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ATLANTIC SALMON AND TROUT POPULATIONS AND FISHERIES

River Derg & Tributaries Catchment Status Report 2007 The Loughs Agency (FCILC)

_________________________________________

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

ATLANTIC SALMON AND TROUT POPULATIONS AND FISHERIES River Derg and Tributaries Catchment Status Report ____________________________________ Report Reference LA/CSR/05/08

Written and Prepared by: Art Niven, Fisheries Research Officer Rachel Buchanan, Geographical Information System (GIS) Officer Declan Lawlor, Environmental Officer The Loughs Agency (Foyle Carlingford and Irish Lights Commission)

For further information contact: Loughs Agency 22, Victoria Road Londonderry BT47 2AB

Loughs Agency Carlingford Regional Office Darcy Magee Court Dundalk Street Carlingford, Co Louth

Tel: 028 71 34 21 00 Fax: 028 71 34 27 20 E-mail:general@loughs-agency.org

Tel: 042 93 83 888 Fax: 042 93 83 888 E-mail:carlingford@loughs-agency.org

www.loughs-agency.org Cover picture of hen salmon in breeding dress courtesy of Atlantic Salmon Trust

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

TABLE OF CONTENTS

1.0 INTRODUCTION ............................................................................ 8 1.1 THE DERG CATCHMENT .......................................................................................8 FIG 1.1 UPPER SECTION OF THE RIVER DERG ........................................................................... 9 FIG 1.11 FOYLE AND CARLINGFORD CATCHMENTS .................................................................. 10

1.2 ATLANTIC SALMON AND SEA TROUT ...................................................................11 1.3 NON SALMONID FISH SPECIES ............................................................................11 FIG 1.3 SAMPLE OF FISH FROM THE FOYLE ESTUARY .............................................................. 11

2.0 ATLANTIC SALMON STOCKS ................................................... 12 2.1 REDD COUNTS ..................................................................................................12 TABLE 2.1 REDD COUNTS FOR FOYLE SYSTEM AND DERG CATCHMENT 2003/04 – 2007/08 ..... 12 FIG 2.11 REDD COUNTS FOR FOYLE SYSTEM AND DERG CATCHMENT 2003/04 – 2007/08........ 12

2.2 JUVENILE ABUNDANCE ......................................................................................13 TABLE 2.2 LOUGHS AGENCY SEMI-QUANTITATIVE ELECTROFISHING CLASSIFICATION SYSTEM ... 14 FIG 2.21 RIVER DEG (FOYLE AREA) CATCHMENT FRY INDEX 2001-2007 .................................. 14 FIG 2.22 SITE CLASSIFICATIONS FOR DERG CATCHMENT SALMON ............................................ 14 FIG 2.23 DERG CATCHMENT SALMON ...................................................................................... 15 FIG 2.24 DERG CATCHMENT SALMON ...................................................................................... 15 FIG 2.25 SALMON 0+ ELECTROFISHING SITE CLASSIFICATION 2007.......................................... 16 FIG 2.26 SALMON 0+ ELECTROFISHING SITE CLASSIFICATION 2006.......................................... 17 FIG 2.27 SALMON 0+ ELECTROFISHING SITE CLASSIFICATION 2005.......................................... 18 FIG 2.28 SALMON 0+ ELECTROFISHING SITE CLASSIFICATION 2004.......................................... 19 FIG 2.29 SALMON 0+ ELECTROFISHING SITE CLASSIFICATION 2003.......................................... 20

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

3.0 TROUT STOCKS ......................................................................... 21 FIG 3 ELECTROFISHING SURVEY AND TROUT PARR .................................................................. 21 FIG 3.1 RIVER DERG (FOYLE AREA) CATCHMENT FRY INDEX 2001-2007. ................................. 21 FIG 3.11 SITE CLASSIFICATIONS FOR DERG CATCHMENT TROUT .............................................. 21 FIG 3.12 DERG CATCHMENT TROUT ........................................................................................ 22 FIG 3.13 DERG CATCHMENT TROUT ........................................................................................ 22 FIG 3.14 TROUT 0+ ELECTROFISHING SITE CLASSIFICATION 2007 ............................................ 23 FIG 3.15 TROUT 0+ ELECTROFISHING SITE CLASSIFICATION 2006 ............................................ 24 FIG 3.16 TROUT 0+ ELECTROFISHING SITE CLASSIFICATION 2005 ............................................ 25 FIG 3.17 TROUT 0+ ELECTROFISHING SITE CLASSIFICATION 2004 ............................................ 26 FIG 3.18 TROUT 0+ ELECTROFISHING SITE CLASSIFICATION 2003 ............................................ 27

4.0 MARINE SURVIVAL .................................................................... 28 TABLE 4 MARINE SURVIVAL RATES FOR THE RIVER BUSH OF 1SW GRILSE .............................. 28 FIGURE 4B PICTURE FROM THE IRISH RESEARCH VESSEL CELTIC EXPLORER .......................... 30 FIGURE 4C ROTARY SCREW TRAP IN POSITION ON THE RIVER FAUGHAN. ................................. 30 TABLE 4.1 NUMBERS AND AVERAGE WEIGHT AND LENGTH OF SALMON SMOLTS. ....................... 31 TABLE 4.12 RECAPTURE DATA FROM RIVER FAUGHAN CWT PROGRAMME............................... 31 FIGURE 4D SALMON SMOLT RUN TIMING .................................................................................. 31 TABLE 4.13 AGE CLASS OF SALMON SMOLTS MIGRATING ......................................................... 32 FIG 4.14 FROM TOP TO BOTTOM, ATLANTIC SALMON SMOLTS. ................................................. 32

5.0 ADULT ABUNDANCE ................................................................. 33 5.1 RECREATIONAL FISHERIES .................................................................................33 TABLE 5 DECLARED ROD CATCH RETURNS FOR SALMON AND SEA TROUT. ................................ 33 TABLE 5.1 DECLARED CATCH FROM THE DERG CATCHMENT ................................................... 33

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

5.2 COMMERCIAL FISHERIES ....................................................................................34 TABLE 5.2 DECLARED CATCH FROM THE COMMERCIAL SALMON FISHERIES 1998-2007............. 34 FIG 5.21 COMMERCIAL FISHING .............................................................................................. 35

5.3 COUNTERS ........................................................................................................35 FIG 5.31 FISH COUNTING FACILITIES AT SION MILLS ON THE RIVER MOURNE............................ 35 TABLE 5.32 SION MILLS FISH COUNTER FIGURES 2002-2007 .................................................. 35 FIG 5.33 MONTHLY FISH COUNT AT SION MILLS IN 2007 .......................................................... 36 FIG 5.34 MONTHLY FISH COUNTS ........................................................................................... 36

5.4 CONSERVATION LIMITS/SPAWNING TARGETS .......................................................37 TABLE 5.41 UPSTREAM OF SION MILLS ESTIMATED EGG DEPOSITION 2002-2007..................... 37

6.0 HABITAT MONITORING ............................................................. 38 FIG 6 LIFE CYCLE UNIT DEPICTING THE TYPE OF HABITAT FOUND IN SPAWNING ......................... 38 FIG 6.11 HABITAT OVERVIEW KEY FOR THE DERG CATCHMENT ................................................ 39 FIG 6.12 DERG CATCHMENT HABITAT SURVEY MAP 1............................................................... 40 FIG 6.13 DERG CATCHMENT HABITAT SURVEY MAP 2............................................................... 41 FIG 6.14 DERG CATCHMENT HABITAT SURVEY MAP 3............................................................... 42 FIG 6.15 DERG CATCHMENT HABITAT SURVEY MAP 4............................................................... 43 FIG 6.16 DERG CATCHMENT HABITAT SURVEY MAP 5............................................................... 44 FIG 6.17 DERG CATCHMENT HABITAT SURVEY MAP 6............................................................... 45

7.0 LAND USE ................................................................................... 46 FIG 7 DERG CATCHMENT LAND USE CLASSIFICATION ............................................................... 46 FIG 7.1 DERG CATCHMENT LAND USE CLASSIFICATION MAP ..................................................... 47

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

8.0 WATER QUALITY ....................................................................... 48 FIG 8.0 LOUGHS AGENCY CHEMICAL WATER QUALITY TESTING IN THE LABORATORY ................. 48 FIG 8.01 DERG CATCHMENT AVERAGE SUSPENDED SOLIDS RESULTS 2007 .............................. 51 FIG 8.02 DERG CATCHMENT AMMONIA RESULTS 2007. VALUES ARE IN MG/L ............................ 52 FIG 8.03 DERG CATCHMENT PHOSPHOROUS RESULTS 2007. VALUES ARE IN MG/L ................... 53 FIG 8.04 DERG CATCHMENT BIOLOGICAL OXYGEN DEMAND (BOD) RESULTS 2007.................. 54 FIG 8.05 DERG CATCHMENT BIOLOGICAL MONITORING WORKING PARTY RESULTS 2007 ......... 55 TABLE 8.1 CHEMICAL GQA CLASS LIMITING CRITERIA .............................................................. 56 TABLE 8.2 BIOLOGICAL GQA CLASS LIMITING CRITERIA ........................................................... 57

8.1 FAVOURABLE CONDITION TABLES, TARGET LEVELS ..............................................58 TABLE 8.3 FAVOURABLE CONDITION TARGETS FOR ATLANTIC SALMON ..................................... 58 FIG 8.07 CHEMICAL GENERAL QUALITY ASSESSMENT (GQA) DERG CATCHMENT 2006............ 59 FIG 8.08 BIOLOGICAL GENERAL QUALITY ASSESSMENT (GQA) FAUGHAN CATCHMENT 2006 ... 60

9.0 CONSERVATION AND PROTECTION ....................................... 61 TABLE 9 BREAKDOWN OF CONSERVATION AND PROTECTION DUTIES, DERG CATCHMENT .......... 61 TABLE 9.01 SEIZED NETS, SALMON, ROD/REELS AND VEHICLES IN THE FOYLE SYSTEM ............ 61

9.1 HABITAT IMPROVEMENT WORKS .........................................................................61 FIGURE 9.10 ARTIFICIAL IMPOUNDMENT AT THE OUTFLOW OF LOUGH DERG............................. 62 FIGURE 9.11 SECONDARY IMPOUNDMENT ON THE RIVER DERG ............................................... 62 FIGURE 9.12 DEWATERED STRETCH OF RIVER DERG BELOW IMPOUNDMENTS.......................... 63 FIGURE 9.13 GOOD QUALITY SALMONID NURSERY HABITAT DOWNSTREAM ............................... 63 FIGURE 9.14 SOLUTION, OFFSET BOULDER WEIR..................................................................... 64 FIGURE 9.15 OFFSET BOULDER WEIR ..................................................................................... 64 FIGURE 9.16 OFFSET BOULDER WEIR. FIGURE 9.17 LOCATION OF SECONDARY IMPOUNDMENT. FIGURE 9.18 DEFLECTOR GROYNE. 2006 ............................................................................... 65

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

9.2 FINFISH AQUACULTURE......................................................................................66 FIGURE 9.2 SMOLT REARING FACILITY ON THE UPPER RIVER DERG NEAR LOUGH DERG........... 66

10.0 ENVIRONMENTAL ISSUES ...................................................... 66 11.0 DESIGNATED AREAS .............................................................. 68 12.0 GENETIC STUDY ...................................................................... 69 13.0 POLLUTION MONITORING ...................................................... 70 14.0 FISHERY OFFICERS FAUGHAN AREA REPORT 2007.......... 70 14.1 FISHERY OFFICERS REPORT .............................................................................70

15.0 ACTIONS FOR 2008.................................................................. 72 15.1 FOYLE AND CARLINGFORD AREAS ONGOING ACTIONS FOR 2008 .......................72 15.2 DERG CATCHMENT SPECIFIC ACTIONS FOR 2008 ..............................................73

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

River Derg and Tributaries Catchment Status Report 1.0

INTRODUCTION

The River Derg and tributaries catchment status report has been updated in 2008 to include results and reviews for 2007. This catchment status report introduces the major issues affecting the fishery resources of the River Derg and its tributaries. It is anticipated that circulation of this report will encourage debate between stakeholders and the Loughs Agency. Feedback would be welcomed and will contribute towards future reports. The fisheries of the Foyle and Carlingford systems are of great environmental, social and economic importance. It is within this context that the Loughs Agency aims to manage, conserve, protect, improve and develop the inland fishery resources, preserving native biodiversity and contributing towards the sustainable development of the catchments. The River Derg and tributaries catchment status report provides background information on the aquatic environment within the Derg catchment, presents the results of survey work carried out by the Loughs Agency, disseminates catch statistics and outlines planned action. The primary fish species present within the Derg catchment include Atlantic salmon (Salmo salar L.), Trout (Sea Trout and resident Brown Trout) (Salmo trutta L.), Sea Lamprey (Petromyzon marinus), River/Brook Lamprey (Lampetra sp.), European Eel (Anguila anguila L.), Pike (Esox lucius) and Perch (Perca fluviatilis). Flounder (Platichthys flesus L.), Twaite Shad (Alosa fallax Lacépède), Grey Mullet (Chelon labrosus) and European Smelt (Osmerus eperlanus L.) are present within the Foyle estuary. Activities that have the potential to contribute negatively on the fishery resources and the habitats that support these populations are outlined and remedial activities presented. 1.1

The Derg Catchment

The River Derg and tributaries have a channel length of approximately 60km and a catchment area of 438km2. The rivers generally flow in an easterly direction from the Killeter uplands through the town of Castlederg to its confluence with the River Mourne. The main River Derg drains Lough Derg and the surrounding catchment. The primary tributaries of the Derg catchment include the Mournebeg River, Leaghany River and Glendergan River. The Derg valley is broad in nature and is enclosed by an undulating landscape of rounded hills. The Derg catchment has many shallow tributary valleys with gently undulating landform. In places low embankments enclose the main River Derg to protect agriculturally productive land from flooding,

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

this is predominantly restricted to the lower end of the catchment where the land is more suited to intensive agricultural use. Extensive patches of peaty marsh, scrubby fen woodland and open moorland dominate the upland areas of the catchment. Stone walls and hedgerows enclose field boundaries and drainage ditches. There is little forestry in the lower Derg valley which is in stark contrast to the upper Derg valley and Killeter uplands where extensive commercial coniferous forestry plantations are maintained. The coniferous forestry plantations within the Derg catchment create hard angular lines across the landscape and overshadow many of the burns and tributaries of the upper Derg catchment. There are large areas of cut over blanket bog and large expanses of intact bog of national and international importance within the catchment. The Derg catchment has a number of important mesotrophic lakes (middle level of nutrients) and oligotrophic lakes (low level of nutrients). The Derg catchment is a cross border river catchment with the headwaters and Lough Derg in the Republic of Ireland and the main river and tributaries predominantly in Northern Ireland.

Fig 1.1 Upper section of the River Derg. Note large scale coniferous forestry plantations

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Fig 1.11 Foyle and Carlingford Catchments illustrating the main rivers of the systems and highlighting the River Derg and Tributaries River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

1.2

Atlantic Salmon and Sea Trout

Salmon and Sea Trout are referred to as being anadromous meaning that they migrate between the freshwater and marine environments returning to freshwater to reproduce. This complex life history exposes them to varied environmental pressures and recreational and commercial fisheries. Adult Atlantic salmon return to their natal rivers where spawning takes place. Sea trout also demonstrate an ability to return to their natal river but their homing instinct may not be as strong as those of the Atlantic salmon. After the eggs hatch the juveniles (initially referred to as fry and then parr) remain in freshwater for up to three years. Smoltification is the physiological adaptation which occurs when the juvenile salmon change from the parr stage (freshwater phase) to the smolt stage (marine phase). In the Foyle system this can occur after one, two or three years. Most Foyle salmon (referred to as post smolts) will remain after smoltification in the North Atlantic for one year and are referred to on their return to the coast and rivers as grilse. Salmon which stay at sea for longer than one year are referred to as multi sea winter (MSW) salmon. 1.3

Non Salmonid Fish Species

As highlighted earlier populations of other non salmonid fish species occur within the Derg catchment. At present monitoring is targeted at salmonid species however with obligations under the Water Framework Directive it is envisaged that other non salmonid fish species will be monitored more closely in the future. Fish species presence and abundance can act as a good environmental/ecological indicator demonstrating the ability of the aquatic habitat to support a diverse array of native species. Populations of the European Eel, River/Brook and Sea Lamprey form an important part of the native fisheries biodiversity of the Derg catchment. Non native fish species including Pike and Perch have colonised still waters within the Derg catchment. Maintaining high standards of water quality and appropriate habitat for these species is essential for the overall health of the aquatic ecosystem.

Fig 1.3 Sample of fish from the Foyle Estuary

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

2.0

ATLANTIC SALMON STOCKS

In order to describe the status of salmon stocks each of the following points need to be considered: • • • • • 2.1

Redd Counts Juvenile abundance Marine survival Adult abundance Exploitation

Redd Counts

Redds are spawning nests created by salmon or trout. Differentiation between salmon and trout redds can be made as salmon redds tend to be larger in size and trout tend to spawn earlier than salmon within the Foyle system. Research within the Foyle system using extensive annual redd count data has highlighted a good relationship between the number of redds and the total annual catch of salmon. Table 2.1 shows redd count data for the Derg catchment and the Foyle system. Water flow is of significance when monitoring redds as in high water conditions the ability to see and count redds in rivers is impaired. Figure 2.11 outlines redd counts within the Foyle area and the Derg catchment. Area

2003/04

2004/05

2005/06

2006/07

2007/08

Foyle System

3163

2478

5354

*1338

3039

Derg Catchment

536

498

*N/A

567

Derg as a % of Foyle

*N/A

Table 2.1 Redd counts for Foyle system and Derg catchment 2003/04 – 2007/08. *Note 2007/08 had extremely poor water conditions for redd counting. N/A denotes that no redd count was conducted due to water conditions.

Derg Catchment

6000

Foyle System Number of Redds

5000 4000 3000 2000 1000 0 2003/4

2004/5

2005/6

2006/7

2007/8

Year

Fig 2.11 Redd counts for Foyle system and Derg catchment 2003/04 – 2007/08

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

2.2

Juvenile Abundance

Within the Loughs Agency jurisdiction trends in abundance of juvenile salmonids are monitored by annual semi-quantitative electrofishing surveys. The numbers, age and species of fish captured during five minute timed electrofishing surveys are compared with previous years data allowing for change to be monitored, facilitating suitable fishery management practices to be implemented. In 2007 a total of 487 sites were semi-quantitatively electrofished within the Foyle system. The results for each site for salmon and trout are classified as excellent (>25 fish), good (15-24 fish), fair (5-15 fish), poor (1-4 fish) and absent (0 fish), Table 2.2. Figures 2.21, 2.22, 2.23, 2.24, 2.25, 2.26, 2.27, 2.28 and 2.29 outline the salmon 0+ electrofishing results and site classifications for the Derg catchment over recent years. Semi-quantitative electrofishing was developed to monitor 0+ salmonids (fry/young of the year). In order to quantify the abundance of 1+ salmonids (parr and older) fully quantitative electrofishing surveys are required which can be used to calculate fish densities within a defined area. Rivers and tributaries with good environmental quality are more likely to support good populations of each year class. Fish populations can vary considerably over time and location, it is therefore necessary to monitor the populations over a period of years to highlight meaningful trends before considering remedial activities such as habitat improvement works. These trends are being continually monitored by the Loughs Agency and the most appropriate management options considered. There are a variety of reasons why electrofishing sites may be perceived to be under producing, these can include, lack of suitable juvenile habitat, the presence of impassable obstacles to migratory fish species on lower sections of a tributary, pollution, inconsiderate channel maintenance, tunnelling by bank side vegetation, stream gradient and poor forestry practices etc. The critical point is to recognise the major factors at play and to investigate all possible reasons for underproduction accepting that there may be inherent reasons as to why production may not be improved upon in certain areas. When the same areas are surveyed for other non salmonid species it may be discovered that they provide habitat more suited to these species. Habitat improvement works and the rational behind them are discussed in greater detail later. Obligations under the Water Framework Directive will drive future quantitative surveys of both salmonid and non salmonid species under proposed Surveillance, Operational, Investigative and Protected Area monitoring programmes.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Symbol

Grade

Number of 0+ Salmonids >25

Excellent Good

15-24

Fair

5-14

Poor

1-4

Absent

Table 2.2 Loughs Agency semi-quantitative electrofishing classification system for 0+ salmon and trout Mean Salmon 0+

25 Mean Number of Fry/5 min fishing

Mean Trout 0+ Mean Salmon & Trout 0+ 20

0 2001

2002

2003

2004

2005

2006

2007

Year

Fig 2.21 River Deg (Foyle area) catchment fry index 2001-2007. Note number of sites surveyed has fluctuated annually from 22 in 2001 to 44 in 2007, the number of sites surveyed has stabilised since 2003. Salmon Fry 2003-2007

Absent

Classification

Poor 2007 Fair

2006 2005 2004

Good

2003 Excellent

Proportion of Sites %

Fig 2.22 Site classifications for Derg catchment salmon 0+ electrofishing as a percentage of all sites fished, 2003 – 2007

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Salmon Fry 2007

16% 29% Excellent

16%

Good Fair Poor Absent

16%

23%

Fig 2.23 Derg catchment salmon 0+ electrofishing site classifications as a percentage of all sites fished in 2007

Salmon Fry 2006

13% 28% 11% Excellent Good Fair Poor Absent

31%

17%

Fig 2.24 Derg catchment salmon 0+ electrofishing site classifications as a percentage of all sites fished in 2006

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

( !

( ! ( !

! ( ( ! ! (

( !

( ! ( !

( ( ! !

( ! !! ( (

( !

( ! ( !

( ! ( ! ! (

( ! ( !

( !

( ! ( !

( !

( ! ! (

( !

( ! ( !

( (! ! ! ( ( ! ( !

( ! ( !

Legend ! None (0) ( ( Poor (1 - 4) ! ( Fair (5 - 14) ! ( Good (15 - 24) ! ( Excellent (25 - 200) !

Derg Electrofishing Results for Salmon 0+ 2007

4 Kilometers

Fig 2.25 Salmon 0+ electrofishing site classification 2007

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Fig 2.26 Salmon 0+ electrofishing site classification 2006

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Fig 2.27 Salmon 0+ electrofishing site classification 2005

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Fig 2.28 Salmon 0+ electrofishing site classification 2004

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Fig 2.29 Salmon 0+ electrofishing site classification 2003 River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

3.0

TROUT STOCKS

Annual trends in the populations of juvenile trout are also monitored within the Loughs Agency jurisdiction using the same methodology and classification system as those employed for salmon. The semi quantitative electrofishing results for trout fry in the Derg catchment and site classifications are displayed in Figs 3.1, 3.11, 3.12, 3.13, 3.14,3.15, 3.16 and 3.17.

Mean Number of Fry/5 min fishing

Fig 3 Electrofishing survey and trout parr Mean Salmon 0+

Mean Trout 0+ Mean Salmon & Trout 0+

20 15 10 5 0 2001

2002

2003

2004

2005

2006

2007

Year

Fig 3.1 River Derg (Foyle area) catchment fry index 2001-2007. Note number of sites surveyed has fluctuated annually from 22 in 2001 to 44 in 2007, the number of sites surveyed has stabilised since 2003. Trout Fry 2003-2007

Classification

Absent Poor 2007 Fair

2006 2005

Good

2004 2003

Excellent 0

Proportion of Sites %

Fig 3.11 Site classifications for Derg catchment trout 0+ electrofishing as a percentage of all sites fished, 2002 – 2006

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Trout Fry 2007

0% 0% 11%

41%

Excellent Good Fair Poor Absent 48%

Fig 3.12 Derg catchment trout 0+ electrofishing site classifications as a percentage of all sites fished in 2007

Trout Fry 2006

0% 2% 20% Excellent Good Fair Poor 54%

Absent 24%

Fig 3.13 Derg catchment trout 0+ electrofishing site classifications as a percentage of all sites fished in 2006

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

( !

( ! ( !

! ( ( !

( !

( ! ( !

( !

( ! ( !

( ( ! !

! ( (! ! (

( !

( ! ( !

( ! ( ! ! (

( ! ( !

( !

( ! ( !

( !

( ! ! (

( !

( ! ( !

( !! ( ( ! ( ! ! (

( ! ( !

Legend ! None (0) ( ( Poor (1 - 4) ! ( Fair (5 - 14) ! ( Good (15 - 24) ! ( Excellent (25 - 200) !

Derg Electrofishing Results for Trout 0+ 2007

4 Kilometers

Fig 3.14 Trout 0+ electrofishing site classification 2007

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Fig 3.15 Trout 0+ electrofishing site classification 2006

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Fig 3.16 Trout 0+ electrofishing site classification 2005

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Fig 3.17 Trout 0+ electrofishing site classification 2004

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Fig 3.18 Trout 0+ electrofishing site classification 2003 River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

4.0

MARINE SURVIVAL

The numbers of salmon that survive to return to the freshwater environment are greatly influenced by conditions in the marine environment. Climate change leading to changes in sea surface temperatures, prey abundance, high seas fishing, marine pollution, sub lethal levels of pollution and predation all have an effect on the Atlantic salmon and indeed other migratory fish species chances of survival. Marine survival trends are monitored on a number of index rivers in the North East Atlantic where total trapping facilities are available for both migrating juvenile and adult populations. Total trapping allows for an accurate count of all migrant smolts (total freshwater production) and returning adults to be made and therefore an accurate estimate of marine survival. These projects are facilitated by the use of Coded Wire Tags (CWT). Coded wire tags are small (2-3mm long) micro tags that are injected automatically by a CWT device into the snout cartilage of anaesthetised fish remaining there for the duration of the life of the fish. CWT fish also have their adipose fin (small fin between the dorsal fin and caudal fin (tail fin)) removed so that they can be identified in the various fisheries that may intercept them. In Ireland a comprehensive screening programme is conducted at all major landing ports and markets. This programme is important in monitoring the effect of the salmon fisheries on salmon stocks from rivers both within and outside of the island of Ireland. Trends in marine survival for the River Bush (nearest index river to the Foyle system) confirm patterns observed elsewhere on the southern stocks of North Eastern Atlantic salmon, which indicate that marine survival can be variable between stocks and years. In the River Bush marine survival has decreased considerably over recent years as outlined in Table 4. Year of Smolt Cohort Pre 1996 2002 2003 2004 2005 2006

Year of Returning 1SW Grilse Pre 1996 2003 2004 2005 2006 2007

Marine Survival % Circa 20% 5.9 4.3 4.6 4.2 13.0

Table 4 Marine survival rates for the River Bush of 1SW grilse (after exploitation at sea) pre 1996 and 2002-2006 smolt cohort. Data supplied by Agri Food and Bioscience Institute, River Bush Salmon Research Station

The figures outlined in table 4 are mirrored by those for other index rivers monitoring the southern stocks of North Eastern Atlantic salmon populations. These figures suggest that salmon are facing increased pressure for survival at sea. A major new international research project called SALSEA - Merge has been developed by scientists from the North Atlantic Salmon Conservation Organisation (NASCO) parties and its research wing the International Atlantic Salmon Research Board (IASRB). There are twenty

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consortium members in total including the Loughs Agency. SALSEA aims to monitor how Atlantic salmon use the ocean; where they go; how they use ocean currents, and the ocean’s food resources, and what factors influence migration and distribution at sea. Research cruises commenced in 2008 to collect the necessary data to answer the questions listed above. Over 426 post smolts were caught by the two Irish cruises and 363 post smolts caught by the Faroese in the areas highlighted below. Further information and project details can be found at: http://www.nasco.int/sas/salsea.htm

Fig 4 Proposed marine survey areas for salmon in 2008

Fig 4a RV Celtic Explorer

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Figure 4b Picture from the Irish Research Vessel Celtic Explorer taken during the second SALSEA research cruise 16-24th May 2008

Since 2003 partial smolt trapping including CWT tagging has been conducted in the Faughan catchment using a rotary screw trap, Fig 4.

Figure 4c Rotary screw trap in position on the River Faughan directly below the fish pass at Campsie barrage.

Smolt trapping can have a number of objectives including the monitoring of both salmonid and non salmonid species. Sampling of the age composition, obtaining information on run timing and recording length/weight data is conducted in tandem with the tagging programme. As mentioned above total counts of migrating smolts can be made on rivers. Where this is unfeasible due to the absence of total trapping facilities, total smolt migration can be estimated by means of a mark-recapture experiment. In 2004 an estimate of total smolt production for the Faughan catchment was made by a mark-recapture study resulting in a minimum run size estimate of 33,854 migrating salmon smolts. The estimate was a minimum due to a River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

number of high water events that prevented the smolt trap from fishing for a period of time during the peak smolt migration period. Tables 4.1 and 4.12 outline numbers of salmon smolts tagged from 2003-2006 and recapture data for 2003 and 2004. Year

No of Salmon Smolts Tagged 2113 2500 2210 1025 2062

2003 2004 2005 2006 2007

Average Length (mm) 149 134 133 133 135

Average Weight (g) 33.45 24.6 23.6 25.36 27.1

Table 4.1 Numbers and average weight and length of salmon smolts tagged on the River Faughan 2003-2007. Coded Wire Tagging equipment was purchased by the Loughs Agency in 2005 with funding secured from the European Regional Development Fund through the INTERREG IIIA Programme, administered by the Environment and Heritage Service, on behalf of the Department of Environment.

Year Tagged 2003

Year Recaptured Numbers Recaptured 2004 12

2004

2005

2006

Recapture Location Greencastle, Burtonport, Malin Head, Belmullet and Torr Head Greencastle, Malin Head, Donegal and Galway Bay Greencastle

Table 4.12 Recapture data from River Faughan CWT programme. Data for fish tagged in 2006 and recovered in 2007 will not be available until 2008.

600 2004

500

2005

400

2006

300

2007

200 100 23-May

21-May

19-May

17-May

15-May

13-May

11-May

09-May

07-May

05-May

03-May

01-May

29-Apr

27-Apr

25-Apr

23-Apr

21-Apr

19-Apr

17-Apr

15-Apr

13-Apr

11-Apr

09-Apr

07-Apr

05-Apr

0 03-Apr

Number of Salmon Smolts Trapped

River Faughan

Date

Figure 4d Salmon smolt run timing and abundance from rotary screw trap sub sample, River Faughan 2004-2007. Breaks in data are due to closure of trap during high water conditions

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

In 2004 a detailed examination was carried out on the age class of migrating salmon smolts in the Faughan catchment, Table 4.13. Age at Smolting 1 2 3

% 13 83 4

Table 4.13 Age class of salmon smolts migrating from the Faughan catchment in 2004

Fig 4.14 From top to bottom, Atlantic salmon smolts from the Faughan Catchment, brook lamprey, river lamprey and sea lamprey also caught in the River Faughan smolt trap.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

5.0

ADULT ABUNDANCE

Adult Atlantic salmon abundance is assessed in three ways: directly by using commercial netting/recreational rod catches and fish counters and indirectly by reference to conservation limits/spawning targets. Using catch data as a measure of population status is a well established and extensively used technique. In the Foyle system annual commercial and recreational catch data has been recorded since the establishment of the Foyle Fisheries Commission in 1952, with some data available before this period. The relationship between catch and stock is complex and care should be applied in interpretation. A more precise measure of catch incorporates fishing effort (number of licences issued or the amount of time fished) and is referred to as catch per unit effort (CPUE). 5.1 Recreational Fisheries One problem encountered when analysing catch data is unreported catch. All recreational fishers are required by law to make catch returns. This information facilitates management decision making and therefore it is vitally important that all catch returns are accurate and made promptly at the seasons end. Year

Declared Rod Catch Salmon

2000 2001 2002 2003 2004 2005 2006 2007

723 3188 5117 1844 2285 4084 3476 4929

Declared Rod Catch Sea Trout >40cm 417 450 1010 361 75 413 469 379

Returns as a % of Licences Issued 2.55 17.68 27.93 15.5 13.99 25.77 37 22.11

Table 5 Declared rod catch returns for salmon and sea trout >45cm in the Foyle and Carlingford areas. Note figures include the Clanrye and Whitewater in the Carlingford area from 2001 onwards. Carcass tagging was introduced in 2001.

Year

Declared Catch Derg Catchment Salmon

2002 2003 2004 2005 2006 2007

614 156 84 324 157 310

Declared Catch Derg Catchment Sea Trout >40cm 14 3 0 6 10 7

Table 5.1 Declared catch from the Derg catchment for salmon and sea trout 2001-2007

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Fig 5.11 Recreational fisher

5.2

Commercial Fisheries

Commercial fisheries have traditionally operated within the Foyle sea area, Lough Foyle and tidal River Foyle. The drift net and draft net fisheries as well as the rod fisheries have been closely regulated with a real time management regime in place to monitor the numbers of fish migrating up key rivers. If predetermined numbers of fish have not been counted by the strategically placed electronic fish counters at Sion Mills weir (River Mourne), Campsie Barrage (River Faughan) and the Plumb Hole (River Roe) then specified closures of the commercial and/or recreational fisheries are enforced. In 2007 new regulations were introduced to reduce the number of commercial nets operating within the Foyle area and all mixed stock interceptory drift nets seaward of Lough Foyle were curtailed. This decision was made to comply with the EU Habitats Directive, similar curtailment of mixed stock fisheries were introduced in the Republic of Ireland. Within the Foyle area this was achieved through a voluntary hardship scheme. 18 out of 112 drift nets remain in Lough Foyle, those remaining have been reduced in size from 900m to 500m and 10 out of 50 draft nets remain. This represents a significant reduction of netting effort. Regulations were also introduced to limit the numbers of fish which could be retained by the recreational rod fishery throughout the Foyle and Carlingford areas. Year

Drift Catch

Draft Catch

1999 2000 2001 2002 2003 2004 2005 2006 *2007

15397 22333 13500 28851 15741 12800 13391 6160 2598

7893 10339 9476 11917 16991 9490 12143 6031 2774

Total Drift and Draft 23290 32672 22976 40768 32732 22290 25534 12191 5372

Table 5.2 Declared catch from the commercial salmon fisheries 1998-2007. Note 100% rate of catch returns. *Reduced numbers of commercial nets operating in the Foyle area from 2007

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Fig 5.21 Commercial Fishing. Draft netting on the tidal River Foyle and drift netting at sea

5.3

Counters

Within the Foyle system a number of river catchments have electronic fish counting facilities that provide estimates on the run timing and abundance of fish >45cm. A time series of counts for the Sion Mills fish counting station on the River Mourne is outlined in table 5.32. The Sion Mills fish counting station counts fish destined for all rivers located upstream of this point including the Derg catchment.

Fig 5.31 Fish counting facilities at Sion Mills on the River Mourne

Year 2002 2003 2004 2005 2006 2007

Number of fish >45cm 12991 12129 10270 9397 9926 *3714

Table 5.32 Sion Mills fish counter figures 2002-2007. *Note low count in 2007 was influenced by high water levels during peak run timing during June and July. Sion Mills is a partial counter and does not cover the entire length of the weir. In high water levels as experienced in 2007 significant numbers of fish can bypass the counting channels. Methods to reduce this are being investigated as part of the Fish Counter Programme Review, commissioned in 2008.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Sion Mills (River Mourne) 1200

Number of Fish >45cm

1000

800

600

400

200

0 Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Month

Fig 5.33 Monthly fish count at Sion Mills in 2007

Fish Counts 2007 Faughan Roe

2500

Mourne Finn

Number of Fish >45cm

2000

1500

1000

500

0 Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Month

Fig 5.34 Monthly fish counts on the River Faughan, River Roe, River Finn and River Mourne at Sion Mills in 2007

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

5.4

Conservation Limits/Spawning targets

Another way to assess adult salmon stock status is to monitor run sizes on rivers and to compare them with predefined reference points called conservation limits. In the Foyle system the conservation limits define a level of spawning that optimises the sustainable catch by commercial and recreational fisheries. If exploitation rates increase above the sustainable catch levels the catch may increase in the short-term but the stock will eventually reduce. Conservation limits demarcate the undesirable spawning stock level at which recruitment would begin to decline significantly (NASCO). The real time management regime incorporating the setting of management targets and spawning targets implemented in the Foyle aims to manage the fisheries and spawning populations in a sustainable manner. The management and spawning targets are set for the various river catchments based on the amount and quality of nursery habitat present. River habitat surveys are carried out along each stretch of river and graded according to the type and quality. Egg deposition levels are set according to the quality grading of each section of nursery habitat. There are four grades of nursery habitat, however for the purpose of setting egg deposition levels only grades 1-3 are utilised. Grade 1 denotes the best quality habitat. The egg deposition rate/carrying capacity is set as follows. Grade 1 = 10 eggs per m², grade 2 = 5 eggs per m² and grade 3 2.5 eggs per m². The total number of eggs is calculated by multiplying the area of each grade of nursery habitat by the appropriate density of eggs per m². 25% is deducted from the management target allowing for loss of salmon by angling (15%) and poaching and predation (10%). The remaining figure is referred to as the conservation limit/spawning target. Once the number of eggs required for each river has been established this can be converted to a total number of fish required to achieve the management targets and conservation limit/spawning targets. The average fecundity (number of eggs produced per female) of Foyle salmon has been estimated at 2500 and the ratio of female to male salmon estimated at 60:40. When combined with the amount of nursery habitat of the various grades this equates to the conservation limit/spawning target. A management target of 8000 adult Atlantic salmon has been set for above Sion Mills, this equates to a conservation limit/spawning target of over 6000 salmon or 9,000,000 eggs. Year 2002 2003 2004 2005 2006 *2007

No of Fish Across Counter 12991 12129 10270 9397 9926 *3714

Estimated Egg Deposition 14,614,875 13,645,125 11,553,750 10,571,625 11,166,750 *4,178,250

Table 5.41 Upstream of Sion Mills estimated egg deposition 2002-2007. *Note 2007 figures are a minimum estimate of escapement due to high water levels resulting in the bypassing of the Sion Mills counting channels.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

6.0

HABITAT MONITORING

The Loughs Agency has carried out extensive habitat surveys on all the major rivers and tributaries within the Foyle and Carlingford catchments. Habitat surveys are carried out on foot. Although time consuming this is at present the best method for classifying the various grades of habitat. Habitat is classified into one of three life cycle units Fig 6, the presence and order of which is essential to the productive capacity of a salmonid river. Other non salmonid species also benefit from diverse in-channel habitat. The life cycle unit categories include spawning, nursery and holding habitat. Each category is then graded on a scale of 1-4, 1 representing the best quality attainable and 4 the worst. Other data collected during these surveys include channel width and impassable barriers to migratory fish species.

Fig 6 Life cycle unit depicting the type of habitat found in spawning, nursery and holding zones

Fig 6.1 Examples of spawning, nursery and holding habitat

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

1 3 2 6 4 5

Derg Habitat Overview

4 Kilometers

Fig 6.11 Habitat overview key for the Derg catchment

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Habitat Survey Ungraded 1 Nursery 2 Nursery 3 Nursery 4 Nursery 1 Holding 2 Holding 3 Holding 4 Holding 1 Spawning 2 Spawning 3 Spawning 4 Spawning

0.25

0.5

0.75

1 Kilometers

Derg Habitat Survey 1

Fig 6.12 Derg catchment habitat survey map 1 River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Habitat Survey Ungraded 1 Nursery 2 Nursery 3 Nursery 4 Nursery 1 Holding 2 Holding 3 Holding 4 Holding 1 Spawning 2 Spawning 3 Spawning 4 Spawning

0.25

0.5

0.75

1 Kilometers

Derg Habitat Survey 2

Fig 6.13 Derg catchment habitat survey map 2 River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Habitat Survey Ungraded 1 Nursery 2 Nursery 3 Nursery 4 Nursery 1 Holding 2 Holding 3 Holding 4 Holding 1 Spawning 2 Spawning 3 Spawning 4 Spawning

Mourne Beg Habitat Survey 3 (Derg Catchment)

0.25

0.5

0.75

1 Kilometers

Fig 6.14 Derg catchment habitat survey map 3 River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Habitat Survey Ungraded 1 Nursery 2 Nursery 3 Nursery 4 Nursery 1 Holding 2 Holding 3 Holding 4 Holding 1 Spawning 2 Spawning 3 Spawning 4 Spawning

Derg Habitat Survey 4

0.25

0.5

0.75

1 Kilometers

Fig 6.15 Derg catchment habitat survey map 4 River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Habitat Survey Ungraded 1 Nursery 2 Nursery 3 Nursery 4 Nursery 1 Holding 2 Holding 3 Holding 4 Holding 1 Spawning 2 Spawning 3 Spawning 4 Spawning

Derg Habitat Survey 5

0.25

0.5

0.75

1 Kilometers

Fig 6.16 Derg catchment habitat survey map 5 River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Habitat Survey Ungraded 1 Nursery 2 Nursery 3 Nursery 4 Nursery 1 Holding 2 Holding 3 Holding 4 Holding 1 Spawning 2 Spawning 3 Spawning 4 Spawning

Derg Habitat Survey 6

0.2

0.4

0.6

0.8 Kilometers

Fig 6.17 Derg catchment habitat survey map 6 River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

7.0

LAND USE

Land use classification is an important tool when assessing the potential impacts within a particular river catchment or indeed when looking at specific land use and land management practices. Land use impacts could have either a positive or negative impact on rivers and tributaries. A good understanding of the land use within a catchment is therefore imperative in managing at a catchment scale. Land use in Northern Ireland has been captured using satellite imaging technology and classified to type. The following figures outline the broad land use classification within the Derg Catchment.

Primary Land Use in the Derg Catchment

Pastures

26%

33%

Agriculture/Natural Vegetation Coniferous forests Natural grassland Moors and heathland Transitional woodland scrub

8% 4% 1%

6% 19%

Peatbogs Water bodies

Fig 7 Derg catchment land use classification

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

512 324 321 324 321 112

243

324

313 142

231 312

324

312

322

322 321 412

412

322

512

321

Legend 112 - discont. urban 142 - sport & leisure 231 - pastures 243 - agric. & nat. veg. 312 - coniferous forest 313 - mixed forest 321 - natural grasslands 322 - moors and heath 324 - trans. wood. 412 - peatbogs 512 - water bodies

412

4 Kilometers

Derg Corine 2000 Landuse Survey

Fig 7.1 Derg catchment land use classification map River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

8.0

WATER QUALITY

Routine water quality monitoring within the Foyle and Carlingford areas is conducted by the Northern Ireland Environment Agency (NIEA) of the Department of the Environment for Northern Ireland and the County Councils in the Republic of Ireland (Donegal County Council and Louth County Council). Routine sampling is conducted regularly for both chemical and biological General Quality Assessments (GQA). In addition to the routine river monitoring carried out by the NIEA and the County Councils the Loughs Agency conducts proactive and reactive pollution investigations to investigate or highlight problems or potential problems which may have an effect on the aquatic environment and ultimately on the fish species and aquatic habitats. In 2007 the Loughs Agency instigated a programme of monitoring at the tributary level for assessments of chemical and biological water quality. Four stations on tributaries of the River Derg were monitored for chemical water quality parameters including Biological Oxygen Demand (BOD), Suspended Solids, Ammonia and Phosphorous. Biological water quality was assessed using the Biological Monitoring Working Party (BMWP) a biotic scoring index.

Fig 8.0 Loughs Agency chemical water quality testing in the laboratory

The Loughs Agency also maintains a mobile pollution response unit containing aerating equipment and absorbent and non absorbent booms for

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

oil and chemical spills. The unit can be rapidly deployed to the site of a pollution incident. Water Quality Parameters The following water quality parameters are monitored through the Loughs Agency monitoring programme and determined from water samples in the laboratory: • • • •

Biochemical Oxygen Demand (BOD) Ammonia Phosphorus Suspended Solids

BOD Any organic matter discharged into a river provides an immediate source of food for bacteria. These bacteria will break down the organic matter eventually into simple compounds such as carbon dioxide and water. Biochemical Oxygen Demand or Biological Oxygen Demand (BOD) is a chemical procedure for determining how fast biological organisms use up oxygen in a body of water. It is considered as an indication of the quality of a watercourse Ammonia (NH3) Ammonia is generally found in small amounts in rivers and streams. This is due to microbiological activity and the resultant reduction of compounds containing nitrogen. High levels of ammonia can occur as a result from sewage pollution and have detrimental impacts on fish species. Phosphorus (PO4) The over-loading of nutrients such as phosphorus in watercourses often leads to a process known as eutrophication. Eutrophication is a major environmental issue in Irish rivers and lakes. Sources of phosphorus include agricultural fertilizers and household detergents. Suspended Solids Particulate matter may be organic or inorganic in nature. Organic solids may consist of algal growths, indicative of eutrophic conditions. Inorganic solids generally are the result of discharge washings from sand and gravel extraction activities or quarries. Suspended solids can affect plant growth and fish habitats. The following parameters are also recorded at each sample station by means of an electronic measuring probe: •

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

•

Temperature

• •

Dissolved Oxygen Conductivity

pH This is a measure of the hydrogen ion concentration of a solution and therefore an indication of whether a liquid is acid or alkaline. The pH scale ranges from 0 (very acid) to 14 (very alkaline), with results generally influenced by geological conditions. Fish can be susceptible to changes in pH. Low pH levels are generally found in catchments with high forestry operation impacts. Temperature The effect of changes in temperature on living organisms, such as fish, can be critical. Thermal discharges from urban and industrial sources can lead to temperature increases in watercourses and increased stress on aquatic habitats and associated species. Dissolved Oxygen Sufficient levels of oxygen saturation in fresh waters are generally an indication of good ecological status and ideal for fish life. The main point to remember about oxygen solubility is that it has an inverse relationship with temperature. This helps explain why DO levels are generally lowest during summer low flow conditions, increasing the risk of pollution from discharges at this time. Conductivity The conductivity or electrical conductivity of a watercourse is a measure of its ability to conduct an electric current. Electrical conductivity estimates the amount of total dissolved salts, or the total amount of dissolved ions in the water. Electrical Conductivity is controlled by geology and any variations may be sourced to increased ions from wastewater from sewage treatment plants or urban run-off from roads.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

05-03

! 05-04 ( ( !

( !

05-02

05-01

Legend

! 0 - 10 Favourable Nursery Conditions ( ( 10 - 25 Acceptable Migratory Passage ! ( > 25 Unacceptable !

Derg Average Suspended Solids Results 2007

4 Kilometers

Fig 8.01 Derg catchment average suspended solids results 2007. Values are in mg/l River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

13-01

( !

05-03

! 05-04 ( ( !

( !

05-02

( ! ( !

07-02

05-01

07-01

!Legend ( ( 0 - 0.25 Very Good ! ( 0.25 - 0.6 Good ! ( 0.6 - 1.3 Fairly Good ! ( 1.3 - 2.5 Fair ! ( 2.5 - 9 Poor ! ( > 9 Bad !

Derg 90th Percentile Ammonia Results 2007

4 Kilometers

Fig 8.02 Derg catchment Ammonia results 2007. Values are in mg/l River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

05-03

! 05-04 ( ( !

( !

05-02

05-01

Legend

! 0 - 0.20 Acceptable Conditions ( ( > 0.20 Unacceptable Conditions !

Derg 90th Percentile Phosphorus Results 2007

4 Kilometers

Fig 8.03 Derg catchment phosphorous results 2007. Values are in mg/l River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

05-03

! 05-04 ( ( !

( !

05-02

05-01

Legend

! 0 - 2.5 Very Good ( ( 2.5 - 4 Good ! ( 4 - 6 Fairly Good ! ( 6 - 8 Fair ! ( 8- 15 Poor ! ( > 15 Bad !

Derg 90th Percentile BOD (mg/l) Results 2007

4 Kilometers

Fig 8.04 Derg catchment Biological Oxygen Demand (BOD) results 2007. Values are in mg/l River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Fig 8.05 Derg catchment Biological Monitoring Working Party results 2007 * Note Loughs Agency invertebrate monitoring was conducted during the summer months of 2007 River Derg and Tributaries Catchment Status Report 55

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

NIEA routinely monitor both the chemical and biological water quality within the rivers of Northern Ireland. In relation to chemical monitoring an extensive network of sampling stations are monitored for a variety of chemicals. The General Quality Assessment (GQA) is defined by limits for the concentrations of Biological Oxygen Demand (BOD), ammonia and dissolved oxygen (DO). The measures listed are indicators of the affect on water quality by waste water discharges and agricultural run-off containing organic material. Water quality can be affected by a variety of sources and the GQA determinands provide a recognised assessment of water quality. The overall GQA class assigned to a section of river is based on the worst performing of the three measures (BOD, ammonia and DO). Table 8.01 outlines the standards for the chemical GQA. GQA Class

A (Very Good) B (Good) C (Fairly Good) D (Fair) E (Poor) F (Bad)

Dissolved Oxygen (% Sat) 10-percentile 80 70 60 50 20 <20

BOD (mg/l) 90-percentile

Ammonia (mg/l) 90-percentile

2.5 4 6 8 15 -

0.25 0.6 1.3 2.5 9.0 -

Table 8.1 chemical GQA class limiting criteria

The above table can be summarised as follows: for BOD and ammonia the section of river should contain less than the stated levels for at least 90% of the time. DO levels must not fall below the stated levels for more than 10 percent of the time. In relation to biological monitoring an extensive network of sampling stations is also routinely monitored. The biological GQA is defined by observed measures of the abundance and diversity of macro invertebrates (for example freshwater shrimps, insect larvae and molluscs) compared to expected values as derived from a UK computer model adapted for Northern Ireland called River Invertebrate Prediction and Classification System (RIVPACS) Different species of macro invertebrates are more sensitive to specific forms of pollution and therefore environmental quality indices (EQIs) based on biological results may be used to assess water quality. Macro invertebrates are also the dominant prey of both salmonid and some non salmonid fish species. The measure of diversity of a macro invertebrate community can be a more reliable indicator of the pollution pressures within a catchment than relying solely on an assessment of chemical water quality. The impacts of pollution on a macro invertebrate community are longer lasting and can highlight intermittent pollution impacts that may be missed through chemical water quality monitoring. Biotic scoring systems have been developed to assign a score based on a standardised system to each sample site. One such system is the Biological

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Monitoring Working Party (BMWP). Generally the higher the BMWP score the better quality of the macro invertebrate community which reflects better water quality. Based on a combination of biotic scoring systems biological GQA classes are assigned to sections of river. The two EQIs used are as follows: EQItaxa = BMWP Observed Number of Taxa BMWP Predicted Number of Taxa (as derived from UK model) EQIASPT = BMWP Observed ASPT (Average Score Per Taxon) BMWP Predicted ASPT (as derived from UK model) Biological Class A (Very Good) B (Good) C (Fairly Good) DC (Fair) E (Poor) F (Bad)

EQI for ASPT 1.00 or above 0.90-0.99 0.77-0.89 0.65-0.76 0.50-0.64 <0.50

EQI for Taxon 0.85 or above 0.70-0.84 0.55-0.69 0.45-0.54 0.30-0.44 <0.30

Table 8.2 Biological GQA class limiting criteria Figure 8.06 Flattened mayfly nymph from the order ephemeroptera high scoring macro invertebrate indicative of good water quality.

European Council Directive 92/43/EEC of the 21st of May 1992 on the Conservation of Natural Habitats and on Wild Flora and Fauna (Also known as the Habitats Directive) was enacted in Northern Ireland under the European Communities Nature Conservation (Natural Habitats etc.) Regulations (Northern Ireland) 1995. This indicates that those areas designated as areas of nature conservation designated for salmon should strive to achieve the water quality targets that are necessary for the designated species, which has additions to the GQA standards. While it is current government policy for all rivers to meet the General Quality Assessment Standards, the Agency feels that favourable conditions standards as detailed below should be the water quality targets for all salmonid rivers within its jurisdiction.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

8.1

Favourable condition tables, target levels

Natural Heritage of Northern Ireland Environment Agency have suggested guidelines for the determination of water quality, the first being the proposed UK Guidance on Conservation Objectives from monitoring designated sites and includes the following, which are considered as the favourable conditions tables. They recommend Biological GQA Class A or B with no drop in class from the existing station, and Chemical GQA Class A or B depending on which type. This is in addition to no drop in class from the existing station. In addition to these favourable conditions tables, based on publications from Conserving Natura 2000 Rivers, the European Life Series, Ecology Series; No 7 Ecology of the Atlantic Salmon, Salmo Salar L. these publications have indicated that there are specific favourable conditions for this species. An annual mean of less than 10 milligrams per litre suspended solids for nursery grounds, and annual mean of less than 25 milligrams per litre for migratory passage and the setting of soluble reactive phosphorous targets in relation to river reach types which should be as near background levels. Parameter

Level

Percentile

BOD mg/l

2.5

GQA class A

Ammonia mg/l Dissolved Oxygen % Saturation Unionised Ammonia mg/l

0.25

GQA class A

0.025

GQA class A Favourable Conditions Habitat Forming Specific for Atlantic Salmon

Suspended solids mg/l 10 Nursery grounds 25 Migratory passage Soluble Reactive Background Phosphorous mg/l Table 8.3 Favourable condition targets for Atlantic salmon

Reason

Specific for Atlantic Salmon

The Water Quality data in the reports has come from the Northern Ireland Environment Agency, Water Management Units Water Quality Archive. It is accepted by the Agency that monitoring is designed to ensure that water quality is monitored to ensure compliance with European Union directives. The monitoring however does not tie in well with the habitat and electrofishing survey monitoring carried out by the Loughs Agency, and as such the Loughs Agency instigated its own monitoring programmes in 2007 to link fish life, macro invertebrates and water quality into one holistic site evaluation. Additionally Northern Ireland Environment Agency, Water Management Unit data is not released in real-time and the data displayed in the above evaluation is for 2006, where the Loughs Agency status report is for 2007. By collecting and analysing water quality data the Loughs Agency can react to local water quality issues more effectively.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Chemical GQA Very Good Good Fairly Good Fair Poor Bad

Derg Chemical Water Quality 2006

4 Kilometers

Fig 8.07 Chemical General Quality Assessment (GQA) Derg catchment 2006. Data supplied by NIEA River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Biological GQA Very Good Good Fairly Good Fair Poor Bad

Derg Biological Water Quality 2006

4 Kilometers

Fig 8.08 Biological General Quality Assessment (GQA) Faughan catchment 2006. Data supplied by NIEA River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

9.0

CONSERVATION AND PROTECTION

The Loughs Agency continues to carry out an active fishery protection role throughout the catchments of the Foyle and Carlingford areas including the sea area, River Foyle and on all tributaries. Tables 8 and 8.1 outline the number of patrols and some duties carried out by the Loughs Agency staff in the Derg catchment and seizures for the Foyle area. A team of Fishery Officers are responsible for the Derg catchment dividing their time between the Owenkillew catchment, Glenelly catchment, Mourne catchment and the standing waters within the Loughs Agency Central zone. This is in addition to regular fishery protection patrols on the River Foyle. Year

Patrol Hours

2006 2007

554 780

No of Licence Checks 172 214

Joint Patrols

On-site Inspections

0 0

37 35

Table 9 Breakdown of conservation and protection duties, Derg catchment 2007

Year Nets Salmon Rod&Reel Vehicles

2007 100 56 85 0

2006 97 91 26 2

2005 114 118 10 1

2004 181 130 16 1

2003 198 155 12 0

2002 207 94 22 0

Table 9.01 Seized nets, salmon, rod/reels and vehicles in the Foyle system 2002-2007

9.1

Habitat Improvement Works

In addition to the traditional protection duties carried out by the Loughs Agency staff conservation and improvement of habitat has been increasing over recent years. Over time man has imposed significant changes on the natural courses of many rivers and flood plains. The driving forces behind these changes have included amongst others; arterial drainage schemes to provide more suitable land for agricultural purposes, urban sprawl, infrastructure expansion (roads etc.), flood defences, water abstraction and hydro power generation. All have had a significant impact on the natural meanderings and discharges of rivers and tributaries resulting in faster runoff of floodwaters ultimately leading to a change in the morphology and flow regime of rivers and resultant impacts on fisheries. While all these processes have had some impact within the Foyle system, it is still considered to be a relatively natural system with natural river structure present in the catchments headwaters. In areas that have been altered methods for reinstating lost habitat are investigated and where appropriate action taken. River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

In 2003 the Loughs Agency became aware of a problem at the outflow of Lough Derg. The outflow had been impounded to maintain water levels within the Lough, Figure 9.10 and 9.11. Any activities with the potential to cause an impact on the fishery resources of the Foyle and Carlingford area need to be officially sanctioned by the Loughs Agency and other relevant statutory bodies in Northern Ireland or the Republic of Ireland. In this instance the Loughs Agency had not been consulted and the source of the River Derg had been artificially blocked. The impoundment prevented upstream and downstream migrating fish from accessing the river and lough as well as dewatering a considerable section of the river, significantly impacting upon the salmonid nursery habitat and associated aquatic and riparian flora and fauna immediately downstream of the lough outflow, figures 9.12 and 9.13.

Figure 9.10 Artificial impoundment at the outflow of Lough Derg into the River Derg. Photograph taken looking downstream

Figure 9.11 Secondary impoundment on the River Derg looking upstream towards first impoundment

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Figure 9.12 Dewatered stretch of River Derg below impoundments

Figure 9.13 Good quality salmonid nursery habitat downstream of impoundments highlighting dewatering

The severe dewatering of the River Derg in 2003 was due to conflicting stakeholder objectives. From a fishery perspective river water flow needs to be maintained to facilitate the passage of upstream and downstream migratory fish species of various life history stages in order to provide access to and from Lough Derg. The Loughs Agency endeavoured to apply a solution that would be acceptable to all stakeholders. This involved removing any barriers to fish migration and guaranteed river flow in the upper section of the River Derg. An offset boulder weir was also constructed, figure 9.14, which acted as an impoundment yet allowed water and migrating fish over in all flow conditions. The river directly downstream of the location of the second impoundment was narrowed to facilitate migratory fish passage in all flow conditions. This was achieved by constructing a deflector groyne on the left hand bank increasing flow and water depth, figure 9.15.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Offset Boulder Weir

Figure 9.14 Solution, offset boulder weir, location of secondary impoundment opened for fish access and deflector location.

Offset Boulder Weir Secondary Impoundment Removed Deflector

Figure 9.15 Offset boulder weir, location of secondary impoundment opened for fish access and deflector groyne location. Picture taken in 2005 immediately after works were completed.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

In-channel works were completed in 2005 after a number of temporary measures had been used to accommodate fish passage. Figures 9.16-9.18 show the site one year after the works were completed. The river substrate has stabilised providing suitable nursery habitat and possibly some spawning habitat. Water levels of the lough were maintained and access for upstream and downstream migrating fish was possible in all flow conditions.

Figure 9.16 Offset boulder weir. Figure 9.17 Location of secondary impoundment. Figure 9.18 Deflector groyne. 2006

In late 2006 early 2007 the Loughs Agency were dismayed to discover that the in-channel improvement works, constructed at significant expense in 2005 had been removed without permission or consultation and the passage of migratory fish impeded once again. The Loughs Agency is investigating this incident and has implemented temporary measures to facilitate fish passage. In 2006 a number of in-channel habitat improvement schemes were completed on feeder tributaries of Lough Derg. The schemes were designed to improve juvenile salmonid production and included the installation of habitat units, bankside protection and fencing.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

9.2

Finfish Aquaculture

Fish rearing facilities are located on both the main River Derg and on the Mournebeg River. Salmon smolts are produced for the marine aquaculture sector on the River Derg and Rainbow trout are produced on the Mournebeg River for human consumption. Water is abstracted from the Derg catchment to facilitate propagation and will be monitored by the Loughs Agency in conjunction with other statutory bodies in both Northern Ireland and the Republic of Ireland.

Figure 9.2 Smolt rearing facility on the Upper River Derg near Lough Derg.

10.0 ENVIRONMENTAL ISSUES Some environmental issues affecting water quality have already been outlined previously. The following list presents some of the main habitat pressures to salmonids within the Foyle system: • •

Agricultural activities – enrichment from natural and artificial fertilisers often make their way into watercourses, enhancing problems with eutrophication. Forestry activities – planting and felling operations can lead to increased loading of suspended solids in watercourses. Established forestry as a major upland land use has been attributed to increased acidification.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

• • •

•

• •

•

• •

Barriers to migration – a range of natural and anthropogenic features on rivers can lead to barriers for migrating salmonids and other fish species. These can include weirs and hydro-electric schemes. Gravel removal – gravel is extremely important for the creation of redds for spawning fish. Removal of gravel from the river bed in sensitive areas can destroy potential spawning and nursery habitat. Quarrying activities – the extraction of aggregates such as rock, sand and gravel has the potential to cause increased levels of suspended solids in nearby watercourses. Sufficient mitigation measures should be in place at such sites to trap increased sediment loads entering rivers and streams. Abstraction – water abstraction from watercourses for a range of uses is increasing throughout the Foyle and Carlingford catchments. Unless appropriately assessed and licenced, these activities have the potential to reduce residual flow levels and alter the ecological status of our rivers. This is even more concerning in the light of climate change. Peat harvesting – Peat harvesting still occurs in small upland pockets throughout the Foyle system. It has the potential to increase sediment loading in receiving waters. Sewage treatment – sewage and waste water treatment works are under considerable pressure with the increase in urban development in our towns and villages. Several inadequate systems throughout the Foyle system continue to pollute rivers. Hydropower – small-scale hydropower schemes are beginning to appear on rivers throughout the Foyle and Carlingford catchments. Baseline fishery data must be provided to allow for sufficient assessment of any proposed scheme, unless located above an impassable fish barrier. Urban development – the expansion of large-scale housing developments and the associated pressures on waste water and sewage treatment works are a potential source of water pollution in the event of overflows. Drainage and canalisation – these have direct impacts on the quality of available fishery habitat within the catchments. Canalisation in particular can lead to the removal of important spawning, nursery or holding areas of rivers. Industrial discharges – larger urban areas with industrial discharges have the potential to cause pollution through toxic discharges and can alter the temperature of the watercourse. Septic tanks – a proliferation of single dwellings and their septic tanks is an ongoing area of concern. Initial research from parts of the Foyle system indicate that this is major contributor to decreased water quality and local increases in suspended solids.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

11.0 DESIGNATED AREAS The European Commission Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora (EU Habitats Directive 92/43/EEC) requires that all member states designate Special Areas of Conservation (SACs) in order to protect threatened habitats and species. The European Commission Directive on the Conservation of Wild Birds (Birds Directive 79/409/EEC) also requires the designation of Special Protected Areas (SPA’s). Together the designated SAC’s and SPA’s create the NATURA 2000 network of protected sites. A number of rivers have been designated as SAC’s both in Northern Ireland and in the Republic of Ireland. One of most recent additions to the list of SACs is the River Foyle and Tributaries SAC which includes the River Derg, Mournebeg River and Glendergan River. Atlantic salmon is listed as an Annex II and Annex V species within the directive meaning that they are of community interest requiring the designation of an SAC (only in fresh water). “The River Foyle and its tributaries have the largest population of Atlantic salmon in Northern Ireland. The majority of the salmon returning are grilse (single wintering salmon), with a smaller but important number of spring salmon (multi-wintering salmon) also occurring. Research has indicated that individual sub-catchments within the system support genetically distinct salmon populations” (Environment and Heritage Service). Within the Derg catchment there is a diverse range of landscapes, habitats and species. National and as mentioned above European Legislation requires that important and threatened landscapes, species and habitats are protected by various designations. At the national level the primary designations within the Derg catchment include the designation of Areas of Special Scientific Interest (ASSI) including Moneygal Bog which is one of the finest raised bog pool systems in Northern Ireland with associated species of importance and Moneygal Bog Part II an area of cutover lowland raised bog important for its vegetative ecology providing habitat for a diverse range of birds including Snipe, Woodcock and Meadow Pipit. Essan Burn and Mullyfamore, a large area of blanket bog with intact hydrology and vegetation including the carnivorous plant Sundew, is also an ASSI. Killeter Nature Reserve part of the National Nature Reserve network (NNR) and has been designated to protect its blanket bog and associated species. At the European level Special Areas of Conservation (SAC’s) have been designated to protect landscapes, species and habitats of international importance. Within the Derg catchment these include, Moneygal Bog as above, the River Foyle and its tributaries incorporating the River Derg, the Mourne Beg River and the Glendergan River designated for important Atlantic Salmon populations and river habitat which is viewed as being fast flowing 10 River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

spate rivers characterised by sequences of rapid, riffle and run. The channels are natural and composed of large cobble substrate with scattered boulders and sandy deposits. At the top end of the River Derg there is good representative riparian and in-stream vegetation including Water Crowfoot (Ranunculus species). Otters are also present within the catchment. Dunragh Lough/Pettigo Plateau has also been designated as an SAC. The area includes part of the Derg catchment on the western shore of Lough Derg. It comprises an extensive complex of blanket bog, wet heath, lakes and pools and associated flora and fauna covering an area of low hills and broad basins. Lough Derg has been designated a Special Protected Area (SPA). The Lough Derg SPA was designated for its populations of Lesser Black-backed Gull (the largest colony in the Republic of Ireland), Herring Gull and Greenland Whitefronted Geese (current status unknown). Populations of Common Gull, Tufted Duck, Mallard, Goldeneye and Greylag Geese can also be seen on Lough Derg. From a fisheries perspective it is not only important to conserve and protect the natural fisheries biodiversity but as part of an ecosystem management approach it is essential to be aware of the wider interconnections between different species and their habitats.

12.0 GENETIC STUDY A baseline genetic survey was carried out in the Foyle system in 2003 and a resurvey conducted between 2006 and 2008 to analyse the populations of Atlantic salmon present within the Foyle catchment. Results confirmed the existence of genetically distinct populations between and within the rivers and tributaries of the Foyle area. An understanding of these genetically differentiated populations is required to facilitate appropriate management of conservation measures and the commercial/recreational fisheries. The report concluded that genetic diversity is high between and within the various salmon populations present in the Foyle system. Each population has evolved over time creating distinct populations (with some gene flow from straying fish) that are best suited to the conditions present in a particular river or tributary. The non-uniform nature of the populations adds to the diversity of life history strategies exercised by Foyle salmon. Distinct differences such as run-timing and age at smolting can act as natures insurance policy to any catastrophic events which would threaten a homogenous population. The report stated that the current genetic structure and diversity of Foyle salmon is representative of what might be regarded as the native structure of wild salmon populations. The maintenance of genetic diversity is a core requirement for the long-term sustainability of wild populations, preserving the biodiversity of the wild salmonids of the Foyle system is therefore a primary objective of the Loughs Agency.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

13.0 POLLUTION MONITORING The Loughs Agency has a statutory obligation to monitor the pollution of watercourses. In conjunction with the Northern Ireland Environment Agency all reported pollution incidents are investigated.

14.0 FISHERY OFFICERS DERG AREA REPORT 2007 In 2007 a review of the issues impacting salmonid production within the Derg Catchment was conducted by Fishery Officers Sean Rowe, Tommy McAree and Brian Ward in response to specific issues highlighted by Loughs Agency monitoring programmes. Areas of low production were highlighted based on poor electrofishing results, poor water quality results and habitat survey information. These areas were investigated by the fishery officers. 14.1

Fishery Officers Report

The Leaghany River, tributary of the River Derg was highlighted for further investigation. Poor fish counts had been recorded at two sites in 2007 in addition to low counts in previous years. A low BMWP score had also been recorded on this river. The site investigated was sampled for invertebrates using a kick sampling method and water samples taken for chemical analysis. Electrofishing results from previous years were assessed instead of conducting out of season surveys which may have impacted on any spawning fish. It was also noted that the suitability of the catching net used in previous electrofishing sampling was questioned as the substrate is dominated by large cobbles which can be difficult to survey around and reduce capture efficiency. A habitat survey undertaken two years previously during the redd counting season included pH readings of the main river and its tributaries. These pH readings ranged from low to extremely low. This site is also at a relatively high altitude and surrounded by coniferous forestry. New drains have also been made along side the road which could allow flushed acid waters to reach the main river quicker and at higher concentrations. This may also cause a higher suspended solid reading due to the lack of barriers and natural filtration systems. There are no known physical barriers downstream to the movement of fish. It can also be reported that a reasonable population of salmonid fry and parr are present a number of miles upstream. This was confirmed when the upstream site was fished to capture salmon fry and parr for analysis as part of the genetics study. In conclusion there appears to be low pH readings most likely due to the sites proximity to coniferous forestry, making this habitat unsuitable for salmonids. There also appears to be poor invertebrate numbers and diversity of species.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

As a population of fish are present upstream of this site this appears to be a localised problem. The Mournebeg River, tributary of the River Derg was also highlighted for further investigation. The top six electrofishing stations have had poor results in recent years with habitat related issues being identified including a build up of silt. Two sites were investigated for invertebrates using a kick sampling method and water samples were taken for chemical analysis. Electrofishing results from previous years were assessed instead of conducting out of season surveys which may have impacted on any spawning fish. The top site investigated showed a large build up of dark brown fines along the bank. The substrate was checked and found to contain a large amount of fines as well. This site is about 0.5 to 1km from the mouth of Lough Mourne, which supplies the local area with drinking water. A small water treatment plant operates on the opposite shore and would use the type of fines for filtration beds. Old sand heaps from the filtration beds were found along the shore of the lough. An EPA inspector informed us earlier in the year that flooding had occurred and water levels had been the highest recorded. It had been so high that the river burst its banks and washed over a retaining wall near the “V” notched weir. It was also found that further down the river a trout farm had complained about the amount of silt that had washed into its tanks. The second site investigated was found to be high in silt content as well. Between the two sites a large coniferous forest is situated and removal of a large area of the forest nearest the river is being undertaken. New drains have also been made along side the road which would allow flushed acid waters to reach the main river quicker and at higher concentrations. This may also cause a higher suspended solid reading due to the lack of barriers and natural filtration systems. The location is also of a high altitude. As regard to physical barriers downstream to the movement of fish, at the aforementioned fish farm, a man made weir has been built and has been known to dry the bed of the river between the weir and the outlet of the fish farm during low water conditions. In conclusion pH readings are not out of the ordinary for this type of river and there appears to be poor invertebrate levels. The survey identified no obvious sources of pollution. High levels of silt are present. This may be due to the flooding of the area carrying silt from the Lough to the river. However on the day of analysis the river was reasonably low and any sand heaps around the lough appeared to be well away from the waterline. It may be advisable to ensure the water treatment plant keep the waste sand well away from the shore as it seems to be the only possibility for the cause of the siltation. It is also worthy of note that on previous occasions an area of river adjacent to the fish farm has been recorded as being dry due to total abstraction of the available water by the fish farm, this would have not only the obvious effect on

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

the fish life within this stretch but also would form an impassable barrier to migratory species of fish.

15.0 ACTIONS FOR 2008 In order to fully utilise the extensive data resources collected and held by the Loughs Agency on the fish populations and habitats of the Derg catchment it is necessary to focus attention on specific management objectives. The Loughs Agency has stated in its corporate plan 2008-2010 that it will conserve, protect, manage and improve the fisheries of the Foyle and Carlingford areas. By way of fulfilling these objectives a targeted series of actions utilising data collected over recent years will be implemented. Fishery owners and angling clubs/associations will continue to be consulted regarding any proposed works and stakeholder input sought. 15.1

Foyle and Carlingford Areas Ongoing Actions for 2008

Good water quality is essential for the conservation of productive aquatic ecosystems. Fish populations rely on unpolluted water for survival and feeding. The Loughs Agency is committed to ensuring deleterious matter does not enter any watercourse. Routine monitoring is conducted throughout the Foyle and Carlingford areas. Proactive pollution visits and water quality monitoring will continue in 2008. Water quantity is becoming an increasingly important issue from a fisheries management perspective with continuing demand from a variety of sources including industry, hydro power generation and abstraction for meeting the ever growing needs of industry and the wider population. The Loughs Agency are aware of the conflicting needs of aquatic environments and water resource users and comment on development issues which may have an impact on the important aquatic resources of the Foyle and Carlingford areas with reference to national and international obligations. In-channel and riparian habitat improvement projects provide an important mechanism by which to improve and protect valuable fishery resources. Over recent years the Loughs Agency has developed a number of projects designed to improve the survival and production of robust populations of juvenile salmonid and other native fish species. These programmes will continue where funding is available. The Loughs Agency also encourages local stakeholder groups to source appropriate funding to develop collaborative habitat improvement projects. The Loughs Agency can provide advice and recommendations for in-channel and riparian improvements and are eager to facilitate the development of such programmes. Work is continuing to assess and record all Barriers to Migration within the catchments of the Foyle and Carlingford areas and these will be incorporated into the Loughs Agency Geographical Information System (GIS). Where finances are available the removal of artificial barriers will be investigated.

River Derg and Tributaries Catchment Status Report

Loughs Agency of the Foyle Carlingford and Irish Lights Commission

Predation by cormorants and seals of economically important fish species continues to be a contentious issue. The Loughs Agency will continue to promote the development of a management strategy incorporating economic, social and environmental factors. The Loughs Agency will continue to monitor the salmon and inland fishery resources of the Foyle and Carlingford areas, utilising best practice methods including fish counters, juvenile population surveys and catch returns. The importance of the Atlantic salmon resource has been further highlighted by recent genetic studies which have identified the presence of genetically distinct populations of salmon between and within main river catchments. This information will be utilised when developing habitat improvement programmes to ensure the presence of a diverse resource capable of withstanding change. Invasive species in both aquatic and riparian habitats have become an important issue in fisheries management and in wider environmental management. Invasive species have the potential to significantly alter ecosystems and their function. The Loughs Agency is contributing towards the development and implementation of invasive species codes of practice. 15.2

Derg Catchment Specific Actions for 2008

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Conduct a barriers to migration study on the main River Derg and all tributaries

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Develop potential habitat improvement projects including riparian buffer zone creation, fencing, native species planting and in-channel habitat improvements including spawning bed and nursery habitat improvement.

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Monitor forestry operations adjacent to watercourses or areas likely to impact on watercourses.

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Monitor all referred development proposals.

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Conduct ongoing water quality monitoring and investigate areas highlighted as being of concern.

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Assist with Water Framework Directive fish monitoring programme.

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Conduct annual fish population surveys and spawning specific habitat surveys.

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Monitor all sand and gravel extraction sites and onsite water management practices.

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Ensure all fish passes, dams and mill races meet required standards.

River Derg and Tributaries Catchment Status Report