Ballycotton Bay AA

110 Pages·2014·8.66 MB·English

Marine Institute
Ballycotton Bay SPA Appropriate Assessment
December 2014
Plan Design Enable
Marine Institute Bird Studies

Ballycotton Bay Special Protection Area (4022)

Appropriate Assessment of Aquaculture

rd
23 December 2014

Notice
This report was produced by Atkins Ecology for the Marine Institute for the specific purpose of the Marine
Institute Bird Studies project.

This report may not be used by any person other than Marine Institute without the Marine Institute's express
permission. In any event, Atkins accepts no liability for any costs, liabilities or losses arising as a result of the
use of or reliance upon the contents of this report by any person other than the Marine Institute.

Document History
JOB NUMBER: RK2927 DOCUMENT REF: -
2927Dg20_Ballycotton_Bay AA_Rev1.doc

1 Final POD & JD POD POD JN 23-12-2014
0 Draft for comment POD & JD POD POD JN 18-12-2014
Revision Purpose Description Originated Checked Reviewed Authorised Date
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Ballycotton Bay Special Protection Area: Appropriate Assessment of Aquaculture and Fisheries
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Contents
Section Page
Executive Summary v 
Acknowledgements i 
1.  Introduction 1 
Site Location 2 
Site Description 3 
Scope of the assessment 6 
Structure of this report 9 
Constraints to this assessment 9 
2.  Methodology 11 
General 11 
Data sources 11 
Subsites 12 
Definition of habitat zones 16 
Analyses of waterbird distribution 30 
Aquaculture assessment methodology 33 
3.  Conservation objectives 39 
Ballycotton Bay SPA 39 
Ballymacoda Bay SPA 40 
Cork Harbour SPA 41 
Blackwater Estuary SPA 42 
4.  Screening 44 
Ballycotton Bay SPA 44 
Other SPAs within 15km 45 
5.  Status and distribution of the SCI species 48 
Ballycotton Bay SPA 48 
6.  Intertidal oyster cultivation 72 
Scope of activity 72 
Potential impacts 72 
Impact assessment 74 
Selection of species for detailed analysis 74 
7.  In-combination effects of aquaculture and fisheries with other activities 80 
Introduction 80 
Other patterns of site usage 80 
Disturbance 80 
Habitat Loss 82 
Water Quality 82 
8.  Concluding Statement 83 
9.  References 84 
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Review of disturbance by activity type 95 

Citation: -
O’Donoghue, P. and Deasy, J. (2014). Ballycotton Bay Special Protection Area: Appropriate Assessment of
Intertidal Oyster Cultivation. Unpublished Report prepared by Atkins for the Marine Institute.

Cover Photograph – Ballycotton Bay.

List of Tables

Table 2.1 Tide information for BWI I-WeBS counts at Ballycotton Bay SPA used in the analysis for this
assessment.
Table 2.2 Tidal zones used by various species groups.
Table 2.3 Criteria for assessing significance with reference to attribute 1 of the conservation objectives.
Table 3.1 Attributes and targets for the conservation objectives for non-breeding populations of Teal, Ringed
Plover, Golden Plover, Grey Plover, Lapwing, Black-tailed Godwit, Bar-tailed Godwit, Curlew, Turnstone,
Common Gull and Lesser Black-backed Gull in Ballycotton Bay SPA.
Table 3.2 Attribute and target for the conservation objective for wetlands at Ballycotton Bay SPA.
Table 3.3 Attributes and targets for the conservation objectives for non-breeding populations of Bar-tailed Godwit,
Black-tailed Godwit, Curlew, Dunlin, Golden Plover, Lapwing, Redshank and Wigeon in the Blackwater
Estuary SPA.
Table 3.4 Attribute and target for the conservation objective for wetlands in the Blackwater Estuary SPA.
Table 4.1 Habitat zones and major prey resources likely to be used by SCI species in the Inner Ballycotton SPA.
Table 4.2 Habitat zones and major prey resources likely to be used by SCI species in the Ballycotton Bay SPA.
Table 5.1 Changes in SCI populations at Ballycotton Bay using 5-year I-WeBS mean peak counts.
Table 5.2 Conservation condition and population trends of the SCI assessment species in the Ballycotton Bay SPA
(after NPWS, 2014b).
Table 5.3 I-WeBS data broken up into broad habitat types based on subdivisions utilised by I-WeBS counter when
undertaking surveys. Data covers 2007/08 to 2013/14 (excluding 2009/10 and 2010/11).
Table 6.1 Calculations of predicted impacted area on habitat zones within Ballycotton Bay SPA due to proposed
aquaculture sites.
Table 6.2 Calculations of predicted impacted area on habitat zones for three subsites, 0L575, 0L576 and 0L581 at
the southern end of Ballycotton Bay SPA due to proposed aquaculture sites.
Table 6.3 Summary of relative population displacement based on proportion of habitat lost and proportion of SCI
using that area.
Table 8.1 Summary of impact assessment.

List of Figures

Figure 1.1 Boundary of Ballycotton Bay SPA shown with proposed aquaculture sites locations.
Figure 1.2 Special Protection Areas in the vicinity of Ballycotton Bay.
Figure 1.3 Site names used in the assessment.
Figure 2.1 Boundary of area covered by I-WeBS high tide counts around Ballycotton Bay SPA.
Figure 2.2 Boundary of NPWS baseline waterbird survey monitoring subsites around Ballycotton Bay SPA
(surveyed in 2010/2011).
Figure 2.3 Transects followed by BirdWatch Ireland NEWS monitoring counts around Ballycotton Bay SPA.
Figure 2.4 Subsites used to subdivide the beach zone at Ballycotton Bay for low tide counts performed by Pat
Smiddy over the winter 1999/2000.
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Figure 2.5 Biotope mapping from Ballycotton Bay (Merc Consultants, 2012).
Figure 2.6 Results of GPS tide mapping exercise with spatial distribution of broad habitat zones within Ballycotton
Bay SPA based on MERC biotope mapping and contemporary aerial photographs.
Figure 5.1 Mean number of Teal recorded at each subsite across four low tide surveys undertaken during the
NPWS baseline waterbird survey at Ballycotton Bay in 2010/2011 (across all behaviours and habitats).
Figure 5.2 Mean number of Ringed Plover recorded at each subsite across four low tide surveys undertaken during
the NPWS baseline waterbird survey at Ballycotton Bay in 2010/2011 (across all behaviours and
habitats).
Figure 5.3 Mean count of Ringed Plover recorded from the beach at Ballycotton Bay during low tide surveys (LT ± 2
hours) undertaken during the winter of 1999/00.
Figure 5.4 Mean number of Golden Plover recorded at each subsite across four low tide surveys undertaken during
the NPWS baseline waterbird survey at Ballycotton Bay in 2010/2011 (across all behaviours and
habitats).
Figure 5.5 Mean number of Grey Plover recorded at each subsite across four low tide surveys undertaken during
the NPWS baseline waterbird survey at Ballycotton Bay in 2010/2011 (across all behaviours and
habitats).
Figure 5.6 Mean count of Grey Plover recorded from the beach at Ballycotton Bay during low tide surveys (LT ± 2
hours) undertaken during winter of 1999/00.
Figure 5.7 Mean number of Lapwing recorded at each subsite across four low tide surveys undertaken during the
NPWS baseline waterbird survey at Ballycotton Bay in 2010/2011 (across all behaviours and habitats).
Figure 5.8 Mean number of Bar-tailed Godwit recorded at each subsite across four low tide surveys undertaken
during the NPWS baseline waterbird survey at Ballycotton Bay in 2010/2011 (across all behaviours and
habitats).
Figure 5.9 Mean count of Bar-tailed Godwit recorded from the beach at Ballycotton Bay during low tide surveys (LT
± 2 hours) undertaken during winter of 1999/00.
Figure 5.10 Mean number of Black-tailed Godwit recorded at each subsite across four low tide surveys undertaken
during the NPWS baseline waterbird survey at Ballycotton Bay in 2010/2011 (across all behaviours and
habitats).
Figure 5.11 Mean count of Black-tailed Godwit recorded from the beach at Ballycotton Bay during low tide surveys
(LT ± 2 hours) undertaken during winter of 1999/00 (Nov to Feb).
Figure 5.12 Mean number of Curlew recorded at each subsite across four low tide surveys undertaken during the
NPWS baseline waterbird survey at Ballycotton Bay in 2010/2011 (across all behaviours and habitats).
Figure 5.13 Mean count of Curlew recorded from the beach at Ballycotton Bay during low tide surveys (LT ± 2 hours)
undertaken during winter of 1999/00.
Figure 5.14 Mean number of Turnstone recorded at each subsite across four low tide surveys undertaken during the
NPWS baseline waterbird survey at Ballycotton Bay in 2010/2011 (across all behaviours and habitats).
Figure 5.15 Mean count of Turnstone recorded from the beach at Ballycotton Bay during low tide surveys (LT ± 2
hours) undertaken during winter of 1999/00.
Figure 5.16 Mean number of Common Gull recorded at each subsite across four low tide surveys undertaken during
the NPWS baseline waterbird survey at Ballycotton Bay in 2010/2011 (across all behaviours and
habitats).
Figure 5.17 Mean count of Common Gull recorded from the beach at Ballycotton Bay during low tide surveys (LT ± 2
hours) undertaken during winter of 1999/00 (Nov to Feb).
Figure 5.18 Mean number of Lesser Black-backed Gull recorded at each subsite across four low tide surveys
undertaken during the NPWS baseline waterbird survey at Ballycotton Bay in 2010/2011 (across all
behaviours and habitats).
Figure 5.19 Peak count of Lesser Black-backed Gull recorded from the beach at Ballycotton Bay during low tide
surveys (LT ± 2 hours) undertaken during winter of 1999/00.
Figure 6.1 Habitat zones that occur within the proposed aquaculture licence sites in Ballycotton Bay SPA based on
biotope mapping (MERC, 2012), GPS tide mapping and contemporary aerial photography.
Figure 6.2 Areas of available intertidal habitat that occur within the proposed aquaculture licence sites in
Ballycotton Bay.
Figure 7.1 Peak disturbance assessments recorded at each subsite in Ballycotton Bay during the NPWS baseline
waterbird surveys.

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List of Plates

Plate 1.1 Oyster trestles at Ballymacoda Bay; showing heavy growth of green algae.
Plate 1.2 Lines of oyster trestles at Dungarvan Bay; ongoing maintenance.
Plate 2.1 Marsh / subsite 0L580.
Plate 2.2 Allen’s Pool (0L580).
Plate 2.3 Beach, lower shore and reefs north of Ballynamona Carpark (0L581).
Plate 2.4 Upper Beach, with dunes to rear (0L581) - mapped as Barren or amphipod dominated mobile sand
shores (LS.LSa.MoSa) by Merc Consultants (2012).
Plate 2.5 Extensive area of stone-reef dominated by macroalgae (fucoid) cover on lower shore; with green algae
covered mixed sand / stone substrate in the foreground (in 0L579, 581 & 576).
Plate 2.6 Extensive area of stone-reef dominated by macroalgae (fucoid) (in 0L579, 581 & 576).
Plate 2.7 Green and purple algae favoured by Light-bellied Brent Geese & Wigeon on sand / stony substrate (in
0L581 & 576).
Plate 2.8 Stony reef further up the shore with extensive cover of green algae (in 0L576).
Plate 2.9 Mid and low shore section of the outer beach - characterised as Polychaete/bivalve dominated muddy
sand shores (LS.LSa.MuSa) (Merc Consultants, 2012) (0L576).
Plate 2.10 Shingle upper shore (characteristic of barrier which historically sealed the lake) (0L576).
Plate 2.11 Area of upper shore with partially eroded peat visible close to the surface and green algae (0L576).
Plate 2.12 Mussel bed (0L576).
Plate 2.13 Extensive areas of green algae in 0L576.
Plate 2.14 Ballynamona Lake (0L575) – showing extensive lower saltmarsh (Salicornia) encroachment.
Plate 2.15 Strandline deposits of macroalgae. With dunes to the rear (0L581).
Plate 2.16 Realigned channel of Shanagarry Stream (with signs of beach erosion on outward curve) (0L581).
Plate 2.17 Beach looking north from Shangarry public carpark – where beach narrows (0L581-0L576).
Plate 2.18 Mudflat in 0L576; with ample evidence of lugworm.
Plate 2.19 Ardnahinch Wetland (0L578).

Appendices

Appendix A Scientific names of species mentioned in the text.

Appendix B Diet of SCI Species

Appendix C Disturbance Review (from NPWS, 2014b)

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Executive Summary
This report contains the Appropriate Assessment of proposed aquaculture activities in Ballycotton Bay. The
activities being assessed are within the Ballycotton Bay SPA (site code 004022) and this SPA is the primary
focus of this assessment.
There are three other SPAs within 15 km of the proposed aquaculture and shellfishery areas in Ballycotton
Bay: Cork Harbour (site code 004030), Ballymacoda Bay (site code 004023) and Blackwater estuary (site
code 004028). These SPAs are all included in this assessment.
This assessment is based on a desktop review of existing information. This included published reports and
papers and unpublished data from waterbird surveys. Where relevant, the report identifies information gaps
that may affect the reliability of the conclusions of this assessment.
Constraints to the assessment include the lack of detailed information about the proposed aquaculture
activities; lack of information about the nature of waterbird responses to some of the activities assessed and
generic biotope mapping.
Methodology
Analysis of the likely impacts of activities covered in this assessment was based on calculations of spatial
overlap between the SCI species distribution and the spatial extent of the activities. These analyses focus on
distribution patterns of feeding, or potentially feeding birds, as the main potential impacts will be to the
availability and/or quality of feeding habitat, although we have included assessment of potential impacts on
roosting birds, where relevant. The distribution of waterbird was analysed using data from the Irish Wetland
Bird Survey (I-WeBS) counts of Ballycotton Bay (mainly using data from 2006/07-2010/11); National Parks
and Wildlife Service (NPWS) baseline waterbird survey counts (mainly low tide counts carried out in
2010/11) and additional low-tide date provided by the I-WeBS counter. Maps of flock locations from the
NPWS baseline waterbird survey low-tide counts and descriptions of waterbird distribution (NPWS (2014)1
have also been used to interpret the patterns derived from these analyses.
The methodology used to identify potentially significant impacts is focussed on the Conservation Objectives,
and their attributes, that have been defined and described for the Ballycotton Bay SPA. Impacts that will
cause displacement of 5% or more of the total Ballycotton Bay population of a non-breeding SCI species
have been assessed as potentially having a significant negative impact.
Conservation objectives
The Special Conservation Interests (SCIs) of the Ballycotton Bay SPA include non-breeding populations of
Bar-tailed Godwit, Black-tailed Godwit, Common Gull, Curlew, Golden Plover, Grey Plover, Lesser Black-
backed Gull, Lapwing, Ringed Plover, Teal and Turnstone.2 The conservation objectives for these species
are to maintain their favourable conservation condition, which are defined by there being stable or increasing
long-term population trends and no significant decrease in numbers or range of areas used within
Ballycotton Bay.
The wetland habitats within the Ballycotton Bay SPA and the waterbirds that utilise this resource are an
additional SCI (the wetlands and water birds SCI). The conservation objective for this SCI is to maintain its

1 NPWS (2014). Ballycotton Bay Special Protection Area (Site Code 4022): Conservation objectives supporting document.
2 NPWS (2011). Conservation objectives for Ballycotton Bay SPA [004022]. Generic Version 4.0. Department Of Arts, Heritage and
The Gaeltacht
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favourable conservation condition, which is defined by there being no significant decrease in the permanent
area occupied by wetland habitats.
Screening
All of the SCI species for the Ballycotton Bay make significant use of subtidal and/or intertidal habitat within
the SPA and were, therefore, carried forward for full Appropriate Assessment.
Many of the SCI species listed for Ballymacoda Bay SPA, Blackwater Estuary SPA and Cork Harbour SPA
are the same as those listed for Ballycotton Bay; in addition to a number of additional species which are not
qualifying interests at Ballycotton. The possibility of movement of waders and wildfowl between Ballycotton
Bay SPA and Ballymacoda Bay SPA, Blackwater Estuary SPA and Cork Harbour SPA cannot be
discounted. Linkages between the SPA sites are poorly understood; although they do share many of the
same species (see Table 4.2, which presents a summary of the qualifying interests of all coastal SPAs close
to the proposed scheme).
Description of aquaculture activities
Intertidal culture of the Pacific Oyster (Crassostrea gigas) using oyster trestles is widespread in Ireland and
occurs in 16 SPAs and the potential impact of this activity on waterbird populations will be an issue in a
number of Appropriate Assessments. At Ballycotton Bay it is proposed to culture Pacific Oyster in Ireland
uses trestles in intertidal habitat; the proposed licence blocks also extend into the shallow subtidal. The
trestles are usually located in the lower part of the intertidal zone, in areas that are only fully exposed on low
spring tides. While no information is available at this time as to the % occupation of the licence blocks by
trestles; large blocks of trestles are usually located on sandflats such as those that characterise Ballycotton
Bay. The assessment is therefore based on full occupation of the licence blocks applied for. These are
located in two groups; a single large southerly block (20.75ha) and a northerly block (17.7ha) comprised of 5
no. applications; totalling 38.46ha overall.
It is understood that half grown oysters are to be ongrown at Ballycotton Bay in mesh bags placed on top of
the trestles, where they are on-grown until they are ready for harvesting. Oyster husbandry activities mainly
take place during spring low tides. At sites with large areas of trestle blocks, husbandry activities may take
place on every suitable tide.
Assessment of aquaculture activities
Presently, there are no established aquaculture activities within the boundaries of Ballycotton Bay SPA. The
proposed aquaculture plots are located in the south side of Ballycotton Bay and are divided into two main
blocks, a northern and southern block. The southern block is 20.75 ha in total and is not subdivided. The
northern block is 17.7 ha in total and is subdivided into 5 sub-sites. The total area of proposed aquaculture
licence areas is 38.46 ha.
As noted due to the extent of trestles proposed and their location within prime areas of soft sedimentarty
habitat we focused our detailed assessment on those species which demonstrably are linked to this habitat
type.
The potential impact on these species is summarised in Table 8.1. Of the four species considered – Ringed
Plover, Grey Plover, Black-tailed Godwit and Bar-tailed Godwit – three of these species are showing
significant long-term (14-year) population declines at Ballycotton. Only Black-tailed Godwit is increasing at
Ballycotton Bay as it is on a national basis. Furthermore, the declines exhibited at Ballycotton Bay are at
odds with national trends for both Ringed Plover and Bar-tailed Godwit. Grey Plover, in contrast is declining
at both a site and a national level.
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Ringed Plover, Black-tailed Godwit and Bar-tailed Godwit all show a negative response to oyster trestles
(Gittings and O’Donoghue, 2012); while Grey Plover is totally excluded by trestles.
As noted above two approaches can be taken to the assessment of loss of soft sedimentary habitat used by
these species; i) calculation of displacement based only on soft sedimentary habitats on the beach and ii)
calculation of displacement based only on soft sedimentary habitats on the beach and within the lake. As
Black-tailed Godwit, Grey Plover and Ringed Plover have been noted to feed within the lake option ii) may
better represent the true situation for these species; however, as Bar-tailed show a preference for feeding
along the tideline option i) may better represent impacts on Bar-tailed Godwit.
Table 1 – Summary of impact assessment.
Long-term i) Relative ii) Relative
Special Site Population population population population Potential
CInotenrseesrtvsa (tSioCnI s) Trend (1b 4 year) decline d(bisepalcahce omnelyn)t (dbiesapclahc &em laeknet) Impact
>25%
Ringed Plover -15 N 39% 24% Significant
Grey Plover -37 Y 38% 23% Significant
Unlikely to be
Significant
due to
Black-tailed Godwit +72 N 15% 9% flexibility &
use of
habitats other
than beach
Bar-tailed Godwit -50 Y 30% 18% Significant
Thus a potential significant negative impact arising from the proposal to place trestles as per licence blocks
shown on Figure 1.1 cannot be discounted. By reassessing using only the NPWS baseline waterbird survey
counts (a series of 4 no. low-tide counts) the relative displacement recorded increases further.
Cumulative impacts
This assessment considered the cumulative impacts of the combined effects of the aquaculture and other
activities within the SPA (including recreational activities, boat traffic, a planned seaplane service, historical
habitat loss, hand collection of shellfish, bait digging and effluent discharge).
Disturbance levels at Ballycotton Bay would appear to be high such that it is possible, that disturbance from
recreational activity in the intertidal zone could have in-combination effects with displacement impacts from
aquaculture activities that cause a measurable increase in the overall cumulative impact to Ringed Plover,
Grey Plover and Bar-tailed Godwit. While shellfish picking seems to be a regular occurrence at Ballycotton
Bay, there is insufficient information on this practice to comment further.
Historical habitat loss in Ballycotton Lake has also had significant impacts on the bird community of
Ballycotton Bay – as noted in Smiddy and O’Halloran (2006 a/b).
It is proposed to capture and treat effluent from Ballycotton, Shanagarry and Garryvoe; an Appropriate
Assessment for this scheme concluded that this project would not adversely impact on the SCI species for
Ballycotton Bay.

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Acknowledgements
We are grateful to Brian O’Loan (BIM) for providing information about proposed aquaculture activities in
Ballycotton Bay. Francis O’Beirn (Marine Institute) provided useful information and answered many queries.
We are also grateful to Pat Smiddy for provided information, insight and data about waterbird counts and
distribution in Ballycotton Bay, and for permission to use his unpublished data. Thanks also to Olivia Crowe
(BirdWatch Ireland) and Lesley Lewis and David Tierney (NPWS) who also assisted with the provision of bird
data.
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