal crayfish and invasive plants into the Spey and its tributaries.
The current survey also provided addition data on existing native fish populations. The trout population within the Skating Pond was a surprising and interesting find. The age structure was fairly complex and scales indicated that the majority of the trout had spent their growth within the river. However, there was a proportion showed more rapid growth consistent with enhanced feeding in ponds. A number of the trout were silvery indicating they were smolting and ready to progress to sea. However, a clear exit from the pond is not readily available and these may become constrained in the pond.
The Pond clearly provides a valuable habitat for trout and also for eels it is recommended that if the pond is drained the trout and eel stocks be collected and held in tanks and re-introduced back to the pond when the work is complete. Better provision for fish passage in and out of the Pond should also be installed.
Results from Loch Beag and the Bogach for pike and eels were better using this technique that the gill netting used previously in 2004. A wider range of sizes and age classes of pike were collected and all the fish were returned alive. Scales from the pike indicated fairly typical growth and age patterns for Highland lochs and was similar to data from Treasurer and Owen, (1991) for Deeside lochs and previous data for Speyside Lochs (R.Laughton, pers comm .). A good sample of eels was also gained but no age structuring was possible. The results indicate that the Lochs provide valuable habitat for eels which are currently in decline across the UK and Europe and again the introduction of new species may have detrimental effects on this population.
25 Results from Loch Davan and Kinord were encouraging with no reports of non native fish. Perch, pike and eels were all captured. CPUE for pike and eels was similar between each loch. However, CPUE for perch was much lower in Kinord than Davan and there is no clear reason why this should be. There also appeared to be a lack of 2+ perch at both lochs. This could reflect a weakness in the age class which may relate to the very dry summer prevailing in 2003. This may have led to a loss of habitat or reduced spawning success.
The length frequency results for pike indicate a similar pattern to Loch Beag/Bogach although 3 year olds appear to be absent from the Kinord catch. However, the pike population seem similar in age structure to earlier data analysed by Treasurer and Owen (1991) for Davan and Kinord.
The eel catch in both lochs was good and although age was not determined there is probably a good range of age classes present. Similar to Loch Beag these Lochs offer important refuges for eels in their freshwater development.
In general the survey illustrates the importance of collecting information on loch systems, valuable data on fish populations was gained from lochs in both Deeside and Speyside. Native populations include pike, perch, trout and eel and these areas offer important habitats for these species some of which, eels and sea trout, are currently in decline nationally. Non native fish species were also recorded in Loch Beag and Alvie on Speyside and these are a direct result of mis-guided stocking activities to increase fish variety for angling purposes. There was no evidence of any species establishing through the release or discard of live bait by anglers. All the lochs surveyed either strongly discourage the practice or have banned it and it is recommended that the Cairngorms Park Authority further strength this approach.
26
5. SUMMARY OF RECOMMENDATIONS
Fish fauna are an important part of the wildlife within the Cairngorms National Park and the populations within stillwaters are still poorly monitored and understood. The following actions are recommended:
• A regular monitoring programme should be established for lochs within the Cairngorms National Park. An initial baseline survey should be conducted for all lochs and the followed by a rolling programme possibly visits every 3 to 5 years. • Monitoring should use multiple sampling techniques to a range of species are caught and minimum damage is done to existing stocks. Boat electrofishing with some refinements can provide a useful additional monitoring tool. • Some historical data for Lochs within the Cairngorms does exist and this should be collated and reviewed. • Lochs should not be stocked with non-native species. In addition better information and controls on trout stocking should also be considered. • The use of live baiting should be banned. • Sensible and sustainable fishing should be encouraged and developed. • An inventory of ponds within the Cairngorms National Park and species held within them should be created and maintained. • A non-native species public awareness programme should be developed.
27 6. ACKNOWLEDGEMENTS
This project was funded by Leader +, Cairngorms National Park Authority and Scottish Natural Heritage.
We are grateful to Stephen Corcoran (Cairngorms LBAP Officer) who facilitated this project.
The success of the project was due to the dedicated efforts of staff from Stellar Environmental who completed the electrofishing to a high standard, often in atrocious weather conditions. Thanks also must go to the staff of the Dee and Spey Fishery Boards and Dr Peter Cosgrove who assisted with electro-fishing.
The authors are indebted to the following for allowing access to the lochs and providing practical assistance when necessary Ken Taylor and Kirk Taylor of Kinrara Estate (Loch Beag and the Bogach), Jamie Williamson of Alvie Estate (Lochs Beag and Alvie), Frank Law of Seafield Estate (Skating Pond, Grantown), Abernethy Angling Association (mainstem Spey), Scottish Natural Heritage (Lochs Davan and Kinord).
We are also grateful to Dr Peter Maitland (Fish Conservation Centre) and Ross Gardiner (FRS Pitlochry) for their help in confirming the identity of the Orfe.
28 7. REFERENCES
Harvey, J. and Cowx, I.G. 1996. Electric fishing for the assessment of fish stocks in large rivers. In: (Cowx, I.G. ed) Stock Assessment in Inland Fisheries. Fishing News Books. Pp11-26
K.J. Redgewell*, R. Laughton* and Hudson, A. 2004. Survey of Lochs in the Spey and Dee Catchments for Non-Native Fish Species. Spey Research Report 05/04.
SFCC 1998. A Guide to the SFCC Electrofishing Protocol. (ed Puhr, C.) Scottish Fisheries Co-ordination Centre, Pitlochry. 19pp.
Treasurer, J.R. and Owen, R. 1991. Food and growth of pike, Esox lucius , in simple fish communities in lakes of different trophic status. Aquatic Living Resources, 4, 289- 292.
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