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LOUGHS AGENCY OF THE FOYLE CARLINGFORD AND IRISH LIGHTS COMMISSION

Stillwater Status Report: Lough Ash, County Tyrone Stillwater Fish Stock Survey Loughs Agency of the Foyle Carlingford and Irish Lights Commission Art Niven & Mark McCauley

A lake fish stock assessment was conducted to record indicative species composition and abundance of Lough Ash, County Tyrone during early November 2011.

Headquarters 22, Victoria Road Derry~Londonderry BT47 2AB Northern Ireland Tel: +44(0)28 71 342100 Fax: +44(0)28 71 342720 general@loughs-agency.org www.loughs-agency.org

Regional Office Dundalk Street Carlingford Co Louth Republic of Ireland Tel+353(0)42 938 3888 Fax+353(0)42 938 3888 carlingford@loughs-agency.org www.loughs-agency.org

Report Reference LA/Lake/01/11 CITATION: Niven, A.J. & McCauley, M. (2015) Stillwater Status Report: Lough Ash, County Tyrone. Loughs Agency, 22, Victoria Road, Derry~Londonderry Page 2 of 19 [Type a quote from the

DOCUMENT CONTROL

Name of Document

Stillwater Status Report: Lough Ash, County Tyrone

Author (s):

Art Niven & Mark McCauley

Authorised Officer:

John McCartney

Description of Content:

Stillwater Fish Stock Assessment

Approved by:

John Pollock

Date of Approval:

June 2015

Assigned review period:

5 years

Date of next review:

June 2015

Document Code

LA/LAKE/01/11

This documents comprises

TOC

Text List of tables Table of Figures

No. Appendices

Version Control Table Version No. Version 1

Status Draft

Author (s) Art Niven

Reviewed by

Approved by

Date of issue

John McCartney

John Pollock

30/06/2015

Revision 2 Revision 3 Version 3

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TABLE OF CONTENTS

TABLE OF CONTENTS ......................................................................................... 4 ACKNOWLEDGEMENTS ...................................................................................... 6 PROJECT STAFF 2011.......................................................................................... 6 EXECUTIVE SUMMARY ....................................................................................... 7 1.0

INTRODUCTION ........................................................................................ 8 Fig 1. Lough Ash ......................................................................................... 8

2.0 METHODS .................................................................................................... 9 Fig 2. Details of survey nets deployed ........................................................ 9 Fig 3. Recovery of nets on Lough Ash, 2011 ............................................. 10 Fig 4. Lough Ash net locations .................................................................. 11 Fig 5. Lough Mourne 50 metre grids ........................................................ 12 3.0 RESULTS ..................................................................................................... 13 3.1 SPECIES RICHNESS .................................................................................. 13 Fig 6. Number of each fish species captured by each gear type during the survey of Lough Ash, 2011 ....................................................................... 13 Fig 7. Stocked Brown trout from Lough Ash, Co Tyrone. .......................... 13 3.2 FISH ABUNDANCE................................................................................... 14 Fig 8. Mean (± S.E.) CPUE and BPUE for all fish species recorded on Lough Ash, 2011 ................................................................................................. 14 Fig 9. Fish species captured from Lough Ash, Co Tyrone in 2011.............. 14 Fig 10. Mean (± S.E.) CPUE for all fish species captured in Lough Ash, 2011. ................................................................................................................. 15 3.3 LENGTH FREQUENCY DISTRIBUTION ...................................................... 17 Fig 14. Length frequency Trout, Lough Ash 2011 (N=25) .......................... 17 Fig 15. Survey in progress on Lough Ash .................................................. 17 3.4 FISH AGE AND GROWTH ......................................................................... 18 Page 4 of 19

4.0 DISCUSSION ............................................................................................... 18 5.0

RECOMMENDATIONS ............................................................................. 18

ACKNOWLEDGEMENTS The Loughs Agency sponsoring departments, board and staff are gratefully acknowledged for the funding, support and assistance provided to conduct stillwater fish stock assessments and status reporting in the Foyle and Carlingford areas. Land owners and angling associations are also gratefully acknowledged for their co-operation.

PROJECT STAFF 2011 Fisheries Biologist/Project Manager

Art Niven

GIS Officer

Rico Santiago

For further information contact art.niven@loughs-agency.org

@ArtNiven

Loughs Agency TV

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EXECUTIVE SUMMARY A Water Framework Directive compliant stillwater fish stock assessment was carried out on Lough Ash, Co Tyrone in November 2011. The Loughs Agency commenced a small rolling programme of lake fish surveys in 2010 to gain a better understanding of fish composition and abundance of the standing waterbodies within the Foyle and Carlingford areas. The information collected can be used for many purposes ranging from formal Water Framework Directive classification, baseline survey for use in the scrutiny of any future proposals and for contributing towards the sustainable development of the angling amenity. Initially selected as one of four surveillance lakes within the Foyle and Carlingford areas requiring a Water Framework Directive compliant fish survey Lough Ash, Co Tyrone was subsequently dropped from the list of surveillance lakes by the Northern Ireland Environment Agency when lakes under 50 hectares were later deselected as surveillance sites. The 2011 fish stock assessment noted the presence of two fish species in Lough Ash, stocked Brown trout and three spined Stickleback with a total of 35 individual fish captured during the survey. Stocked Brown trout were the most common fish species encountered. It is anticipated that this survey report could significantly contribute towards the future sustainable development of angling initiatives, infrastructure and development plans for Lough Ash, Co Tyrone through highlighting the species and their relative abundance to fishery managers. Potential exists for a wellmanaged stocked fishery to be maintained by the owner of the fishing rights. If access to the Fish in Lakes 2 Water Framework Directive classification tool was available a WFD compliant classification could also be derived for Lough Mourne and provided to the Northern Ireland Environment Agency for national reporting purposes.

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1.0 INTRODUCTION Lough Ash is located approximately 5km south-east of Donemana, Co. Tyrone along the B48 road between Donemana and Ballynamallaght in the Burn Dennett catchment. The lake is located at an altitude of 160 metres above sea level and its principal dimensions are; · Length: 750m long, maximum width 280 metres · Surface area: 15.95 hectares · Mean depth: 3.2 metres, maximum depth: 11.5 metres

Fig 1. Lough Ash

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2.0 METHODS Lough Ash was surveyed over one night on the 9th of November 2011 according to the methodology described in the Water Framework Directive compliant NS Share Methods Manual for systematic surveying of lakes for fish (NSSHARE, 2008). Prior to the commencement of the fish survey bathymetric data was sourced from the Northern Ireland Environment Agency to ensure the survey methodology could be followed. A total of 9 nets were set as summarised in Figure 2. Net Type

No. Deployed

Water depth (m)

Dutch fyke nets (chain of 3) Multi-mesh gill nets

0 – 2.9

Multi-mesh gill nets

3 – 5.9

Multi-mesh gill nets

6 – 11.9

Fig 2. Details of survey nets deployed

Survey locations were chosen within randomly selected 50m X 50m grid squares overlaid on a bathymetric map of the lough. A handheld Trimble Geo HT GPS was used to record the precise location of each net. The location and depth of each net is shown in Figure 4. Any fish which were alive and in good condition were measured and released live after removal from the nets. All other fish were removed from the nets and identified and measured on site.

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Fig 3. Recovery of nets on Lough Ash, 2011

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Fig 4. Lough Ash net locations

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Fig 5. Lough Mourne 50 metre grids

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3.0 RESULTS 3.1 SPECIES RICHNESS Two fish species were recorded on Lough Ash in November 2011 with a total of 35 fish captured during the survey. A list of species encountered and captured by each gear type is compiled in Figure 6. Brown trout were the most common fish species encountered during the survey. Common name

Scientific name

Benthic gill nets

Surface gill nets

Fyke nets

Total

Brown trout

Salmo trutta

Stickleback

Gasterosteus aculeatus

Fig 6. Number of each fish species captured by each gear type during the survey of Lough Ash, 2011

Fig 7. Stocked Brown trout from Lough Ash, Co Tyrone.

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3.2 FISH ABUNDANCE Fish abundance, mean catch per unit effort (CPUE) was calculated as the mean number of fish caught per metre of net. Fish biomass, mean biomass per unit effort (BPUE) was calculated as the mean weight of fish caught per metre of net. For all fish species except eel, CPUE/BPUE is based on all nets including fyke nets, whereas eel CPUE/BPUE is based on fyke nets only. Weights were not available from those fish which were released alive. In such cases, weights were calculated from the length weight relationship of recorded fish. A summary of CPUE and BPUE data for each species is shown in Figure 8. Brown trout were the dominant fish species in terms of abundance. Scientific name Salmo trutta

Common name Brown trout

2011 CPUE 0.092 (0.041)

Gasterosteus aculeatus

Stickleback

0.037 (0.014)

2011 BPUE 45.925 (21.096)

Fig 8. Mean (± S.E.) CPUE and BPUE for all fish species recorded on Lough Ash, 2011

Fig 9. Fish species captured from Lough Ash, Co Tyrone in 2011

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CPUE (Number of fish/m net)

0.3

0.2

0.1

0 Trout

Stickleback Species

Fig 10. Mean (± S.E.) CPUE for all fish species captured in Lough Ash, 2011. 100

BPUE (Mean biomass (g) of fish/m net)

90 80 70 60 50 40 30 20 10 0 Trout

Species

Fig 11 Mean (± S.E.) BPUE for all Brown trout captured in Lough Ash, 2011.

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CPUE (Number of fish/m net)

0.3

0.2

0.1

0 Lough Mourne 2010

Lough Carn 2010 Site

Lough Ash 2011

Fig 12. Mean CPUE for all Brown trout captured in Lough Mourne 2010, Lough Carn 2010 & Lough Ash 2011.

BPUE (Mean biomass (g) of fish/m net)

45 40 35 30 25 20 15 10 5 0 Lough Mourne 2010

Lough Carn 2010 Site

Lough Ash 2011

Fig 13. Mean BPUE for all Brown trout captured in Lough Mourne 2010, Lough Carn 2010 & Lough Ash 2011.

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3.3 LENGTH FREQUENCY DISTRIBUTION A total of 25 Brown trout were captured during the 2011 survey. The trout lengths ranged from 29.7cm to 42.1cm (mean length = 34.3cm). A total of 10 Stickleback were captured during the survey, however no lengths or weights were recorded. 5

Frequency

420 - 429

400 - 409

380 - 389

360 - 369

340 - 349

320 - 329

300 - 309

280 - 289

260 - 269

240 - 249

220 - 229

200 - 209

180 - 189

160 - 169

140 - 149

120 - 129

100 - 109

80 - 89

60 - 69

40 - 49

20 - 29

0-9

Length (mm)

Fig 14. Length frequency Trout, Lough Ash 2011 (N=25)

Fig 15. Survey in progress on Lough Ash

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3.4 FISH AGE AND GROWTH Lough Ash is a stocked Brown trout fishery, it was decided not to take scales for age and growth analysis. Due to the origin of the fish, hatchery fish will display more even growth patterns making seasonal growth pattern identification very difficult. From looking at the length frequency distribution the fish are all larger in length with no fish under 29cm recorded. If smaller fish had been encountered there may have been a remnant reproducing population of wild Brown trout present. Lough Ash forms part of the public angling estate and is managed as a public access fishery by the Department of Culture Arts and Leisure, Inland Fisheries section. The fish are sourced from DCAL’s hatchery and fish farm at Movanagher on the River Bann.

4.0 DISCUSSION Stocked Brown trout were the dominant fish species present in Lough Ash with Three spined stickleback also present. At the time of establishment of the public angling estate Lough Ash and other waters were subject to a programme of fish removal. A barrier to the outflow was also installed to prevent any escape of stocked fish to the wild. At the time of this current study the outflow was inspected and a barrier was observed at the outflow but was not acting as a full barrier to fish migration. The inflowing tributary was not inspected as part of this survey but it would be interesting to know if juvenile trout are present within it. At the time of survey both male and female trout were in an advanced state of reproductive maturity with eggs and milt running from fish. The potential for viable offspring to be produced should be investigated further as it may have ramifications for potential genetic introgression into the local wild brown trout population. 5.0 RECOMMENDATIONS · Conduct an electrofishing survey of the inflowing stream to see if any juvenile trout are present. Page 18 of 19

· Investigate the potential for offspring to be successfully produced by the stocked trout. · Investigate the suitability of the current fish screening arrangements. · Communicate findings internally to colleagues and externally to stakeholders · Continue to conduct stillwater fish surveys temporally and spatially within the Foyle and Carlingford areas.

7.0 REFERENCES Kelly, FL (2008) WFD Surveillance Monitoring Fish in Lakes (2007) Central and Regional Fisheries Board report. Kelly, F.L., Connor, L., Wightman, G., Matson, R., Morrissey, E O’Callaghan, R., Feeney, R., Hanna, G. and Rocks, K., (2009) Sampling fish for the Water Framework Directive – Summary Report 2008. Central and Regional Fisheries Board report. North South Share Aquatic Resource (NS Share). Methods Manual V Fish (2008) European CEN Standard. Water quality-Sampling of fish with multi-mesh gill nets (2005)

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