report supporting appropriate assessment of aquaculture ... · within the slyne head peninsula sac,...

Report supporting

Appropriate Assessment of

Aquaculture Activities in

Slyne Head Peninsula SAC

(Site Code: 2074)

Version: February 2019

Contents

1 PREFACE ................................................................................................................................................... 1

2 EXECUTIVE SUMMARY ............................................................................................................................. 2

2.1 THE SAC .................................................................................................................................................... 2

2.2 ACTIVITIES IN THE SAC ................................................................................................................................. 2

2.3 THE APPROPRIATE ASSESSMENT PROCESS .......................................................................................................... 2

2.4 DATA SUPPORTS .......................................................................................................................................... 3

2.5 FINDINGS ................................................................................................................................................... 3

3 INTRODUCTION ........................................................................................................................................ 4

4 CONSERVATION OBJECTIVES FOR SLYNE HEAD PENINSULA SAC (002074) ................................................ 5

4.1 THE SAC EXTENT ......................................................................................................................................... 5

4.2 QUALIFYING INTERESTS (SAC) ........................................................................................................................ 7

4.3 CONSERVATION OBJECTIVES FOR SLYNE HEAD PENINSULA SAC (SITE CODE 002074) SAC ...................................... 10

4.4 SCREENING OF ADJACENT SACS OR FOR EX SITU EFFECTS ................................................................................... 10

5 DETAILS OF THE PROPOSED PLANS AND PROJECTS ................................................................................ 19

5.1 AQUACULTURE .......................................................................................................................................... 19

5.1.1 Oyster Culture ............................................................................................................................... 19

5.1.2 Salmon Culture .............................................................................................................................. 19

6 NATURA IMPACT STATEMENT FOR THE PROPOSED ACTIVITIES ............................................................. 23

6.1 AQUACULTURE .......................................................................................................................................... 23

7 SCREENING OF AQUACULTURE ACTIVITIES ............................................................................................. 32

7.1 AQUACULTURE ACTIVITY SCREENING ............................................................................................................. 32

8 ASSESSMENT OF AQUACULTURE ACTIVITIES .......................................................................................... 36

8.1 DETERMINING SIGNIFICANCE ........................................................................................................................ 36

8.2 SENSITIVITY AND ASSESSMENT RATIONALE ...................................................................................................... 37

8.3 ASSESSMENT OF THE EFFECTS OF AQUACULTURE PRODUCTION ON THE CONSERVATION OBJECTIVES FOR HABITAT FEATURES

IN THE SLYNE HEAD PENINSULA SAC. ........................................................................................................................ 39

9 IN-COMBINATION EFFECTS OF AQUACULTURE, FISHERIES AND OTHER ACTIVITIES................................ 51

9.1 FISHERIES .............................................................................................................................................. 51

9.1.1 Pot fisheries................................................................................................................................... 53

9.1.2 Tangle nets .................................................................................................................................... 54

9.2 POLLUTION ............................................................................................................................................... 54

10 SAC AQUACULTURE APPROPRIATE ASSESSMENT CONCLUDING STATEMENT AND

RECOMMENDATIONS .................................................................................................................................... 55

10.1 HABITATS ................................................................................................................................................. 55

11 REFERENCES ....................................................................................................................................... 57

List of Tables

Table 1: Conservation objectives and targets for marine habitats Slyne Head Peninsula SAC (site code

002074) (NPWS 2015a, 2015b). Annex I features listed in bold. ........................................................ 11

Table 2: Natura Sites adjacent to Slyne Head Peninsula SAC and qualifying features with initial

screening assessment on likely interactions with aquaculture activities. ............................................. 17

Table 3: Spatial extent (ha) of aquaculture activities overlapping with the qualifying interests (1160

Large shallow inlets and bays, 1170 Reefs) in Slyne Head Peninsula SAC (site code 002074),

presented according to culture, species, method of cultivation and license status. ............................. 22

Table 4: Potential indicative environmental pressures of aquaculture activities within the qualifying

interests of the Slyne Head Peninsula SAC (site code 002074)........................................................... 24

Table 5: Habitat utilisation i.e. spatial overlap in hectares and percentage (given in parentheses) of

aquaculture activity over community types within the qualifying interest 1160 - Large Shallow Inlet and

Bays (Spatial data based on licence database provided by DAFM). .................................................... 34

Table 6: Habitat utilisation i.e. spatial overlap in hectares and percentage (given in parentheses) of

aquaculture activity over community types within the qualifying interest 1170 Reefs (Spatial data based

on licence database provided by DAFM). Habitat data provided in NPWS (2015a, 2015b). ............. 35

Table 7: Matrix showing the characterising community types sensitivity scores x pressure categories for

habitats in Slyne Head Peninsula SAC (ABPMer 2013a-h). Table 9 provides the code for the various

categorisations of sensitivity and confidence ........................................................................................ 43

Table 8: Matrix showing the characterising species sensitivity scores x pressure categories for species

in Slyne Head Peninsula SAC (ABPMer 2013a-h). .............................................................................. 45

Table 9: Codes of sensitivity and confidence applying to species and pressure interactions presented

in Tables 7 and 8. .................................................................................................................................. 47

Table 10: Interactions between the relevant aquaculture activities and the habitat feature Reefs (1170)

constituent communities with a broad conclusion on the nature of the interactions. ............................ 48

Table 11. Interactions between the relevant aquaculture activities and the habitat feature Large Shallow

Inlets and Bays (1160) constituent communities with a broad conclusion on the nature of the

interactions. ........................................................................................................................................... 49

Table 12. Spatial extent of fisheries activities overlapping within the broad habitat qualifying interest of

1160 and 1170 and constituent community types in Slyne head Peninsula SAC. Spatial overlap

presented according to target fisheries species and equipment used. Annex I feature in bold. .......... 52

List of Figures

Figure 1: The extent of the Slyne Head Peninsula SAC (site code002074) and qualifying interests

(habitats). ................................................................................................................................................ 6

Figure 2: Principal benthic communities recorded within the qualifying interests of the Slyne Head

Peninsula SAC (site code 002074) (NPWS 2015a). ............................................................................... 9

Figure 3. Natura 2000 sites adjacent to Slyne Head Peninsula SAC (site code 002074) (NPWS 2015a).

.............................................................................................................................................................. 16

Figure 4. Aquaculture sites in Slyne Head Peninsula SAC (site code 002074). ................................. 20

Figure 5: Access routes to aquaculture sites in Slyne Head Peninsula SAC (site code 002074) and

relevant Marine Community types (access routes not drawn to scale). ............................................... 21

Figure 6: Schematic outlining the determination of significant effects on habitats and marine community

types (MCT) (following NPWS 2015b). ................................................................................................. 37

Figure 7. Fishery activities within Slyne Head Peninsula SAC. ............................................................ 51

1 Preface

In Ireland, the implementation of Article 6 of the Habitats Directive in relation to aquaculture projects

and plans that occur within designated sites is achieved through sub-Article 6(3) of the Directive.

The Habitats Directive is transposed in Ireland in the European Communities (Birds and Natural

Habitats) Regulations 2011. NPWS are the competent authority for the management of Natura 2000

sites in Ireland. Obviously, aquaculture operations existed in coastal areas prior to the designation of

such areas under the Directives. Ireland is thereby assessing both existing and proposed aquaculture

activities in such sites. This is an incremental process, as agreed with the EU Commission in 2009, and

will eventually cover all aquaculture activities in all Natura 2000 sites.

For aquaculture operations, DAFM receives applications to undertake such activity and submits a set

of applications, at a defined point in time, for assessment. The aquaculture applications are then subject

to AA. If the AA or the RA process finds that the possibility of significant effects cannot be discounted

or that there is a likelihood of negative consequence for designated features then such activities will

need to be mitigated further if they are to continue. These assessments are not always explicit on how

this mitigation might be achieved but rather indicate whether mitigation is required or not and what

results should be achieved.

2

2 Executive summary

2.1 The SAC

Slyne Head Peninsula (site code 002074) is designated as a Special Area of Conservation (SAC) under

the Habitats Directive. The marine area is designated for the Annex I habitats Coastal lagoons (1150),

Large shallow inlets and bays (1160) and Reefs (1170).

The bay supports a variety of sub-tidal and intertidal sedimentary and reef habitats. Conservation

Objectives for these habitats were identified by NPWS (2015a) and relate to the requirement to maintain

habitat distribution, structure and function, as defined by characterizing (dominant) species in these

habitats. Guidance on the conservation objectives is provided by NPWS (2015b).

2.2 Activities in the SAC

Aquaculture is confined to Mannin Bay area of the SAC. The main aquaculture activities are oyster and

finfish culture. Oyster culture involves the culture of the pacific oyster (Crassostrea gigas) on trestles

in intertidal areas and subtidally on the seafloor. Finfish culture involves the subtidal culture of Atlantic

salmon (Salmo salar) in net pens.

The profile of the aquaculture industry in the Slyne Head Peninsula (site code 002074), used in this

assessment, was prepared by BIM and is derived from the list of licence applications received by DAFM

and provided to the Marine Institute for assessment in 2018.

2.3 The appropriate assessment process

The function of an appropriate assessment is to determine if the ongoing and proposed aquaculture

activities are consistent with the Conservation Objectives for the Natura site or if such activities will lead

to deterioration in the attributes of the habitats and species over time and in relation to the scale,

frequency and intensity of the activities. NPWS (2015b) provide guidance on interpretation of the

Conservation Objectives, which are, in effect, management targets for habitats and species in the SAC.

This guidance is scaled relative to the anticipated sensitivity of habitats and species to disturbance by

the proposed activities. Some activities are deemed wholly inconsistent with long-term maintenance of

certain sensitive habitats while other habitats can tolerate a range of activities. For the practical purpose

of management of sedimentary habitats, a 15% threshold of overlap between an activity resulting in

persistent disturbance and a habitat is given in the NPWS guidance. Below this threshold disturbance

is deemed to be non-significant. Disturbance is defined as that which leads to a change in the

characterizing species of the habitat (which may also indicate change in structure and function). Such

disturbance may be temporary or persistent in the sense that change in characterizing species may

recover to pre-disturbed state or may persist and accumulate over time.

The appropriate assessment process is divided into a number of stages consisting of a preliminary risk

identification, and subsequent assessment (allied with mitigation measures if necessary) which are

covered in this report. The first stage of the AA process is an initial screening wherein activities, which

cannot have, because they do not spatially overlap with a given habitat nor have a clear pathway for

3

interaction, any impact on the conservation features and are therefore excluded from further

consideration. The next phase is the Natura Impact Statement (NIS) where interactions (or risk of) are

identified. Further to this, an assessment on the significance of the likely interactions between activities

and conservation features is conducted. Mitigation measures (if necessary) will be introduced in

situations where the risk of significant disturbance is identified. In situations where there is no obvious

mitigation to reduce the risk of significant impact, it is advised that caution should be applied in licencing

decisions. Overall, the Appropriate Assessment is both the process and the assessment undertaken

by the competent authority to effectively validate this Screening Report and/or NIS. It is important to

note that the screening process is considered conservative; in that other activities which may overlap

with habitats but which may have, very benign effects are retained for full assessment.

2.4 Data supports

Distribution of habitats and species population data are provided by NPWS1. Scientific reports on the

potential effects of various activities on habitats and species have been compiled by the MI and provide

the evidence base for the findings. The data supporting the assessment of individual activities vary and

provides for varying degrees of confidence in the findings.

2.5 Findings

The appropriate assessment finds that finfish culture at the current scale of activity is consistent with

the Conservation Objectives for the Annex 1 habitats. However, the following observations have been

identified in relation to shellfish culture:

1. Within the Slyne Head Peninsula SAC, the culture (licensed) of oysters (Crassostrea gigas) on

bags & trestles overlaps with the marine community type, Intertidal Reef Community Complex with

the Annex 1 habitat Large shallow inlet and bay (1160) by 15.7% which is greater than the 15%

threshold identified in guidance. It is recommended that the level of overlap be reduced to a

sustainable level.

2. Within the Slyne Head Peninsula SAC, the culture (licensed) of oysters (Crassostrea gigas) on

bags & trestles overlaps with two key communities Zostera dominated community and Maerl

dominated community. This activity is deemed wholly inconsistent with the long-term maintenance

of these important marine community types. As key contributors to biodiversity and being sensitive

to disturbance, these two community types are afforded a high degree of protection and no overlap

with this activity can be tolerated.

3. The risk posed by the culture of diploid Pacific oyster has been identified. Given that the residence

time in Mannin Bay is approx 21 days, this is at the threshold for larval development, associated

with successful recruitment identified in published literature (Kochmann et al. 2013). However,

mitigating factors are the heavy algal cover found intertidally in the area and the fact that the

1 NPWS Geodatabase Ver: September 2013 - http://www.npws.ie/mapsanddata/habitatspeciesdata/

4

oysters are contained in bags on trestles in the intertidal. Any confirmation of oyster recruitment

might be addressed by the removal of diploid oysters from the system.

4. The risk posed by the culture of the pacific oyster, Crassostrea gigas, uncontained on the seabed

cannot be discounted. Given that subtidal oyster culture results in higher reproductive potential,

and the residence time in Mannin Bay is 21 days, it is recommended that careful consideration be

given to licencing subtidal uncontained oyster culture.

3 Introduction

This document assesses the potential ecological interactions of aquaculture activities within the Slyne

Head Peninsula SAC (site code 002074) on the Conservation Objectives (COs) of the site (05/02/2015

Version 1).

The information upon which this assessment is based is a list of applications and extant licences for

aquaculture activities administered by the Department of Agriculture Food and Marine (DAFM) and

forwarded to the Marine Institute as of 2018; as well as the aquaculture profiling information provided

on behalf of the operators by Bord Iascaigh Mara. The spatial extent of aquaculture licences is derived

from a database managed by the DAFM2 and shared with the Marine Institute.

2 DAFM Aquaculture Database version Aquaculture: 30th Aug 2013

5

4 Conservation Objectives for Slyne Head Peninsula SAC (002074)

This report in support of the appropriate assessment of aquaculture in relation to the Conservation

Objectives for Slyne Head Peninsula SAC (site code 002074) is based on Version 1.0 of the objectives

(NPWS 2015a) and supporting documentation (NPWS 2015b). The spatial data for conservation

features was provided by NPWS3.

4.1 The SAC extent

Slyne Head Peninsula SAC (site code 002074) is located on the west coast of Ireland in northwest

Connemara, Co Galway. The SAC comprises the peninsula west of Ballyconneely, Co. Galway. It

extends northwards to Errislannan Point to include the shallow waters of Mannin Bay. The peninsula

is fringed with rocky shores and sandy beaches, with some extensive areas of Machair and several

brackish lakes and lagoons. Inland, the site is a maze of small fields, supporting a mosaic of habitats

dominated by grassland and heath, interspersed with numerous lakes and associated swamp, marsh

and fen.

Slyne Head Peninsula SAC (site code 002074) is designated for the marine Annex I qualifying interests

of Coastal lagoons (1150), Large shallow inlets and bays (1160) and Reefs (1170) (Figure 1). The

Annex I habitat 1160 is a large physiographic feature that may wholly or partly incorporate other Annex

I habitats such as Reefs within its area.

A number of coastal habitats can also be found in the SAC, including Annual vegetation of drift lines

(1210), Perennial vegetation of stony banks (1220), Atlantic salt meadows (Glauco-Puccinellietalia

maritimae) (1330), Petalwort Petalophyllum ralfsii (1395), Mediterranean salt meadows (Juncetalia

maritimi) (1410), Slender Naiad Najas flexilis (1833), Embryonic shifting dunes (2110), Shifting dunes

along the shoreline with Ammophila arenaria (white dunes) (2120), Machairs (*in Ireland) (21A0),

Oligotrophic waters containing very few minerals of sandy plains (Littorelletalia uniflorae) (3110), Hard

oligo-mesotrophic waters with benthic vegetation of Chara spp. (3140), European dry heaths (4030)

Juniperus communis formations on heaths or calcareous grasslands (5130), Semi-natural dry

grasslands and scrubland facies on calcareous substrates (Festuco-Brometalia) (*important orchid

sites) (6210), Molinia meadows on calcareous, peaty or clayey-silt-laden soils (Molinion caeruleae)

(6410), Lowland hay meadows (Alopecurus pratensis, Sanguisorba offvinalis) (6510) and Alkaline fens

(7230).

The extent of the SAC is shown in Figure 1 below. Please note that this SAC overlaps with Slyne Head

to Ardmore Point Islands SPA (004159). It adjoins Slyne Head Islands SAC (000328) and West

Connaught Coast SAC (002998). See section 4.4 below.

05 Feb

3 NPWS Geodatabase Ver: September 2013 - http://www.npws.ie/mapsanddata/habitatspeciesdata/

6

Figure 1: The extent of the Slyne Head Peninsula SAC (site code002074) and qualifying interests (habitats).

7

4.2 Qualifying interests (SAC)

The SAC is designated for the following habitats and species (NPWS 2015a), as listed in Annex I of the

E.U. Habitats Directive:

1150 Coastal lagoons*

1160 Large shallow inlets and bays

1170 Reefs

1210 Annual vegetation of drift lines

1220 Perennial vegetation of stony banks

1330 Atlantic salt meadows (Glauco-Puccinellietalia maritimae)

1395 Petalwort Petalophyllum ralfsii

1410 Mediterranean salt meadows (Juncetalia maritimi)

1833 Slender Naiad Najas flexilis

2110 Embryonic shifting dunes

2120 Shifting dunes along the shoreline with Ammophila arenaria (white dunes)

21A0 Machairs (*in Ireland)

3110 Oligotrophic waters containing very few minerals of sandy plains (Littorelletalia

uniflorae)

3140 Hard oligo-mesotrophic waters with benthic vegetation of Chara spp.

4030 Juniperus communis formations on heaths or calcareous grasslands

5130 European dry heaths

6210 Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco-

Brometalia) (*important orchid sites)

6410 Molinia meadows on calcareous, peaty or clayey-silt-laden soils (Molinion caeruleae)

6510 Lowland hay meadows (Alopecurus pratensis, Sanguisorba offvinalis)

7230 Alkaline fens

8

Eight constituent communities and community complexes recorded within the qualifying interest Annex

1 habitats (i.e. Large Shallow Inlets and Bays (1160) and Reefs (1170)) are listed in NPWS (2015b)

and illustrated in Figure 2 and consist of:

Intertidal sand with Enchytraeidae community complex

Mobile intertidal sand with polychaetes community complex

Zostera-dominated community complex

Maërl-dominated community complex

Subtidal sand with polychaetes and bivalves community complex

Subtidal sand with Kurtiella bidentata community complex

Intertidal reef community complex

Laminaria-dominated community complex

9

Figure 2: Principal benthic communities recorded within the qualifying interests of the Slyne Head Peninsula SAC (site code 002074) (NPWS 2015a).

10

4.3 Conservation objectives for Slyne Head Peninsula SAC (site code 002074) SAC

The conservation objectives for the qualifying interests (SAC) were identified in NPWS (2015a). The

natural condition of the designated features should be preserved with respect to their area, distribution,

extent and community distribution. Habitat availability should be maintained for designated species and

human disturbance should not adversely affect such species. The features, objectives and targets of

each of the qualifying interests within the SAC are listed in Table 1 below.

4.4 Screening of Adjacent SACs or for ex situ effects

In addition to the SAC there are a number of other Natura 2000 sites proximate to the proposed activities

(Figure 3). The qualifying features of these sites are identified in Table 2, where a preliminary screening

is carried out on the likely interaction with aquaculture activities based primarily upon the likelihood of

spatial overlap. As it was deemed that there are no ex situ effects and no effects on features in adjacent

SACs all qualifying features of adjacent Natura 2000 sites were screened out.

11

Table 1: Conservation objectives and targets for marine habitats Slyne Head Peninsula SAC (site code 002074) (NPWS 2015a, 2015b). Annex I

features listed in bold.

Feature (Community Type) Objective Target

1150 Coastal Lagoons Restore favorable conservation condition

22.30ha; The habitat area is stable, subject to slight natural variation. No decline in habitat distribution, subject to natural processes. Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining function and diversity of favourable species and managing levels of negative species.

1160 Large shallow inlets and bays Maintain favourable conservation condition 1540ha; The permanent habitat area is stable or increasing, subject to natural processes. Constituent community types are conserved in a natural condition.

(Intertidal sand with Enchytraeidae

community complex) Maintain favourable conservation condition 14ha; Conserve in a natural condition

(Mobile intertidal sand with

polychaetes community complex) Maintain favourable conservation condition 11ha; Conserve in a natural condition

(Zostera-dominated community

complex) Maintain favourable conservation condition

33ha; Maintain extent and conserve the high quality of the Zostera-dominated community complex subject to natural

processes.

(Maërl-dominated community

complex) Maintain favourable conservation condition

261ha; Maintain extent and conserve the high quality of the Maërl-dominated community complex subject to natural processes.

(Subtidal sand with polychaetes and

bivalves community complex) Maintain favourable conservation condition 288ha; Conserve in a natural condition

(Subtidal sand with Kurtiella bidentata

community complex) Maintain favourable conservation condition 574ha; Conserve in a natural condition

(Intertidal reef community complex) Maintain favourable conservation condition 159ha; Conserve in a natural condition

(Laminaria-dominated community

complex) Maintain favourable conservation condition 14ha; Conserve in a natural condition

12


1170 Reefs Maintain favourable conservation condition

5711ha; The distribution and permanent habitat area is stable or increasing subject to natural processes. Constituent community types are conserved in a natural condition.

(Intertidal reef community complex) Maintain favourable conservation condition 350ha; Conserve in a natural condition

(Laminaria-dominated community

complex) Maintain favourable conservation condition 220ha; Conserve in a natural condition

1210 Annual vegetation of drift lines Maintain favourable conservation condition

0.78ha, Estimate as this habitat is very difficult to measure due to its dynamic nature; The habitat area is stable or increasing, subject to natural processes, including erosion and succession. Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining function and diversity of favourable species and managing levels of negative species.

1220 Perennial vegetation of stony banks Maintain favourable conservation condition

Area unknown; The habitat area is stable or increasing, subject to natural processes, including erosion and succession. Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining function and diversity of favourable species and managing levels of negative species.


Restore favourable conservation condition

4.06ha, Further unsurveyed areas may be present within the site; The habitat area is stable or increasing, subject to natural processes, including erosion and succession. Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining function and diversity of favourable species and managing levels of negative species.

1395 Petalwort Petalophyllum ralfsii Maintain favourable conservation condition

Three known populations; No decline in population distribution or size. No decline in area of suitable habitat. Maintain favourable hydrological conditions and vegetation structure.

13




6.53ha, Further unsurveyed areas may be present within the site; The habitat area is stable or increasing, subject to natural processes. Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining function and diversity of favourable species and managing levels of negative species.

1833 Slender Naiad Najas flexilis Maintain favourable conservation condition

No change to the spatial extent of Najas flexilis within the lake, subject to natural processes. Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining the population distribution and, viability and habitat quality and extent.

2110 Embryonic shifting dunes Restore favourable conservation condition





21A0 Machairs (*in Ireland) Restore favourable conservation condition

276.29ha; The habitat area is stable or increasing, subject to natural processes, including erosion and succession.

Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining function and diversity of favourable species and managing levels of negative species.

14


3110 Oligotrophic waters containing very few minerals of sandy plains

(Littorelletalia uniflorae) Maintain favourable conservation condition

The distribution and classification of lake habitats in the c.29 lakes/ponds in the SAC is not fully known and, therefore, habitat area targets cannot be set. Area stable or increasing subject to natural processes. Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining water quality and function and diversity of typical species.


Maintain favourable conservation condition

Area unknown: The habitat area is stable or increasing, subject to natural processes. Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining water quality and function and diversity of typical species.

4030 European dry heaths Maintain favourable conservation condition

Area unknown: The habitat area is stable or increasing, subject to natural processes. Targets are identified that focus on a wide range of attributes with the ultimate goal of maintaining function and diversity of favourable species and managing levels of negative species.




6210 Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco-Brometalia) (*important orchid sites)


6410 Molinia meadows on calcareous,

peaty or clayey‐silt‐laden soils (Molinion caeruleae)



15





7030 Alkaline fens Maintain favourable conservation condition


16

Figure 3. Natura 2000 sites adjacent to Slyne Head Peninsula SAC (site code 002074) (NPWS 2015a).

17

Table 2: Natura Sites adjacent to Slyne Head Peninsula SAC and qualifying features with initial screening assessment on likely interactions with

aquaculture activities.

NATURA SITE QUALIFYING FEATURES

[HABITAT CODE] AQUACULTURE SCREENING

Slyne head to

Ardmore Point

Islands SPA

(004159)

Barnacle Goose (Branta leucopsis) [A045]

Sandwich Tern (Sterna sandvicensis) [A191]

Arctic Tern (Sterna paradisaea) [A194]

Little Tern (Sterna albifrons) [A195]

No spatial overlap or likely interactions with aquaculture activities in Slyne Head Peninsula SAC – excluded from further analysis

Connemara Bog

Complex SPA

(004181)

Cormorant (Phalacrocorax carbo) [A017]

Merlin (Falco columbarius) [A098]

Golden Plover (Pluvialis apricaria)

[A140]

Common Gull (Larus canus) [A182]

Common gull have demonstrated mixed interactions with Aquaculture structures, with negative interactions when high numbers present. Given the SPA supports 40 breeding pairs (relatively low numbers) it is likely that they will not negatively interact with intertidal aquaculture activities in Mannin Bay. Furthermore, It is not clear that gull species will rely to any great extent on the intertidal habitats found in Slyne Head Peninsula SAC, especially for those that are set at a distance from the SAC particularly if alternative feeding habitat is available, e.g., terrestrial or open water. There is no spatial overlap or likely interactions with aquaculture activities in the Slyne Head Peninsula SAC –exclude from further analysis.

Slyne Head Islands

SAC (000328)

Reefs [1170]

Halichoerus grypus (Grey Seal) [1364]


West Connaught

Coast SAC (002998) Tursiops truncatus (Common Bottlenose Dolphin) [1349]


Connemara Bog

Complex SAC

(002034)

Coastal lagoons [1150]

Reefs [1170]

Oligotrophic waters containing very few minerals of sandy plains (Littorelletalia uniflorae) [3110]

Oligotrophic to mesotrophic standing waters with vegetation of the

Specific features (species) with marine phases (i.e., Salmo salar and Lutra lutra) within this SAC, do not have any attributes that interact with the aquaculture activities found in Mannin Bay. These attributes are specific to freshwater and/or confined to the southern portion of the SAC (migration from Cashla and Owenmore Rivers) and are therefore, sufficiently far removed such that interaction with aquaculture activities in Mannin Bay are highly unlikely. These attributes are excluded from further analysis.

For all other qualify features listed there is no spatial overlap or likely interactions with aquaculture activities in Slyne Head Peninsula SAC – excluded from further analysis.

18

NATURA SITE QUALIFYING FEATURES

[HABITAT CODE] AQUACULTURE SCREENING

Littorelletea uniflorae and/or Isoeto-Nanojuncetea [3130]

Natural dystrophic lakes and ponds [3160]

Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation [3260]

Northern Atlantic wet heaths with Erica tetralix [4010]

European dry heaths [4030]

Molinia meadows on calcareous, peaty or clayey-silt-laden soils (Molinion caeruleae) [6410]

Blanket bogs (* if active bog) [7130]

Transition mires and quaking bogs [7140]

Depressions on peat substrates of the Rhynchosporion [7150]

Alkaline fens [7230]

Old sessile oak woods with Ilex and Blechnum in the British Isles [91A0]

Euphydryas aurinia (Marsh Fritillary) [1065]

Salmo salar (Salmon) [1106]

Lutra lutra (Otter) [1355]

Najas flexilis (Slender Naiad) [1833]

19

5 Details of the proposed plans and projects

5.1 Aquaculture

Aquaculture in the Slyne Head Peninsula SAC is comprised of shellfish and finfish culture (Figure 4).

Descriptions of spatial extents of existing and proposed activities within the qualifying interests of Slyne

head Peninsula SAC were calculated using coordinates of activity areas in a GIS. The spatial extent

of the various aquaculture activities (current and proposed) overlapping the habitat features is

presented in Table 3 (data provided by DAFM).

5.1.1 Oyster Culture

There are three oyster culture licenses currently in operation within the SAC. At two of these sites the

pacific oyster Crassostrea gigas is licenced for intensive farmed using bags & trestles, the remaining

site involves the extensive culture of C gigas on the seafloor. A single operator runs all of the shellfish

aquaculture in Mannin Bay, and has been growing C. gigas on two sites in bay since 2001. The seed

is all diploid, is sourced from France (Naissan), and is put to sea in March each year on intertidal trestles

in small gauge bags within the five-hectare site. Several times a year the seed is taken to a shed close

to the shore for grading, returned to mesh bags of appropriate size and replaced on the trestles. In the

second year, some half-grown oysters are grown on the four-hectare seabed site to later be harvested

by trawl, but the vast majority is finished intertidally on trestles. Harvesting takes place in November

and December. Dedicated access routes exist for sites not accessed by boat and are provided in Figure

5. These routes are typically single or double tracks that run along the most stable shore from the point

of entry to the aquaculture sites.

There are two new applications for the culture of oysters on bags and trestles in the intertidal using the

methodologies identified above.

5.1.2 Salmon Culture

Mannin Bay Salmon Company was established in 1988. It operates a single salmon on-growing site

within the Slyne Head SAC, adjacent to Curhownagh Quay, where there are six cages. This site is

used for on-growing yearling fish sourced from winter sites in Bertraghboy or Ballinakill Bays. Fish are

put on site around March time, and grown on for up to six months. Feeding is done automatically and

feed boats are supplied from the quay at Curhownagh. Grading takes place in-situ using grading nets.

Fish are harvested at around 3.5kg from the quay and taken for processing at Kilkieran. Blood and

other effluent of harvest are disposed of at the processing plant.

20

Figure 4. Aquaculture sites in Slyne Head Peninsula SAC (site code 002074).

21

Figure 5: Access routes to aquaculture sites in Slyne Head Peninsula SAC (site code 002074) and relevant Marine Community types (access routes not drawn to

scale).

22

Table 3: Spatial extent (ha) of aquaculture activities overlapping with the qualifying interests

(1160 Large shallow inlets and bays, 1170 Reefs) in Slyne Head Peninsula SAC (site code

002074), presented according to culture, species, method of cultivation and license status.

Species Licence Number

Method

1160 - Large Shallow Inlets

and Bays (1,540 ha)

1170 - Reefs (571 ha)

Area (ha) % Feature Area (ha) % Feature

Oysters T9/517A Intensive 27.57 1.8 21.85 3.83


Oysters T9/417A Extensive 4.00 0.26 0.05 0.01

Oysters T9/417B Intensive 5.04 0.33 4.39 0.77

Oysters T9/417C Intensive 3.12 0.20 2.60 0.46

Salmon T9/140 Intensive 3.00 0.19 0.04 0.01

Access Routes 1.92 0.13 1.92 0.34

Totals 64.54ha 4.19% 39.1ha 6.86%

23

6 Natura Impact Statement for the proposed activities

The potential ecological effects of activities on the conservation objectives for the site relate to the

physical and biological effects of aquaculture structures and human activities on designated species,

intertidal and sub-tidal habitats and invertebrate communities and biotopes within those broad habitat

types. The overall effect on the conservation status will depend on the spatial and temporal extent of

aquaculture activities during the lifetime of the proposed plans and projects and the nature of each of

these activities in conjunction with the sensitivity of the receiving environment.

6.1 Aquaculture

Within the qualifying interest of the Slyne Head Peninsula SAC, the species cultured are:

Oysters (Crassostrea gigas), in suspended culture (bags & trestles) and subtidally on the

seafloor.

Atlantic salmon (Salmo salar) in net pens.

Details of the potential biological and physical effects of these aquaculture activities on the habitat

features, their sources and the mechanism by which the impact may occur are summarised in Table 4,

below. The impact summaries identified in the table are derived from published primary literature and

review documents that have specifically focused upon the environmental interactions of mariculture

(e.g. Black 2001; McKindsey et al. 2007; NRC 2010; O’Beirn et al. 2012; Cranford et al. 2012; ABPMer

2013a-h).

Filter feeding organisms, for the most part, feed at the lowest trophic level, usually relying primarily on

ingestion of phytoplankton. The process is extractive in that it does not rely on the input of feedstuffs

in order to produce growth. Suspension feeding bivalves such as oysters and mussels can modify their

filtration to account for increasing loads of suspended matter in the water and can increase the

production of faeces and pseudofaeces (non-ingested material) which result in the transfer of both

organic and inorganic particles to the seafloor. This process is a component of benthic-pelagic coupling

(Table 4). The degree of deposition and accumulation of biologically derived material on the seafloor

is a function of a number of factors discussed below.

One aspect to consider in relation to the culture of shellfish is the potential risk of alien species arriving

into an area among consignments of seed or stock sourced from outside of the area under

consideration. When the seed is sourced locally (e.g. mussel culture) the risk is likely zero. When seed

is sourced at a small size from hatcheries in Ireland, the risk is also small. When seed is sourced from

hatcheries outside of Ireland (this represents the majority of cases particularly for oyster culture

operations) the risk is also considered small, especially if the nursery phase has been short. When ½-

grown stock (oysters and mussels) is introduced from another area (e.g. France, UK) the risk of

introducing alien species (hitchhikers) is considered greater given that the stock will have been grown

in the wild (open water) for a prolonged period (i.e. ½-grown stock). Furthermore, the culture of a non-

native species (e.g. the Pacific Oyster - Crassostrea gigas) may also present a risk of

24

Table 4: Potential indicative environmental pressures of aquaculture activities within the qualifying

interests of the Slyne Head Peninsula SAC (site code 002074).

Metier/

Activity

Pressure category

Pressure Potential effects Equipment Duration

(days)

Time of

year

Factors constraining the activity

Aquaculture - Shellfish

Intertidal Oyster Culture

Physical

Current alteration

Structures may alter the current regime and resulting increased deposition of fines or scouring.

Trestles and bags, bouchot poles, frames and service equipment

365 All year

At low tide only

Surface disturbance

Ancillary activities at sites, e.g. servicing, transport increase the risk of sediment compaction resulting in sediment changes and associated community changes.

Shading Prevention of light penetration to seabed potentially impacting light sensitive species

Biological

Non-native species introduction

Potential for alien species to be included with culture stock (hitch-hikers).

Disease risk

In event of epizootic the ability to manage disease in uncontained subtidal populations is compromised.

Organic enrichment

Faecal and pseudofaecal deposition on seabed potentially altering community composition

Subtidal Shellfish culture

Physical

Surface disturbance

Abrasion at the sediment surface and redistribution of sediment

Dredge Once quarterly

Seasonal

Weather for site access. Size of shellfish and market constraints

Shallow disturbance

Sub-surface disturbance to 25mm

Biological

Monoculture

Habitat dominated by single species and transformation of infaunal dominated community to epifaunal dominated community.

Good site management and animal husbandry.

By-catch mortality

Mortality of organisms captured or disturbed during the harvest or process, damage to structural fauna of reefs

Dredge Once quarterly

Seasonal

Non-native species introduction

Potential for alien species to be included with culture stock (hitch-hikers). Naturalization of non -native species.

Disease risk

In event of epizootic the ability to manage disease in uncontained subtidal shellfish populations would likely be compromised. The risk introduction of disease causing organisms by introducing seed originating from the ‘wild’ in other jurisdictions

Nutrient exchange

Increased primary production. N2 removal at harvest or denitrification at sediment surface

25

Table 4 cont'd: Potential indicative environmental pressures of aquaculture activities within the qualifying

interests of the Slyne Head Peninsula SAC (site code 002074).

Aquaculture - Finfish

Salmon Biological

Nutrient exchange

Increased primary production. N2 removal at harvest or denitrification at sediment surface.

365 Good site management and animal husbandry.

Fallow periods when no fish in the cages in the water.

Organic enrichment

Faecal and waste food on seabed potentially altering community composition

365

Disease risk

Management of parasites and diseases in finfish culture is an ongoing challenge to culturist.

365

26

establishment of this species in the SAC. Recruitment of C. gigas has been documented in a number

of bays in Ireland and appears to have become naturalised (i.e. establishment of a breeding population)

in two locations (Kochmann et al. 2012; 2013) and may compete with the native species for space and

food. The residence time within Mannin Bay is 21days, which is the threshold for an increased risk of

the retention of C. gigas in the system and therefore recruitment of the Pacific Oyster has the potential

to occur. Furthermore, the risk of successful oyster reproduction is increased with the culture of oysters

subtidally (on the seafloor) where higher reproductive condition in oysters has been measured (Mag

Aoidh, 2011).

Suspended Shellfish Culture: Suspended culture may result in faecal and pseudo-faecal material

falling to the seabed. In addition, the loss of culture species to the seabed is also a possibility. The

degree to which the material disperses away from the location of the culture system (longlines or

trestles) depends on the density of mussels on the line, the depth of water and the current regime in

the vicinity. Cumulative impacts on seabed, especially in areas where assimilation or dispersion of

pseudofaeces is low, may occur over time. A number of features of the site and culture practices will

govern the speed at which pseudofaeces are assimilated or dispersed by the site. These relate to:

Hydrography – will govern how quickly the wastes disperse from the culture location and the

density at which they will accumulate on the seafloor.

Turbidity in the water - the higher the turbidity the greater the production of pseudo-faeces and

faeces by the filter feeding animal and the greater the risk of accumulation on the seafloor.

Density of culture – suspended mussel culture is considered a dense culture method with high

densities of culture organisms over a small area. The greater the density of organisms the

greater the risk of accumulations of material. The density of culture organisms is a function of:

o depth of the site (shallow sites have shorter droppers and hence fewer culture

organisms)

o the husbandry practices proper maintenance will result in optimum densities on the

lines in order to give high growth rates as well as reducing the risk of drop-off of culture

animals to the seafloor and sufficient distance among the longlines to reduce the risk

of cumulative impacts in depositional areas.

In addition, placement of structures associated with shellfish culture can influence the degree of light

penetration to the seabed. This is likely important for organisms and habitats e.g. Maërl and seagrasses

that need sun light for production. Trestles or lines will to a degree limit light penetration to the seabed

and may therefore reduce production of photosynthesising species. Intertidal shellfish culture:

Oysters are typically cultured in the intertidal zone using a combination of plastic mesh bags and

trestles. Their specific location in the intertidal is dependent upon the level of exposure of the site, the

stage of culture and the accessibility of the site. The habitat impact from oyster trestle culture is typically

localised to areas directly beneath the culture systems and are broadly similar to those highlighted

above. The physical presence of the trestles and bags may reduce water flow and allow suspended

material (silt, clay as well as faeces and pseudo-faeces) to fall out of suspension to the seafloor. The

build-up of material will typically occur directly beneath the trestle structures and can result in

27

accumulation of fine, organically rich sediments. These sediments may result in the development of

infaunal communities distinct from the surrounding areas. Whether material accumulates is dictated by

a number of factors, including:

Hydrography – low current speeds (or small tidal range) may result in material being deposited directly

beneath the trestles. If tidal height is high and large volumes of water moved through the culture area

an acceleration of water flow can occur beneath the trestles and bags, resulting in a scouring effect or

erosion and no accumulation of material.

Turbidity of water – as with suspended mussel culture, oysters have very plastic response to increasing

suspended matter in the water column with a consequent increase in faecal or pseudo-faecal

production. Oysters can be cultured in estuarine areas (given their polyhaline tolerance) and

consequently can be exposed to elevated levels of suspended matter. If currents in the vicinity are

generally low, elevated suspended matter can result in increase build-up of material beneath culture

structures.

Density of culture – the density of oysters in a bag and consequently the density of bags on a trestle

will increase the likelihood of accumulation on the seafloor. In addition, if the trestles are located in

close proximity a greater dampening effect can be realised with resultant accumulations. Close

proximity may also result in impact on shellfish performance due to competitive interactions for food.

Exposure of sites - the degree to which the aquaculture sites are exposed to prevailing weather

conditions will also dictate the level of accumulated organic material in the area. As fronts move through

culture areas, increased wave action will resuspend and disperse material away from the trestles.

Shading may be an issue as a consequence of the structures associated with intertidal oyster culture.

The racks and bags are held relatively close to the seabed and therefore may shade sensitive species

(e.g. seagrasses) found underneath.

Sub-tidal shellfish culture i.e. bottom culture of oysters/mussels: This activity involves relaying

shellfish on the seabed. There may be increased enrichment due to production of faeces and

pseudofaeces. The existing in-faunal community may be changed as a result. Seabed habitat change

may also result as a result of dredging during maintenance and harvesting. Uncontained sub-tidal

shellfish culture will lead to change in community structure and function through the addition, at high

percentage cover, of an epi-benthic species (living on the seabed) to an infaunal sedimentary

community.

The activities associated with this culture practice (dredging of the seabed) are considered disturbing

which can lead to removal and/or destruction of infaunal species and changes to sediment composition.

In addition, the location of large numbers of a single epifaunal species onto what is, in essence, an

infaunal dominated system will likely result in a change to the habitat.

Physical disturbance caused by compaction of sediment from foot traffic and vehicular traffic.

Activities associated with the culture of intertidal shellfish include the travel to and from the culture sites

28

and within the culture sites using tractors and trailers as well as the activities of workers within the site

boundaries.

Other considerations: The high density of the culture organisms in the bottom cultivation method can

lead to exclusion of native biota.

Due to the nature of the culture methods (high-density), the risk of transmission of disease within

cultured stock is high. However, given that Crassostrea gigas does not appear to occur in the wild the

risk of disease transmission to ‘wild’ stock is considered low. The risk of disease transmission from

cultured oysters to other species is unknown.

Finfish Culture: Within the Slyne Head Peninsula SAC, there is 1 licenced marine finfish culture site

assigned for the culture of salmon.

Finfish culture differs from shellfish culture in that there is an input of feed into the system and therefore

a net input of organic matter to the system. This material will be found in the system in the form of

waste feed (on the seafloor), solid waste (faeces), waste because of net cleaning all of which usually

accumulates on the seafloor and dissolved material (predominantly fractions rich in nitrogen). For the

most part, the majority of organic material builds up on the seabed generally in and around the footprint

of the salmon cages with a ‘halo’ effect evident in areas where dispersion occurs driven by local

hydrographic conditions. This is typically referred to near-field effects. Similar to shellfish, the quantity

of material that might accumulate on the seabed will be a function of the quantity of fish held in cages,

the stage of culture, the health of the fish (unhealthy fish will generally eat less), husbandry practices

(are the fish fed too much too quickly?), the physical characteristic of the solid particles and, as

mentioned above, hydrographic conditions.

Wildish et al. (2004) and Silvert and Cromey (2001) both summarize the factors (listed above) that

govern the level of dispersion of material from the cages to the seafloor. Many of the factors are

subsequently incorporated into modelling efforts, which are used to predict likely levels of impact. The

impact of organic matter on sedimentary seafloor habitat typically evolves after the gradient defined by

Pearson-Rosenberg (1978), whereby as the level of organic enrichment increases the communities

(macrofaunal species number and abundance) found within the sedimentary habitats will also change.

Typically, low levels of enrichment facilitates an increase in species abundance and biomass followed

by a decrease in all biological metrics as enrichment increases to a point where azoic conditions prevail

and no biota are found. The impact on biota is a consequence of the decrease in oxygen and a build-

up of by-products such as ammonia and sulphides brought about by the breakdown of the organic

particles, which are considered toxic to marine biota. The shift from an oxygenating to reducing

environment in the sediment could be such that the effect is mirrored in the water column as well (i.e.

reduction in oxygen levels). The output of dissolved material resulting from finfish cages is typically in

the form of ammonia, phosphorous and dissolved organic carbon (DOC) originating directly from the

culture organisms, or from the feed and/or faecal pellets. Similar to particulate waste, the impact of

dissolved material is a function of the extent (intensity) of the activity and properties of the receiving

environment (e.g., temperature, flushing time). While elevated levels of nutrient have been reported

near fish farms, no significant effect on chlorophyll has been demonstrated (Pearson and Black, 2000).

29

Diseases: It is likely that the first outbreaks of infectious diseases in marine aquaculture operations

were caused by pathogens originating in wild hosts and as culture extent and intensity increases the

transmission of pathogens (back) to the wild fish stocks is a likely consequence (OIE, 2004; DIPNET

2006). The result of such pathogen transmission back to wild fish is however, unknown, as reports of

clinical effects or significant mortality in wild fish populations are largely unavailable. Numerous

reviews, models, risk assessments and risk analysis have been carried out or developed in order to

determine the potential for disease interaction and pathogen exchange between farmed and wild finfish

(OIE 2004, Bricknell et al. 2006, DIPNET 2006, and Peeler et al. 2007). On foot of these outputs, there

is general acceptance among scientists and managers that pathogens can be transmitted between

organisms used in mariculture and those found in the wild and vice-versa (ICES 2014).

The risk of infection in marine organisms, are influenced by a number of environmental factors including

temperature, salinity and dissolved oxygen (Grant and Jones 2011), as well as factors particular to the

biology of pathogen, e.g., replication rates, virulence. Transmission of pathogens is facilitated by one

or a combination of three mechanisms, i.e., horizontal, vertical and vector-borne. Horizontal

transmission refers to the direct movement through the water column of a pathogen between

susceptible individuals and the open design of most mariculture cages allows the potential for

bidirectional transmission of pathogens between wild and captive fish (Johansen et al. 2011). Vertical

transmission involves the passing of a pathogen with milt or eggs, resulting in infection among offspring.

Pathogens can also be spread by a third host or vector. Vectors can include other parasites, fish,

piscivorous animals or inanimate objects such as clothing, vessels or equipment.

Disease transmission within culture systems is a primary concern of operators and because of

monitoring and screening, a far greater knowledge base relating to disease causing organisms and

their transmission is available relating to cultured stocks rather than wild stocks. As a result of the lack

of empirical data relating to diseases specific to wild stocks, it has been difficult to partition population

effects in wild-stocks caused by diseases from those caused by other processes (ICES 2010). Ireland

enjoys a high health status (Category 1) in relation to the fish/shellfish on farms, in rivers and lakes and

remains free of many diseases that occur in other countries (www.fishhealth.ie). In Ireland, there are

programmes in place that govern the movement of (fish and shellfish) stock for on-growing among sites.

These movement controls are supported by a risk-based fish health surveillance programme which is

operated on a nationwide basis by the Marine Institute, in co-operation with private veterinary

practitioners. Ireland is currently free of the following salmonid diseases covered by (Council Directive

2006/88/EC):

Infectious Salmon Anaemia (ISA)

Viral Haemorrhagic Septicaemia (VHS)

Infectious Haematopoetic Necrosis (IHN)

Gyrodactylosis

Apart from the diseases listed under EU legislation, routine tests are carried out for other diseases

found in marine salmonids in Ireland e.g. Pancreas Disease (PD), Infectious Pancreatic Necrosis (IPN),

Furunculosis etc. Such diseases are present in Ireland and whilst their control is not covered by

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32006L0088:EN:NOT

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32006L0088:EN:NOT

30

legislation, all finfish farmers in the country have agreed to comply with the parameters of a Code of

Practice and Fish Health Handbook, jointly agreed between the Marine Institute and the Irish Farmers

Association (IFA). These documents cover all aspects of disease prevention and control on Irish fish

farms with the twin objectives of minimising disease outbreaks and of dealing with them in a timely and

responsible fashion, should they arise. The net outcome should be a decrease in mortality rates on fish

farms and a corresponding decrease in potential pathogen transfer to wild stocks. Ensuring the ongoing

good health of farmed stocks and the regular monitoring of environmental conditions will also help to

minimise the disease impacts, which may be caused by infection from wild stocks in the vicinity of the

cages.

Disease Management: Council Directive 2006/88/EC on animal health requirements for aquaculture

animals and products thereof, and on the prevention and control of certain diseases in aquatic animals

form the legislative basis that governs the monitoring and management of disease outbreaks in

mariculture operations in Ireland. For diseases not listed in this Directive, a Code of Practice and Fish

Health Handbook has been developed jointly by the State and industry with the primary objectives of

disease prevention and control.

The adoption of chemotherapeutants and some vaccination programmes have assisted in reducing the

abundance and spread of many pathogens. In addition, the principles outlined in the Fish Health

Handbook mentioned above such as improved biosecurity practices on farms, fallowing sites to break

transmission cycles, disease testing of fish prior to transfer, single year class stocking, coordinating

treatments and harvesting within embayments etc have mitigated the transmission of pathogenic

organisms.

In summary, it is clear that a number of broad factors govern the transfer of diseases between

susceptible organisms. While statistical correlations have been demonstrated in terms of abundance of

cultured fish and disease occurrence in wild fishes, extreme caution must apply in terms of applying

causality. It is important to note that the only way to determine the link between disease outbreaks in

aquaculture installations and detection in wild fish is to empirically measure or observe pathogen

transfer. Furthermore, when a risk presents, it not clear if the impact on the wild fish is expressed at the

individual and/or population level. While certain effects have been demonstrated at the level of

individuals, research has not yet clearly identified or quantified these links at the population level.

Disease management programmes operated on a statutory basis by the State and on a voluntary basis

by industry via Codes of Practice, assist in ensuring that pathogen transfer both to and from farmed fish

is kept to a minimum.

Parasites: Sea lice are a group of parasitic copepods found on fish worldwide. There are two species

of sea lice commonly found on cultured salmonids in marine conditions around the coast of Ireland,

Caligus elongatus Nordmann, which infests over eighty different species of marine fish, and

Lepeophtheirus salmonis Krøyer (the salmon louse), which infests only salmon, trout and closely related

salmonid species. L. salmonis, the salmon louse, is the more serious parasite on salmon, both in terms

of its prevalence and effects. It has been reported as a common ecto-parasite of both wild and farmed

salmon at sea.

31

Returning wild salmon have been found to carry an average of 10 or more adult egg bearing females

on their return to the Irish coastline (Copley et al. 2005; Jackson et al. 2013a) from their feeding grounds

in the Atlantic. Having evolved their relationship with salmon and trout over many millennia, the parasite

is well adapted to target its host species and it is ubiquitous to all the coastal waters around Ireland and

indeed throughout the range of the Atlantic salmon (Jackson et al. 2013b).

Salmon, whether wild or cultured, go to sea from fresh water free of sea lice and only pick up the

infestation after they enter the marine phase of their lives. Sea lice infestations can inflict damage to

their hosts through their feeding activity on the outside of the host's body by affecting the integrity of the

fish’s epithelium, which impairs its osmoregulatory ability and leaves the fish open to secondary

infections. In extreme cases this can lead to a reduced growth rate and an increased morbidity in

affected individuals.

Marine finfish farms are perceived by certain sectors to be problematic because of the proximity of some

operations to river mouths and a concern over the possible impact on wild migratory salmonid fisheries

through infestation with sea lice. The studies on the impacts of lice infestation on smolts (Jackson et

al. 2011, 2013) suggest that sea lice induced mortality on outwardly migrating smolts is likely a minor

and irregular component of marine mortality in the stocks studied. This conclusion is further supported

by the finding of no correlation between the presence of aquaculture and the performance of adjacent

wild salmon stocks.

Parasite Management: Based on the evidence from targeted studies, the information collected as part

of the National Sea Lice Monitoring and Control Programme, scientific reports published by the Marine

Institute, and in-line with external advice, it is concluded that there is a robust and effective management

programme in place in Ireland to control sea lice infestation on farmed fish. Furthermore, there is no

empirical evidence to support the suggestion that the fisheries are being adversely affected by unusual

levels of sea lice infestation, whether of farmed origin or from other sources.

32

7 Screening of Aquaculture Activities

A screening assessment is an initial evaluation of the possible impacts that activities may have on the

qualifying interests. The screening is a filter, which may lead to exclusion of certain activities or

qualifying interests from appropriate assessment proper, thereby simplifying the assessments, if this

can be justified unambiguously using limited and clear-cut criteria. Screening is a conservative filter

that minimises the risk of false negatives.

In this assessment screening of the qualifying interests against the proposed activities is based primarily

on spatial overlap i.e. if the qualifying interests overlap spatially with the proposed activities; then

significant impacts due to these activities on the conservation objectives for the qualifying interests is

not discounted (not screened out) except where there is absolute and clear rationale for doing so.

Where there is relevant spatial overlap full assessment is warranted. Likewise, if there is no spatial

overlap and no obvious interaction is likely to occur, then the possibility of significant impact is

discounted and further assessment of possible effects is deemed not to be necessary. Table 3 provides

spatial overlap extent between designated habitat features and aquaculture activities within the

qualifying interests of the Slyne Head Peninsula SAC.

7.1 Aquaculture Activity Screening

Where the overlap between an aquaculture activity (and access routes) and a feature is zero and there

is no likely interaction identified, it is screened out and not considered further. The Annex I habitat of

Coastal Lagoons (1150) has no spatial overlap with (existing and proposed) aquaculture activities and

is therefore excluded from further consideration in this assessment.

Table 3 highlights the spatial overlap between (existing and proposed) aquaculture activities (and

access routes) and habitat features (i.e. Large shallow inlets and bays (1160) and Reefs (1170)).

Tables 5 and 6 provide an overview of overlap of aquaculture activities and specific community types

(identified from Conservation Objectives) within the broad habitat features 1160 and 1170, respectively.

Where the overlap between an aquaculture activity and a qualifying feature is zero and there is no likely

interaction, it is screened out and not considered further in the assessment. Therefore the following

qualifying features (habitats and species) are excluded from further consideration in this assessment:

1150 Coastal lagoons*

1210 Annual vegetation of drift lines

1220 Perennial vegetation of stony banks


1395 Petalwort Petalophyllum ralfsii


1833 Slender Naiad Najas flexilis

33

2110 Embryonic shifting dunes


21A0 Machairs (*in Ireland)

3110 Oligotrophic waters containing very few minerals of sandy plains

(Littorelletalia uniflorae)



5130 European dry heaths

6210 Semi-natural dry grasslands and scrubland facies on calcareous

substrates (Festuco-Brometalia) (*important orchid sites)

6410 Molinia meadows on calcareous, peaty or clayey-silt-laden soils (Molinion

caeruleae)


7230 Alkaline fens

Furthermore, of the eight community types (see Tables 5, 6) listed under the qualifying habitat interests

of the SAC two (Intertidal sand with Enchytraeidae community complex and Mobile intertidal sand with

polychaetes community complex) have no spatial overlap between them and any aquaculture activities.

On this basis, the community types Intertidal sand with Enchytraeidae community complex and Mobile

intertidal sand with polychaetes community complex are excluded from further analysis of aquaculture

interactions.

When overlap was observed it was estimated in a GIS application and calculated on the basis of

coverage of specific activity (representing different pressure types), licence status (licenced or

application) intersecting with designated conservation features and/or sub-features (community types).

34

Table 5: Habitat utilisation i.e. spatial overlap in hectares and percentage (given in parentheses) of aquaculture activity over community types within the qualifying

interest 1160 - Large Shallow Inlet and Bays (Spatial data based on licence database provided by DAFM).

Habitat data provided in NPWS (2015a, 2015b). (Int = Intensive; Ext = Extensive; L = Licensed).

Large Shallow Inlet and Bays (1160)-MCT

Species Site

Intertidal reef community

complex - 159 ha

Laminaria-dominated community

-198 ha

Subtidal sand with

polychaetes and bivalves community

complex – 288 ha

Subtidal sand with Kurtiella

bidentata community

complex - 574 ha

Zostera-dominated community

complex - 33 ha

Maërl-dominated community

complex - 261 ha

Intertidal sand with

Enchytraeidae community

complex – 14 ha

Mobile intertidal sand

with polychaetes community

complex - 11 ha

Area % Area % Area % Area % Area % Area % Area % Area %

Oyster-Int (A) T9/517A 14.83 9.32 7.01 3.5 - - 3.42 0.60 0.89 2.70 0.004 <0.01 - - - -

Oyster-Int (A) T9/518A 5.61 3.53 2.64 1.34 - - 0.77 0.13 2.4 7.27 8.34 1.53 - - - -

Oyster-Ext (L) T9/417A <0.01 <0.01 0.045 0.02 3.95 1.37 - - - - - - - - - -

Oyster-Int (L) T9/417B 1.35 0.85 3.04 1.54 0.65 0.23 - - - - - - - - - -

Oyster-Int (L) T9/417C 1.50 0.94 1.1 0.56 0.14 0.05 - - - - - - - - - -

Salmon (L) T9/140 <0.01 <0.01 0.038 0.02 2.96 1.03 - - - - - - - - - -

Access Routes 1.71 1.08 0.02 <0.01 - - - - - - - - - - - -

Totals 25.02 ha

15.7 %

13.89 ha

6.99 %

7.7 ha

2.68 %

4.19 ha

0.73 %

3.29 ha

9.97 %

8.34 ha

1.54 ha

- - - -

35

Table 6: Habitat utilisation i.e. spatial overlap in hectares and percentage (given in parentheses) of aquaculture activity over community types within the qualifying

interest 1170 Reefs (Spatial data based on licence database provided by DAFM). Habitat data provided in NPWS (2015a, 2015b).

Reefs (1170) – MCT

Culture Species Site Method

Intertidal reef community complex

(350ha)


(220ha)

Area (ha) % Feature Area (ha) % Feature



Oysters T9/417 A Extensive <0.01 <0.01 0.045 0.02

Oysters T9/417 B Intensive 1.35 0.39 3.04 1.38

Oysters T9/417 C Intensive 1.48 0.42 1.10 0.5

Salmon T9/140 Intensive - - 0.04 0.02

Access Routes 1.71 0.49 0.02 <0.01

Totals 24.99ha 6.99% 13.91ha 6.32%

36

8 Assessment of Aquaculture Activities

8.1 Determining significance

The significance of the possible effects of the proposed activities on habitats, as outlined in the Natura

Impact Statement (Section 6) and subsequent screening exercise (Section 7), is determined here in the

assessment. The significance of effects is determined on the basis of Conservation Objective guidance

for constituent habitats and species (Figure 2 and NPWS 2015a, 2015b).

Habitats and species that are key contributors to biodiversity and which are sensitive to disturbance

should be afforded a high degree of protection i.e. thresholds for impact on these habitats is low and

any significant anthropogenic disturbance should be avoided. Within the Slyne Head Peninsula SAC,

the qualifying habitats/species considered subject to potential disturbance and therefore, carried further

in this assessment are:

- 1160 Large shallow inlets and bays

- 1170 Reefs

For broad habitats and sedimentary communities (Figure 2) significance of impact is determined in

relation to, first and foremost, spatial overlap (refer below Figure 6). Subsequent disturbance and the

persistence of disturbance are considered as follows:

1. The degree to which the activity will disturb the qualifying interest. By disturb is meant

change in the characterising species, as listed in the Conservation Objective guidance

(NPWS 2015b) for constituent communities. The likelihood of change depends on the

sensitivity of the characterising species to the activities in question. Sensitivity results from

a combination of intolerance to the activity and/or recoverability from the effects of the

activity (see Section 8.2 below).

2. The persistence of the disturbance in relation to the intolerance of the community. If the

activities are persistent (high frequency, high intensity) and the receiving community has a

high intolerance to the activity, (i.e. the characterising species of the communities are

sensitive and consequently impacted) then such communities could be said to be

persistently disturbed.

3. The area of communities or proportion of populations disturbed. In the case of community

disturbance (continuous or ongoing) of more than 15% of the community area it is deemed

significant. This threshold does not apply to sensitive habitats (e.g. Zostera, Maërl) where

any physical disturbance should generally be avoided.

Effects will be deemed to be significant when cumulatively they lead to long-term change (persistent

disturbance) in broad habitat/features (or constituent communities) resulting in an impact greater than

15% of the area.

37

Figure 6: Schematic outlining the determination of significant effects on habitats and marine community

types (MCT) (following NPWS 2015b).

8.2 Sensitivity and Assessment Rationale

This assessment used a number of sources of information in assessing the sensitivity of the

characterising species of each community recorded within the benthic habitats of the Slyne Head

Peninsula SAC. The primary source of information is a series of commissioned reviews by the Marine

Institute which identify habitat and species sensitivity to a range of pressures likely to result from

aquaculture and fishery activities (ABPMer 2013a-h). These reviews draw from the broader literature,

including the MarLIN Sensitivity Assessment (Marlin.ac.uk) and the AMBI Sensitivity Scale (Borja et al.,

2000) and other primary literature. Sensitivity of a species to a given pressure is the product of the

intolerance (the susceptibility of the species to damage, or death, from an external factor) of the species

38

to the particular pressure and the time taken for its subsequent recovery (recoverability is the ability to

return to a state close to that which existed before the activity or event caused change). Life history

and biological traits are important determinants of sensitivity of species to pressures from aquaculture.

In the case of species, communities and habitats of conservation interest, the separate components of

sensitivity (intolerance, recoverability) are relevant in relation to the persistence of the pressure:

For persistent pressures i.e. activities that occur frequently and throughout the year recovery

capacity may be of little relevance except for species/habitats that may have extremely rapid

(days/weeks) recovery capacity or whose populations can reproduce and recruit in balance with

population damage caused by aquaculture. In all but these cases and if sensitivity is moderate

or high then the species/habitats may be negatively affected and will exist in a modified state.

Such interactions between aquaculture and species/habitat/community represent persistent

disturbance. They become significantly disturbing if more than 15% of the community is thus

exposed (NPWS 2015a).

In the case of episodic pressures i.e. activities that are seasonal or discrete in time both the

intolerance and recovery components of sensitivity are relevant. If sensitivity is high but

recoverability is also high relative to the frequency of application of the pressure then the

species/habitat/community will be in favourable conservation status for at least a proportion of

time.

The sensitivities of the community types (or surrogates) found within the Slyne Head Peninsula SAC to

pressures similar to those caused by aquaculture (e.g. smothering, organic enrichment and physical

disturbance) are listed, where available, in Table 7. The sensitivities of species which are characteristic

(as listed in the Conservation Objective supporting document) of benthic communities to pressures

similar to those caused by aquaculture (e.g. smothering, organic enrichment and physical disturbance)

are listed, where available, in Table 8. The following guidelines broadly underpin the analysis and

conclusions of the species and habitat sensitivity assessment:

Sensitivity of certain taxonomic groups such as emergent sessile epifauna to physical pressures

is expected to be generally high or moderate because of their form and structure (Roberts et al.

2010). Also high for those with large bodies and with fragile shells/structures, but low for those

with smaller body size. Body size (Bergman and van Santbrink 2000) and fragility are regarded

as indicative of a high intolerance to physical abrasion caused by fishing gears (i.e. dredges).

However, even species with a high intolerance may not be sensitive to the disturbance if their

recovery is rapid once the pressure has ceased.

Sensitivity of certain taxonomic groups to increased sedimentation is expected to be low for

species which live within the sediment, deposit and suspension feeders; and high for those

sensitive to clogging of respiratory or feeding apparatus by silt or fine material.

Recoverability of species depends on biological traits (Tillin et al. 2006) such as reproductive

capacity, recruitment rates and generation times. Species with high reproductive capacity, short

39

generation times, high mobility or dispersal capacity may maintain their populations even when

faced with persistent pressures; but such environments may become dominated by these (r-

selected) species. Slow recovery is correlated with slow growth rates, low fecundity, low and/or

irregular recruitment, limited dispersal capacity and long generation times. Recoverability, as

listed by MarLIN, assumes that the impacting factor has been removed or stopped and the habitat

returned to a state capable of supporting the species or community in question. The recovery

process is complex and therefore the recovery of one species does not signify that the associated

biomass and functioning of the full ecosystem has recovered (Anand & Desrocher, 2004) cited

in Hall et al., 2008).

8.3 Assessment of the effects of aquaculture production on the Conservation Objectives for

habitat features in the Slyne Head Peninsula SAC.

Aquaculture pressures on a given habitat are related to vulnerability (spatial overlap or exposure of the

habitat to the equipment/culture organism combined with the sensitivity of the habitat) to the pressures

induced by culture activities. To this end, the location and orientation of structures associated with the

culture organism, the density of culture organisms, the duration of the culture activity and the type of

activity are all important considerations when considering risk of disturbance to habitats and species.

NPWS (2015b) provides lists of species characteristic of benthic communities of Reefs (1170) that are

defined in the Conservation Objectives.

1. Habitat Area - it is unlikely that the activities proposed will reduce the overall extent of

permanent habitat within the feature Reefs (1170). The habitat area is likely to remain stable.

2. Community Distribution - (conserve a range of community types in a natural condition).

This attribute considered interactions with the two constituent community types listed found

within the qualifying interest of Reefs (1170). The intertidal reef habitat, which is predominantly

bedrock, supports a Fucoid-dominated reef community complex that is dominated by brown

algal species and a faunal aspect typical of the rocky intertidal (i.e. gastropods, and barnacles).

A Laminaria- dominated community complex occurs on a mosaic of bedrock, cobbles and

boulders (0-14m) and is characterised by the kelp L. hyperborea with an associated flora and

fauna of fucoids and red algae with sponges, echinoderms and encrusting forms. Both Reef

community types have overlap with aquaculture activities (Table 7.1).

Table 7 lists the community types (or surrogates) and Table 8 lists the constituent taxa and

both provide a commentary of sensitivity to a range of pressures. The risk scores are derived

from a range of sources identified above. The pressures are listed as those likely to result from

intertidal oyster culture (bags and trestle) within the SAC.

Table 10 below identifies the likely interactions between the existing and proposed aquaculture

activities and the broad habitat feature of Reef (1170) and its constituent community types, with

a broad conclusion and justification on whether the activity is considered disturbing to the

feature in question. It must be noted that the sequence of distinguishing disturbance is as

highlighted above, whereby activities with spatial overlap on habitat features are assessed

40

further for their ability to cause persistence disturbance on the habitat. If persistent disturbance

is likely then the spatial extent of the overlap is considered further. If the proportion of the

overlap exceeds a threshold of 15% disturbance of the habitat then any further licencing should

be informed by interdepartmental review and consultation (NPWS 2015c).

While intertidal oyster culture might result in long-term change to the community type listed

above, existing and/or proposed activity including access route activity (individually or

combined) does not extend beyond 15% of the community type. Spatial analysis indicates that

combined existing and proposed cultivation activity overlap with approximately, 6.86% of the

habitat feature (1170) Reefs (see Table 3) and 6.99% and 6.32% of the constituent community

types, Intertidal reef community complex and Laminaria-dominated community, respectively

(Table 6).

The constituent communities identified in the Annex 1 feature, Large Shallow Inlets and Bays (1160)

are:

1. Intertidal sand with Enchytraeidae community complex

2. Mobile intertidal sand with polychaetes community complex

3. Zostera-dominated community complex

4. Maërl-dominated community complex

5. Subtidal sand with polychaetes and bivalves community complex

6. Subtidal sand with Kurtiella bidentata community complex

7. Intertidal reef community complex

8. Laminaria-dominated community complex

For Large Shallow Inlets and Bays (1160) there are a number of attributes (with associated targets)

relating to this habitat feature as well as its constituent community types (NPWS 2015b);

1. Habitat Area – it is unlikely that the activities proposed will reduce the overall extent of

permanent habitat within the feature Large Shallow Inlet and Bays. The habitat area is likely to

remain stable.

2. Community Distribution - (conserve a range of community types in a natural condition).

This attribute considered interactions with 6 of the community types listed above and exclude

two sensitive communities (i.e., Zostera-dominated community and Maerl-dominated

community). Of the 6 communities, 2 have no overlap with aquaculture activities. Therefore,

the following 4 community types, found within the qualifying interest 1160 of the SAC have

overlap with aquaculture activities:

1. Subtidal sand with polychaetes and bivalves community complex

2. Subtidal sand with Kurtiella bidentata community complex

3. Intertidal reef community complex

4. Laminaria-dominated community complex

41

The community types listed above will be exposed to differing ranges of pressures from

aquaculture activities. Some of these may result in more chronic and long term changes in

community composition which were considered during the assessment process. Such activities

in dredging for oyster which will result in physical disturbance to infanal communities and

longline mussel culture and finfish farming which results in organic loading on the seabed

resulting in biogeochemical changes to sediment and a likely change in faunal compositions –

whether this results in permanent change to the community type is unclear. Table 7, where

possible, lists the community types (or surrogates) and Table 8 lists the constituent taxa and

both provide a commentary of sensitivity to a range of pressures. The risk scores in Table 7

and 8 are derived from a range of sources identified above. The pressures are listed as those

likely to result from the primary aquaculture activities carried out in the Slyne Head Peninsula

SAC. Aquaculture activities in the Slyne Head Peninsula SAC comprises of both finfish and

shellfish production. Considered in the assessment are intertidal oyster culture (bag and

trestle), subtidal oyster on-bottom culture and Atlantic salmon culture in net pens.

Table 11 below identify the likely interactions between the relevant aquaculture activities and

the broad habitat feature (1160) and their constituent community types, with a broad conclusion

and justification on whether the activity is considered disturbing to the feature in question. It

must be noted that the sequence of distinguishing disturbance is as highlighted above, whereby

activities with spatial overlap on habitat features are assessed further for their ability to cause

persistence disturbance on the habitat. If persistent disturbance is likely then the spatial extent

of the overlap is considered further. If the proportion of the overlap exceeds a threshold of 15%

disturbance of the habitat (or each constituent community type) then any further licencing

should be informed by interdepartmental review and consultation (NPWS 2015b). In addition,

combined activities listed overlap with 4.19% of habitat feature (1160) Large Shallow Inlet and

Bay (Table 3). While some activities (e.g. bottom oyster and salmon cage culture) might result

in long-term change to the community types identified above (Tables 3 and 5).

3. Community Extent and Structure Targets – focusing upon Mearl and Zostera

communities

The focus of these attributes is primarily upon the 2 community types, Zostera-dominated

community and Maerl-dominated community. These communities are considered highly diverse

and sensitive community types which host a wide range of taxa. The ‘keystone’ species in each

community type (Maerl and Zostera) is considered important and sensitive in their own right.

Given the highly sensitive natures of these community types and constituent taxa (Tables 7 and

8), it is highly likely that aquaculture activities of any type which overlap these community types

and the pressures may result in long-term or permanent change to the extent of these

community types and the impact upon their structure and function cannot be discounted. This

effect will come about by the physical removal or damage caused by the activities on any of the

highly diverse taxa associated with these community types (Table 11). Maerl and Zostera are

42

very sensitive to the following which may result as a consequence of intertidal oyster culture

operations:

Maërl and Zostera are highly/very highly sensitive to Physical Pressure/Damage due to:

Trampling (access by foot/vehicle)

Surface/Shallow/Deep disturbance

Siltation (addition of fine sediments, pseudofaeces and fish food)

Smothering (addition of materials biological or non-biological to the surface)

Prevention of light reaching seabed/features

Maërl and Zostera are sensitive to Changes in Habitat:

Increase in turbidity/suspended sediment

Change in water flow due to permanent/semi-permanent structures placed in the water

column).

Organic enrichment-water column

Organic enrichment of sediments-sedimentation

Decrease in oxygen levels - sediment

Maërl and Zostera are sensitive to Biological Pressures:

Decrease in oxygen levels - water column

Introduction of non-native species

On the basis of the above, oyster culture in Mannin Bay (Slyne Head Peninsula SAC) is

considered disturbing to Maerl dominated community and Zostera Dominated Community.

Introduction of non-native species: As already outlined, oyster culture may present a risk in terms of

the introduction of non-native species as the Pacific oyster (Crassostrea gigas) itself is a non-native

species. Recruitment of C. gigas has been documented in a number of Bays in Ireland and appears to

have become naturalised (i.e. establishment of a breeding population) in two locations (Kochmann et

al 2012; 2013) and may compete with the native species for space and food. In addition to having large

number of diploid oysters in culture, Kochmann et al (2013) identified long residence times and large

intertidal areas as factors likely contributing to the successful recruitment of oysters in Irish bays. In

addition, a recent study (Kochmann and Crowe, 2014) has identified heavy macroalgal cover as a

potential factor governing successful recruitment, with higher cover resulting in lower recruitment.

Furthermore, MagAoidh (2011) demostrated that oysters grown subtidally have been shown to mature

earlier and have higher reproductive condition. Oyster production in the Slyne Head Peninsula SAC

does fulfil some of these criteria, i.e., subtidal culture and long residence time (i.e. approx 21 days –

Dabrowski 2011). Therefore the risk of successful establishment of the Pacific oyster in Slyne Head

Peninsula SAC cannot be discounted.

43

Table 7: Matrix showing the characterising community types sensitivity scores x pressure categories for habitats in Slyne Head Peninsula SAC (ABPMer 2013a-h). Table 9 provides the code for the various categorisations of sensitivity and confidence

Pressure Type Physical Damage Change in Habitat Quality Biological Pressures

Chemical Pollution

Ph

ysic

al

Pre

ssu

res

Community Type (EUNIS code)

Su

rface

Dis

turb

an

ce

Sh

allo

w D

istu

rba

nce

Dee

p D

istu

rba

nce

Tra

mplin

g-A

cce

ss b

y fo

ot

Tra

mplin

g-A

cce

ss b

y v

eh

icle

Extra

ctio

n

Silta

tion

(ad

ditio

n o

f fine s

ed

ime

nts

,

pse

ud

ofa

eces, fis

h fo

od

)

Sm

oth

erin

g (a

dditio

n o

f ma

teria

ls

bio

log

ica

l/no

n-b

iolo

gic

al to

the s

urfa

ce

)

Cha

ng

es to

sed

ime

nt c

om

positio

n-

incre

ased

co

ars

en

ess

Cha

ng

es to

sed

ime

nt c

om

positio

n-

incre

ased

fine

se

dim

en

t pro

portio

n

Cha

ng

es to

wa

ter flo

w

Incre

ase

in tu

rbid

ity/s

uspe

nd

ed

se

dim

ent

Decre

ase

in tu

rbid

ity/s

usp

en

de

d

se

dim

ent

Org

an

ic e

nric

hm

en

t-wate

r co

lum

n

Org

an

ic e

nric

hm

en

t of s

edim

en

ts-

se

dim

enta

tion

Incre

ased

rem

ova

l of p

rima

ry

pro

ductio

n-p

hyto

pla

nkto

n

Decre

ase

in o

xyge

n le

ve

ls- s

ed

imen

t

Decre

ase

in o

xyge

n le

ve

ls-w

ate

r

co

lum

n

Intro

ductio

n o

f non

-na

tive

specie

s

Rem

ova

l of T

arg

et S

pe

cie

s

Rem

ova

l of N

on

-targ

et s

pe

cie

s

Eco

syste

m S

erv

ices-L

oss o

f bio

mass

Intro

ductio

n o

f antifo

ula

nts

Intro

ductio

n o

f me

dic

ine

s

Intro

ductio

n o

f hyd

roca

rbo

ns

Pre

ve

ntio

n o

f light re

ach

ing

se

abe

d/fe

atu

res

Subtidal Sand with

polychaetes and bivalves

community complex

(A5.4)

H (*)

M (*)

M (*)

NE NE N-L (*)

L-M (*)

L-M (*)

H (*)

H (*)

H (*)

H (*)

H (*)

H (*)

H (*)

H (*)

M (*)

M (*)

L (*)

H (*)

H (*)

NA H (*)

H (*)

M (*)

H (*)

Subtidal sand with

Kurtiella bidentata (A5.4)

H (*)

M (*)

M (*)

NE NE N-L (*)

L-M (*)

L-M (*)

H (*)

H (*)

H (*)

H (*)

H (*)

H (*)

H (*)

H (*)

M (*)

M (*)

L (*)

H (*)

H (*)

NA H (*)

H (*)

M (*)

H (*)

Maërl-dominated community (A5.51)

H (***)

H-VH (***)

H (***)

H (***)

H (***)

H-VH (***)

H-VH (***)

H-VH (***)

NS (*)

NS (*)

NS (*)

H (*)

NS (*)

H (*)

H (***)

NS (*)

H (**)

H (**)

H (***)

VH (***)

NS (*)

NE NE NE NE VH (*)

Zostera dominated community complex (A2.6, A5.5)

M-H (***)

M-VH (***)

M-VH (***)

M-H (***)

M-H (***)

M-VH (***)

VH (***)

VH (***)

M (*)

M (***)

M (*)

H (***)

NS (*)

H (***)

H (***)

NS (*)

H-VH (*)

H-VH (*)

H (**)

NS (*)

NS (*)

NA NEv NEv NS (***)

H-VH (**)

Fucoid-dominated

intertidal reef community

complex (A1.21)

NS (*)

NA NA NS (*)

NE NA L (*)

M-VH (*)

NA NA NS (*)

NS (*)

NS (*)

NS (*)

NE NS (*)

NE NS (*)

NS (*)

NS (*)

NS (*)

NA NS (*)

NS (*)

NS (*)

NS (*)

Laminaria-dominated

community complex

(A3.21)* Scoring for

A3.22

NS (*)

NA NA NE NE NA NS (*)

M-VH (*)

NA NA NS (*)

NS (*)

NS (*)

NS (*)

NE NS (*)

NE NS (*)

NS (*)

NS (*)

NS (*)

NA NS (*)

NS (*)

NS (*)

NS (*)

44

Note: *No sensitivity listed for this community type using scores for similar habitat as listed.

45

Table 8: Matrix showing the characterising species sensitivity scores x pressure categories for species in Slyne Head Peninsula SAC (ABPMer 2013a-h).

Table 9 provides the code for the various categorisations of sensitivity and confidence

Pressure Type

Physical Damage Change in Habitat Quality Biological Pressures Chemical Pollution

Ph

ys

ical

Pre

ss

ure

Species

Su

rface

Dis

turb

an

ce

Sh

allo

w D

istu

rba

nce

Dee

p D

istu

rba

nce

Tra

mplin

g-A

cce

ss b

y fo

ot

Tra

mplin

g-A

cce

ss b

y v

eh

icle

Extra

ctio

n

Silta

tion

Sm

oth

erin

g (a

dditio

n o

f ma

teria

ls

bio

log

ica

l or n

on

-bio

log

ica

l to th

e

su

rface

)

Cha

ng

es to

sed

ime

nt c

om

positio

n-

incre

ased

co

ars

en

ess

Cha

ng

es to

sed

ime

nt c

om

positio

n-

incre

ased

fine

se

dim

en

t pro

portio

n

Cha

ng

es to

wa

ter flo

w

Incre

ase

in tu

rbid

ity/s

uspe

nd

ed

se

dim

ent

Decre

ase

in tu

rbid

ity/s

usp

en

de

d

se

dim

ent

Org

an

ic e

nric

hm

en

t-wate

r co

lum

n

Org

an

ic e

nric

hm

en

t of s

edim

en

ts-

se

dim

enta

tion

Incre

ased

rem

ova

l of p

rima

ry

pro

ductio

n-p

hyto

pla

nkto

n

Decre

ase

in o

xyge

n le

ve

ls- s

ed

imen

t

Decre

ase

in o

xyge

n le

ve

ls-w

ate

r

co

lum

n

Intro

ductio

n o

f non

-na

tive

specie

s

Rem

ova

l of T

arg

et S

pe

cie

s

Rem

ova

l of N

on

-targ

et s

pe

cie

s

Intro

ductio

n o

f antifo

ula

nts

Intro

ductio

n o

f me

dic

ine

s

Intro

ductio

n o

f hyd

roca

rbo

ns

Pre

ve

ntio

n o

f light re

ach

ing

se

abe

d/fe

atu

res

Nematoda NS (***)

NS (***)

NS (***)

NS (***)

NS (*)

L (*)

NS (*)

NS (***)

NS (***)

NS (***)

NS (*)

NS (*)

NS (*)

NS (*)

NS (***)

NS (*)

L (***)

L (***)

NS (***)

NS (*)

L (*)

NS (***)

NEv L

(***) NS (*)

Lanice conchilega

NS (*)

NS-L

(***)

NS-L

(***)

NS (*)

NS-L (*)

M-H (*)

NS (*)

M-H (*)

NS (*)

NS (***)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

M (*)

M (*)

M-H (*)

NS (*)

NS (*)

NS (*)

NEv L

(***) NS (*)

Nephtys cirrosa

NS (*)

L (***)

L (***)

NS (*)

L (*)

L(*) NS (***)

NS (*)

L (*)

NS (*)

L (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

M (*)

M (*)

NS (*)

NS (*)

NEv NEv NS (*)

Thyasira flexuosa

L (*)

L (***)

L (*)

L (*)

L (*)

M-H (*)

NS (*)

M-H (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (***)

NS (*)

M (***)

M (***)

M (*)

NS (*)

NS (*)

NS (***)

NEv NS (***)

NS (*)

Scoloplos armiger

NS (*)

L (*)

L-M (*)

NS (*)

L (*)

H (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NS (***)

NS (***)

NS (*)

M (***)

M (***)

M (*)

M (**)

NS (*)

NS (*)

NEv NEv NS (*)

Ascophyllum nodosum

L (*)

NA NA L

(***) NE NA

NS (***)

VH (*)

NA NA NS (***)

L-NS (***)

NS (*)

NS (*)

NE NS (*)

NE NS (*)

M (***)

H (***)

NS (*)

NS (***)

NEv NS (***)

H (***)

Fucus sp. L (*) NA NA

L (***)

NE NA M

(***)

H (*) NA NA

NS (*)

L-NS (***)

NS (**)

NS (***)

NE NS (*)

NE NS (*)

NS (*)

NS (*)

NS (*)

NS (*)

NEv NS (*)

M (*)

Laminaria digitata

NS (*)

NA NA NE NE NA NS (***)

H (*)

NA NA NS (***)

M (***)

NS (*)

NS (*)

NE NS (*)

NE NEv M

(***) H

(***) NS (*)

NS (*)

NEv NS (***)

M (*)

Laminaria hyperborea

L (*)

NA NA NE NE NA NS (***)

H (*)

NA NA NS (***)

M (***)

NS (*)

NS (***)

NE NS (*)

NE NEv M (*)

M (***)

NS (*)

NS (*)

NEv NS (***)

M (*)

Saccorhiza polyschides

L (*)

NA NA NE NE NA NS (*)

M (*)

NA NA NS (***)

M (*)

L (*)

NS (*)

NE NS (*)

NE NS (*)

M (*)

M (*)

NS (***)

NEv NEv NS (*)

M (*)

46

Pressure Type

Physical Damage Change in Habitat Quality Biological Pressures Chemical Pollution

Ph

ys

ical

Pre

ss

ure

Species

Su

rface

Dis

turb

an

ce

Sh

allo

w D

istu

rba

nce

Dee

p D

istu

rba

nce

Tra

mplin

g-A

cce

ss b

y fo

ot

Tra

mplin

g-A

cce

ss b

y v

eh

icle

Extra

ctio

n

Silta

tion

Sm

oth

erin

g (a

dditio

n o

f ma

teria

ls

bio

log

ica

l or n

on

-bio

log

ica

l to th

e

su

rface

)

Cha

ng

es to

sed

ime

nt c

om

positio

n-

incre

ased

co

ars

en

ess

Cha

ng

es to

sed

ime

nt c

om

positio

n-

incre

ased

fine

se

dim

en

t pro

portio

n

Cha

ng

es to

wa

ter flo

w

Incre

ase

in tu

rbid

ity/s

uspe

nd

ed

se

dim

ent

Decre

ase

in tu

rbid

ity/s

usp

en

de

d

se

dim

ent

Org

an

ic e

nric

hm

en

t-wate

r co

lum

n

Org

an

ic e

nric

hm

en

t of s

edim

en

ts-

se

dim

enta

tion

Incre

ased

rem

ova

l of p

rima

ry

pro

ductio

n-p

hyto

pla

nkto

n

Decre

ase

in o

xyge

n le

ve

ls- s

ed

imen

t

Decre

ase

in o

xyge

n le

ve

ls-w

ate

r

co

lum

n

Intro

ductio

n o

f non

-na

tive

specie

s

Rem

ova

l of T

arg

et S

pe

cie

s

Rem

ova

l of N

on

-targ

et s

pe

cie

s

Intro

ductio

n o

f antifo

ula

nts

Intro

ductio

n o

f me

dic

ine

s

Intro

ductio

n o

f hyd

roca

rbo

ns

Pre

ve

ntio

n o

f light re

ach

ing

se

abe

d/fe

atu

res

Ulva sp. L (*)

NA NA L(*) NE NA NS (***)

L (*)

NA NA NS (*)

NS (**)

NS (**)

NS (***)

NE NS (*)

NE NEv NEv NS (*)

NS (*)

NS (***)

NEv L

(***) M

(***)

47

Table 9: Codes of sensitivity and confidence applying to species and pressure interactions presented

in Tables 7 and 8.

Species x Pressure Interaction Codes for Tables 8 and 9

NA Not Assessed

Nev No Evidence

NE Not Exposed

NS Not Sensitive

L Low

M Medium

H High

VH Very High

* Low confidence

** Medium confidence

*** High Confidence

In summary, it is concluded that, with two exceptions, the spatial extent of aquaculture activities

individually and in-combination do not pose a risk of significant disturbance to the qualifying interests

of the Slyne Head Peninsula SAC. This conclusion is based primarily upon the spatial overlap and

sensitivity analysis (Tables 7 and 8). The exceptions are the activity (suspended oyster culture)

occurring over Maërl dominated community and Zostera dominated community. In spite of the low

spatial overlap of the culture, it is still considered potentially disturbing to these extremely sensitive

habitat types, where any physical disturbance should generally be avoided.

The risk posed by the culture of diploid Pacific oyster should be considered. Given that the residence

time in Mannin Bay is approx 21 days, this is at the threshold for larval development, associated with

successful recruitment identified in published literature (Kochmann et al. 2013).

Furthermore, the risk posed by the culture of the Pacific Oyster, Crassostrea gigas, uncontained on the

seabed cannot be discounted. Given that subtidal oyster culture results in higher reproductive potential,

and the residence time in Mannin Bay is 21 days, it is recommended that careful consideration be given

to licencing subtidal oyster culture.

48

Table 10: Interactions between the relevant aquaculture activities and the habitat feature Reefs (1170) constituent communities with a broad conclusion on the nature of the interactions.

1170 Reefs

Culture Type Location Method Intertidal reef community complex

(350ha)


(220ha)

Oysters

(C. gigas)

Bags & trestles

Intertidal Intensive

Disturbing: Yes Justification: The impact of access routes and shading caused by

trestles can impact on macro-algae species. The stock is confined in bags; seed is sourced from hatcheries and is diploid. As the residence time within the bay is 21days, the risk of retention of C. gigas spat and hence recruitment of the species possibly resulting in the species becoming established within the bay is heightened. Spatial overlap, including access routes is 6.99% of this community type.

Disturbing: Yes Justification: The shading caused by trestles can impact on

macro-algae species. The stock is confined in bags; seed is sourced from hatcheries and is diploid. As the residence time within the bay is 21days, the risk of retention of C. gigas spat and hence recruitment of the species possibly resulting in the species becoming established within the bay is heightened. Spatial overlap, including access routes is 6.28% of this community type.

Oysters

(C. gigas)

Bottom culture

Subtidal Extensive NA

Disturbing: Yes Justification: Given the relatively sporadic nature of dredging,

the species have high recoverability and are tolerant of the impacts of this aquaculture type. However, due to the uncontained placement on the seafloor, wide scale impacts are possible, as diploid stock is used which increases the risk of reproduction than if triploid stock is used. In addition, as the residence time within the bay is 21days, this also increases the risk of retention of C. gigas spat and hence recruitment of the species possibly resulting in a non-native species becoming established within the bay. Spatial overlap is 0.02% of this community type.

Salmon

(Salmo salar)

Net pens

Subtidal Intensive NA

Disturbing: Yes Justification: Persistent organic deposition will impact the

species found in this marine community type. Spatial overlap is 0.02% of this community type.

Cumulative Impact of Aquaculture

Disturbing: No Justification: The cumulative pressure of likely impacting activities

is 6.99% on this habitat. The risk of successful reproduction of non-native C. gigas cannot be discounted.

Disturbing: Yes Justification: The risk of successful reproduction of non-native C. gigas cannot be discounted.The cumulative pressure of likely impacting activities is 6.32% on this habitat.

49

Table 11. Interactions between the relevant aquaculture activities and the habitat feature Large Shallow Inlets and Bays (1160) constituent communities with a broad conclusion on the nature of the interactions.

1160 Large Shallow Inlets and Bays

Culture Type Location Method Intertidal reef community complex

(159 ha)


(198 ha)

Subtidal sand with polychaetes and bivalves community complex

(288 ha)

Subtidal sand with Kurtiella bidentata community complex

(574 ha)

Oysters (C. gigas)

Bags & trestles Intertidal Intensive

Disturbing: Yes Justification: The impact of access routes and shading

caused by trestles can impact on macro-algae species. The stock is confined in bags; seed is sourced from hatcheries and is diploid. As the residence time within the bay is 21days, the risk of retention of C. gigas spat and hence recruitment of the species possibly resulting in the species becoming established within the bay is heightened. This activity, including access routes (1.08%), overlaps 15.2% of this habitat type (>15% threshold).

Disturbing: Yes Justification: The impact of access routes and shading

caused by trestles can impact on macro-algae species. The stock is confined in bags; seed is sourced from hatcheries and is diploid. As the residence time within the bay is 21days, the risk of retention of C. gigas spat and hence recruitment of the species possibly resulting in the species becoming established within the bay is heightened. This activity, including access routes (0.001%), overlaps 6.95% of this habitat type (<15% threshold).

Disturbing: Yes Justification The habitat and fauna are sensitive to the

following impacts: Change in habitat quality (organic enrichment - faeces & and pseudofaeces) due to the high density of stock; Physical pressures (prevention of light reaching seabed - due to physical structures). The stock is confined in bags; seed is sourced from hatcheries and is diploid. As the residence time within the bay is 21days, the risk of retention of C. gigas spat and hence recruitment of the species possibly resulting in the species becoming established within the bay is heightened. This activity overlaps 0.28% of this habitat type (<15% threshold).


following impacts: Change in habitat quality (organic enrichment - faeces & and pseudofaeces) due to the high density of stock. Physical pressures (prevention of light reaching seabed - due to physical structures). The stock is confined in bags; seed is sourced from hatcheries and is diploid. As the residence time within the bay is 21days, the risk of retention of C. gigas spat and hence recruitment of the species possibly resulting in the species becoming established within the bay is heightened. This activity overlaps 0.73% of this habitat type (<15% threshold).

Oysters (C. gigas)

Bottom culture Subtidal Extensive NA

Disturbing: Yes Justification: Due to the uncontained placement on the

seafloor, wide scale impacts are likely, as diploid stock is used which increases the risk of reproduction than if triploid stock is used. In addition, as the residence time within the bay is 21days, this also increases the risk of retention of C. gigas spat and hence recruitment of the species possibly resulting in a non-native species becoming established within the bay. This activity overlaps 0.02% of this habitat type.


following impacts: Physical damage (i.e. harvest by dredge); Change in habitat quality (organic enrichment - faeces & and pseudofaeces) due to the high density of stock. Due to the uncontained placement on the seafloor, wide scale impacts are likely, as diploid stock is used which increases the risk of reproduction than if triploid stock is used. In addition, as the residence time within the bay is 21days, this also increases the risk of retention of C. gigas spat and hence recruitment of the species

possibly resulting in a non-native species becoming established within the bay. This activity overlaps 1.37% of this habitat type.

NA

Salmon (Salmo salar)

Net pens Subtidal Intensive

Disturbing: Yes Justification: Persistent organic deposition will impact

the species found in this marine community type. This activity overlaps <0.01% of this habitat type.

Disturbing: Yes Justification: Persistent organic deposition will impact

the species found in this marine community type. This activity overlaps 0.02% of this habitat type.

Disturbing: Yes Justification Persistent organic deposition will impact

the species found in this marine community type. This activity overlaps 1.03% of this habitat type.

NA


Disturbing: Yes Justification: The risk of successful reproduction of non-native C. gigas cannot be discounted. The cumulative pressure of likely impacting activities is 15.7% on this habitat (>15%)

Disturbing: Yes Justification: The risk of successful reproduction of non-native C. gigas cannot be discounted. The cumulative pressure of likely impacting activities is 6.99% on this habitat.



50

Table 11 cont'd: Interactions between the relevant aquaculture activities and the habitat feature Large Shallow Inlets and Bays (1160) constituent communities with a broad conclusion on the nature of the interactions.

1160 Large Shallow Inlets and Bays

Culture Type Location Method Zostera-dominated community complex

(33 ha)

Maërl-dominated community complex

(261 ha)

Oysters (C. gigas)

Bags & trestles Intertidal Intensive

Disturbing: Yes Justification

The community is sensitive to the following impacts: Physical damage (Surface disturbance, Trampling, Smothering, Siltation) Change in habitat quality (Organic enrichment - faeces & and pseudofaeces) due to the high density of stock; Biological pressures (decrease in oxygen level in the water, introduction of non-native species) Physical pressures (prevention of light reaching seabed - due to physical structures). This is regarded as a sensitive/keystone habitat and any disturbance should be avoided. Spatial overlap is 9.97% of this community type. However, this threshold does not apply to sensitive habitats (e.g. Zostera) where any physical disturbance should be avoided.

Disturbing: Yes Justification

The community is sensitive to the following impacts: Physical damage (Surface disturbance, Trampling, Smothering, Siltation) Change in habitat quality (Organic enrichment - faeces & and pseudofaeces) due to the high density of stock; Biological pressures (decrease in oxygen level in the water, introduction of non-native species) Physical pressures (prevention of light reaching seabed - due to physical structures). This is regarded as a sensitive/keystone habitat and any disturbance should be avoided. Spatial overlap is 1.54% of this community type. However this threshold does not apply to sensitive habitats (e.g. Maërl) where any physical disturbance should generally be avoided

Oysters (C. gigas)

Bottom culture Subtidal Extensive NA NA

Salmon (Salmo salar)

Net pens Subtidal Intensive NA NA


Disturbing: Yes Justification: The cumulative pressure of likely impacting activities is 9.97%

on this habitat. This is regarded as a sensitive/keystone habitat and any disturbance should be avoided.

Disturbing: Yes Justification: The cumulative pressure of likely impacting activities is

1.54% on this habitat. This is regarded as a sensitive/keystone habitat and any disturbance should be avoided.

51

9 IN-COMBINATION EFFECTS OF AQUACULTURE, FISHERIES AND OTHER ACTIVITIES

9.1 FISHERIES

Fisheries activities occurring in the Slyne Head Peninsula SAC are potting for a range of species and

tangle netting for crayfish (Figure 9). Table 12 presents the spatial extent of these fishing activities

overlapping the Annex 1 feature 1160 – Large Shallow inlets and bays and 1170-Reefs, in addition to

their constituent community types.

Fishery overlaps between 13-57% of QI habitat 1170 – Reefs. Of the two community types associated

with 1170-Reef, spatial coverage ranges from 3% to 88% for shrimp and crab potting, respectively. For

the QI 1160 Large shallow inlets and bays, fishing activities ranged from 17-96% spatial overlap. For

some community types (Mearl and Zostera), coverage was 100%.

Figure 7. Fishery activities within Slyne Head Peninsula SAC.

52

Table 12. Spatial extent of fisheries activities overlapping within the broad habitat qualifying interest of 1160 and 1170 and constituent community types in Slyne head

Peninsula SAC. Spatial overlap presented according to target fisheries species and equipment used. Annex I feature in bold.

Fishery Type

Crayfish (Tangle net) Shrimp (Creel) Crab (Creel) Lobster (Creel)

Overlap (ha)

% Overlap Overlap

(ha) %

Overlap Overlap

(ha) %

Overlap Overlap

(ha) %

Overlap

Reef (571 ha) 76.46 13.39 87.38 15.30 330.25 57.84 88.98 15.58

Intertidal reef community complex (350 ha)

19.99 5.71 10.25 2.93 136 38.86 23.25 6.64

Laminaria-dominated community complex (220 ha)

56.24 25.56 77.13 35.06 194 88.18 65.49 29.77

Large Shallow Inlet and Bay (1540 ha)

274.88 17.85 807.19 52.41 1493.59 96.99 636.16 41.31

Intertidal sand with Enchytraeidae community complex (14 ha) - - 0.59 4.21 6.67 47.64 2.99 21.36

Mobile intertidal sand with polychaetes community complex (11 ha) - - 0.34 3.09 9.67 1.69 - -

Zostera-dominated community complex (33 ha) - - 32.77 99.30 32.82 99.45 0.42 1.27

Maërl-dominated community complex (261 ha) - - 261.03 100.00 261 100.00 - -

Subtidal sand with polychaetes and bivalves community complex (288 ha)

213.13 74.00 2.28 0.79 288 100.00 266.11 92.40

Subtidal sand with Kurtiella bidentata community complex (574 ha) - - 422.79 73.66 572.29 99.70 292.67 50.99

Intertidal reef community complex (159 ha)

5.57 3.50 10.25 6.45 127.43 80.14 8.74 5.50

Laminaria-dominated community complex (198 ha)

56.17 28.37 77.13 38.95 194.09 98.03 65.24 32.95

53

9.1.1 Pot fisheries

The pressures caused by potting on benthic habitats is due to ‘direct hit’ of the pot on the seabed, the

effect of movements of ropes connecting pots, the effects of anchoring the gear, the effects of dragging

pots and ropes along the seabed during hauling and passive dragging or movement of gear along the

seabed in strong tides or during stormy weather. Lost gear may entangle and move some distances

along the seabed. Fishing with strings of pots, is expected to have greater effects than fishing with

single pots due to dragging effects during hauling of gear (references in Barnette 2001). The effects of

the pressure will depend on the habitat the gear is fished in as habitats have difference resilience and

recoverability to the pressures. Epibenthic species may have some resilience to pressures caused by

pot fishing (Eno 2000).

The response of specific community types to pressures caused by potting for shrimp will vary depending

on the physical and biological characteristics of the community

Maerl community:

Although the physical force of shrimp pots and ropes falling onto maerl is likely to be insufficient to

cause significant damage to living maerl thalli or to significantly reduce the complexity of the algal matrix

the process of anchoring and hauling gear could damage the algal matrix and emergent epi-faunal

species.

The intensity and duration of activity within year and the persistence of this activity across a number of

years may lead to cumulative effects and modification of the habitat because the recovery capacity of

sensitive species is lower than the spatial extent and frequency of the footprint of the fishery4.

Zostera community:

Zostera has moderate recoverability from physical abrasion4.

Reef communities:

Laminaria has low resilience but high recoverability to physical disturbance.

The physical disturbance to Laminaria cause by pots is likely to be lower than towed gear. Resilience

is probably high to pots and overall sensitivity to pots can be considered low

Sedimentary communities

Species associated with the mixed sediment community complex include small bodied infaunal species

of polychaetes and bivalves.

Infaunal species of polychaetes and bivalves are likely to be insensitive to seabed surface pressures

caused by shrimp pots.

4 The Impacts of Potting for Shrimp (Palaemon serratus) on seagrass and maërl habitats in Roaringwater Bay. August 2016.

Report prepared by MERC and the Marine Institute. 61pp.

54

Static fishing gear is highly unlikely to modify the sedimentary habitat and therefore will not lead to any

change in benthic community structure or function.

9.1.2 Tangle nets

These nets generally target crayfish (Palinurus elephas) and Turbot (Psetta maximus). The impact of

tangle netting on benthic habitats is considered minor.

The likelihood of capture of Seal and cetaceans in static nets is high. The consequence for the

populations concerned depends on the total by-catch. However, further consideration of tangle net

impacts are beyond the scope of this report given the minor nature of benthic impacts.

Conclusions: the likely in-combination effects of fishing activities and aquaculture activities are

considered low for 6 of 8 community types. For both Mearl and Zostera dominated communities, there

is likely in-combination disturbance with shellfish aquaculture activities (which overlap these community

types). The advice above relating to mitigating interactions between shellfish culture and the sensitive

community types, therefore, holds.

9.2 Pollution

The Shellfish Water Characterisation Study prepared by the Department of Environment for Mannin

Bay5 was consulted in order to identify any pressures that might result in additive or synergistic

pressures to those identified as originating from aquaculture activities. No direct discharge points or

other pressures were identified that might act in-combination with aquaculture activities.

5 https://www.housing.gov.ie/water/water-quality/shellfish-waters/mannin-bay-final-characterisation-report

https://www.housing.gov.ie/water/water-quality/shellfish-waters/mannin-bay-final-characterisation-report

55

10 SAC Aquaculture Appropriate Assessment Concluding Statement and Recommendations

In the Slyne Head SAC, there are two types of aquaculture activity currently being carried out. Based

upon this and the information provided in the aquaculture profiling (Section 5), the likely interaction

between this aquaculture and conservation features (habitats and species) of the site were considered.

An initial screening exercise resulted in a number of habitat features and species being excluded from

further consideration by virtue of the fact that no spatial overlap of the culture activities was expected

to occur. The habitats and species excluded from further consideration are 1150 Coastal lagoons*,

1210 Annual vegetation of drift lines, 1220 Perennial vegetation of stony banks, 1330 Atlantic salt

meadows (Glauco-Puccinellietalia maritimae), 1395 Petalwort Petalophyllum ralfsii, 1410

Mediterranean salt meadows (Juncetalia maritimi), 1833 Slender Naiad Najas flexilis, 2110 Embryonic

shifting dunes, 2120 Shifting dunes along the shoreline with Ammophila arenaria (white dunes),

21A0 Machairs (*in Ireland), 3110 Oligotrophic waters containing very few minerals of sandy plains

(Littorelletalia uniflorae), 3140 Hard oligo-mesotrophic waters with benthic vegetation of Chara spp.,

4030 Juniperus communis formations on heaths or calcareous grasslands, 5130 European dry heaths,

6210 Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco-Brometalia)

(*important orchid sites), 6410 Molinia meadows on calcareous, peaty or clayey-silt-laden soils

(Molinion caeruleae), 6510 Lowland hay meadows (Alopecurus pratensis, Sanguisorba offvinalis) and

7230 Alkaline fens.

10.1 Habitats

Conclusions and Recommendations - Aquaculture Activities: A full assessment was carried out

on the likely interactions between aquaculture operations (as proposed) and the Annex 1 habitats Large

shallow inlets and bays (1160) and Reefs (1170). The likely effects of the aquaculture activities

(species, structures) were considered in light of the sensitivity of the constituent habitats and species

of the Annex 1 habitats. Of the eight community types listed under the remaining habitat features two

(Intertidal sand with Enchytraeidae community complex and Mobile intertidal sand with polychaetes

community complex) were excluded from further analysis as they had no overlap with aquaculture

activities.

Based upon the scale of spatial overlap and the relatively high tolerance levels of the habitats and

species therein, the general conclusions relating to the interaction between current and proposed

aquaculture activities with habitats is that consideration can be given to licencing (existing and

applications) in the Annex 1 habitats – Large Shallow Inlets and Bays (1160) and Reefs (1170) with the

following exceptions:

1. Intertidal reef community complex – the cumulative impact of disturbing activities over this

marine community type within Annex 1 habitat Large shallow inlet and bay (1160) is 15.7%,

i.e., greater than the threshold of 15%. It is recommended that this level of overlap be reduced

to a sustainable level.

56

2. Zostera-dominated community- This habitat is not tolerant of any overlap of any activity. The

cumulative pressure of likely impacting activities on this habitat is 9.97%.

3. Maerl-dominated community - This habitat is not tolerant of any overlap of any activity. The

cumulative pressure of likely impacting activities on this habitat is 1.54%.

4. The risk posed by the culture of diploid Pacific oyster should be considered. Given that the

residence time in Mannin Bay is approx 21 days, this is at the threshold for larval development,

associated with successful recruitment identified in published literature (Kochmann et al. 2013).

However, mitigating factors are the heavy algal cover found intertidally in the area and the fact

that the oysters are contained in bags on trestles in the intertidal. Any confirmation of oyster

recruitment might be addressed by the removal of diploid oysters from the system.

5. The risk posed by the culture of the Pacific Oyster, Crassostrea gigas, uncontained on the

seabed cannot be discounted. Given that subtidal oyster culture results in higher reproductive

potential, and the residence time in Mannin Bay is 21 days, it is recommended that careful

consideration be given to licencing subtidal oyster culture. The risk may be mitigated if the

culture is carried out using triploid oysters, is contained and carried out in culture areas that are

clearly defined within the broader licenced plot and subject to ongoing monitoring of oyster

reproductive condition and/or recruitment in the Bay.

57

11 References

ABPMer. 2013a. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report VIII: Vegetation dominated communities (Saltmarsh and Seagrass). Report No. R. 2053 for Marine Institute, Ireland.

ABPMer. 2013b. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report VI: Biogenic reefs (Sabellaria, Native oyster, Maerl). Report No. R. 2068 for Marine Institute, Ireland.

ABPMer. 2013c. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report I: Intertidal and Subtidal Muds. Report No. R. 2069 for Marine Institute, Ireland.

ABPMer. 2013d. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report II: Intertidal and Subtidal Sands. Report No. R. 2070 for Marine Institute, Ireland.

ABPMer. 2013e. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report III: Intertidal and Subtidal muddy sands and sandy muds. Report No. R. 2071 for Marine Institute, Ireland.

ABPMer. 2013f. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report IV: Intertidal and Subtidal mixed sediments. Report No. R. 2072 for Marine Institute, Ireland.

ABPMer. 2013g. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report IV: Intertidal and Subtidal coarse sediments. Report No. R. 2073 for Marine Institute, Ireland.

ABPMer. 2013h. Tools for appropriate assessment of fisheries and aquaculture activities in Marine and Coastal Natura 2000 sites. Report VII: Intertidal and Subtidal reefs. Report No. R. 2074 for Marine Institute, Ireland.

Barnette, M. (2001). A review of the fishing gear utilised within the south east region and their potential impacts on essential habitat. NOAA Technical Memorandum NMFS-SEFSC-449, 62pp.

Bergman, M.J.N. and van Santbrink, J.W. 2000. Mortality in megafaunal benthic populations caused by trawl fisheries on the Dutch continental shelf in the North Sea 1994. ICES Journal of Marine Science 57(5), 1321-1331.

Borja, A., Franco, J. & Pérez, V. 2000. A marine biotic index of establish the ecological quality of soft-bottom benthos within European estuarine and coastal environments. Marine Pollution Bulletin. 40: 1100 – 1114.

Black, K.D., 2001. Sustainability of aquaculture. Environmental impacts of aquaculture, 199-212.

Bricknell, I.R., Bron, J.E. & Bowden, T.J. 2006. Diseases of gadoid fish in cultivation: a review. ICES Journal of Marine Science: Journal du Conseil:63(2), 253-266.

Byrne, A., Moorkens, E.A., Anderson, R., Killeen, I.J. & Regan, E.C., 2009. Ireland Red List No. 2 – Non Marine Molluscs. National Parks and Wildlife Service, Department of the Environment, Heritage and Local Government, Dublin, Ireland.

Cranford, Peter J., Pauline Kamermans, Gesche Krause, Alain Bodoy, Joseph Mazurié, Bela Buck, Per Dolmer, David Fraser, Kris Van Nieuwenhove, Francis X. O’Beirn, Adoración Sanchez-Mata, Gudrun G. Thorarinsdóttir, and Øivind Strand. 2012. An Ecosystem-Based Framework for the Integrated Evaluation and Management of Bivalve Aquaculture Impacts. Aquaculture Environment Interactions. 2:193-213.

DIPNET 2006. Risk assessment and predictive modelling – a review of their application in aquatic animal health. Work-Package 2, Deliverable 2.1 (Editors: Peeler, E.J., Murray, A.G., Thebault, A., Brun, E., Thrush, M.A. and Giovaninni, A.) in Disease interactions and pathogen exchange between farmed and wild aquatic animal populations – A European network (DIPnet). Veterinærmedisinsk Oppdragsenter AS, Oslo.

Eno, C. et al. (2001). Effects of crustacean traps on benthic fauna. ICES J. Mar. Sci. 58, 11-120.

58

Grant, A., Jones, S. 2011. Pathways of effects between wild and farmed finfish and shellfish in Canada: potential factors and interactions impacting the bi-directional transmission of pathogens. Canadian Science Advisory Secretariat, Science Advisory Report, Research Doc. 2010/018, 58p.

Hall, K., Paramor, O.A.L., Robinson L.A., Winrow-Giffin, A., Frid C.L.J., Eno, N.C., Dernie, K.M., Sharp, R.A.M., Wyn, G.C.& Ramsay, K. 2008. Mapping the sensitivity of benthic habitats to fishing in Welsh waters- development of a protocol. CCW [Policy Research] Report No: [8/12], 85pp.

ICES. 2014. Second Interim Report of the Working Group on Pathology and Diseases of Marine Organisms (WGPDMO), 25–28 February 2014, ICES Headquarters, Copen-hagen, Denmark. ICES CM 2014/SSGHIE:02. 28 pp.

Jackson D, Cotter D, O’Maoileidigh N, O’Donohoe P, White J, Kane F, Kelly S, McDermott T, McEvoy S, Drumm A, Cullen A & Rogan G. 2011. An evaluation of the impact of early infestation with the salmon louse Lepeophtheirus salmonis on the subsequent survival of outwardly migrating Atlantic salmon, Salmo salar L., smolts. Aquaculture 320, 159-163.

Jackson D, O'Donohoe, P., McDermott T., Kane F., Kelly S. & A. Drumm. 2013a. Report on Sea Lice Epidemiology and Management in Ireland with Particular Reference to Potential Interactions with Wild Salmon (Salmo salar) and Freshwater Pearl Mussel (Margaritifera margaritifera) Populations. Irish Fisheries Bulletin No 43, Marine Institute. http://hdl.handle.net/10793/893

Jackson, D., Kane, F., O’Donohoe, P., Mc Dermott, T., Kelly, S., Drumm, A. & J. Newell 2013b. Sea lice levels on wild Atlantic salmon returning to the Coast of Ireland. Journal of fish Diseases, 36(3) 293-298.

Johansen, LH., Jensen, I., Mikkelsen, H., Bjørn, PA., Jansen, PA. & Ø, Bergh. Disease interaction and pathogens exchange between wild and farmed fish populations with special reference to Norway. Aquaculture. 2011;315:167–86

Johnson, D. 2008. Environmental indicators: Their utility in meeting the OSPAR Convention's regulatory needs. ICES Journal of Marine Science 65:1387-1391.

Kochmann, J., Carlsson, J., Crowe TP & S. Mariani.2012 Genetic evidence for the uncoupling of local aquaculture activities and a population of an invasive species—a case study of Pacific oysters (Crassostrea gigas). Journal of Hereditary 103:661–671

Kochmann, J., O’Beirn, F, Yearsley J. & T.P. Crowe. 2013. Environmental factors associated with invasion: modeling occurrence data from a coordinated sampling programme for Pacific oysters. Biological Invasions DOI 10.1007/s10530-013-0452-9.

MagAoidh, R. 2011. Reproduction of Crassostrea gigas in Irish Waters; An analysis of gametogenesis and condition comparing tidal location and ploidy level. M.Sc. Thesis, University College Dublin. 84pp.

McKindsey, CW, Landry, T, O’Beirn, FX & , IM. Davies. 2007. Bivalve aquaculture and exotic species: A review of ecological considerations and management issues. Journal of Shellfish Research 26:281-294.

McNeill, G., Nunn, J & D. Minchin, 2010. The slipper limpet Crepidula fornicata Linnaeus, 1758 becomes established in Ireland. Aquatic Invasion (Supplement 1: S21- S25.

National Research Council, 2009. Shellfish Mariculture in Drakes Estero, Point Reyes National Seashore, California. National Academy Press, Washington, DC.

National Research Council, 2010. Ecosystems Concepts for Sustainable Bivalve Culture. National Academy Press, Washington, DC.

NPWS, 2015a. Conservation Objectives: Slyne Head Peninsula SAC 002074. National Parks and Wildlife Service, Department of Arts, Heritage and the Gaeltacht. Department Arts, Heritage and the Gaeltacht. Version 1 (February 2015); 37pp.

NPWS, 2015b. Slyne Head Peninsula SAC (site code: 002074): Conservation Objectives supporting document – marine habitats and species. National Parks and Wildlife Service, Department Arts, Heritage and the Gaeltacht. Version 1 (January 2015); 19pp.

http://www.dfo-mpo.gc.ca/csas/csas/Publications/SAR-AS/2009/2009_071_E.pdf

http://www.dfo-mpo.gc.ca/csas/csas/Publications/SAR-AS/2009/2009_071_E.pdf

http://hdl.handle.net/10793/893

59

O’Beirn, F.X., McKindsey, C. W., Landry, T. & B. Costa-Pierce. 2012. Methods for Sustainable Shellfish Culture. 2012. pages 9174-9196 In: Myers, R.A. (ed.), Encyclopedia of Sustainability Science and Technology. Springer Science, N.Y.

OIE 2004. Handbook on Import risk analysis for animals and animal products. Volume 1: Introduction and qualitative risk analysis. .World Organisation for Animal Health. 59pp.

Pearson, T.H. & K.D. Black. 2000. The environmental impacts of marine fish cage culture. Environmental impacts of aquaculture: 1-31.

Pearson, T.H. & Rosenberg, R. 1978. Macrobenthic succession in relation to organic enrichment and pollution of the marine environment. Oceanography and Marine Biology: An Annual Review:16, 229–311.

Peeler, E.J., Murray, A.G., Thebault, A., Brun, E., Giovaninni, A. & Thrush, M.A. 2007. The application of risk analysis in aquatic animal health management. Preventive Veterinary Medicine: 81(1), 3-20.

Silvert, W. & Cromey, C. J. 2001. 7 Modelling impacts .Environmental impacts of aquaculture. 5: 154.

Wildish, D.J., Hughes-Clarke, J. E., Pohle, G. W., Hargrave, B. T., & Mayer, L. M. 2004. Acoustic detection of organic enrichment in sediments at a salmon farm is confirmed by independent groundtruthing methods. Marine Ecology Progress Series. 267: 99-105.

report supporting appropriate assessment of aquaculture ... · within the slyne head peninsula sac,...

Documents