Attachment B.2 Characteristics and Composition of the Substance Or Material for Disposal

POC Maintenance Dredging Application | January 2014

Attachment B.2 Characteristics and Composition of the Substance or Material for Disposal

Reports included as part of this attachment:

• Assessment of Benthic and Fisheries Impacts of Maintenance Dredging in Lough Mahon and the Lower River Lee, Aquatic Services Unit (March 2013) [included separately within Attachment B.2]. Relevant references include:

Section 2.2 – Sub-tidal Benthos Survey

Section 2.4 – Inter-tidal Survey Results & Overview

Section 2.5 – Sub-tidal Surveys

• Water Injection Dredging Tracer Study, Van Oord (July 2012) [included as part of Attachment D.3]. Relevant references include:

Section 2.2 – Tracer Particle Size

Section 3.2 – Sampling Survey

Section 4 – Data and Results

Castletownbere Feasibility Report | December 2013

• June 2011 Sediment Sampling Results [included separately within Attachment B.2]. In summary, these results describe that the sampled material generally comprises black mud with over 50%-60% fraction size less than 63 microns.

• June 2013 Sediment Sampling Results [included as part of Attachment B.1 (i)]. In summary, these results describe that the sampled material generally comprises mud with over 60% fraction size less than 63 microns.

Report Reference: IBM0455/R/KG Revision Number: - 2 rpsgroup.com/ireland

Assessment of Benthic and Fisheries Impacts of Maintenance Dredging in Lough Mahon and the Lower River Lee

(2011-2012)

Commissioned by: Port of Cork

Undertaken by: Aquatic Services Unit (UCC) (March 2013)

TABLE OF CONTENTS

SUMMARY 3

IINTRODUCTION 7

Study Outline 7 Receiving Environment 7 Sampling Areas 7 Sampling Frequency and Timing 8 Data Analysis and Study Outputs 9 Feasibility of Achieving the Study Goals 9

METHODOLOGY & RESULTS – BENTHOS 11

Intertidal Soft Sediment Survey 11 Sub-tidal Soft Benthos Survey 13 Sample Processing 16 Intertidal Survey Results & Overview 17 Community Analysis of Intertidal Data 65 Discussion of Intertidal Results 66 Subtidal Surveys 68 Community Analysis of Subtidal Data 92 Discussion of Subtidal Data 92

METHODOLOGY & RESULTS – FISH 94

Overview 94 Timing 94 Methods 94 Fisheries Results 97 Implications of Fish and Invertebrate Diet for the Dredging in Lough Mahon 121 Type of Dredging and Potential Impacts 122 Overall Conclusion from Fisheries Surveys 122

REFERENCES 124

Appendix 1: Trawl Results and Maps of Trawl Tracks 126

SUMMARY

Introduction and Brief

As part of a study to assess the potential impacts of dredging within the Lower River Lee and Lough Mahon, the Port of Cork commissioned the Aquatic Services Unit to undertake a study of the intertidal and subtidal infaunal benthos and of the fisheries within the and adjacent to the dredged channel from the City Quays upstream as far as Marino Point at the lower end of Lough Mahon.

Survey Outline and Methods

The survey concentrated on 4 main areas and a control site in the North Channel at Rossmore.

Area 1 was between the City Quays and Marina Power Station, Area 2 stretched from the Marina Power Station as Blackrock Castle; Area 3 stretched from Blackrock Castle to approximately half way down Lough Mahon, while Area 4 continued to the end of Lough Mahon to the bend opposite Marino Point

Sampling included intertidal core sampling and sub-tidal grab sampling within the study areas as well as fishing in all the same areas using a range of fishing gear types.

The study comprised a main baseline and a main follow-up survey covering all sampling methods in in all survey areas in May/June 2011 i.e. pre-dredging and again in May/June 2012 about 5-9 months post-dredging. A quarterly survey was undertaken in late February/early March 2-6 months post dredging involving a reduced sampling intensity. Some additional baseline fisheries surveying (confined to beam trawling) was undertaken in late August 2011 just prior to the start of dredging.

Benthic Survey – Methods and Results

Intertidal Macrobenthic Sampling

4 intertidal transects were studied, T1-T3 in the greater Lough Mahon area (T1 by Hop Island, T2 by Carrigrenan, T3 inside Marino and T4 the control site in the North Channel at Rossmore).

At each site, replicate stove-pipe cores were taken at three tidal heights High Shore, Mid-Shore and Low Shore.

Pre-dredging sampling took place in May 2011, and post-dredging took place in February 2012 and June 2012.

The results indicate that there was a pronounced difference between the numbers and biomass of macroinvertebrate infauna between the four transects with T1 and T4 having higher numbers and biomass on all sampling occasions than T2 and T3.

There was also a pronounced difference between the numbers and biomass of invertebrates between shore heights at all transects with the low shore almost always having considerably lower abundances and biomass than the mid or high shore stations and the high shore sites tending to have the highest numbers and biomass at all transects during all three sampling occasions.

During February 2012, some 2-3 months after the cessation of maintenance dredging in the shipping channel there was a pronounced drop in both faunal numbers and biomass at all transects including the control site (T4). Because this decrease was so clear across all sites including the control and at all tidal heights it was considered to be a normal seasonal trend. Such seasonal drops in biomass and numbers are widely reported in the scientific literature.

During the June follow up survey, some 5-7 months after the cessation of maintenance dredging, macroinvertebrate populations from the February, saw a significant increase across all transects, again this would be expected as a normal seasonal trend on intertidal mudflats. The results varied between transects and between shore heights, so for instance at T1 the biomass at the high and low shore stations increased to the levels recorded in the May 2011 baseline survey, while the mid-shore sites remained as low as during February 2012. At T2, biomass remained the same or increased at all tidal heights compared to the May 2011 baseline and at T3 the low shore biomass did not increase above the levels recorded in February, whereas at the mid-shore and high shore stations they did. Finally at the control site T4 in Rossmore, while stations at all three shore heights increased in biomass compared to the February seasonal low, only the low shore site reached (and exceeded) the values recorded during the May 2011 baseline. This latter result is attributed to fine- scale patchiness in the distribution of benthic invertebrates.

Finally, when all of the data from all three sampling runs is pooled and analysed using a multivariate analysis technique – MDS (Multi Dimensional Scaling), all the data points (transects, tidal heights and sampling occasions) pool together into a single cluster, which indicates that we are dealing with a single intertidal faunal community typical of sandy mud conditions.

The inter-transect, inter shore height and between sampling run variation noted within the data is concluded to fall within normal temporal and spatial variability ranges typical of such communities with little if any influence from the maintenance dredging operations in the shipping channel.

Subtidal benthic Infauna

Subtidal benthic grabs were taken in four sampling areas (Area 1 to 4) during the study and at three stations across the channel within each of these four locations.

Sampling for benthic infauna was carried out on three occasions, namely May 2011 before maintenance dredging of the channel and in February 2012 and June 2012 after the dredging had taken place.

The results indicate that at virtually all stations within in all four locations there was a drop in infaunal macroinvertebrate biomass, when the May 2011 data is compared with the June 2012 data. On average the reduction in biomass is in the order of around 50%. This change has been attributed to the dredging and was expected. It is notable that localised colonies of the Peacock fan worm (Sabella pavonina) on the un-dredged margins of the channel, do not appear to have been adversely impacted by the dredging, suggesting that the impacts to the macroinvertebrate infauna were largely confined to the channel itself.

Fisheries Surveys, Schedule, Methods and Results

Baseline fisheries surveys were conducted in the four survey areas (Areas 1-4) and at the Rossmore control site in May/June 2011 with a main follow-up survey in May June 2012. In addition, some

limited additional baseline data was collected in August 2011 just prior to the commencement of dredging while a more extensive quarterly follow up survey was carried out in February 2012.

4 gear types were deployed, baited traps (Areas 1 and 2), fyke nets (Areas 1-4 and the control site), beam trawls Areas 1-4 and Rossmore and seine nets –Rossmore.

The main target of the surveys were the fish species living on and in close proximity to the bottom as it would be expected that these would more likely to be impacted than mid-water (pelagic) species. In addition however the levels of larger mobile epibenthic / hyperbenthic crustaceans were also surveyed, principally Crangon (brown shrimp) and green crab (Carcinus maenas) both of which were widespread and abundant within the study area and both of which are considered important components of the estuarine food web.

Both baited fish traps and fyke nets caught large amounts of green crab in May/June 2011 and again in May/June 2012 at all of the sites where they were deployed. Although biomass was reduced at some stations in 2012 compared to 2011, the data is quite variable between sites and so a definite statement of cause and effect cannot be made.

In addition to crab, both traps and fyke nets caught small numbers of fish including dogfish, cod, pollack, eel, flounder, plaice, bull-rout, hooknose, sand-smelt and most frequently 5-bearded rockling. The small numbers preclude any conclusions being drawn about these fish.

The most intensive aspect of the fisheries survey was the beam-trawling which resulted the capture of 26 species, which when combined with the species 3 species which were only taken in fykes (i.e. lesser spotted dogfish, bull-rout and sand smelt) brings to 29 the number of species recorded during the survey. The majority of these are either classified as Estuarine Species (Nilsson’s pipefish, black goby, common goby) that are strongly tied to the estuarine environment, Marine Migrants (dab, plaice, flounder) which spawn at sea and whose juveniles use the estuarine environment for food and or shelter from predators, or a combination of both (sand goby, hooknose, greater pipefish). Almost half of the species encountered were only noted on one or two occasions, including grey gurnard, whiting, transparent goby and a conger eel larva.

The most widespread and populous species included, sand goby, dab, plaice and hooknose, followed by flounder, Nilsson’s pipefish and greater pipefish, with black goby also being common in Areas 4 and Rossmore. Common goby was only found in numbers in the intertidal zone of Rossmore where they were taken in a beach seine net.

Trawl returns were slightly lower both in terms of species and numbers of individuals in February 2012, although dab were more widespread and more numerous in February 2012 than during any of the other three sampling runs.

There was no reduction in diversity between the May/June 2011 baseline survey and the May/June 2012 main follow-up survey and all the more common species were all well represented on the latter occasion also. Gut contents analysis undertaken for the study showed a significant proportion of benthic infauna in the diet of species such as juvenile plaice, dab, sand goby, black goby and flounder. Given that the benthic survey indicated a reduction in the biomass of infaunal macroinvertebrates within the dredged channel, one might expect these species to be adversely impacted. However, all of these species consume a range of benthic prey, and a number (including flounder, sand goby and dab in particular) are known to be very opportunistic in their dietary habits and would therefore be expected to shift to other food sources e.g. mobile epibenthic crustaceans

(e.g. amphipods) and pelagic food items such as calanoid copepods and mysids, thereby dampening the impact of the reduced infaunal prey biomass. Juvenile plaice and to a lesser extent black goby, which appear to be more small polychaete and larger polychaete specialists respectively may be more susceptible. However, the data from the trawls doesn’t indicate any clear reduction in plaice frequency or numbers between the 2011 and 2012 summer surveys, while data on black goby isn’t frequent enough to make any definite statement in this regard.

It is important to note that in the case of marine spawners such as plaice, dab and flounder for example, the strength of the next annual recruitment of young fish from the plankton will not be impacted by such a small-scale, localised anthropogenic disturbance as the channel dredging in Lough Mahon, i.e. the dredging in any given year will not determine the number of recruits to the population in the following year(s).

Crangon and green crab were by far the dominant mobile epibenthic faunal species captured in trawls and they occurred in all areas. There is some indication from the data that the wet weight biomass of both species in May/June 2012 catches was down in the region of 50% on the baseline data, although the high level of variability in the data makes this a tentative observation only. If the data does indicate a real reduction, then, based on published papers it could be within normal inter- annual variation in biomass in the case of Crangon at least. If it is due to dredging, it seems unlikely that the overall food web implications would be very significant, given that both species are still very numerous within the dredged channel. Given that both species are known to be predators of small fish including gobies and plaice, a reduction in their density could also have beneficial knock-on effects by reducing predation on juvenile fish. The changes observed however are fairly modest and they are considered unlikely to have very significant impacts within the study area as a whole, especially considering that the dredged channel is bounded by extensive sub-tidal and intertidal banks which remain unaffected by the dredging and which harbour all the same species.

Recommendations

A shortcoming of studies of this type is that they tend to take a snapshot in time, with little if any previous data and follow-up data available to put the findings into context. This is especially problematic when a significant degree of inter-annual variability in numbers and biomass of certain species might be expected. In order to reduce this effect and to assist in distinguishing between variability due to normal inter-annual changes in biological communities and that associated with dredging, it is suggested that limited annual sampling might be considered. Given that the Port Authority will require to undertake maintenance dredging about every three years, it would be useful to carry out limited annual sampling in the intervening years as follows. One of the Area 4 intertidal transects and sub-tidal sampling points could be sampled (once in summer and once in winter). In addition, a 2-m beam trawl could be taken in June each year in Area 3 and Area 4, with a record kept of the species landed and their relative dominance. The size distribution of the Crangon and green crabs landed would also be taken measured from the trawl catch and this would also provide useful contextual data for follow-up studies in the future.

1 INTRODUCTION

1.1 Study Brief

The Aquatic Services Unit were commissioned by the Port of Cork to assess the impact of the Port’s Proposed Maintenance Dredging Programme in Cork Harbour on the benthic infauna of the intertidal and subtidal habitats adjoining the shipping channel from the City Quays as far as Marino Point at the seaward end of Lough Mahon. The project also aimed to assess the impacts of the dredging on the mobile epifauna and fish within the same area.

1.2 Study Outline

The project has been designed to get a comprehensive overview of the main components of the fauna within the study area. Benthic macroinvertebrates (mainly oligochaetes and polychaete worms and bivalve molluscs), were sampled in intertidal and sub-tidal areas using cores and grabs respectively, while mobile epibenthic fauna mainly crustaceans, (shrimp and crab) and small fish were sampled using beam trawls, while fish and crustaceans were also targeted in baited pots, fyke nets and beach seine nets, as appropriate.

Benthic macroinvertebrates were identified, counted and their wet-weight biomass measured while fish were identified counted and measured. A selection of fish species, especially the most numerous were retained for gut contents analysis. Mobile epibenthic crustaceans were identified and bulk weighed, with a representative sample retained for size frequency analysis.

The aim of the sampling programme was to assess whether there were any measurable before-after differences in each of the sampled components of the aquatic ecosystem that could be attributed to the dredging. This was to be achieved by direct changes in biomass and community structure as well as an analysis of the food-chain linkage between each component to see whether these had be altered due to the dredging and whether such change had adversely impacted the overall functioning of the estuarine ecosystem within the study area.

1.3 Receiving Environment

The estuary comprises a narrow channel from the City Berths as far as Blackrock Castle and after that widens out into the mud and sandy mud expanses of Lough Mahon. The intertidal area of Lough Mahon comprises mud and sandy mud flats, both north and south of the shipping channel, with narrow rocky belts in the mid to upper intertidal and extensive mussel beds in places e.g. by Carrigrenan Point on Little Island. A bit off the main channel, between Marino Point and Fota, there are extensive intertidal flats, which are used by waterfowl as feeding areas in the appropriate seasons.

1.4 Sampling Areas

The study area was divided up into 4 sampling areas (Area 1 to Area 4) and a control site (see Figure 1). The areas are as follows: Area 1- City berths to the Marina Power Station. Area 2 - Tivoli to Blackrock Castle, Area 3 Upper Lough Mahon from Blackrock Castle to Hop Island and Area 4 - Lower Lough Mahon from Hop Island to Marino Point. The control site was located in the North Channel just south of Rossmore (Figure 1.1).

1.5 Sampling Frequency and Timing

See Table 1.1 for a summary of the sampling programme as undertaken. A baseline sampling was undertaken in May and June 2011 when the full range of sampling was undertaken in all four study areas and the control, in advance of dredging. As dredging didn’t commence until late August, a short beam-trawl survey was added prior to the commencement of Water Injection Dredging (WID) which was undertaken from the City Berths to below the Tivoli Docks. Due to technical matters, the WID failed to give satisfactory results in the Tivoli Docks area and Trailer Suction Hopper Dredging (TSHD) was repeated in this area and continued on down the main Lough Channel to just beyond the bend at Marino Point. The dredging was undertaken in a number of short campaigns and finally concluded in early January 2012. The first ‘quarterly’ re-survey was undertaken in late February and early March and included intertidal and subtidal benthic sampling in all 4 areas and the control and beam trawling in all the same area. Three to four months later from late May to Mid June 2012 i.e. about 8 months since Area 1 and much of Area 2 had been dredged (WID) and about months 6 since Area 3 and 4 had been dredged (TSHD) a full follow-up survey involving the full range of sampling methods was carried out.

Area 1 Area 2 Area 3 Area 4 Control Baseline Survey (May-June 2011) Intertidal Benthic Sampling x x x x x Subtidal Benthic Sampling x x x x Baited Traps x x Fyke Nets x x x x x Seine Nets x Trawls x x x x x

Additional Sampling (August 2011) Trawls x x x x

Dredging (Late August 2011 to early January 2012) x x x x

Quarterly Sampling (February - March 2012) Intertidal Benthic Sampling x x x x x Subtidal Benthic Sampling x x x x x Trawls x x x x x

Main Follow-up Survey (May-June 2012) Intertidal Benthic Sampling x x x x x Subtidal Benthic Sampling x x x x Baited Traps x x Fyke Nets x x x x x Seine Nets x Trawls x x x x x

Table 1.1 Cork Harbour Study schedule

1.6 Data Analysis and Study Outputs

The study plan was designed to account for natural spatial and temporal variation in the intertidal and subtidal macroinvertebrate infauna and the mobile epibenthos and fish populations within the shipping channel. The study seeks to assess the effect of dredging on the macrobenthic and fish communities based on both the temporal and spatial variation in the biomass of benthic and epibenthic species and fish and their associated prey. To achieve this goal four broad steps were proposed in the study design as follows:

(1) The results of gut contents will be used to establish the trophic links between each major fish species and their prey species, thus providing a clear picture of the food webs at play at the study sites, and hence the flows of matter and energy of importance to production in the fishery.

(2) The background levels of variation in the quantitative and qualitative data describing the abundance of the benthic and epibenthic fauna will be compared across sites and over the one full year of survey. This will provide an assessment of the impact of the dredging on the productivity of the system.

(3) The effect of dredging on the biomass of the benthic and epibenthic fauna will be estimated from step (2). The length-weight measurements will provide an assessment of how dredging has impacted the size structure, composition, and hence productivity of the fished community.

(4) The effect of dredging on the loss to fisheries will be assessed by analysing the observed shifts in fish diet, by combining the food web analyses (step 1) and the observed changes in the benthic and epibenthic fauna of importance to the fish (step 3). Changes in fish standing stock will be assessed before and after the dredging, and these will be related to prey productivity before and after dredging.

1.7 Feasibility of Achieving the Study Goals

While items 1, 2 & 3 were achieved for the most part, item 4, which depended on estimating standing fish stock turned out to be overly ambitious due to limitations in the intensity of fish sampling that could be achieved. This shortcoming in the study programme implementation, however, hasn’t prevented the completion of most of the study elements nor prevented us from making significant relevant observations on the various aquatic compartments sampled which in turn has allowed measured conclusions to be drawn about the impact of the maintenance dredging within the study area.

Figure 1.1: Cork Harbour Study Area

2 METHODOLOGY & RESULTS - BENTHOS

2.1 Intertidal Soft Benthos Survey

Four survey areas were selected. These survey areas were:

Lough Mahon South (Hopp Island) Lough Mahon North (Carrigrenan) Lough Mahon East (Marino Point) Rossmore, North Channel

In each area a single transect was taken with positions recorded and marked along the high, mid and low shore areas. These sites were marked with bamboo poles inserted into the sediment to allow for ease of identification during repeat surveys.

Field Surveys

The baseline fieldwork was carried out on the 18th / 19th May, 2011. All sampling stations were positioned using a handheld GPS (Trimble Geo-XM GPS unit). A list of the stations sampled are presented in Table 2.1.1 and these stations are displayed on a map (Figure 2.1.1). These sites were then re-visited in February 2012 (9th & 13th) and June 2012 (18th & 26th).

Easting Northing Easting (m) Northing (m) (m) (m) Transect 1 High 173887.9 69534.9 Transect 3 High 178028.1 70187.2 Transect 1 Mid 174055.0 69748.2 Transect 3 Mid 177772.1 70172.0 Transect 1 Low 174315.9 70047.1 Transect 3 Low 177376.1 70156.4 Transect 2 High 176439.6 70956.4 Transect 4 High 182338.2 70720.4 Transect 2 Mid 176189.8 70830.9 Transect 4 Mid 181922.5 70571.3 Transect 2 Low 176003.4 70698.5 Transect 4 Low 181535.6 70401.1

Table 2.1.1 Positions of intertidal soft sediment biological sampling stations. All locations given in Irish Grid.

Intertidal Core Sampling

Samples were collected at each site using the following methods:

3 x Replicate 19cm Ø cores (Area = 0.028m2) were taken to a depth of 20cm at each shore height. Each core was placed in a plastic bag with 2 waterproof labels and transported to the laboratory (Plate 3.1f).

A 7cm Ø core was taken to a depth of approximately 5cm for granulometric and Loss on Ignition (LOI) analyses. The contents from each core was then carefully transferred to a pre-labelled plastic zip-lock bag and stored in a cooler box with ice packs for transport back to the laboratory.

Figure 2.1.1 Map showing locations of intertidal soft sediment sampling positions in Cork Harbour.

2.2 Sub-tidal Soft Benthos Survey

Subtidal Grab Sampling

Four survey areas were selected. These survey areas were:

City Area (Custom Quay to Marina Generating Station)) Tivoli Area (Marina Generating Station – Blackrock Castle) Ringmahon (Blackrock Castle – Ringmahon Point) Lough Mahon (From Ringmahon Point to Marino Point)

In each area a series of 3 (occasionally 4) grabs were collected, with three replicate grabs taken where possible at each sampling point. An additional grab was collected for particle size and loss on ignition analyses.

2011 Survey

All sub-tidal grabs were collected on the 15th & 29th June 2011 and were sampled using a 0.045m2 stainless steel, weighted Van-Veen Grab for benthic faunal analysis. All sampling stations were positioned using a GPS (Trimble Geo-XM). A list of the stations sampled are presented in Table 2.2.1 and these stations are displayed on a map (Figure 2.2.1)

Easting Northing Easting (m) Northing (m) (m) (m) Area 1 G1 168706 17980 Area 3 G1 173184 71933 Area 1 G2 168714 72035 Area 3 G2 173315 71883 Area 1 G3 168658 72089 Area 3 G3 173209 71883 Area 2 G1 170584 72169 Area 4 G1 176098 69926 Area 2 G2 170494 72160 Area 4 G2 176099 69883 Area 2 G3 170414 72139 Area 4 G3 176049 69846 Area 4 G4 176012 69806

Table 2.2.1 Positions of sub-tidal soft sediment sampling stations. All locations given in Irish Grid.

Figure 2.2.1 Location of grab samples collected in June 2011. 13

February 2012 Survey

Sampling was undertaken on 28th February 2012 to collect a single set of grabs in Area 4 and two sets of grabs in Area 3. Sample positions from June 2011 were used to navigate to the sites (Table 2.3.2 & Fig. 2.3.2).

Easting (m) Northing (m) Area 3 G1 173119 71910 Area 3 G2 No Record No Record Area 4 G1 176048 69846

Table 2.3.2 Positions of sub-tidal soft sediment sampling stations (Feb 2012). All locations given in Irish Grid. [No sample positions were recorded for Area 3 Grab 2 – navigation to previous points used during survey].

Figure 2.3.2 Location of grab samples collected in February 2012.

June 2012 Survey

All sub-tidal grabs were collected on the 18th June 2012 and were sampled using a 0.045m2 stainless steel, weighted Van-Veen Grab for benthic faunal analysis. All sampling stations were positioned using a GPS (Trimble Geo-XM). A list of the stations sampled are presented in Table 2.3.3 and these stations are displayed on a map (Figure 2.3.3)

Easting (m) Northing Easting (m) Northing (m) (m) Area 1 G1 168704 71976 Area 3 G1 173193 71936 Area 1 G2 168720 72043 Area 3 G2 173116 71877 Area 1 G3 168653 72088 Area 3 G3 173220 71881 Area 2 G1 No Record No Record Area 4 G1 176078 69935 Area 2 G2 No Record No record Area 4 G2 176080 69937 Area 2 G3 170412 72134 Area 4 G3 176089 69936 Area 4 G4 176084 69934

Table 2.3.3 Positions of sub-tidal soft sediment sampling stations. All locations given in Irish Grid. [No sample positions were recorded for Area 2 Grabs 1 & 2 – navigation to previous points used during survey].

Figure 2.3.3 Location of grab samples collected in June 2012.

Sampling Methodology

At each station:

3 x 0.045m2 Van-Veen grab taken for benthic faunal analysis. 1 x 0.045m2 Van-Veen grab from which a small amount of sediment was retained for Particle Size Analysis and Loss on Ignition Analysis.

2.3 Sample Processing

Granulometric Analysis

Granulometric analysis was carried out on oven dried sediment samples from each station. The sediment was passed through a series of nested brass test sieves with the aid of a mechanical shaker. The brass sieves chosen were 4mm, 2mm, 1mm, 500µm, 250µm, 125µm and 63µm. The sediments were then divided into three fractions: % Gravel (>2mm), % Sand (<2.0mm >63µm) and % Silt-Clay (<63µm). Further analysis of the sediment data was undertaken using the Gradistat package (Blott & Pye, 2001).

Organic Matter Analysis

Organic matter was estimated using the Loss on Ignition (LOI) method. One gram of dried sediment was ashed at 450˚C for 6 hours and organic carbon was calculated as % sediment weight loss.

Biological sample processing

On returning to the laboratory all faunal samples were sieved on a 1mm mesh sieve within 24 hours of collection. Samples were preserved in 4% buffered formalin to which an organic dye (Rose- Bengal) had been added. All fauna were identified to the lowest taxonomic level possible using standard keys to north-west European fauna.

Data analysis]

Multivariate analysis of the faunal data was undertaken using the statistical package PRIMER v. 5 (Clarke & Gorley, 2001). Species that were present in less than one station per grid was removed from the multivariate analysis. All abundance data was fourth root transformed to reduce the importance of highly abundant species. A Bray-Curtis similarity matrix was produced and this similarity matrix was used for the cluster analysis and non-metric Multi-Dimensional Scaling (MDS) analysis.

Cluster analysis allows for creation of a 2-dimensional structure (dendogram) based on the similarity of stations to each other, and allows for the identification of discrete groups based on faunal similarities.

Non-metric multidimensional scaling (MDS) was undertaken on the Bray-Curtis similarity matrix to produce an ordination. This MDS ordination was then used to identify groups of samples which have similar faunal assemblages. Each MDS ordination also produces a stress value which allows for a good interpretation of how good the two-dimensional plot represents the multi-dimensional sample relationship. Clarke and Warwick (1994) have provided guidelines on these values and their relationship with the faunal plots. These are outlined below

• Stress Value <0.05: Excellent representation of the data. • Stress Value <0.10: Good representation of the data. Some fine detail may be misinterpreted. • Stress Value <0.20: Useful representation of the data. Some detail may be misinterpreted. • Stress Value >0.20: Data should be viewed with caution. The data may be randomly distributed within the ordination and may not represent the underlying dataset.

2.4: Intertidal Survey Results & Overview

Transect 1: Hop Island Survey area

Transect 1 is located along the soft sediment intertidal area adjacent to Hopp Island along the southern shore of Lough Mahon. Samples were located along a transect from the inner margins of Hop Island extending to the low shore level. The shore transect measures approximately 670 meters (Fig 2.4.1)

Figure 2.4.1 Location of sampling locations along Transect 1 – Hop Island

May 2011 Results

PSA Results

Results from Particle Size analysis of sediment collected in May 2011 highlights the relative homogenous distribution of sediment type across the shore. The sediment is dominated by poorly sorted sandy muds. Loss on Ignition results show values typical of mud dominated environments (Table 2.4.1).

Table 2.4.1 Particle Size and Loss on Ignition Results – May 2011

T1 High T1 Mid T1 Low % Gravel 1.0% 0.0% 0.0% % Sand 23.1% 38.0% 35.4% % Mud 75.9% 62.0% 64.6% Textural Poorly sorted slightly gravelly Poorly sorted sandy mud Poorly sorted sandy mud Group sandy mud % LOI 6.9% 6.3% 5.1%

Faunal Results

Upper and mid-shore sites returned the greatest diversity and abundances compared to the low shore site (Table 2.4.2, 2.4.3, 2.4.4 & 2.4.5). This is to be expected as the low shore site is exposed to greater water movement, being in close proximity to the main water channel. The faunal communities identified across the intertidal area at Transect 1 contains fauna which are common in Polychaete/bivalve dominated mid-estuarine mud shores (JNCC Habitat type LS.LMu.MEst; EUNIS Code A2.31).

May-11 May-11 May-11 T1 High T1 High T1 High A B C Oligochaetae 138 198 268 Nereis sp. 19 36 26 S. plana 23 22 21 Streblospio sp. 11 18 16 Tharyx sp. 3 7 2 Cyathura carinata 1 3 7 Eteone spp. 5 3 1 Polydora sp. 2 3

Mya arenaria 3

Gari fervensis 1

Table 2.4.2 Fauna identified along the high shore section of Transect 1, May 2011

May-11 May-11 May-11 T1 Mid T1 Mid T1 Mid A B C Streblospio sp. 76 22 79 Oligochaetae 26 8 45 Nephtys sp. 10 9 8 Scrobicularia plana 6 8 10 Nereis spp. 4 8 8 Tharyx sp. 9 4 4 Polydora sp, 8 1

Heteromastus filiformis 4

Eteone spp. 1 3

Macoma balthica 1 1

Mya arenaria 2

Ampharete indet. 1 1

Gari fervensis 1

Cyathura carinata 1

Glycera sp. 1

Spionidae indet. 1

Table 2.4.3 Fauna identified along the mid shore section of Transect 1, May 2011

May-11 May-11 May-11 T1 Low T1 Low T1 Low A B C Streblospio sp. 11 29 10 Nephtys sp. 10 9 7 Oligochaetae 1 6 1 Scrobicularia plana 2 2

Ampharete indet. 2

Gari fervensis 1

Table 2.4.4 Fauna identified along the low shore section of Transect 1, May 2011

T1High T1High T1High T1Mid T1Mid T1Mid T1Low T1Low T1Low A B C A B C A B C Species 9 9 7 10 10 12 4 5 4 Abundances 205 291 341 142 66 163 24 47 20 Shannon- 1.17 1.14 0.828 1.51 1.94 1.52 1.06 1.09 1.09 Wiener Pielou’s 0.535 0.518 0.425 0.655 0.841 0.61 0.766 0.679 0.789 Evenness Simpson 0.478 0.489 0.63 0.335 0.182 0.321 0.392 0.436 0.385 Dominance

Table 2.4.5 Primary and derived indices for the sample points along Transect 1 – May 2011.

Biomass results from the survey of May 2011 indicates high biomass levels along the upper and mid shore areas of the transect, with lower biomass present along the low shore area. The primary sources of biomass along these areas are the polychaete and mollusc groups (Fig. 2.4.2).

Figure 2.4.2 Combined biomass (g wet wt) from each tidal height along Transect 1 – May 2011.

February 2012 Results

PSA Results

Results from Particle Size analysis of sediment collected in Feb 2012 is similar to that recorded in May 2011. The sediment is dominated by poorly sorted sandy muds. Loss on Ignition results show values typical of mud dominated environments (Table 2.4.6).

T1 High T1 Mid T1 Low % Gravel 0.0% 0.0% 0.0% % Sand 37.4% 35.1% 51.0% % Mud 62.6% 64.9% 49.0% Textural Poorly sorted sandy mud Poorly sorted sandy mud Poorly sorted muddy sand Group % LOI 7.5% 7.2% 5.1%

Table 2.4.6 Particle Size and Loss on Ignition Results – May 2011

Faunal Results

Faunal results for February 2012 are similar to those identified in June 2011, with increased abundances and diversity located along the upper and mid shore sections of the transect, with lower diversity and abundances at the low shore station (Table XX)

Feb-12 Feb-12 Feb-12 T1 High T1 High T1 High A B C Oligochaetae 353 214 257 Streblospio sp. 66 78 37 Nereis sp. 11 11 11 Scrobicularia plana 6 3 4 Tharyx 6 7

Spionidae indet. 11

Eteone spp. 3 3 2 Cyathura carinata 1 3 2 Cerastoderma edule 1

Hydrobia ulvae 1

Carcinas maenas 1

Heteromastus filiformis 1

Capitella capitata 1

Table 2.4.7 Fauna identified along the high shore section of Transect 1, Feb 2012

Feb-12 Feb-12 Feb-12 T1 Mid T1 Mid T1 Mid A B C Streblospio sp. 24 62 4 Oligochaetae 14 3 1 Nephtys sp. 4 3 5 Tharyx sp. 1 7

Nereis spp. 1 2

Eteone spp. 1 1

Fabulina fabula 1

Gari fervensis 1

Heteromastus filiformis 1

Table 2.4.8 Fauna identified along the mid shore section of Transect 1, Feb 2012

Feb-12 Feb-12 Feb-12 T1 Low T1 Low T1 Low A B C Streblospio sp. 11 11

Tharyx sp. 2 8 11 Nephtys sp. 3 3

Ampharete indet. 1 1

Oligochaetae 1

Spionidae indet. 1

Table 2.4.9 Fauna identified along the low shore section of Transect 1, Feb 2012

Upper and mid-shore sites returned the greatest diversity and abundances compared to the low shore site (Tables2.4.7 – 2.4.10). The faunal communities identified across the intertidal area at Transect 2 contains fauna which are common in Polychaete/bivalve dominated mid-estuarine mud shores (JNCC Habitat type LS.LMu.MEst; EUNIS Code A2.31).

T1High T1High T1High T1Mid T1Mid T1Mid T1Low T1Low T1Low A B C A B C A B C Species 9 9 8 7 7 4 2 3 6 Abundances 448 331 315 46 79 11 5 20 28 Shannon- 0.751 1.08 0.691 1.25 0.857 1.16 0.673 0.845 1.33 Wiener Pielou’s 0.342 0.49 0.332 0.641 0.44 0.838 0.971 0.769 0.743 Evenness Simpson 0.644 0.476 0.681 0.374 0.628 0.355 0.52 0.465 0.324 Dominance

Table 2.4.10 Primary and derived indices for the sample points along Transect 1 – February 2012.

Biomass results from the survey of February 2012 indicates higher biomass levels along the upper shore area of the transect, with lower biomass present along the mid and low shore areas. The primary sources of biomass along these areas are the polychaete and mollusc groups (Fig. 2.4.3).

Figure 2.4.3 Combined biomass (g wet wt) from each tidal height along Transect 1 – February 2012.

June 2012 Results

PSA Results

Results from Particle Size analysis of sediment collected in June 2012 indicates the relatively homogenous distribution of sediment type across the shore. The sediment is dominated by poorly sorted sandy muds. Loss on Ignition results show values typical of mud dominated environments, although values are slightly reduced compared to May 2011 (Table 2.4.11).

T1 High T1 Mid T1 Low % Gravel 0.0% 0.0% 0.0% % Sand 31.7% 27.6% 47.4% % Mud 68.3% 72.4% 52.6% Textural Poorly sorted sandy mud Poorly sorted sandy mud Poorly sorted sandy mud Group % LOI 4.5% 5.5% 5.4%

Table 2.4.11 Particle Size and Loss on Ignition Results – May 2011

Faunal Results

Jun-12 Jun-12 Jun-12 T1 High T1 High T1 High A B C Oligochaetae 168 190 217 Tharyx sp. 1 39 50 Nereis sp. 20 22 12 Streblospio sp. 11 34 7 Scrobicularia plana 16 12 14 Polydora sp. 8

Heteromastus filiformis 3 3

Cyathura carinata 1 4

Hydrobia ulvae 4

Eteone spp. 1 1

Macoma balthica 1

Carcinas maenas 1

Nephtys sp. 1

Table 2.4.12 Fauna identified along the high shore section of Transect 1, June 2012

Jun-12 Jun-12 Jun-12 T1 Mid T1 Mid T1 Mid A B C Nephtys sp. 4 2 6 Streblospio sp. 4 4 4 Oligochaetae 4 5

Scrobicularia plana 1 3 1 Spionidae indet. 3

Nereis spp. 1 1

Table 2.4.13 Fauna identified along the mid shore section of Transect 1, June 2012

Jun-12 Jun-12 Jun-12 T1 Low T1 Low T1 Low A B C Nephtys sp. 4 2 3 Streblospio sp. 2 1 2 Oligochaetae 3

Tharyx sp. 2

Crangon crangon 1

Table 2.4.14 Fauna identified along the low shore section of Transect 1, June 2012

The upper shore site in June 2012 returned the highest abundances and diversity compared to the mid and low shore sites (Table 2.4.15). The faunal communities identified across the intertidal area at Transect 1 in June 2012 contains fauna which are common in Polychaete/bivalve dominated mid- estuarine mud shores (JNCC Habitat type LS.LMu.MEst; EUNIS Code A2.31).

T1High T1High T1High T1Mid T1Mid T1Mid T1Low T1Low T1Low A B C A B C A B C Species 8 12 6 5 4 5 4 3 2 Abundances 221 319 301 16 10 17 11 4 5 Shannon- 0.897 1.41 0.912 1.53 1.28 1.4 1.34 1.04 0.673 Wiener Pielou’s 0.431 0.568 0.509 0.949 0.923 0.871 0.968 0.946 0.971 Evenness Simpson 0.594 0.388 0.552 0.227 0.3 0.273 0.273 0.375 0.52 Dominance

Table 2.4.15 Primary and derived indices for the sample points along Transect 1 – June 2012.

Biomass results from the survey of June 2012 indicates higher biomass levels along the upper shore area of the transect, with lower biomass present along the mid and low shore areas. The primary sources of biomass along these areas are the polychaete and mollusc groups (Fig. 2.4.4).

Figure 2.4.4 Combined biomass (g wet wt) from each tidal height along Transect 1 – June 2012.

Overview of Transect 1 Results

The sediment along Transect 1 remains relatively contact across the three survey periods with the low shore sites remaining coarser across the survey period. The PSA results for both mid and high shore sites indicate a similar sediment type at both sites across the survey period (Fig. 2.4.5)

Figure 2.4.5 Transect 1 combined ternary.

Faunal results along Transect 1 show that the dominant species present during each sampling period remains similar, indicating that the faunal communities present are relatively stable. Abundances and diversity along the High Shore site remains relatively constant across the survey period. This is reflected in the biomass results for the same period, with reduction in biomass in February 2012 and a recovery to May 2011 levels in June 2012 (Fig. 2.4.6). Abundances and diversity were reduced in both February 2011 and June 2012 when compared to May 2011 for the mid shore sites. This is reflected in the biomass results for the same period (Fig. 2.4.7). Results from the low shore section mirror those identified in the upper shore area, with a reduced biomass in February 2012 and a recovery to May 2011 levels in June 2012 (Fig. 2.4.8)

Fig 2.4.6: Biomass (g wet wt) (May 2011 – June 2012) at the High Shore section of Transect 1.

Fig 2.4.7 Biomass (g wet wt) (May 2011 – June 2012) at the Mid Shore section of Transect 1.

Fig 2.4.8 Biomass (g wet wt) (May 2011 – June 2012) at the Low Shore section of Transect 1.

Transect 2: Carrigrenan Survey area

Transect 2 is located along the soft sediment intertidal area adjacent to Carrigrenan located along the northern shore of Lough Mahon. Samples were located along a transect from the inner margins of the soft sediment area extending to the low shore level. The shore transect measures approximately 600 meters (Fig 2.4.9)

Figure 2.4.9: Location of sampling locations along Transect 2 – Carrigrenan.

May 2011 Results

PSA Results

Results from Particle Size analysis of sediment collected in May 2011 highlight the relatively homogenous distribution nature of the sediment across the shore, which is dominated by poorly sorted sandy muds. Loss on Ignition results show values typical of mud dominated environments (Table 2.4.16)

T2 High T2 Mid T2 Low % Gravel 0.0% 0.0% 0.0% % Sand 38.0% 45.2% 46.5% % Mud 62.0% 54.8% 53.5% Textural Poorly sorted sandy mud Poorly sorted sandy mud Poorly sorted sandy mud Group % LOI 5.6% 5.3% 7.7%

Table 2.4.16 Particle Size and Loss on Ignition Results – May 2011

Faunal Results

Upper and mid-shore sites returned the greatest diversity and abundances compared to the low shore site, although variation in abundances amongst the replicates indicates the presence of localised patchiness in faunal distribution (Tables 2.4.17 – 2.4.20). The faunal communities identified at Transect 2 stations contains fauna which are common in Polychaete/bivalve dominated mid-estuarine mud shores (JNCC Habitat type LS.LMu.MEst; EUNIS Code A2.31).

May-11 May-11 May-11 T2 High T2 High T2 High A B C Streblospio sp. 49 18 16 Oligochaetae 35 16 9 Nephtys sp. 21 19 17 Scrobicularia plana 7 1 4 Mya arenaria 1

Mytilus edulis 1

Crangon crangon 1

Nereis spp. 1

Tharyx sp. 1

Polydora sp, 1

Table 2.4.17 Fauna identified along the high shore section of Transect 2, May 2011

May-11 May-11 May-11 T2 Mid T2 Mid T2 Mid A B C Streblospio sp. 16 25 19 Nephtys sp. 12 15 16 Oligochaetae 2 7

Ampharete indet. 1 1

Crangon crangon 1

Nereis spp. 1

Eteone spp. 1

Table 2.4.18 Fauna identified along the mid shore section of Transect 2, May 2011

May-11 May-11 May-11 T2 Low T2 Low T2 Low A B C

Streblospio sp. 9 64

Nephtys sp. 6 12

Oligochaetae 6 5

Scrobicularia plana 1 3 2 Tharyx sp. 1 1

Table 2.4.19 Fauna identified along the low shore section of Transect 2, May 2011

T2High T2High T2High T2Mid T2Mid T2Mid T2Low T2Low T2Low A B C A B C A B C Species 7 6 5 3 4 6 5 1 5 Abundances 115 56 47 29 43 45 23 3 84 Shannon- 1.33 1.31 1.34 0.809 0.913 1.27 1.34 0 0.795 Wiener Pielou’s No 0.684 0.728 0.834 0.737 0.658 0.712 0.833 0.494 Evenness Record Simpson 0.311 0.301 0.291 0.477 0.462 0.33 0.293 1 0.605 Dominance

Table 2.4.20 Primary and derived indices for the sample points along Transect 2 – May 2011.

Biomass results from the survey of May 2011 indicates higher biomass levels along the upper and mid shore areas of the transect, with lower biomass present along the low shore area. The primary source of biomass within these areas are derived from polychaetes (Fig. 2.4.10).

Figure 2.4.10 Combined biomass (g wet wt) from each tidal height along Transect 2 – May 2011.

February 2012 Results

PSA Results

Results from Particle Size analysis of sediment collected in February 2012 shows an increase in coarser material compared to May 2011. The sediment is dominated by poorly sorted muddy sands. Loss on Ignition results show values typical of mud dominated environments (Table 2.4.21)

T2 High T2 Mid T2 Low % Gravel 0.0% 0.0% 0.0% % Sand 55.2% 48.1% 57.5% % Mud 44.8% 51.9% 42.5% Textural Poorly sorted muddy sand Poorly sorted sandy mud Poorly sorted muddy sand Group % LOI 7.2% 7.8% 8.7%

Table 2.4.21 Particle Size and Loss on Ignition Results – February 2012

Faunal Results

Upper and mid-shore sites returned the highest diversity and abundances compared to the low shore site (Table XX & XX). The faunal communities identified along Transect 2 contains fauna which are common in Polychaete/bivalve dominated mid-estuarine mud shores (JNCC Habitat type LS.LMu.MEst; EUNIS Code A2.31).

Feb-12 Feb-12 Feb-12 T2 High T2 High T2 High A B C Oligochaetae 90 33 123 Streblospio sp. 18 9 39 Nephtys sp. 1 9 1 Spionidae indet. 2 2

Nereis spp. 1 2

Eteone spp. 1

Table 2.4.22 Fauna identified along the high shore section of Transect 2, Feb 2012

Feb-12 Feb-12 Feb-12 T2 Mid T2 Mid T2 Mid A B C Oligochaetae 200 13 100 Streblospio sp. 97 40 64 Tharyx sp. 11 3

Nephtys sp. 6 1 5 Nereis spp. 3 1 1 Spionidae indet. 3

Scrobicularia plana 1

Cyathura carinata 1

Capitella capitata 1

Arenicola marina 1

Table 2.4.23 Fauna identified along the mid shore section of Transect 2, February 2012

Feb-12 Feb-12 Feb-12 T2 Low T2 Low T2 Low A B C Streblospio sp. 20 33 42 Oligochaetae 14 33 5 Nephtys sp. 6 9 5 Tharyx sp. 2 3 3 Polydora sp, 4 3

Ampharete indet. 1 2

Scoloplos armiger 1 2

Cerastoderma edule 1

Nereis spp. 1

Table 2.4.24 Fauna identified along the low shore section of Transect 2, February 2012

T2High T2High T2High T2Mid T2Mid T2Mid T2Low T2Low T2Low A B C A B C A B C Species 5 3 6 7 6 6 7 7 6 Abundances 112 51 168 321 59 172 48 82 60 Shannon- 0.626 0.894 0.734 0.952 0.956 0.876 1.48 1.29 1.08 Wiener Pielou’s 0.389 0.814 0.41 0.489 0.533 0.489 0.763 0.665 0.601 Evenness Simpson 0.672 0.481 0.59 0.481 0.512 0.477 0.284 0.338 0.51 Dominance

Table 2.4.25 Primary and derived indices for the sample points along Transect 2 – February 2012.

Biomass results from the survey of February 2012 indicate similar biomass across all shore levels. Overall, biomass along the transect was low with combined values less than 0.4g at all shore heights (Fig. 2.4.11). 34

Figure 2.4.11 Combined biomass (g wet wt) from each tidal height along Transect 2 – Feb 2012.

June 2012 Results

PSA Results

Results from Particle Size Analysis of sediment collected in June 2012 indicates the relatively homogenous nature of the sediment along the which was dominated by poorly sorted sandy muds. Loss on Ignition results show values typical of mud dominated environments, although values are slightly reduced compared to May 2011 and February 2012 (Table 2.4.26)

Table 2.4.26 Particle Size and Loss on Ignition Results – June 2012

Faunal Results

Results from the survey of June 2012 records increased abundances species numbers at the high shore site compared to other shore heights on Transect 2.

Jun-12 Jun-12 Jun-12 T2 High T2 High T2 High A B C Oligochaetae 18 20 106 Streblospio sp. 5 10 21 Nephtys sp. 3 2 3 Scrobicularia plana 2 1

Tharyx sp. 3

Nereis spp. 1 1

Crangon crangon 1

Ampharete indet. 1

Eteone spp. 1

Phyllodoce sp. 1

Table 2.4.27 Fauna identified along the high shore section of Transect 2, June 2012

Jun-12 Jun-12 Jun-12 T2 Mid T2 Mid T2 Mid A B C Nephtys sp. 2 4 5 Crangon crangon 2 2 5 Mya arenaria 1

Streblospio sp. 1

Spionidae indet. 1

Pisces indet 1

Table 2.4.28 Fauna identified along the mid shore section of Transect 2, June 2012

Jun-12 Jun-12 Jun-12 T2 Low T2 Low T2 Low A B C Streblospio sp. 12 2 12 Nephtys sp. 8 12 4 Oligochaetae 2 2

Scoloplos armiger 2 1

Table 2.4.29 Fauna identified along the low shore section of Transect 2, June 2012

The upper shore site in June 2012 returned the highest abundances and diversity compared to the mid and low shore sites (Tables 2.4.27-2.4.30). The communities identified along Transect 2 in June 2012 contains fauna which are common in Polychaete/bivalve dominated mid-estuarine mud shores (JNCC Habitat type LS.LMu.MEst; EUNIS Code A2.31).

T2High T2High T2High T2Mid T2Mid T2Mid T2Low T2Low T2Low A B C A B C A B C Species 6 6 6 3 3 4 3 3 4 Abundances 32 35 133 5 7 12 22 16 19 Shannon- 1.34 1.15 0.668 1.05 0.956 1.14 0.916 0.736 1.01 Wiener Pielou’s 0.747 0.64 0.373 0.96 0.87 0.825 0.834 0.67 0.729 Evenness Simpson 0.363 0.414 0.661 0.36 0.429 0.361 0.438 0.594 0.457 Dominance

Table 2.4.30 Primary and derived indices for the sample points along Transect 2 – June 2012.

Biomass results from June 2012 are affected by the presence of a single large Mya arenaria collected in one of the three replicates within the mid shore site. With this species removed, biomass is reduced along the mid and low shore compared to those identified in the upper shore (Fig. 2.4.12).

Figure 2.4.12 Combined biomass measurements (g wet wt) from each tidal height along Transect 2 – June 2012.

Overview of Transect 2 Results

The sediment present along Transect consists primarily of sandy muds and muddy sands. This remained consistent across the duration of the study programme (Fig. 2.4.13).

Figure 2.4.13 Transect 2 combined ternary.

Faunal results along Transect 2 showed that the dominant species present during each sampling campaign remained the same. Abundances and diversity at the high shore stations also remained constant across the 3 survey campaigns. However, as with Transect 1 High Shore, there is a reduction in biomass in February 2012, but this is restored to pre-dredge levels in Jun 2012 (Fig. 2.4.14). There was an increase in abundances along the mid-shore level in February 2012, when compared to May 2011. This isn’t reflected in the biomass, which shows a large decrease between the two survey periods. Abundances decrease in June 2012, when compared to February 2012 and May 2011 surveys, although biomass increased (Fig 2.4.15). This increase in biomass is because of the presence of a single adult Mya present in the June 2012 survey, which accounted for 98% of the biomass present. Results from the low shore are relatively consistent across the survey period, with an increase in abundances and diversity in Feb 2012 when compared to the summer months of 2011 and 2012. However, the biomass is reduced in February, with similar values being recorded for both May 2011 and June 2012 (Fig. 2.4.16).

Fig 2.4.14 Biomass (g wet wt) (May 2011 – June 2012) at the High Shore section of Transect 2.

Fig 2.4.15 Biomass (g wet wt) (May 2011 – June 2012) at the Mid Shore section of Transect 2.

Fig 2.4.16 Biomass (g wet wt) (May 2011 – June 2012) at the Low Shore section of Transect 2.

Transect 3: Marino Point Survey area

Transect 3 is located along the soft sediment intertidal area north of Marino Point located along the eastern shore of Lough Mahon. Samples were located along a transect from the inner margins of the soft sediment area extending to the low shore level. The shore transect measures approximately 710 meters (Fig 2.4.17)

Figure 2.4.17 Location of sampling locations along Transect 3 – Marino Point.

May 2011 Results

PSA Results

Results from the Particle Size Analysis indicates the presence of sandy muds along the length of the transect at Marino Point. Loss on Ignition (LOI) values are consistent with muddy environments (Table 2.4.31).

T3 High T3 Mid T3 Low % Gravel 0.0% 0.0% 0.0% % Sand 47.6% 32.8% 46.3% % Mud 52.4% 67.2% 53.7% Textural Group Poorly sorted sandy mud Poorly sorted sandy mud Poorly sorted sandy mud % LOI 6.1% 7.5% 5.7%

Table 2.4.31 Particle Size and Loss on Ignition Results – May 2011

Faunal Results

Faunal results indicate that the highest abundances and diversity were located at the upper shore station of the transect (Tables 2.4.32 – 2.4.35). The faunal communities identified along Transect 2 in May 2011 contain species which are common in Polychaete/bivalve dominated mid-estuarine mud shores (JNCC Habitat type LS.LMu.MEst; EUNIS Code A2.31).

May-11 May-11 May-11 T3 High T3 High T3 High A B C Oligochaetae 83 44 14 Streblospio sp. 28 10 7 Nephtys sp. 11 14 12 Tharyx sp. 18

Ampharete indet. 7 4 6 Scrobicularia plana 2 1 1 Nereis spp. 1 1 2 Eteone spp. 4

Crangon crangon 1

Juv Decapod 1

Polydora sp, 1

Arenicola marina 1

Table 2.4.32 Fauna identified along the high shore section of Transect 3, May 2011

May-11 May-11 May-11 T3 Mid T3 Mid T3 Mid A B C Nephtys sp. 14 21 11 Streblospio sp. 8 7 19 Oligochaetae 14 7 11 Crangon crangon 2 1

Nereis spp. 2 1

Scrobicularia plana 2

Ampharete indet. 1

Phyllodoce sp. 1

Table 2.4.33 Fauna identified along the mid shore section of Transect 3, May 2011

May-11 May-11 May-11 T3 Low T3 Low T3 Low A B C Nephtys sp. 23 25 26 Streblospio sp. 23 7 4 Scrobicularia plana 5 2 1 Ampharete indet. 2 2

Nereis spp. 1

Oligochaetae 1

Scoloplos armiger 1

Table 2.4.34 Fauna identified along the low shore section of Transect 3, May 2011

T3High T3High T3High T3Mid T3Mid T3Mid T3Low T3Low T3Low A B C A B C A B C Species 9 9 6 7 5 4 6 5 3 Abundances 155 77 42 43 37 42 55 37 31 Shannon- 1.44 1.33 1.53 1.56 1.15 1.15 1.21 0.993 0.523 Wiener Pielou’s 0.654 0.606 0.857 0.801 0.712 0.829 0.677 0.617 0.476 Evenness Simpson 0.341 0.38 0.244 0.254 0.395 0.342 0.36 0.499 0.721 Dominance

Table 2.4.35 Primary and derived indices for the sample points along Transect 3 – May 2011.

Biomass results from the survey of May 2011 indicate higher biomass levels along the upper and mid shore areas of the transect, with lower biomass present along the low shore section. The primary source of biomass at these stations are polychaete worms (Fig. 2.4.18).

Figure 2.4.18 Combined biomass (g wet wt) from each tidal height along Transect 3 – May 2011.

February 2012 Results

PSA Results

Results from Particle Size analysis of sediment collected in February 2012 shows an increase in coarser material compared to May 2011. The sediment was dominated by poorly sorted muddy sands. Loss on Ignition results show values typical of mud dominated environments (Table 2.4.36)

T2 High T2 Mid T2 Low % Gravel 0.3% 0.0% 0.0% % Sand 52.2% 39.9% 51.6% % Mud 47.6% 60.1% 48.4% Textural Poorly sorted slightly gravelly Poorly sorted sandy mud Poorly sorted muddy sand Group muddy sand % LOI 4.6% 4.8% 5.6%

Table 2.4.36 Particle Size and Loss on Ignition Results – February 2012

Faunal Results

Faunal results indicate that the highest abundances and diversity were located along the upper shore station of the transect (Tables 2.4.37 – 2.37.40). The faunal communities identified along Transect 2 in February 2012 contain species which are common in Polychaete/bivalve dominated mid-estuarine mud shores (JNCC Habitat type LS.LMu.MEst; EUNIS Code A2.31).

Feb-12 Feb-12 Feb-12 T3 High T3 High T3 High A B C Oligochaetae 94 39 85 Streblospio sp. 17 5 13 Ampharete indet. 9 11 13 Tharyx sp. 11 9 5 Nephtys sp. 2 4 3 Nereis spp. 3

Eteone spp. 1 1 1 Scrobicularia plana 1

Macoma balthica 1

Cerastoderma edule 1

Spionidae indet. 1

Table 2.4.37 Fauna identified along the high shore section of Transect 3, February 2012

Feb-12 Feb-12 Feb-12 T3 Mid T3 Mid T3 Mid A B C Oligochaetae 5 18 22 Streblospio sp. 7 34

Spionidae indet. 34

Nephtys sp. 7 7 5 Ampharete indet. 2 4

Macoma balthica 1

Nereis spp. 1

Table 2.4.38 Fauna identified along the mid shore section of Transect 3, February 2012

Feb-12 Feb-12 Feb-12 T3 Low T3 Low T3 Low A B C Nephtys sp. 3 4 7 Streblospio sp. 4 2

Oligochaetae 2 1

Scoloplos armiger 1 1

Nereis spp. 1

Tharyx sp. 1

Table 2.4.39 Fauna identified along the low shore section of Transect 3, February 2012

T3High T3High T3High T3Mid T3Mid T3Mid T3Low T3Low T3Low A B C A B C A B C Species 8 9 6 5 4 4 3 3 5 Abundances 136 74 120 22 60 65 6 9 12 Shannon- 1.07 1.52 0.99 1.42 1 1.07 1.01 0.965 1.23 Wiener Pielou’s 0.514 0.692 0.553 0.885 0.723 0.775 0.921 0.878 0.767 Evenness Simpson 0.505 0.324 0.528 0.264 0.425 0.398 0.389 0.407 0.389 Dominance

Table 2.4.40 Primary and derived indices for the sample points along Transect 3 – February 2012.

Biomass results from the survey of February 2012 indicates slightly higher biomass levels along the upper and mid shore areas of the transect, with lower biomass present along the low shore area. The primary source of biomass within these areas was polychaetes and occasional molluscs in the upper shore site (Fig. 2.4.19). Biomass in the area is low with all tidal heights returning biomass values of less than 0.6g.

Figure 2.4.19 Combined biomass (g wet wt) from each tidal height along Transect 3 – February 2012.

June 2012 Results

PSA Results

Results from the Particle Size Analysis indicates the presence of sandy muds along the length of the transect. LOI values are slightly reduced when compared to those identified in May 2011. The LOI results are similar for both upper and mid-shore stations, whereas the lower shore sample is less than half the levels of the former stations (Table 2.4.41).

T3 High T3 Mid T3 Low % Gravel 0.0% 0.0% 0.0% % Sand 45.1% 42.4% 44.1% % Mud 54.9% 57.6% 55.9% Textural Group Poorly sorted sandy mud Poorly sorted sandy mud Poorly sorted sandy mud % LOI 5.6% 5.2% 2.3%

Table 2.4.41 Particle Size and Loss on Ignition Results – June 2012

Faunal Results

Faunal results indicate that the highest abundances and diversity were recorded at the upper-shore site of the Marino Point Transect (Tables 2.4.42 – 2.4.45). The communities identified at Transect 2 in February 2012 contained fauna which are common in Polychaete/bivalve dominated mid- estuarine mud shores (JNCC Habitat type LS.LMu.MEst; EUNIS Code A2.31).

Jun-12 Jun-12 Jun-12 T3 High A T3 High B T3 High C

Oligochaetae No Record 31 45 Streblospio sp. 2 9

Nephtys sp. 6 2

Nereis spp. 5

Tharyx sp. 2 1

Scrobicularia plana 1

Hydrobia ulvae 1

Crangon crangon 1

Arenicola marina 1

Table 2.4.42 Fauna identified along the high shore section of Transect 3, June 2012

Jun-12 Jun-12 Jun-12 T3 Mid T3 Mid T3 Mid A B C Nephtys sp. 1 7 3 Streblospio sp. 1 3

Nereis spp. 2 1

Ampharete indet. 3

Hydrobia ulvae 1

Crangon crangon 1

Scoloplos armiger 1

Table 2.4.43 Fauna identified along the mid shore section of Transect 3, June 2012

Jun-12 Jun-12 Jun-12 T3 Low T3 Low T3 Low A B C Nephtys sp. 2 4 4 Streblospio sp. 1 8

Scoloplos armiger 2 3

Mya arenaria 1

Crangon crangon 1

Ampharete indet. 1

Table 2.4.44 Fauna identified along the low shore section of Transect 3, June 2012

T3High T3High T3High T3Mid T3Mid T3Mid T3Low T3Low T3Low A B C A B C A B C No Species 9 4 4 3 4 5 2 3 Record No Abundances 50 57 6 10 8 7 5 15 Record Shannon- No 1.35 0.667 1.24 0.802 1.26 1.55 0.5 1.01 Wiener Record Pielou’s No 0.615 0.481 0.896 0.73 0.906 0.963 0.722 0.919 Evenness Record Simpson No 0.414 0.65 0.333 0.54 0.312 0.224 0.68 0.396 Dominance Record

Table 2.4.45 Primary and derived indices for the sample points along Transect 3 – June 2012. [No results for T3 High A]

Biomass results from the survey of June 2012 indicates higher biomass levels along the upper and mid shore areas of the transect, with lower biomass present along the low shore area. The primary source of biomass areas along the transect are polychaetes (Fig. 2.4.20).

Figure 2.4.20 Combined biomass (g wet wt) from each tidal height along Transect 3 – June 2012.

Overview of Transect 3 Results

The sediment present along Transect 3 consisted primarily of sandy muds and muddy sands. The mid shore sites contained the highest levels of mud throughout the course of the survey (Fig. 2.4.21).

Figure 2.4.21 Transect 3 combined ternary.

Faunal results from Transect 3 show that the dominant species present during each sampling campaign remained consistent, indicating the faunal communities present are relatively stable. The high shore site on Transect 3 recorded similar abundances and diversity during the course of the survey. Biomass results from the high shore site show a reduction in biomass in February 2012, compared to May 2011 and a recovery to pre-dredge levels in June 2012 (Fig. 2.4.22). Faunal abundances were much reduced in June 2012 along the mid shore site when compared to May 2011 and February 2012, although biomass levels are similar to those identified in May 2011 (Fig. 2.4.23). Faunal abundances and diversity are reduced in the low shore site during February 2012 and June 2012 when compared to numbers recorded in May 2011. This is also reflected in the biomass values, which show much lower biomass levels in February 2011 and June 2012 compared to levels obtained in May 2011 (Fig. 2.4.24).

Fig 2.4.22 Biomass (g wet wt) (May 2011 – June 2012) at the High Shore section of Transect 3.

Fig 2.4.23 Biomass (g wet wt) (May 2011 – June 2012) at the Mid Shore section of Transect 3.

Fig 2.4.24 Biomass (g wet wt) (May 2011 – June 2012) at the Low Shore section of Transect 3.

Transect 4: Rossmore Survey area

Transect 4 is located along the soft sediment intertidal area of Rossmore Bay located along the northern shore of the Great Channel area. Samples were located along a transect from the inner margins of the soft sediment area extending to the low shore level. The shore transect measures approximately 930 meters (Fig 2.4.25)

Figure 2.4.25 Location of sampling locations along Transect 4 – Rossmore.

May 2011 Results

PSA Results

Results from the Particle Size Analysis indicates the presence of sandy muds across the survey area. LOI values are consistent with levels expected in muddy environments (Table 2.4.46).

T4 High T4 Mid T4 Low % Gravel 0.0% 2.1% 0.0% % Sand 36.2% 45.8% 56.9% % Mud 63.8% 52.1% 43.1% Textural Group Poorly sorted sandy mud Poorly sorted sandy mud Poorly sorted sandy mud % LOI 6.8% 8.9% 5.9%

Table 2.4.46 Particle Size and Loss on Ignition Results – May 2011

Faunal Results

Results from the faunal analysis indicate the presence of increased abundances and species numbers in the upper shore section of Transect 4 (Tables 2.4.47 - 2.4.50). The species identified along the transect are common in Polychaete/bivalve dominated mid-estuarine mud shores (JNCC Habitat type LS.LMu.MEst; EUNIS Code A2.31).

May-11 May-11 May-11 T4 High T4 High T4 High A B C Ampharete indet. 154 136 129 Hydrobia ulvae 5 97

Tharyx sp. 44 8 4 Streblospio sp. 38 11 3 Mya arenaria 12 15 16 Oligochaetae 16 13 1 Cerastoderma edule 8 6 8 Nereis spp. 7 8 7 Nephtys sp. 9 5 1 Scrobicularia plana 1 5

Macoma balthica 3

Crangon crangon 2

Eteone spp. 2

Table 2.4.47 Fauna identified along the high shore section of Transect 4, May 2011

May-11 May-11 May-11 T4 Mid T4 Mid T4 Mid A B C Oligochaetae 66 117 55 Streblospio sp. 15 12 9 Tharyx sp. 4 13 8 Nephtys sp. 3 9 6 Ampharete indet. 1 7 4 Nereis spp. 4 1 4 Scrobicularia plana 2 2 3

Table 2.4.48 Fauna identified along the mid shore section of Transect 4, May 2011

May-11 May-11 May-11 T4 Low T4 Low T4 Low A B C Oligochaetae 7 1

Crangon crangon 3 3

Nephtys sp. 2 2

Scrobicularia plana 1 1

Streblospio sp. 1

Table 2.4.49 Fauna identified along the low shore section of Transect 4, May 2011

T4High T4High T4High T4Mid T4Mid T4Mid T4Low T4Low T4Low A B C A B C A B C Species 10 10 11 7 7 7 1 4 4 Abundances 292 208 274 95 161 89 3 13 5 Shannon- 1.54 1.35 1.36 1.05 1.01 1.32 0 1.16 1.33 Wiener Pielou’s 0.67 0.588 0.567 0.539 0.52 0.679 **** 0.835 0.961 Evenness Simpson 0.325 0.444 0.353 0.513 0.545 0.41 1 0.373 0.28 Dominance

Table 2.4.50 Primary and derived indices for the sample points along Transect 4 – May 2011.

Results from the survey of May 2011 indicate higher biomass levels along the upper shore station, with biomass dominated by molluscs and polychaetes. The mid shore site is dominated by polychaetes, with little biomass present at the low shore station (Fig. 2.4.26).

Figure 2.4.26 Combined biomass (g wet wt) from each tidal height along Transect 4 – May 2011.

February 2012 Results

PSA Results

Results from Particle Size analysis of sediment collected in February 2012 showed an increase in coarser material compared to May 2011. The sediment was dominated by poorly sorted muddy sands. Loss on Ignition results show values typical of mud dominated environments (Table 2.4.51)

T4 High T4 Mid T4 Low % Gravel 0.0% 2.1% 0.0% % Sand 48.5% 54.3% 63.9% % Mud 51.5% 45.7% 36.1% Textural Group Poorly sorted sandy mud Poorly sorted muddy sand Poorly sorted muddy sand % LOI 4.5% 5.4% 5.6%

Table 2.4.51 Particle Size and Loss on Ignition Results – May 2011

Faunal Results

Results from the faunal analysis indicate the presence of increased abundances and species numbers in the upper shore section of Transect 4 (Tables 2.4.52 – 2.4.55). The species identified along the transect are common, and typical for the Polychaete/bivalve dominated mid-estuarine mud shores community (JNCC Habitat type LS.LMu.MEst; EUNIS Code A2.31).

Feb-12 Feb-12 Feb-12 T4 High T4 High T4 High A B C Hydrobia ulvae 10 5 3 Ampharete indet. 1 10 4 Streblospio sp. 2 3 9 Nereis spp. 3 4 4 Tharyx sp. 5 2 3 Nephtys sp. 3 1 2 Oligochaetae 4

Scrobicularia plana 1 1

Macoma balthica 1

Mytilus edulis 1

Table 2.4.52 Fauna identified along the high shore section of Transect 4, February 2012

Feb-12 Feb-12 Feb-12 T4 Mid T4 Mid T4 Mid A B C Oligochaetae 31 20 39 Streblospio sp. 15 16 19 Ampharete indet. 2 2 5 Nephtys sp. 6 2

Spionidae indet. 2

Fabulina fabula 1

Gari fervensis 1

Table 2.4.53 Fauna identified along the mid shore section of Transect 4, February 2012

Feb-12 Feb-12 Feb-12 T4 Low T4 Low T4 Low A B C Streblospio sp. 8 5 8 Oligochaetae 5 6 2 Nephtys sp. 4 1 1 Tharyx sp. 3

Table 2.4.54 Fauna identified along the low shore section of Transect 4, February 2012

T4High T4High T4High T4Mid T4Mid T4Mid T4Low T4Low T4Low A B C A B C A B C Species 7 7 9 4 4 6 3 3 4 Abundances 25 26 31 50 44 67 17 12 14 Shannon- 1.66 1.67 2 0.915 1.14 1.1 1.06 0.918 1.12 Wiener Pielou’s 0.851 0.858 0.911 0.66 0.821 0.612 0.96 0.836 0.805 Evenness Simpson 0.238 0.231 0.159 0.478 0.36 0.426 0.363 0.431 0.398 Dominance

Table 2.4.55 Primary and derived indices for the sample points along Transect 4 – February 2012.

Biomass results from the survey of February 2012 indicates higher biomass levels along the upper shore of the transect, with biomass dominated by molluscs and polychaetes. The mid shore area is dominated by polychaetes, with little biomass present along the low shore area (Fig. 2.4.27).

Figure 2.4.27 Combined biomass (g wet wt) from each tidal height along Transect 4 – February 2012.

June 2012 Results

PSA Results

Results from the Particle Size Analysis indicates the presence of sandy muds along the length of the transect. The PSA and LOI sample for T4 Low was not processed. LOI values are typical for muddy environments (Table 2.4.56)

T4 High T4 Mid T4 Low % Gravel 0.0% 0.0% No record % Sand 35.5% 48.7% No record % Mud 64.5% 51.3% No record Textural Group Poorly sorted sandy mud Poorly sorted sandy mud No record % LOI 4.8% 5.2% No record

Table 2.4.56 Particle Size and Loss on Ignition Results – June 2012

Faunal Results

Results from the faunal analysis indicate the presence of increased abundances and species numbers in the upper shore section of Transect 4 (Tables 2.4.57 – 2.4.60). The species identified are common typical for the Polychaete/bivalve dominated mid-estuarine mud shores community (JNCC Habitat type LS.LMu.MEst; EUNIS Code A2.31).

Jun-12 Jun-12 Jun-12 T4 High T4 High T4 High A B C Hydrobia ulvae 55 5 204 Ampharete indet. 49 58 58 Nephtys sp. 2 5 1 Streblospio sp. 7 1

Oligochaetae 2 6

Tharyx sp. 7 1

Nereis spp. 1 3 3 Scrobicularia plana 1 1

Cerastoderma edule 2

Heteromastus filiformis 1

Phyllodoce sp. 1

Table 2.4.57 Fauna identified along the high shore section of Transect 4, June 2012

Jun-12 Jun-12 Jun-12 T4 Mid T4 Mid T4 Mid A B C Oligochaetae 18 205 169 Streblospio sp. 8 92 51 Ampharete indet. 2 3 9 Nephtys sp. 3 4 5 Tharyx sp. 12

Spionidae indet. 5 1

Scrobicularia plana 2 3

Cerastoderma edule 1

Crangon crangon 1

Platynereis sp. 1

Table 2.4.58 Fauna identified along the mid shore section of Transect 4, June 2012

Jun-12 Jun-12 Jun-12 T4 Low T4 Low T4 Low A B C Streblospio sp. 19 18 6 Oligochaetae 3 3 1 Gammarus sp. 2 1 1 Nephtys sp. 2 2

Ampharete indet. 1 1 1 Tharyx sp. 2

Scrobicularia plana 1

Table 2.4.59 Fauna identified along the low shore section of Transect 4, June 2012

T4High T4High T4High T4Mid T4Mid T4Mid T4Low T4Low T4Low A B C A B C A B C Species 10 7 6 5 6 9 6 4 6 Abundances 127 74 273 33 310 252 29 23 12 Shannon- 1.36 0.86 0.721 1.23 0.82 1.05 1.18 0.73 1.47 Wiener Pielou’s 0.591 0.442 0.403 0.765 0.458 0.479 0.659 0.527 0.822 Evenness Simpson 0.343 0.626 0.604 0.372 0.526 0.495 0.455 0.633 0.306 Dominance

Table 2.4.60 Primary and derived indices for the sample points along Transect 4 – June 2012.

Biomass results from the survey of June 2012 indicate higher biomass at the upper shore transect site, with biomass dominated by molluscs and polychaetes. The mid shore site was dominated by polychaetes, with very little biomass present at the low shore site (Fig. 2.4.28).

Figure 2.4.28 Combined biomass (g wet wt) from each tidal height along Transect 4 – June 2012.

Overview of Transect 4 Results

The sediment present along Transect 4 consists primarily of sandy muds and muddy sands. The low shore sites contained the greatest levels of coarser materials throughout the survey (Fig. 2.4.29).

Figure 2.4.29 Transect 3 combined ternary.

Faunal results from Transect 4 indicate the dominant species present during each sampling campaign remained consistent, indicating that the communities present were relatively stable. The high shore site at Transect 4 showed a reduction of in faunal abundances from May 2011 to February 2012 with a partial recovery to May 2011 levels in June 2012. Biomass levels show a reduction in February 2012 compared from values obtained in May 2011. The relatively high values recorded in May 2011 are a result of high bivalve numbers which weren’t recorded in subsequent surveys (Fig. 2.4.30). Faunal diversity and abundances were much reduced in February 2012 compared to May 2011. There was a partial recovery to May 2011 levels in June 2012. However, biomass values in the mid-shore level of Transect 4 were lower in February 2011 and June 2012 when compared to levels identified in May 2011 (Fig. 2.4.31). The low shore recorded an increase in faunal abundances in February 2012 compared to May 2011 and a further increase in June 2012, although in each case from a very low base when compared to the mid and upper shore sites. This is reflected in the biomass results for this section (Fig. 2.4.32).

Fig 2.4.30 Biomass (g wet wt) (May 2011 – June 2012) at the High Shore section of Transect 4.

Fig 2.4.31 Biomass (g wet wt) (May 2011 – June 2012) at the Mid Shore section of Transect 4.

Fig 2.4.32 Biomass (g wet wt) (May 2011 – June 2012) at the Low Shore section of Transect 4.

Community Analysis of Intertidal Data

A closer look at the faunal data using multivariate analysis indicates a large degree of similarity between the transects during each survey. This indicates that the control transect used for the current survey (Transect 4 – Rossmore) contained a similar faunal community compared to the three test transects (Transects 1-3) (Fig. 2.4.33).

(a) (b)

(c) Figure 2.4.33 Two-dimensional multidimensional scaling (MDS) ordination for the benthic communities across all Intertidal Transect Areas in May 2011(a), Feb 2012(b) and June 2012(c).

Although some changes were identified in biomass and faunal abundances across the transects during the course of the study, Figure 2.4.34 shows the output of an MDS ordination of the data Combined across the three years. As can be seen from the data, there is little difference between the communities across all transects during the three study periods, with all years clustering together, with little separation. This indicates a relatively stable infaunal community present across each of the transects. As a result, it can be stated that the community structure during the course of the dredging activity remained stable.

Figure 2.4.34 Two-dimensional multidimensional scaling (MDS) ordination for the benthic communities across all survey periods.

Discussion on Intertidal Results

Results from the intertidal survey indicate the presence of pronounced differences in faunal abundances and biomass across each survey area during the course of the survey. Within each transect area there were large differences between the low shore abundances and biomass when compared to the upper and mid shore abundances and biomass. However, the faunal communities identified in each area remained similar.

The initial survey, undertaken in May 2011 identified across shore variation in both abundances and biomass at each of the four transect areas. In each transect area, the low shore area contained lower abundances and lower biomass when compared to both the upper and mid-shore levels. However, the identified communities remained similar across the shore.

A follow up survey was undertaken in February 2012. Results from the survey indicated that communities remained similar to those identified in May 2011. However, very notable reduction in the biomass of the fauna at each shore height and at each transect was recorded compared to May 2011. This reduction in biomass occurred across all transects (including the control transect at Rossmore [T4]). This has been identified as a seasonal trend, which is widely reported in the scientific literature (e.g. Beukema, 1974).

The final survey was undertaken in June 2012 and increases in faunal abundance and biomass were identified at all stations when compared to the February 2012 survey. This natural, seasonal variation is fully expected. Biomass levels across the upper shore stations all returned to pre-dredge levels at three of the four transects, the exception being the control site at Rossmore (Transect 4). Biomass levels along the mid-shore of Transects 1, 2 & 4 did not recover to pre-dredge values. Biomass levels in the lower shore saw a full return to pre-dredge levels in 3 of the 4 sites, the exception being Transect 3. As such, it is not expected that the maintenance dredging which had occurred 5 months previously had any impact in the intertidal mudflats present adjacent to the dredge area.

Comparisons of the faunal data using multidimensional scaling (MDS) shows the similarities between each of the transects across all the years. The control site remained similar to all other transect areas during the course of the survey. In addition, closer examination of the faunal data across the

three survey periods (May 2011, February 2012 & June 2012) indicates very little separation in the communities during this time scale.

Although there are some large scale differences in the biomass values between May 2011 and June 2012, these occur across all transect areas, including the control site. As such, the inter-transect, inter shore height and between sampling run variation noted within the data is concluded to fall within normal temporal and spatial variability ranges typical of such communities with little if any influence from the maintenance dredging operations in the shipping channel.

2.5 Subtidal Surveys

Area 1: City Area (Custom Quay to Marina Generating Station)

Area 1 extends from the Custom House Quay in Cork city along the river to the Marina Generating Station (Fig. 2.5.1).

Figure 2.5.1 Location of sampling locations within Area 1.

May 2011 Results

PSA Results

Results from Particle Size analysis of sediment collected in May 2011 indicate the presence of soft sediments across the area. The dominant sediment type was mud with a significant proportion of sand. During sample collection, the sediment was identified as being highly anoxic, with a strong hydrogen sulphide smell. Loss on Ignition results were very high, indicating the presence of large amounts of readily biodegradable organic material in the sediment (Table 2.5.1)

Area 1 G1 Area 1 G2 Area 1 G3 % Gravel 0.3% 0.0% 0.0% % Sand 43.1% 43.1% 53.7% % Mud 56.6% 56.9% 46.3% Textural Poorly Sorted Slightly Gravelly Poorly Sorted Sandy Mud Poorly Sorted Muddy Sand Group Sandy Mud % LOI 16.1% 15.3% 17.1%

Table 2.5.1 Particle Size and LOI for Area 1, May 2011

Faunal Results

Faunal results for May 2011 indicate a stressed benthic community, with fauna dominated by 2 taxa. Variation between the replicates indicates large amounts of local heterogeneity in the infaunal distribution in the area (Table 2.5.2). Habitat classification of this area is difficult due to the lack of fauna present, but sediment type and location indicates it may be classified as ‘Sublittoral mud in variable salinity’ (SS.SMu.SMuVs).

June 11 June 11 June 11 June 11 June 11 June 11 June 11 June 11 June 11 Area 1 Area 1 Area 1 Area 2 Area 1 Area 1 Area 1 Area 1 Area 1 G1a G1b G1c G2a G2b G2c G3a G3b G3c Nephtys sp. ------4 9 - Streblospio sp. - - - 2 - - - - -

Table 2.5.2 Faunal Results from Area 1, May 2011

June 2012 Results

PSA Results

Results in June 2012 were similar to those identified in May 2011. Sediments were dominated by muds and a strong anoxic smell was again in evidence. Loss on Ignition results were very high. (Table 2.5.3)

Area 1 G1 Area 1 G2 Area 1 G3 % Gravel 0.0% 0.0% 0.0% % Sand 54.6% 35.4% 34.2% % Mud 45.4% 64.6% 65.8% Textural Poorly Sorted Muddy Sand Poorly Sorted Sandy Mud Poorly Sorted Sandy Mud Group % LOI 17.2% 18.7% 16.7%

Table 2.5.3 Particle Size and LOI for Area 1, June 2012

Faunal Results

Only a single specimen was recorded in Area 1 in June 2012. Habitat classification of this area is difficult due to the lack of fauna present (Table 2.5.4), but sediment type and location indicates it may be classified as ‘Sublittoral mud in variable salinity’ (SS.SMu.SMuVs).

June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 Area 1 Area 1 Area 1 Area 2 Area 1 Area 1 Area 1 Area 1 Area 1 G1a G1b G1c G2a G2b G2c G3a G3b G3c Nephtys sp. 1 ------

Table 2.5.4 Faunal Results from Area 1, June 2012

Comparison between May 2011 & June 2012.

Results from both Particle Size Analysis and Loss on Ignition indicate very little change in the sedimentary conditions between the pre- and post-dredging conditions of the benthos across the surveyed areas of Area 1 (Fig. 2.5.2). Results from the faunal analysis also reflect this, with no fauna being recorded in 2011, and only a single replicate recording 5 individuals from 2 species in June 2012.

Figure 2.5.2 Ternary plot of sediment from Area 1 across both years

Faunal diversity is much reduced in Area 1 following the cessation of dredging. It is important to note that the community identified in 2011 was identified as being highly stressed, with only two taxa recorded in low abundances across the three grab sites. The faunal community identified in 2012 is also identified as being highly stressed, with only a single taxa recorded in a single grab replicate. As a result of the faunal reduction, biomass in the area from 2012 is also much reduced when compared to 2011 (Fig. 2.5.3).

Figure 2.5.3 Total station biomass (g wet wt) at each grab sampling station for Area 1. 71

Overall, the community present in 2012 is reduced in terms of diversity and abundances, as well as biomass when compared to 2011. It is important to note that the community identified in 2011 was characterised as a stressed community.

Area 2: Tivoli Area (Marina Generating Station – Blackrock Castle)

Area 2 is located from the Marina Generating Station to Blackrock Castle, taking in the stretch adjacent to the deepwater area at Tivoli (Fig. 2.5.4).

Figure 2.5.4 Location of sampling locations within Area 2 (Tivoli).

May 2011 Results

PSA Results

Results from Particle Size analysis of sediment collected in May 2011 indicate that the dominant sediment type in area was mud. Loss on Ignition results are high and show values typical of mud dominated environments (Table 2.5.5)

Area 2 G1 Area 2 G2 Area 2 G3 % Gravel 0.0% 0.0% 0.0% % Sand 29.6% 44.9% 34.4% % Mud 70.4% 55.1% 65.6% Textural Poorly Sorted Sandy Mud Poorly Sorted Sandy Mud Poorly Sorted Sandy Mud Group % LOI 11.3% 10.0% No Record

Table 2.5.5 Particle Size and LOI for Area 2, May 2011 73

Faunal Results

A total of three taxa were identified in the survey from May 2011. The dominant taxa identified in the survey was the polychaete worm Nephtys sp. In addition, the small spionid polychaete Streblospio sp. was also present in significant numbers across the area (Table 2.5.6). Habitat classification of this area is difficult due to the lack of key identifying fauna, but sediment type and location suggest it may be classified as ‘Sublittoral mud in variable salinity’ (SS.SMu.SMuVs).

June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 Area 2 Area 2 Area 2 Area 2 Area 2 Area 2 Area 2 Area 2 Area 2 G1a G1b G1c G2a G2b G2c G3a G3b G3c Nephtys sp. 5 4 5 2 10 2 6 13 6 Oliochaetae ------1 Streblospio sp. - 22 - 1 1 - - 1 -

Table 2.5.6 Faunal Results from Area 2, May 2011.

June 2012 Results

PSA Results

Results from Particle Size analysis of sediment collected in June 2012 was similar to that identified in May 2011. Samples were dominated by fine mud. Loss on Ignition results were high and are typical of mud dominated environments (Table 2.5.7)

Area 2 G1 Area 2 G2 Area 2 G3 % Gravel 0.0% 0.0% 0.0% % Sand 35.6% 48.1% 48.9% % Mud 64.4% 51.9% 51.1% Textural Poorly sorted sandy mud Poorly sorted sandy mud Poorly sorted sandy mud Group % LOI 10.5% 10.0% 10.3%

Table 2.5.7 Particle Size and LOI for Area 2, June 2012

Faunal Results

Faunal results from the grabs in June 2012 indicated the presence of 5 taxa, with the small spionid polychaete Streblospio sp. most abundant (Table 2.5.8). Habitat classification of this area is difficult due to the lack of key identifying fauna, but sediment type and location suggest it may be classified as ‘Sublittoral mud in variable salinity’ (SS.SMu.SMuVs).

June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 Area 2 Area 2 Area 2 Area 2 Area 2 Area 2 Area 2 Area 2 Area 2 G1a G1b G1c G2a G2b G2c G3a G3b G3c Cerastoderma sp. - 1 ------Juv Bivalve - - - - - 1 - - - Nephtys sp. 1 1 - 4 1 - 1 - 1 Streblospio sp. 5 25 23 27 34 13 29 23 4 Tharyx sp. - - - - 1 - - - -

Table 2.5.8 Faunal Results from Area 2, June 2012

Comparison between May 2011 & June 2012.

Results from both Particle Size Analysis and Loss on Ignition indicate very little change in the sedimentary conditions pre- and post-dredging at Area 2 (Fig. 2.5.5).

Figure 2.5.5 Ternary plot of sediment from Area 2 across both years

A change in faunal dominance has been identified between 2011 and 2012. The dominant taxa, both in terms of biomass and abundance was the polychaete worm Nephtys sp. in 2011. Although present in the 2012 survey, the dominant taxa had shifted to the opportunistic Streblospio sp. As a result, the biomass was reduced in 2012 (Fig. 2.5.6).

Figure 2.5.6 Total station biomass (g wet wt) at each grab sampling station for Area 2

Area 3: Ringmahon (Blackrock Castle – Ringmahon Point)

Area 3 is situated between Blackrock Castle to the bend of the channel at Ringmahon Point (Fig. 2.5.7).

Figure 2.5.7 Location of sampling locations within Area 3 – Ringmahon.

May 2011 Results

PSA Results

Results from Particle Size analysis of sediment collected in May 2011 indicate the dominant sediment type in area as mud. Loss on Ignition results show values typical of mud dominated environments (Table 2.5.9)

Area 3 G1 Area 3 G2 Area 3 G3 % Gravel 0.0% 0.0% 0.0% % Sand 34.4% 32.7% 35.4% % Mud 65.6% 67.3% 64.6% Textural Poorly Sorted Sandy Mud Poorly Sorted Sandy Mud Poorly Sorted Sandy Mud Group % LOI 8.2% 6.6% 7.8%

Table 2.5.9 Particle Size and LOI for Area 3, May 2011

Faunal Results

Faunal results from the grabs in May 2011 indicated the presence of 7 taxa, with the polychaete Nephtys sp. the most abundant. Other dominant infauna include the spionid worm, Streblospio sp. and the mollusc Abra sp. (Table 2.5.10). Habitat classification of this area is difficult due to the lack of key identifying fauna, but sediment type and location indicate it may be classified as ‘Nephtys hombergii and Tubificoides spp. in variable salinity infralittoral soft mud’ (SS.SMu.SMuVs.NHomTubi).

May 11 May 11 May 11 May 11 May 11 May 11 May 11 May 11 May 11 Area 3 Area 3 Area 3 Area 3 Area 3 Area 3 Area 3 Area 3 Area 2 G1a G1b G1c G2a G2b G2c G3a G3b G3c Abra sp. 1 2 1 - - 3 2 5 - Bryozoa indet. ------P Nephtys sp. 5 6 7 1 7 7 10 7 6 Spio sp. ------1 Oligochaetae - - 2 - - - 1 - 4 Streblospio sp. 3 8 10 - - - 11 7 1 Tharyx sp. - - - - - 3 - - -

Table 2.5.10 Faunal Results from Area 3, May 2011

June 2012 Results

PSA Results

Results from Particle Size analysis of sediment collected in June 2012 is similar to that identified in May 2011. Samples were dominated by fine sandy mud. Loss on Ignition results show values typical of mud dominated environments (Table 2.5.11)

Area 3 G1 Area 3 G2 Area 3 G3 % Gravel 0.0% 0.0% 0.0% % Sand 49.9% 33.1% 46.1% % Mud 50.1% 66.9% 53.9% Textural Poorly sorted sandy mud Poorly sorted sandy mud Poorly sorted sandy mud Group % LOI 7.6% 9.6% 7.3%

Table 2.5.11 Particle Size and LOI for Area 3, June 2012

Faunal Results

Faunal results from the grabs in June 2012 indicated the presence of 10 taxa, with the polychaetes Nephtys sp. and Streblospio sp. the most abundant (Table 2.5.12). These results are similar to those identified in 2011. Habitat classification of this area is difficult due to the lack of key identifying fauna, but sediment type and location indicates it may be classified as ‘Nephtys hombergii and Tubificoides spp. in variable salinity infralittoral soft mud’ (SS.SMu.SMuVs.NHomTubi).

June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 Area 3 Area 3 Area 3 Area 3 Area 3 Area 3 Area 3 Area 3 Area 2 G1a G1b G1c G2a G2b G2c G3a G3b G3c Abra sp. - - - - - 2 - 1 1 Mya sp. - - 1 - 1 - 2 - - Mytilus edulis - - - 1 - - - - - Bryozoa indet. - - - - - P - - P Nephtys sp. 4 5 6 1 1 1 1 2 1 Spio sp. 1 1 ------Oligochaetae - - 1 1 2 2 - - - Streblospio sp. 5 18 16 3 10 10 14 18 6 Scoloplos sp. - 1 - - - - - 1 - Melita palmata - - - 1 - - - - -

Table 2.5.12 Faunal Results from Area 3, June 2012

Comparison between May 2011 & June 2012.

Results from both Particle Size Analysis indicate the presence slightly coarser sediment in June 2012 compared to May 2011 (Fig. 2.5.8). Results from the Loss on Ignition analysis indicate very little change between the years.

Figure 2.5.8 Ternary plot of sediment from Area 3 across both years

Faunal composition in Area 3 remains similar between 2011 and 2012. The dominant taxa identified in 2011 were all identified in 2012 in similar abundances. In addition, results from 2012 indicate increased faunal diversity across the area, although biomass remains slightly reduced when compared to 2011 (Fig. 2.5.9).

Figure 2.5.9 Total station biomass at each grab sampling station for Area 3.

Quarterly Survey – February 2012

Two grab sites were surveyed in February 2012 as part of the Quarterly survey of Areas 3 and 4. Three replicates were collected at two locations in Area 3, as well as sediment sample for particle size and Loss on Ignition analysis.

Results from the particle size analysis indicate that the sediment at the site consisted of muddy sands and sandy muds (Table 2.5.13). This is similar to the results obtained in the subsequent survey of June 2012. Loss on Ignition results from this survey were higher compared to both May 2011 and June 2012 values.

Area 3 G1 Area 3 G2 % Gravel 0.0% 0.0% % Sand 42.1% 55.1% % Mud 57.9% 44.9% Textural Poorly sorted sandy mud Poorly sorted muddy sand Group % LOI 9.2% 10.3%

Table 2.5.13 PSA and LOI results from February 2012 small scale survey.

Results from the fauna identified in Area 3 in February 2012 indicate a large reduction in diversity and abundances compared to both May 2011 and June 2012 surveys (Table 2.5.14). The dominant species present have previously been recorded in the area, and diversity and abundances were much improved in the June 2012 survey when compared to the February 2012 survey.

February February February February February February Area 3 Area 3 Area 3 Area 3 Area 3 Area 3 G1A G1B G1C G2A G2B G2C Nephtys sp. 3 1 - 1 - 1 Oligo sp. - - - - - 1 Streblospio sp. - - - 8 3 19

Table 2.5.14 Faunal results from Area 3, February 2012.

Area 4: Lough Mahon (From Ringmahon Point to Marino Point)

Area 4 is located at Lough Mahon between Ringmahon Point and Marino Point (Fig. 2.5.10).

Figure 2.5.10 Location of grab samples within Area 4 – Lough Mahon.

May 2011 Results

PSA Results

Sediment in this area is coarser than the other surveyed areas. Large amounts of shell and stone gravel were identified within the area, although areas outside the channels consisted primarily of muddy sands (Table 2.5.15).

Area 4 G1 Area 4 G2 Area 4 G3 Area 4 G4 % Gravel 58.4% No record 0.0% 11.5% % Sand 37.5% No record 43.8% 67.6% % Mud 4.0% No record 56.2% 20.9% Textural Poorly sorted Sandy Poorly sorted Poorly sorted gravelly No record Group Gravel sandy mud muddy sand % LOI 2.4% No record 4.2% 2.5%

Table 2.5.15 PSA Results from grabs collected in Area 4.

Faunal Results

Faunal samples collected in May 2011 recorded the presence of 33 taxa in the faunal grabs across area 4. The dominant taxa present in area 4 are the polychaetes (Pholoe inornata, Phyllodocidae and Syllidae), Oligochaetae and the crustaceans Phtisica marina (Table 2.5.16). In addition, the peacock worm, Sabella pavonina, were identified in a single location in Area 4 indicating the patchy nature of their distribution in the region. Habitat classification of this area is difficult due to the lack of key identifying fauna present, but sediment type and location indicates it may be classified as ‘Infralittoral mixed sediment’ (SS.SMx.IMx). The patchy nature of faunal distribution makes further classification difficult.

Table 2.5.16 Faunal Results from Area 4, May 2011

May 11 May 11 May 11 May 11 May 11 May 11 May 11 May 11 May 11 May 11 May 11 May 11 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 G1a G1b G1c G2a G2b G2c G3a G3b G3c G4a G4b G4c Abra sp. 2 - - 1 ------1 6 Gari sp. - - - 1 ------Bryozoa indet. P P P P P P P - - - - - Nephtys sp. ------1 - - - 2 9 Nereidae - - - 5 ------Spio sp. 1 - - 1 2 ------Oligochaetae 219 111 44 - 23 1 8 - - - - - Streblospio sp. ------7 Ampharete sp. - - 1 - 1 - 3 - - - 4 - Tharyx sp. - - 2 3 3 1 - - - - 1 - Eteone sp. 1 - - 4 9 ------Pholoe inornata 10 10 5 6 13 2 1 - - - 1 - Scoloplos sp. - - - - - 1 ------Phyllodocidae 5 3 4 3 4 3 ------Syllidae 2 3 5 4 2 1 2 - - - - - Terebellidae - - - 8 2 - 3 - - - - - Lineus sp. - 2 ------Heteromastus sp. - - - - 4 - 3 - - - - - Sabella ------69 - Ballanus crenatus P P P P P P ------Anemone indet P - - 1 - 1 - - - - 1 - Pomatoceros P - 7 10 1 ------Hydroidea indet P P P - P ------Sertularia cupressinia ------P - - - - - Porifera indet. ------P - - - - - Carcinas maenas ------1 - - - 1 - Ophiura ophiura 8 - 4 ------Crinoidea indet - - - - 1 ------84

May 11 May 11 May 11 May 11 May 11 May 11 May 11 May 11 May 11 May 11 May 11 May 11 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 G1a G1b G1c G2a G2b G2c G3a G3b G3c G4a G4b G4c Melita palmata - 4 - 1 ------Phthisica marina 1 1 - 12 16 ------Pisidia sp. - - - 1 ------Corophium sp. - 1 - - 6 ------Bodotria sp. 1 - - - 1 ------

June 2012 Results

PSA Results

As identified in May 2011, the sediment in this area is coarser than in the other surveyed areas. Large amounts of shell and stone gravel were identified within the area, although areas outside the channels consisted primarily of muddy sands (Table 2.5.17).

Area 4 G1 Area 4 G2 Area 4 G3 Area 4 G4 % Gravel 95.2% 73.1% 13.9% 0.0% % Sand 2.7% 20.1% 75.8% 60.3% % Mud 2.1% 6.8% 10.4% 39.7% Textural Poorly sorted Poorly sorted muddy Poorly sorted muddy Group Well sorted Gravel gravelly muddy sandy gravel sand sand % LOI 2.4% 2.6% 2.2% 6.3%

Table 2.5.17 PSA Results from grabs collected in Area 4.

Faunal Results

Faunal results from the grabs in June 2012 indicated the presence of 36 taxa in the faunal grabs across area 4, a slight increase from those identified in May 2011. The dominant taxa present in Area 4 were again the polychaetes (Pholoe inornata, Phyllodocidae and Syllidae) and Oligochaetae. The echinoderm, Ophiura ophiura was present in large numbers in a single grab (Table 2.5.18). Similar to May 2011, the peacock worm, Sabella pavonina, was identified at only a single location in Area 4, again highlighting the patchy nature of their distribution within the area. As with the previous survey, habitat classification of this area is difficult due to the lack of key identifying fauna present, but sediment type and location indicates it may be classified as ‘Infralittoral mixed sediment’ (SS.SMx.IMx). The patchy nature of faunal distribution makes further classification difficult.

Table 2.5.18 Faunal Results from Area 4, June 2012

June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 G1a G1b G1c G2a G2b G2c G3a G3b G3c G4a G4b G4c Abra sp. - - 1 - - - - 1 - - - 6 Mytilus edulis - - - - - 1 - 1 1 - - - Dorididae indet. ------3 - - - - - Bryozoa indet. P P P P P P P P P Nephtys sp. ------1 - 1 - 9 Spio sp. - 7 - 1 8 3 - 3 1 - - - Oligochaetae 77 - 6 4 36 - 2 5 12 1 - 1 Streblospio sp. - - - 1 ------3 Ampharete sp. ------2 - - 1 - - Tharyx sp. ------2 18 13 - - 1 Pholoe inornata 1 11 5 2 - - - 4 1 - - - Sabella pavonina ------116 2 Lanice conchilega ------2 2 - 2 - - Capitella capitata ------1 - - - - - Heteromastus sp. - - - 1 1 - 1 12 2 - - - Lineus sp. ------1 Eteone sp. - 2 - - - 4 2 3 - - - - Scoloplos sp. - - - 1 ------Pomatoceros sp. 2 7 P 5 2 4 ------Nematoda - - - - 6 ------Aphrodita spp. - - - - 2 8 ------Syllidae 2 - 1 - - 11 - - 1 - - - Phyllodocidae - 2 4 23 - 18 - 2 3 - - - Polydora indet. - 3 ------Corophium sp. - 11 - 1 - 6 - 1 - - - - Carcinas maenas - 1 1 ------2 Melita palmata - 3 1 ------Pycnogonidae indet - 1 - - - - 1 2 - - - - 87

June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 June 12 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 Area 4 G1a G1b G1c G2a G2b G2c G3a G3b G3c G4a G4b G4c Phtisica marina ------2 1 - - - - Pagurus bernhardus - 1 ------Bodotria sp. ------1 - - - - - Ballanus crenatus P - P P - P P P P - - - Anemone indet ------1 - - - - - Isopoda indet - - - - 2 ------Ophiura ophiura 1 17 6 1 2 ------Crinoidea indet ------1

Comparison between May 2011 & June 2012.

Results from both Particle Size Analysis indicates slightly coarser sediment present in June 2012 compared to May 2011 (Fig. 2.5.11) with an overall reduction in the mud fraction across the area. Results from the Loss on Ignition analysis indicate very little change between the years.

Figure 2.5.11 Ternary plot of sediment from Area 3 across both years

Overall community structure remains similar between 2011 and 2012. The dominant species/taxa identified in 2011 are again dominant in 2012. Abundances are slightly reduced in 2012 when compared to 2011, and this is reflected in the reduced biomass values identified in 2012 (Fig. 2.5.12). However, in areas where the polychaete Sabella pavonina is found, the biomass levels increase (Fig. 2.5.13) although this may be as a result of local patchiness in the area.

Figure 2.5.12 Total station biomass from Grabs 1-3 at Area 4 (Replicates are combined). Sabella pavonina have been omitted.

Figure 2.5.13 Total station biomass from Grabs 1-4 at Area 4 (Replicates are combined). Sabella pavonina have been included.

Quarterly Survey – February 2012

A single grab site was surveyed in Area 4 during February 2012 as part of the quarterly survey of Areas 3 and 4. Three replicates were collected at a single location in Area 4, as well as sediment samples for particle size and loss on ignition analysis.

Results from the particle size analysis indicate that the sediment at the site consisted of coarse gravelly sands (Table 2.5.19). This is similar to the results obtained in the both the May 2011 and June 2012 surveys. Loss on Ignition results from this survey were similar to those obtained in both May 2011 and June 2012.

Area 4 G1 % Gravel 17.7% % Sand 77.3% % Mud 5.1% Textural Poorly sorted gravelly sand Group % LOI 2.2%

Table 2.5.19 PSA and LOI results from February 2012 small scale survey.

Results from the fauna identified in Area 4 in February 2012 are similar to those identified in both May 2011 and June 2012 surveys. A total of 15 taxa were identified at the single location in Area 4. Although the abundances and diversity was reduced, the fauna present have been identified in both other surveys.

February February February Area 4 Area 4 Area 4 G1A G1B G1C Abra sp. - 3 - Nephtys sp. - - 1 Spio sp. - 18 1 Oligochaetae 18 - 12 Streblospio sp. - 1 - Ampharete sp. 4 - 13 Tharyx sp. 8 - 10 Pholoe inornata - 3 - Capitella capitata - - 1 Heteromastus sp. 3 1 4 Eteone sp. - 9 - Syllidae indet. - - 2 Phyllodocidae 3 3 3 Terebellidae - 4 - Carcinas maenas 1 - -

Table 2.5.20 Faunal results from Area 4, February 2012.

Community Analysis of Subtidal Data

The subtidal infaunal abundance data shows the presence of two distinct communities in the subtidal channel. Analysis of the benthic data for Areas 1, 2 & 3 shows it to cluster together indicating a strong similarity in faunal communities across both years in these areas. Area 4 clusters out separately, and in a widely spaced pattern (Figure 2.5.14 (a), indicating the taxonomic differences at this site which are linked to the heterogeneous nature of the sediment there as compared to the other three survey areas.

(a) (b)

Figure 2.5.14 Two-dimensional multidimensional scaling (MDS) ordination for the benthic communities across all Survey Areas – All Years(a), and comparison of faunal communities present between the two survey years(b).

Although the survey area was subjected to extensive maintenance dredging during the course of the study, it is evident that the community structure identified in the survey areas remains similar between the 2011 baseline and the 2012 follow-up surveys (Figure 2.5.14 (b)). However, it should be noted that there is further spacing of the ordination points in June 2012 when compared to 2011, which indicates a slight change in community structure which could point to a community in recovery from a stress event.

Discussion on the Sub-tidal Results

Recovery of faunal communities in dredged sediments is led by opportunistic species such as small polychaetes colonising sediments rapidly after the cessation of the dredging. These eventually give way to the recovery also of what are referred to as equilibrium species1. Once a community has regained 80% of its diversity and biomass compared to pre-dredging levels, it is considered to have fully recovered (Newell et al., 1998). The same author points to recovery rates in estuarine, muddy sediment varying from 6-12 months post cessation of dredging.

Dredging within the survey area commenced in August 2011 and completed in January 2012. Areas between the City Quays to Marino Point were subjected to maintenance dredging between late August 2011 and January 2012. Water injection dredging occurred in Area’s 1 & 2 whilst trailer suction hopper dredging occurred in Area’s 2, 3 & 4.

Results from the sub-tidal survey indicate significant changes in biomass, abundances and diversity in Areas 1, 2 & 3 from pre-dredge levels in 2011 to post dredge levels in 2012. However, faunal

1 Large, relatively long-lived species whose presence often indicate undisturbed conditions. 92

communities identified in the area are consistent with recovering communities as they are dominated by opportunistic species with a smaller representation of equilibrium species in each of these areas. Although biomass levels are much reduced compared to pre-dredge levels, this is not unexpected as dredging had only stopped in the areas 5 months previously. This timescale is consistent with previous studies on the recovery of sub-tidal dredged sediments in estuarine conditions (Bonsdorff, 1980; Newell et al., 1998)

3 METHODOLOGY & RESULTS - FISHERIES

3.1 Overview

The fisheries aspect of the study was intended to assess any before after impacts from the proposed dredging and to gather baseline information on the fish community present and across the study area from the City Quays (Area 1) to Lower Lough Mahon (Area 4) and what it was feeding on. A range of survey methods were employed including baited pots, fyke nets and trawls, seine nets, with most effort employed in the first 3.

3.2 Timing

Fishery surveys were undertaken, in May/June 2011 the main pre-dredging baseline (before dredging), August 2011 (a short trawl survey immediately in advance of the dredging), Late February / early March (1st quarterly) 2012 follow-up about 1-2 months after all dredging activity had ceased and May/June 2012, the main follow-up survey about 6 months after all dredging had ceased.

3.3 Methods

Baited Pots

These are wire-framed nets/traps in series of ten individual traps tied in series and baited with fresh fish and anchored on the bottom . These were deployed in the upper part of the survey area, in Area 1 and Area 2 (Plate 3.1a).

Fyke nets

These consist of two conical nets with concentric metal hoops providing internal support for the nets which have their opening facing each other and joined by a band of vertical netting which intercepts passing fish and directs them toward the net openings (8mm mesh). (Plate 3.1b). These were deployed throughout the study area and at the Rossemore control site.

Beam Trawls

Two types of beam trawl were employed a 1.5m beam (Plate 3.1c) which could be deployed from the ASU’s 4.5m RIB as well as from the Port Authority’s work boat, the Denis Murphy, and a 2m beam trawl which was only deployed from the Denis Murphy (Plate 3.1d). They both had a mesh size of 11mm. The smaller trawl was deployed in all areas including the control site whereas the longer trawl was mainly deployed in Areas 3 and 4 with one deployment in the lower part of Area 2. Trawls were generally 4-10minutes in duration and undertaken at about 1knot. They mainly covered between 300 and 500m but were longer and shorter on occasion depending on tides and bed conditions. Trawling was not linked to tides.

Seine nets

Due to the distance between the main dredged channel and the shore, among other reasons, seine nets were not used in the main study area. A small number of seine nettings were undertaken in the shallow intertidal area of the Rossmore control site. The seine net used a 6mm mesh bag, and were 15m and 25m net length.

Limitations of the Survey Methods

The survey methods were designed to capture bottom or near bottom dwelling species as this was where the main impacts of the dredging were likely to be felt, and while they occasionally caught pelagic species or bentho-pelagic species such as cod, whiting and dogfish, they never caught mullet for example, one of the most widespread species in the Harbour and one that was regularly seen on surveys or whose traces, in the form of grazing marks on intertidal mud surfaces, were widely in evidence in Lough Mahon intertidal areas. Spratt, a small pelagic member of the herring family, which often travel in large shoals known to be present in Cork Harbour (IFI , 2010) were generally not captured by any of our fishing methods. In addition, it is likely that our trawling didn’t capture larger and more mobile specimens of several of the species we did capture (i.e. plaice, flounder and dab), e.g. our largest flounder was taken in a fyke net in Area 4 (25cm).

While our mobile gear did capture a broad size range of brown shrimp (Crangon crangon) it didn’t capture the very numerous smaller epibenthic crustaceans e.g. younger brown shrimp, amphipods and mysids which are widespread in the harbour living at the sediment-water interface (amphipods and brown shrimp) or above it (mysids) and which form an important link between the food produced in the sediments and the water column, and higher orders of the food chain, e.g. fish.

On occasion also it was strongly suspected that the low fish and invertebrate catches e.g. in Area 4 on May 31st 2012 (table A5, Appendix 1) was exacerbated by a very heavy build-up of green and brown algae on the front tickler chain.

It is important to note that zooplankton, mysids, and smaller mobile epibenthic crustaceans e.g. gammarid amphipods were very rarely captured by these survey methods due to the relatively large mesh size employed. These parts of the food chain would require a separate sampling strategy.

(a) (b)

(e)

(f)

Plate 3.1 (a-d) Showing some of the fishing gear deployed: (a) baited traps with catch of green crab, fyke nets being deployed in Lough Mahon, (c) the 1.5m beam trawl with modified shoes for muddier sites, (d) the 2m beam trawl astern of the ‘Denis Murphy’ in Lough, seine net being pulled in (not Cork Harbour), (f) intertidal coring.

3.4 Fisheries Results

Baited Traps

Of the 3 sets of traps which were deployed in May 2011 (May 23rd – May 25th), one was lost (possibly due to a rise in water levels in the river). In May 2012 (May 29th- May 31st) 4 sets of traps were deployed, 3 in the same places as in 2011 and at one new site (Figure 3.1). The first two sets of traps were set in Area 1 and the other two in Area 2. In each case the traps were left to soak for 24rhs.

The pots took almost exclusively green crab (Figure 3.2) with, in addition, a dogfish (Scyliorhinus canicula) (~60cm) and 500g eel (Anguilla anguilla) in Pots 2 (Marina Power station) in May 2011 and 2012 respectively (Plate 3.2).

Figure 3.1 Positions of 4 baited trap sites (Traps 1-4) Traps 1: City Quays Grain Silos, Traps 2: Marina Power Stations, Traps 3: upstream of Tivoli Docks, Traps 4: between Tivoli Docks and Blackrock Castle.

Green Crab in Baited Pots

10 2011

8 2012 Kg

0 City Quays Power Station Tivoli Dock (u/s) Tivoli Dock (d/s) 1 2 3 4

Figure 3.2 Green crab taken in baited traps in May 2011 and May 2012

Plate 3.2 Large eel taken in baited trap close to the Marina power station in Area 1. (May 2012)

Fyke Nets

Fyke nets were deployed across a wider area than the baited pots from Tivoli Docks down to Area 4 (Figure 3.4). In each case the nets were left for approximately 24hrs to fish. As for the baited traps each fyke’s catch was dominated by green crab (Figure 3.3) although there were a range of fish species also taken (Table 3.1). The most frequently encountered species was 5-bearded rockling (Ciliata mustela) present in more than two thirds of fykes followed by eel, dogfish and flounder, all with 3 occurrences. Figure 3.3 indicates that the crab catches were lower in 2012 than in 2011.

Green Crab in Fyke Nets

8 2011 2012

6 Kg

0 Fyke 1 Fyke 2 Fyke 3 Fyke 4 Fyke 5 Fyke 6 Fyke 7

Figure 3.3 Fyke net catches of green crab May 2011 and 2012

Fyke 1 Fyke 2 Fyke 3 Fyke 4 Fyke 5 Fyke 6 Fyke 7 Fyke 7 (a) Eel 2011 1 2012 1 1 Rockling 2011 1 1 1 2012 2 1 1 1 3 3 Dogfish 2011 2 1 2012 1 Flounder 2011 1 1 2012 1 Hooknose 2011 2012 2 Plaice 2011 1 2012 1 Cod 2012 2011 1 Pollack 2011 1 2012

Table 3.1 Fish species taken in fyke nets (May 2011 and May 2012)

100

Figure 3.4 Positions of 7 fyke net sites in 2011 and 2012. Note that at Fyke 7 two fykes nets were deployed in 2012 on opposite sides of the channel.

101

Beam Trawling

Trawling was undertaken during May and June in 2011 and 2012, August 2011, late February/ early March in 2012. Table 3.2 gives the dates in question, the areas surveyed and the type of beam trawled used.

Dates Areas sampled Type of trawl May 24th 2011 A1 – City Quays 1.5m May 25th 2011 A2 & A3 (Tivoli and Upper Lough Mahon) 1.5 May 26th 2011 Rossmore (North Channel control site) 1.5m May 27th 2011 A4 – Mid and Lower Lough Mahon 1.5m August 28th 2011 A1-A4 1.5m 14 & 15th June 2011 A4 and A3/A4 2m February 2012 A3 & A4 1.5m March 1st 2012 A1-A4 and Rossmore 1.5m May 30th 2012 A4 1.5m May 31st A3 1.5m June 1st 2012 Rossmore 1.5m June 18th 2012 Area 4 and A3 2m

Table 3.2 Trawling schedule and type of trawl deployed (2011 and 2012)

Trawling - Detailed Results Tables

Detailed trawl results are presented in Table A1 to A7 in Appendix 1 accompanied by Figure A1 to A13 showing the locations of trawl tracks. The limited beach seine data for Rossmore is also presented in these tables. See Plate 3.3 for examples of some of the species captured.

Trawling - Fish Species Present

A total of 26 species were taken in trawls, while 3 species not encountered in trawls but taken in baited traps or fyke nets were dogfish, 2bull-rout and sand smelt. Table 3.3 lists these species along with their Estuarine Functional Group (EUFG) categories, their Feeding Mode Functional Group (FMFG) categories, their Reproductive Mode Functional Group (RMFG) and their frequency (freq.) of occurrence in 38 European estuaries as reported in Franco et al., (2008). Knowledge of each species 3functional groups and their main characteristics gives an insight into the degree of importance of estuaries for each, as well as their interaction with different estuarine habitats and areas. They also indicate a species food preferences and to some extent where they would fit into the estuarine food web. A key to the various categories under each heading is given in Table 3(a) which has been quoted directly from Appendix 1 of Franco et al. (2008), who assigned these and many more estuarine species from 38 European estuaries into functional groups. The data from Cork Harbour shows a broad range of functional groups but with a particular dominance of Estuarine Species (ES) (Common Goby, Nilsson’s Pipefish, Black Goby) or those Estuarine Species which are also considered Marine Stragglers (MS) (e.g. Sand Goby, Butterfish, Hooknose and Corkwing Wrasse) and Marine Migrants (MM), such as dab, sole, plaice and flounder, which spawn at sea but move inshore and into estuaries as juveniles. It is noteworthy that flounder has elsewhere been classified as an

2 Bull-rout Myoxocephalus scorpius and sand-smelt (Atherina presbyter) were taken in a fyke net in Rossmore 3 Also referred to as a guild 102

Estuarine Resident (Selleslagh and Amara, 2008) and its behaviour in Cork Harbour during this study would lean more to that categorisation.

Functional Groups Categories Common name Scientific name EUFG FMFG RMFG Freq. 1 Dab Limanda limanda MM Bmi, BMa Op 0.37 2 Plaice Pleuronectes platessa MM Bmi, BMa Op 0.45 3 Flounder Platichtys flesus MM Bmi, BMa Op 0.79 4 Sole Solea solea MM Bmi, BMa Op 0.84 5 Cod Gadua moruha MM HZ,HP, Op 0.45 6 Pollack Polacchius pollachius MM,MS HP Op 0.32 7 Whiting Merlangius merlangus MM,MS HP Ob 0.39 8 Saithe Polaccius virens MS 0.32 9 Common Goby Pomatoschistus microps ES Bmi Og 0.71 10 Sand Goby Pomatoschistus minutus ES, MM Bmi Og 0.66 11 Black Goby Gobius niger ES Bmi, HP Og 0.63 12 Rock Goby Gobius paganellus ES Bmi, HP Og 0.26 13 Crystal Goby Crystallogobius linearis MS 0.03 14 Butterfish Pholis gunnellus ES,MS Bmi, Bma Og 0.37 15 Hooknose (pogge) Agonus cataphractus ES,MS Bmi, Bma Ov 0.26 16 Bull-rout Myoxocephalus scorpius ES,MS HP Og 0.37 17 Greater pipefish Syngnathus acus ES,MM,MS Bmi Os 0.61 18 Nilsson's pipefish Syngnathus rostellatus ES HZ,HP, Os 0.37 19 5-bearded Rockling Ciliata mustela MM Bmi, BMa Op 0.39 20 Corkwing wrasse Symphodus melops ES,MS Bmi,Bma Og 0.32 21 Grey gurnard Eutrigla gurnardus MM,MS Bmi, BMa, HP Op 0.45 22 Dragonet Callionymus lyra MS 0.39 23 European eel Anguilla anguilla C 0.87 24 Conger eel (larva) Conger conger MS 0.32 25 Spratt Sprattus sprattus MM PL Op 0.63 26 Sand smelt Antherina presbyter MM PL Ov 0.39 27 15-spined stickleback Spinachia spinachia MM,MS HZ,HP, Og 0.21 28 Dogfish (lesser spotted)Scyliorhinus canicula MS 0.13 29 Thornback Ray Raja clavata MS 0.21

Table 3.3 List of fish species taken in Cork Harbour Survey during 2011 and 2012 along with their respective Estuarine Functional Group (EUFG), Feeding Mode Functional Group (FMFG) and Reproductive Mode Functional Group Categories (RMFG) from Franco et al., 2008 (see Table 3.3(a) below for legend.

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Functional Groups Functional Group Categories Definition Live in freshwater but regularly use estuaries as C = Catadramous pathways of migration to the sea, where they reproduce May breed in the estuary; highly euryhaline ES = Estuarine Species species, able to move throughout the full length of the estuary EUFG Spawn at sea and regularly enter estuaries in (Estuarine Functional MM = Marine Migrant large numbers; highly euryhaline species, able to Group) move throughout the full length of the estuary Spawn at sea; usually associated to coastal marine waters, enter estuaries accidentally in MS = Marine Straggler low numbers; predominantly stenohaline species, occur most frequently in the estuary lower reaches Feed mainly on benthic, epibenthic and Bmi = Microbenthivores hyperbenthic fauna, with prey size <1cm Feed mainly on benthic, epibenthic and Bma =Macrobenthivores hyperbenthic fauna, with prey size >1cm Feed just over the bottom, predominantly on FMFG HP =Hyperbenthivores/Piscivores larger mobile invertebrates living over the (Feeding Functional bottom and fish. Group) Feed just over the bottom, predominantly either HZ = Hyperbenthivore/Zooplanktivore on smaller mobile invertebrates living over the bottom and zooplankton. Feed predominantly on zooplankton and PL = Planktivores occasionally on phytoplankton in the water column, mainly by filter feeding Op = Oviparous with PELAGIC EGGS Buoyant pelagic eggs Ob = Oviparous with BENTHIC EGGS Demersal eggs settling on the substratum Demersal eggs, adhesive or attached to Ov = Oviparous with ADHESIVE EGGS RMFG substratum or vegetation. (Reproductive Post-fertilization parental care of eggs by Functional Group) Og = OVIPAROUS GUARDERS guarding them externally Post-fertilization parental care of eggs by Os = OVIPAROUS SHELTERERS sheltering them in a part of their body

Table 3.3(a) Explanation of Functional Group abbreviations and categories as given in Appendix 1 of Franco et al., 2008)

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(a) (b)

(e) (f)

Plate 3.3 (a-f) Examples of fish and invertebrates taken in the fisheries survey. (a) dab, plaice and sand gobies, (b) Hooknose or pogge (c) Greater pipefish (d) Grey gurnard; (e) Crangon (brown shrimp), starfish (Asterias) and green sea urchin

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Trawling - Main Findings

Of the 26 species taken in trawls, 9 including sand goby, dab, plaice, flounder, hooknose, Nilsson’s pipe fish, greater pipefish and black goby, were recorded in five or more trawls. A smaller list of 6 species including butterfish, sole, dragonet, spratt, transparent goby and 15-spined stickleback were recorded in two to four trawls, while the remaining 14 species were each only recorded in a single trawl. In terms of numbers per trawl, sand goby were most numerous followed by plaice, dab and hooknose, Nilsson’s pipefish, black goby and flounder.

Some species tended to span most of the areas including sand goby, plaice, dab, hooknose, Nilsson’s pipe fish and to a lesser extent flounder, while other species were mainly captured in one or two areas e.g. dragonet toward the lower part of Lough Mahon (Area 4) and black goby and wrasse to the lower part of Lough Mahon and Rossmore. Highest numbers of Nilsson’s pipefish were taken in Area 3 and generally associated with trawls containing large amounts of green and brown seaweed. These distribution patterns are believed to relate to a combination of substrate preferences and salinity tolerances.

As one would expect in an estuarine situation, the numbers of species recorded in trawls declined toward the upper, lower-salinity end of the study area, with the more upstream areas Area 1 and Area 2 recording fewer species than Areas 3 and 4 (Table 3.4). Area 1, the City Quays from the Custom House Quay down to the Marina Power Station, had just 3 species, Area 2 (Marina Power Station to the end Blackrock Castle) had 10, while Areas 3 and 4 each recorded 16 species; 10 species were taken in trawls in Rossmore. Lower salinity in the upper reaches probably explains a considerable amount of this variation. However, habitat diversity is probably also a contributing factor and clearly, Area 4 with mixtures of sand, shell gravel and mud had a significantly greater range of microhabitats than Areas 1 and 2. It is also possible that the very anoxic and organic nature of the mud in Area 1 could be acting as a deterrent to benthic species especially some species of flat fish. Another contributing factor may have been the relatively low densities of infaunal macroinvertebrate biomass, in Area 1 in particular.

As most sampling runs took place during the summer of 2011 and 2012, it would be difficult to detect a seasonal pattern among species. However, in the February 28th and March 1st 2012 samples, dab was clearly the most frequently encountered flatfish species (Table A4, Appendix 1). In contrast, plaice was more numerous and more frequently encountered in summer samples (Tables A6 and A7, Appendix 1).

The numbers of fish collected by trawls were often low and quiet variable within each sampling run and often within a single area. As a result, it isn’t possible from the data to indicate whether there has been any significant change in the fish density as a result of the maintenance dredging which was carried out. Species diversity doesn’t appear to have dropped when the species data for each area is compared before and after, with data for Area 3 recording higher species diversity in May- June 2012 (Table 3.5). It should be noted however that the additional post-dredging species noted in Area 3 (Table A7, Appendix 1) are generally only represented by one individual in just one trawl, so definite conclusions cannot be drawn. What is perhaps more important is that those species, such as dab, plaice and hooknose, which were most prominent in terms of numbers and frequency of occurrence in 2011 samples, were similarly represented in post-dredging sampling events, indicating that the fish community structure remained intact. This observation is quite conservative because it relates in the main to samples taken within the shipping channel, i.e. those directly affected by physical disturbance.

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It is also important to point out that trawling would only be expected to capture the bottom-active or near bottom-active species, i.e. those potentially most likely to be impacted by dredging, while substantially missing more pelagic or larger mobile species such as spratt, mullet, dogfish and cod. For example, while only a few spratt were taken in trawls in the current study, much larger numbers (more than 4000 individuals across 6 samples in one instance), were taken in beach seine nets by Inland Fisheries Ireland during an extensive survey in Lough Mahon in 2010 as part of a Water Framework Directive monitoring in Greater Cork Harbour (Kelly, 2010). These latter species however would be far less likely to be impacted by the dredging.

A1 A2 A3 A4 Rossmore Dab ? x x x x Plaice x x x x Flounder x x x x Sole x x Cod x x x Pollack x x Whiting x Saithe x Common Goby x (x) Sand Goby x x x x x Black Goby x x Rock Goby x Transparent Goby x Butterfish x Hooknose (Pogge) x x x x Short-spined scorpion fish (x) Greater pipefish x x x x Nilsson's pipefish x x x 5-bearded Rockling (x) x x (x) Corkwing wrasse x Wrasse indet. x Grey gurnard x Dragonet x European eel (x) x (x) (x) Conger eel (larva) x Spratt x 15-spined stickleback x Dogfish (x) (x) (x) Sand smelt (x) Thornback Ray x Trawls only 3 10 16 16 10 Trawls , traps & fykes (5) (11) (16) (18) (14)

Table 3.4 Fish species taken in trawls and in other gear (brackets) from each of the 4 study areas and the control site (Rossmore).

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A1 A2 A3 A4 Rossmore 2011 2012 2011 2012 2011 2012 2011 2012 2011 2012 Dab x x x x x x x x x x Plaice x x x x x x x Flounder x x x x Sole x x x Cod x Pollack x x Whiting x Saithe x Sand Goby x x x x x x x x x x Black Goby x x x x Rock Goby x Transparent Goby x Butterfish x x x Hooknose (Pogge) x x x x x Greater pipefish x x x x x Nilsson's pipefish x x x x 5-bearded Rockling x x Corkwing wrasse x x Wrasse (indet) x Grey gurnard x Dragonet x x x European eel x Conger eel (larva) Spratt x x 15-spined stickleback x Thornback Ray x Totasl (trawls only) 2 3 5 7 6 14 10 13 7 8

Table 3.5 Fish species taken in trawls in each of the 4 study areas and the control site (Rossmore) in 2011 and 2012.

Trawling - Invertebrates Captured

While fish were the principal target of the beam trawling surveys, record was kept of invertebrate fauna also because of what they could reveal about the benthic environment and habitats and because of the importance of certain species both as prey items and as predators for fish fauna. Data on invertebrates in general might also be relevant in assessing impact of dredging given the more 4sessile habit of some species. The only invertebrate species, which were systematically weighed or counted were green crab (Carcinus maenas) and Crangon (brown shrimp) because of their abundance and the important ecological roles they are likely to play in the harbour. Such an approach has also been taken in other estuarine studies recently in recognition of the influence these two species may have in structuring fish communities (see Selleslagh and Amara., 2008).

4 Sessile in this instance referred to a species which is attached to the bottom or stays in more or less the same place as compared to mobile species such as fish and shrimp for example. 108

Catches of the latter were generally, weighed or if only a few individuals were present, they were counted instead. All invertebrate data are presented in the same tables as the fish data (Table A1- A7, Appendix 1)

As in the case of fish, invertebrate diversity tended to be highest in Areas 4 and lowest in Areas 2 and 1, while Rossmore was also quite diverse in terms of its invertebrates. Along with higher salinity, this is believed to be due to the greater variety of microhabitats present in Area 4, which include shell gravel, sand and mud (Plate 3.4a),. Harder substrates, for example provide more anchor points for sessile epifauna and algae. In Area 1, the most frequent points of attachment provided in an otherwise mud-dominated environment were beverage cans which were colonised by barnacles, anemones and sea squirts (Plate 3.4b) (Table A3, Appendix 1), all of which experienced a significant drop in representation in Area 1 trawls following dredging. Brittle stars also seem to have dropped in abundance in Area 1, possibly for the same reason. Neither of the latter changes is likely to have a significant knock-on impact on fish in the area however, as neither group is known to be important fish prey items.

Crangon and green crab were, with few exceptions, by far the most frequently encountered and abundant mobile epibenthic invertebrates taken in trawls. Generally, though not invariably, green crab and Crangon were most abundant in Areas 3 and 4, and while green crab were also abundant in Rossmore, Crangon tended to be less so. Crangon and green crab occurred in samples from all areas including Area 1 and both were recorded in most samples. No clear trends are discernible in the data, although February 2012 samples tended to have lower biomass of both species, especially Crangon. This would fit in with a population study of Crangon in the Isle of Man, showing that the greatest biomass was recorded from June to September, with much lower biomass generally outside this period (Oh, et al., 1999). As in the case of fish, the between-trawl variation within a given area and sampling period is such that it would be difficult to say whether or not there had been a clear before-after difference between the baseline (May-June 2011) and the main follow-up sampling (May-June 2012) for either species. The simple arithmetic mean of all trawls for both periods which contained a measurable amount of either species (give here as 20g+) suggests that there was a drop in biomass in both species in the follow-up survey (Table 3.6). The data must be treated with caution however because of the large standard deviation around the mean in both cases and as previously mentioned the general variability in trawl catches, even from the same areas during the same sampling session. The latter can be accounted for by spatial variation in the distribution of target species as well as variability associated with the efficiency of trawling. If the data represents a real drop in biomass at the sampled sites, it may just represent natural inter-annual variation in the species, which in the case of Crangon has been noted elsewhere.(Oh, et al., 1999). However, if the changes are attributable partly or entirely to dredging then it is important to point out that (i) the drop is both cases is not exceptional i.e. a 54% and a 33% reduction on average and (ii) the impacts within the food web may not necessarily be negative, particularly because both species are known to be predators of fish such as goby and juvenile plaice.

Average Biomass in Trawls (g) 2011 2012 2011 2012 Crangon - Average & (Stdev) 539 (674) 246 (206) n=10 n=11 Green Crab - Average & (Stdev) 715 (607) 482 (429) n=12 n=12

Table 3.6 Average weights (g) of Crangon and green crab in trawls in Lough Mahon in May/June 2011 and 2012. Standard deviation of the average given in brackets.

A number of other invertebrates collected during the surveys are also worthy of mention. A tube- dwelling polychaete which is known to occur in muddy places in the lower intertidal and in subtidal 109

areas (Murray et al., 2011) and which has been recorded by the ASU in previous surveys of soft sediments Lower Cork Harbour, occurred regularly in Areas 3 and 4. The species live in long tubes (up to 50cm) which stand up to 10cm clear of the sediment and the worms (up to 30cm in length) extend their head tentacles fan-like to filter feed in the current. Normally this species aggregates into dense patches and so can have a very clumped distribution. During the baseline trawling in May-June 2011, large numbers of these tubes were noted on the front tickler chain of the 2-m beam trawl in Area 4, along with numerous brittlestars and bryozoans. (Plate 3.4c). Given the sedentary nature of this species and its position on the sediment surface, it can be reasonably assumed that it would be very susceptible to bed disturbance including dredging. While, the species was present in trawls also in February 2012 and again in May/June 2012, it is likely that their densities would have been reduced following dredging. The species was also taken in sub-tidal grabs in both the baseline and follow-up surveys (Plate 3.4d) at the edge of the channel in similar quantities suggesting that these marginal stands were not impacted by dredging. Another tube-dwelling polychaete, which occurs widely in intertidal and shallow subtidal sandy areas, was also recorded in trawls and grabs in Area 4 (Lanice conchilega) although at lower densities. It too is likely to have been impacted by dredging in the shipping channel. Both species were recorded in the diets of flat fish and others during the present survey and are significant in that respect. Furthermore, aggregations of Lanice tubes in intertidal areas have been shown to be favoured by juvenile plaice as a food source and by juvenile sole as a refuge (Rambaut et al., in press). Brittle stars are another species which may have been adversely affected by dredging, although they were only rarely taken in the diets of fish during the survey.

Seine Net Survey Results

Seine net surveys were only undertaken in Rossmore in both the baseline and follow-up surveys. The tidal conditions during the follow up however, meant that the netting was far less efficient and catches were poor. In general the catches were dominated by common goby (Pomatoschistus microps), while the dominant invertebrates were Mysids and younger-stage Crangon, both present in large numbers; one seine also contained considerable numbers of green crab. Mysids, which are a small shrimp-like crustacean are important food items for a range of marine species and therefore an important link in the food chain, they were detected in the diet of several species during the current survey. Data for the beach seine catches are presented in Tables A1 and A6 in Appendix 1.

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(a) (b)

Plate 3.4 (a-d) Oyster shell substrate (Area 4); (b) beverage cans with associated sea squirts, barnacles and anemones (Area 1). Peacock worms from the 2m trawl tickler chain (Area 4) June 2011; (d) peacock worms from a grab sample in June 2012 (Area 4).

Fish Diet

In order to get an insight into the diet of fish collected during the survey and to construct a picture of the food-web within the survey area, the gut contents of each of the main species present were examined. The findings of this aspect of the survey are presented below under the heading of each species in question. In the case of some species, the size range of individuals examined, as well as others retained but not examined, is also presented. It is worth noting that as fish get older they often shift their diet from smaller items e.g. benthic meiofauna (e.g. foraminifera, harpactacoid copepods and octracods) and zooplankton to larger infaunal macroinvertebrates or to epibenthic species such as amphipods, Crangon, fish etc.

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Plaice (Pleuronectes platessa)

Most of the plaice caught in trawls were small and appear to be mainly belonging to one year-class (Fig 3.5), with a few larger individuals also present. Gut contents of 47 individuals were examined and the % occurrence of food items recorded is given in Table 3.7

Plaice - size distribution (TL)

10 Numbers 8

0 21-30 31-40 41-50 51-60 61-70 71-80 81-90 91-100 101-110 111-120 121-130 Size intervals (mm)

Figure 3.5 Size distribution of plaice examined for gut contents as well as some not processed. Note that the individuals come from several sites, in both years and were taken in at least two gear types

% Prey Item Occurrence Small polychaetes or oligochaetes 66 Copepods 20 Larger errant of sedentary polychaetes 17 Ostracods 15 Crangon 12 Polychaete parts 10 Bivalves 7 Amphipods 7 Hydrobia 5 Crustie indet 5 Bivalve siphons 2 Foraminifera 2 Mysids 2 Crabs 2

Table 3.7 % occurrence of prey types in the gut contents of 47 plaice from the study area 112

The data presented indicate a wide range of prey items taken but the particular importance of small worms. Also notable is that the smallest plaice also feed on meiofaunal crustaceans including harpactacoid and other copepods and ostracods. Other copepods in the water column immediately above the sediment surface are also likely to feature in the diet of younger specimens. Also noteworthy is the presence of Crangon and the head tentacles of sedentary polychaetes which the fish may be ‘grazing’ on (‘polychaete parts’).

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Dab (Limanda limanda)

Dab were one of the most widely ranging and frequently encountered species during the study. The gut contents of 28 dab were examined and the percent occurrence of prey items recorded is presented in the Table 3.8. The size distribution of the fish examined as well as a number not analysed is presented in Figure 3.6. As with plaice, most of the fish appear to belong to a single year-class presumably 0+, with a few older individuals also present. Dab diet was dominated by meiofauna (copepods, ostracods and foraminifera), some of which are also likely to be planktonic (copepods). The smaller specimens in particular had a high content of these small food items but they were generally quite common in the diet of individuals up to 70mm in length. Other noteworthy items included the heads of Sabella pavonina the peacock worm and head tentacles of other sedentary polychaetes possible including the tube-dwelling Lanice conchilega (the Sand Mason) another sedentary species. The brown shrimp Crangon was also present in the diet of several individuals.

% Prey Item Occurrence Copepods 42.9 Polychaete parts 25.0 Foraminifera 21.4 Ostracods 21.4 Small polychaetes or oligochaetes 17.9 Crangon 17.9 Larger errant or sedentary polychaetes 7.1 Amphipods 7.1 Mysids 7.1 Hydrobia 3.6 Barnacle 3.6

Table 3.8 % occurrence of prey types in the gut contents of 28 dab from the study area

Dab - size distribution (TL)

4 Numbers

0 21-30 31-40 41-50 51-60 61-70 71-80 81-90 91-100 101-110 Size intervals (mm)

Figure 3.6 Size distribution of dab examined for gut contents as well as some not processed. Note that the individuals come from several sites, in both years. 114

Sand Goby (Pomatoschistus minutus)

The gut contents of 30 sand goby were examined and these are presented in Table 3.9 in In decreasing order of occurrence. The size distribution of the fish examined as well as a number not analysed is presented in Figure 3.7. The fish examined had a diet dominated by wide range of small crustaceans and larger and smaller polychaetes.

% Prey Item Occurrence Larger errant or sedentary polychaetes 41.9 Copepods 29.0 Crustacean indet 21.6 Foraminifera 19.4 Crangon 12.9 Crustacean indet 12.9 Small polychaetes or oligochaetes 9.7 Amphipods 9.7 Polychaete parts 6.5 Ostracods 6.5 Isopods 6.5 Mysids 6.5 Hydroid parts ? 6.5 Bivalve siphons 3.2 Brittlestar arms 3.2

Table 3.9 % occurrence of prey types in the gut contents of 30 sand goby from the study area

Sand Goby - size distribution (TL)

5 Numbers 4

0 21-30 31-40 41-50 51-60 61-70 71-80 81-90 Size intervals (mm)

Figure 3.7 Size distribution of sand goby examined for gut contents as well as some not processed. Note that the individuals come from several sites, in both years.

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Flounder (Platichtys flesus)

The gut contents of 15 Flounder were examined and revealed the presence mainly of larger errant or sedentary polychaete worms (Table 3.10). One larger specimen (22cm) caught in a fyke net in Rossmore in 2011, contained more than 20 bivalve siphons thought to be from Mya sp. Flounder were one of only two species whose gut contents contained remains recognisable as fish. The size range of the flounder examined are presented in Fig 3.8. This shows that on-average the flounder were larger than both plaice and dab and it may be that most of the younger year class are present in the very upper estuarine / lower freshwater reaches of rivers such as the Lee, Glashabuoy, Douglas and Owenacurra, with 1+ and older fish dominating in the study area.

Prey item % Occurrence Larger errant or sedentary polychaetes 80.0 Bivalve siphons 13.3 Crab 13.3 Bivalves 6.7 Foraminifera 6.7 Copepods 6.7 Amphipods 6.7 Crangon 6.7 Crustacean indet. 6.7 Fish 6.7

Table 10 % occurrence of prey types in the gut contents of 15 flounder from the study area

Flounder - size distribution (TL)

2 Numbers

Size interval (mm)

Figure 3.8 Size distribution of flounder examined for gut contents as well as some not processed. Note that the individuals come from several sites, in both years and were taken in at least two gear types 116

Black Goby (Gobius niger)

The gut contents of 13 black goby were examined and the results are listed in Table 3.11. And the size distribution of these and a small number of unprocessed animals is presented in Fig 3.9. The data shows that these fish have a high proportion of larger polychaete worms in their diet and, to a lesser extent, small epibenthic crustaceans. This species was recorded only in trawls in Area 4 and Rossmore.

Prey item % Occurrence Larger errant or sedentary polychaetes 84.6 Amphipods 30.8 Isopods 15.4 Bivalve Siphons 7.7 Crustacean parts indet. 7.7

Table 3.11 % occurrence of prey types in the gut contents of 13 black goby from the study area

Black Goby (size distribution)

4 Numbers 3

0 51-60 61-70 71-80 81-90 91-100 101-110 Size intervals (mm)

Figure 3.9 Size distribution of examined for gut contents as well as some not processed. Note that the individuals come from several sites, in both years.

5-bearded Rockling (Ciliata mustela)

Twelve 5-bearded rockling were examined and their diet was dominated by crustaceans including Crangon and crab and in one case fish (Table 3.12). Most rockling were taken in fyke nets set at the 117

edge of the shipping channel, they very rarely occurred in trawls. The rockling captured were in the size range 120-198mm. It was notable that the gut contents of several specimens contained unidentifiable material. A notable feature of the species was the high burden of gut parasites (tapeworms) present in the mid-region of the gut of several of the fish examined.

Prey item % Occurrence Crangon 25.0 Crustacean indet. 25.0 Crabs 25.0 Decapod indet. 8.3 Amphipods 8.3 Mysids 8.3 Polychate residue ? 8.3

Table 3.12 % occurrence of prey types in the gut contents of 12 Five-bearded rockling from the study area

Hooknose (Pogge) (Agonus cataphractus)

The diet of 9 hooknose were examined (Table 3.13 and were found to exclusively contain small epibenthic crustaceans. The hooknose measured were in the size-range 31-118mm total length; they were found in all areas except Rossmore.

% Prey item Occurrence Amphipods 44.4 Crustaceans indet. 33.3 Isopods 22.2 Crangon ? 22.2 Copepods 11.1 Crab 11.1

Table 3.13 % occurrence of prey types in the gut contents of 9 hooknose from the study area

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Cod family

Small numbers of cod family species were caught in trawls and fyke nets their gut contests were as follows (Table 3.14):

Species (size) in mm n Prey items in the gut Cod 2 Copepods (Calanoid), Crangon, (57-220) Crab Pollack 2 Crangon, Mysids, Decapod indet, (77-220) Fish Saithe 1 (60) Crustacean plankton Whiting 1 Crangon, Mysids, Decapod indet, (115) fish

Table 3.14 Prey types in the gut contents of cod family members caught in the study area

Other fish species

The gut contents of one or two specimens of several of the less abundant species were also examined and their diet is listed in Table 3.15.

small polychaetes/oligochaetes, bivalves, foraminifera, copepods, ostracods, Sole (x3) nematodes Dogfish (x 2) crab (soft-back), Crangon, Greater pipefish etc. 15-Spined Stickleback (x1) Amphipods, isopods, small unidentified crustaceans Nilsson's Pipefish (x2) Copepods only Rock Goby (x1) Amphipods, brittle star arms, polychaete residue Grey gurnard (x1) Mysid and other crustacean remains Gut contents poorly preserved but dominated by amphipods and remains of Common goby (several) other small crustaceans Wrasse (x2) Amphipods, Crangon/mysids, small gastropods Spratt Copepods and bivalve or barnacle planktonic stages

Table 3.15 Prey types in the gut contents of several of the remaining fish caught in the study area

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Invertebrates take in Trawls

Crangon (Brown shrimp)

Crangon is an important food item for a range of fishes and in the current study was noted in the gut contents of at least 8 species including, plaice, dab, flounder, cod, whiting, pollack, sand goby and 5- bearded rockling. They area also eaten by common goby and juvenile bass in saltmarsh nursery areas occupied by all three species (Cattrijsse, et al., 1997). One of the features of the species is the wide size range of individuals present in the population (Fig 3.10) which means that as a fish grows it can forage on older larger individuals. However, it is also worth noting that above a certain size Crangon is itself a an important predator of juvenile fish including plaice, dab and sand eel (Oh et al., 2001) and in certain environments can exert an important mortality pressure on newly settling fish (Ansell et al., 1999). The gut contents of just a few larger Crangon were examined as part of this study and the only identifiable items present were all small crustaceans including amphipods, Mysids, and unidentifiable crustacean parts; there was also much amorphous organic residue. In the Seine Estuary, Rybarczyk and Elhaïm (2003) noted that Crangon principally consumed mysids and calanoid copepods, while in Port Eirin Bay, Oh et al, (2001) noted that their principal prey constituents by far in terms of both frequency and biomass were mysids and amphipods. They point out also that other studies have shown that Crangon will also take significant amounts of benthic infauna e.g. Phil & Rosenberg (1984) including polychaetes and bivalves and suggest that this may relate to the nature of the substrate and the availability of prey generally. Finally, Crangon are also cannibalistic when other prey items are in short supply, which is probably an important survival strategy during periods of reduced prey abundance. The Crangon present in Area 3 in June 2012 were distributed across three year-classes (Figure 8), which is a feature of a studied population in Port Erin, Isle of Man also (Oh, et al., 1999).

Crangon Size Distribution - Total Length (Area 3 - June 2012) 140

120

100

60 Numbers

(mm)

Figure 3.10 Size distribution of a full sample of Crangon taken from a trawl in Area 3. Note that the smaller sized individuals are may well be underestimated because not all of them would have been separated from the large amounts of drift seaweed taken in the trawl.

120

Overall, Crangon is likely to be a very important species in the food web dynamics of Cork Harbour due to its high biomass and numbers and its potential links as prey item and predator to most other levels in the food chain.

5Green crab (Carcinus maenas)

Green crab is the other high biomass epibenthic crustacean which occurs throughout Cork Harbour and which was prominent in Areas 1-4 and the control site (Rossmore). Unlike Crangon, green crab were not as widely or frequently noted in the gut contents of fish taken. However, crab (not necessarily all of this species) were noted in the prey of larger individuals of certain fish including cod, dogfish, 5-bearded rockling, plaice and possibly flounder. Crab are vulnerable to predators during molting when their exoskeleton is still soft. In general however, crabs may be more significant as predators within the food chain, than as prey. They have a wide dietary range which varies from area to area, which is considered to relate to the particular availability of prey items in each location. Studies have shown that crabs are a major predator of bivalve molluscs (Ropes, 1968) and they are a big problem in some shellfish aquaculture growing areas for this reason. However, crab also take a wide range of decapods crustaceans including Crangon and other green crab, and also eat errant polychaetes such as Hediste. (Baeta, 2006). Finally, fish have been shown to form a major component of green crabs diet in some areas (Baeta et. al.,2006; Ansell et al., 1999) and algae are also known to occur frequently in small proportions in their diet. Crabs are voracious predators and scavangers and are likely to be a very important component of the Cork Harbour food chain by virtue of the large numbers and biomass of the species recorded during the present survey.

3.5 Implications from Fish and Invertebrate Diet for the Dredging in Lough Mahon

A feature of the diet of many fish in Cork Harbour is the wide range of prey items consumed. In many cases fish will shift their prey intake from area to area and seasonally depending on which prey items are most abundant at the time. This means that there may be a significant degree of buffering within the food web for species so that if a particular prey items is reduced due to natural or anthropogenic causes, that a species can shift their diet to the next most abundant and suitable prey item. In the context of the current study, maintenance dredging is a form of anthropogenic disturbance within the shipping channel which has the potential to temporarily reduce the availability of certain food items especially benthic macrofauna and meiofauna along its course. Immediately, following such disturbance, the process of recolonisation will begin. The sources of this fauna include (i) residual fauna not removed during the dredging process and (ii) mobile epibenthic species such as Crangon and amphipods which live on the margins of the dredged channel and the adjoining subtidal and intertidal banks and can move into the now less densely occupied dredged area. Another very important source is settlement of larvae from the plankton, the magnitude and timing of which will depend on the season, with a spring and early summer settlement expected for many species. Also, drift algae will flush back into the affected channels and provide shelter for some species and a detrital food resource for others. Zooplankton and to a lesser extent mysids are likely to be less impacted by dredging because of their position throughout the water column. Thus species dependent on zooplankton and mysids for example may be largely unaffected by the dredging; Nilsson’s pipefish, spratt, 15-spined stickleback and sand smelt would likely fall into this category as these are less dependent on bottom infauna; Crangon in Cork Harbour may be another. All the gadoids, i.e. cod, whiting, pollack, saithe, and 5-beared rockling, would probably also be less affected given that they feed on fish and or mobile invertebrates which live above the bottom. Species such as juvenile plaice, flounder, dab, black goby, sand goby with a

5 Also known as shore crab 121

greater dependence of benthic infauna and meiofauna in their diet could be potentially more impacted by disturbance caused by dredging. Dab and goby in particular however, have a wide and opportunistic dietary range and might easily shift to other species e.g. mobile epibenthic crustaceans, which would be less impacted by sediment removal/disturbance. Indeed a recent modelling study on sand goby (Freitas et. al., 2011) suggested that sand goby’s growth is not food limited across its distributional range. Juvenile (0+) plaice, 1+ or older flounder and black goby, whose diets in this study contained either a high proportion of small polychaetes (plaice) or larger errant polychaetes (flounder and black goby) are potentially more susceptible. However, the prey species of plaice i.e. small polychaetes (e.g. Spio) have considerable potential for rapid re- colonisation after disturbance, mainly due to settlement from the plankton and so any impact would be expected to be temporary and confined to just one or two seasons (i.e. 3-6 months), depending on the timing of the dredging. In this respect, autumn/ winter dredging may be preferable in order to avoid the main settlement and growth periods of benthic invertebrates, i.e. spring and summer. The larger errant polychaetes, while they too are likely to begin re-colonisation immediately, their recovery would be expected to be longer than for the small opportunistic polychaete species. Full recovery of diversity and structure of benthic infauna may take several years e.g. for peacock worm (Sabella pavonina) beds or sand mason (Lanice conchilega) beds to fully re-establish but in the context of extensive adjoining habitats where these species and others will be largely unaffected, their temporary decline within the dredge channel should be less significant for the ecology of associated species, both fish and invertebrates.

It is important to note that in the case of marine migrants such as plaice and dab which spawn at sea rather than in estuaries, the strength of the new recruitment of 60+ fish in any one year is very unlikely to be affected by such a localised disturbance as channel dredging, even though the growth rate of newly settled individuals could be limited within the dredged channel if the necessary food supplies were severely limited. In the case of flounder, who are also considered marine spawners, their new (0+) recruits settle in the upper estuarine areas beyond the influence of the dredging and are thus be less likely to be affected by food limitation, at least at this early life stage.

3.6 Type of Dredging and Potential Impacts

Water Injection Dredging (WID) was undertaken exclusively in Area 1 and 2 (i.e. from the City Berths to the downstream end of Tivoli dock. Beyond this Trailer Suction Hopper Dredging (TSHD) was undertaken as far as the end of Area 4 just below Marino Point. Accordingly, it is difficult to say anything definite about the respective impacts of either form of dredging from the findings of the present study. Intuitively, because WID doesn’t physically remove dredge material, then in theory at least, there may be some opportunity for smaller benthic fish (gobies, flatfish and hooknose), some infaunal and epibenthic invertebrates to escape significant impact and remain viable for post- dredging re-colonisation. However, the generation of a gravity flow of sediment and associated benthic organisms in a downstream flow may mean that any residual fauna which would avoid displacement would be present in much lower densities. In contrast, the impact of TSHD which physically removes the upper sediment layers and any associated small fish and invertebrates, would be expected to be higher, at least temporarily. Neither of these hypotheses can be properly tested on the basis of the current study findings however.

3.7 Overall Conclusion from Fisheries Surveys

The fisheries surveys undertaken in 2011 and 2012 indicate that the study area within Cork Harbour has a typical estuarine fish community which is dominated by a mixture of more estuarine

60+ fish or young-of-the-year (YOY) fish refers to fish which were spawned are still less than one year old. 122

dependent species and marine species which enter estuaries for either feeding or predator avoidance or both. The surveys also demonstrate the importance of the two mobile epibenthic crustaceans green crab and Crangon (brown shrimp) throughout the study area. Overall, the data is insufficiently intensive to say definitively whether or not the maintenance dredging has had any adverse impact on the fish populations within the survey area. However, the community structure has remained largely the same after the dredging and in this respect the impact of the dredging is not thought to have been significant.

Recommendation: Fisheries

In order to maintain continuity in the data set between triennial dredging campaigns and in order to improve our ability to distinguish between natural background variability and that which may be linked to the dredging, we are suggesting that a June trawl sample be taken in Areas 3 and 4 each year and record be maintained of the species encountered and their relative abundance. In addition we are suggesting that the size-frequency distribution of the Crangon and green crab landed in the trawls are also calculated. These data can then be used to give context to any future before/after surveys of dredging activity.

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4 REFERENCES

Ansell, A.D., Comely C.A., and Robb, L. (1999) Distribution, movements and diet of macrocrustaceans on a Scottish sandy beach with particular reference to predation on juvenile flatfish. Marine Ecology Progress Series 176. 115-130

Baeta, A., Cabral, H.N., Marques, J.C., Pardal, M.A., (2006). Feeding ecology of the green crab, Carcinus maenas (L., 1758) in a temperate estuary, Portugal. Crustaceana 79, 1181-1193.

Beukema, J.J. (1974), Seasonal changes in the biomass of the macro-benthos of a tidal flat area in the Dutch Wadden Sea. Netherlands Journal of Sea Research, 8 (1): 94 – 107.

Blott S.J. and Pye, K. 2001, GRADISTAT, Earth Surf Proc and Landforms 26: 1237-1248

Bonsdorff, E. (1980)’Macrozoobenthic recolonization of a dredged brackish water bay in SW Finland’ Ophelia, 1, 145-155

Cattrijsse, A., Dankwa, H. R. and J. Mees (1997) Nursery function of an estuarine tidal marsh for the brown shrimp Crangon Crangon. Journal of Sea Research 38 109-121

Clarke, K.R. & Gorley, R.N. 2001. PRIMER v5: User Manual/Tutorial. PRIMER-E: Plymouth.

Clarke, K.R., & Warwick, R.M. 2004. Change in marine communities: an approach to statistical analysis and interpretation, 2nd edition. PRIMER-E, Plymouth

Franco, A., Elliott, M., Franzoi, P., Torricelli, P., (2008). Life strategies of fishes in European estuaries: the functional guild approach. Marine Ecology Progress Series 354, 219-228.

Freitas V., Lika, K., Witte J.IJ. van der Veer, H. W. (2011) Food conditions of the sand goby Pomatoschistus minutus in shallow waters: Ananalysis in the context of Dynamic Energy Budget theory. Journal of Sea Research 66, 440-446

Kelly, F (2010) Sampling fish for the Water Framework Directive: Transitional Waters: Greater Cork Harbour. Inland Fisheries Ireland, Dublin.

Newell, R.C., Seiderer, L.J. and Hitchcock, D.R. 1998. The impact of dredging works in coastal waters: A review of the sensitivity to disturbance and subsequent recovery of biological resources on the sea bed. Oceanography and Marine Biology: an Annual Review, 36: 127-178.

Oh, C.-W., Hartnoll, R. G and R. D. M. Nash (1999) Population dynamics of the common shrimp, Crangon Crangon (L.), in Port Erin Bay, Isle of Man, Irish Sea ICES Journal of Marine Science, 56: 718–733.

Oh, C.-W.. Hartnoll, R. G and R. D. M. Nash (2001) Feeding ecology of the common shrimp Crangon crangon in Port Erin Bay, Isle of Man, Irish Sea. Marine Ecology Progress Series 214: 211–223,

Pihl L, Rosenberg R (1984) Food selection and consumption of the shrimp Crangon crangon in some shallow marine areas in western Sweden. Marine Ecology Progress Series 15. 159–168

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Rabaut M. Audfroid Calderón M., Van de Moortel L., van Dalfsen J., Vincx M., Degraer S., and N. Desroy (in press 2012) The role of structuring benthos for juvenile flatfish. Journal of Sea Research

Ropes JW (1968) The feeding habits of the green crab Carcinus maenas (L.). Fish Bull US 67:183-203

Rybarczyk, H. and Elkaïm, B. (2003) An analysis of the trophic network of a macrotidal estuary: the Seine Estuary (Eastern Channel, Normandy, France). Estuarine, Coastal and Shelf Science 58, 775–791

Selleslagh, J.and Amara., R. (2008) Environmental factors structuring fish composition and assemblages in a small macrotidal estuary (eastern English Channel) Estuarine, Coastal and Shelf Science 79, 507–517

Selleslagh, J., Amara, R., Laffargue, P., Lesourd, S., Lepage, M., Girardin, M., (2009). Fish composition and assemblage structure in three Eastern English Channel macrotidal estuaries: a comparison with other French estuaries. Estuarine, Coastal and Shelf Science 81, 149-159.

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Appendix 1 Trawl Results Tables and Maps of Trawl Tracks

126

24/05/2011 25/05/2011 27/05/2011 26/05/2011 Trawls (1.5m beam) May 2011 Trawl 1 Trawl 2 Trawl 3 Trawl 1 Trawl 2 Trawl 3 Trawl 1 Trawl 2 Trawl 3 Trawl 4 Trawl 1 Trawl 2 Seine 1 Seine 2 Seine 3 May 24th-27th 2011 Area 1 Area 1 Area 1 Area 3 Area 3 Area 3 Area 4 Area 4 Area 4 Area 3 Rossmore Rossmore Rossmore Rossmore Rossmore Green Crab (Carcinus maenas) 2g 78g 2g 500g 420g 600g 2100g 700g 6g 6g 304g 540g x9 (small) x23 (small) 1680g Crangon (Brown shrimp) 26g 33g 39g 240g 205g 800g 60g 240 242g 5g 9g ++++ +++ ++ Hermit crab x1 Spider crab (small) + x1 x4 x2 Harbour crab (Liocarcinus) x3 x1 x4 x1 Crab indet (small) x2 Palaemon shrimp 4g 19g 71g ++ Shrimp indet x1 Mysids +++/+ ++ ++ Barnacles (Balanus crenatus) ++ Sea slug (Nudibranch) x1 Sea squirts (Ascidians) 81g ++ + 46g Sea squirt (Styela clava) x1 Bivalve indet. x1 Cuttlefish (Sepiola atlantica) x1 Scale worm (Alentia gelatinos) x1 Hydroids ++ Anenomes ++ ++ x4 x7 Brittlestars 6g x5 ++/+ 34.4g x2 Starfish (Asterias) x2 x4 Featherstars (Antedon) x4 ++/+ Peacock worms (Sabella pavonina) ++ Sponges + 1kg Green sea urchin (Psammechinus) x2 Jellyfish (Aurelia) x1 + + ++++ Butterfish x1 x1 Spratt x1 Common Goby x30+ x 50+ x 100+ Sand Goby x1 x2 x2 x2 x1 Black Goby x10 x8 Rock Goby x1 Plaice x2 x2 x1 x1 x5 Hooknose (Pogge) x1 x1 Wrasse (indet) x1 Red Algae +++ Leaf litter +++ +++ +++ Beverage Cans ++ ++ ++ Table A1 Trawl results for Areas 1, 3, 4 and Rossmore (May 24-27th 2011) Trawl tracks given in Figures A1-A3 below 127

Jun 14th 2011 Jun 15th 2011 Trawls (2m beam) Summer 2011 Trawl 1 Trawl 2 Trawl 1 Trawl 1 Trawl 2 Trawl 1 A4 A4 A3 A4 A4 A3 Green Crab (Carcinus maenas) 110g 120g + 1160g 1300g Fail Crangon (Brown shrimp) 260g 660g + 300g 2350g Edible crab x1 (300g) Harbour crab + Spider crab (small) +/+ Hermit crab x4 Crab indet. +/+ Anenomes spp ++ Brittlestars x20+ ++ ++/+ Starfish (Asterias) + + Feather star (Antedon) + + Sponge + + + Peacock worms (Sabella pavonina) + ++ ++ Sand Mason (Lanice conchilega) + + +/+ +/+ Bryozoans (Nemertisia -like) + Sea slug (Nudibranch) + Green sea urchin + Eel x1 Pipefish (Greater) x1 x1 Butterfish x2 Hooknose (Pogge) x5 x13 Common Goby x1 Sand Goby x3 x24 x17 Black Goby x1 Flounder x1 + x5 Plaice x4 x4 x19 Green seaweed (mainly Ulva) +++ Kelp (mainly L. saccharina) +++ Shell gravel ++ ++ Mud +++ +++

Table A2 2m beam trawl results, Areas 3 & 4, June 14th and 15th 2011 9Trawl tracks in Figure A4 below)

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Figure A1 3 Trawls at City Quays (Area 1) (only position of Trawl 1 shown) May 24th 2011, 3 trawls in Area 3 May 25th 2011. (1.5m beam trawl)

129

Figure A2 May 27th 2011 Area 3 & 4 Trawls (1.5m beam) 130

Figure A3 May 26th 2011 Control Site (Rossmore) Trawl and Beach Seine locations. (1.5m beam trawl) 131

Figure A4 June 14th & 16th 2011 Area 3 and 4 trawl locations. (2m beam trawl – from the Denis Murphy) 132

Trawls (1.5m beam) 2011 Trawl 1 Trawl 2 Trawl 3A Trawl 3B Trawl 5 Trawl 6 Trawl 7 August 25th, 2011 A4 A3 A2 A2 A2 A1 A1 Green Crab (Carcinus maenas) 169g 183g + 49g 250g 300g Crangon (Brown shrimp) 73g 51g 29g 45g 7g 27g + Palaemon shrimp 10g x1 Amphipods ++ Barnacles (B. crenatus) +++ +/+ +++ +++ Anenomes x2 + +++ Brittlestars 212g + + 9g 7g 69g + Starfish (Asterias) 7g 7g 19g 20g + Peacock worms (Sabella pavonina) + + Sand mason (Lanice) + Bryozoans (Alcyonidium sp.) 10g Other Bryozoa + + Mussels (Mytilus) + + Bivalve indet + Hydroids + + Sea squirts (Ascidians) 108g + 32g 880g 830g Sea squirts (Styela clava) x1 + Sponge (2 species) 291g + Dab x2 x1 x1 Spratt x1 Hooknose (Pogge) + Sand Goby x17 x21 x7 Plaice x1 Sole x1 Wrasse (Corkwing) x1 Green seaweed (mainly Ulva) ++ +++ Brown kelp ++ +++ Red Algae ++ Kelp (mainly L. saccharina) ++ +++ ++/+ +++ +++ Mud +++ +++ +++ +++ +++ +++ Bacterial flocc +++ +++ Beverage Cans ++/+ ++/+

Table A3 Trawl results for Areas 1-3 (August 28th, 2011) Trawl tracks given in Figure A5 below

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Figure A5 August 25th 2011 Trawls 1-7 Area 1-4 (1.5m beam trawl)

134

February 28th 2012 March 1st 2012 Trawl 1 Trawl 1 Trawl 2 Trawl 2 Trawl 2 Trawl 3 Trawls (1.5m beam) Feb / Mar 2012 (Rep 1) (Rep 2) (Rep 1) (Rep 2) (Rep 3) (Rep 1) Trawl 3A Trawl 3B Trawl 5 Trawl 6 Trawl 7 Trawl 1 Trawl 2 A4 A4 A4 A4 A3/A4 A3 A2 A2 A2 A1 A1 Rossmore Rossmore Green Crab (Carcinus maenas) 240g 470g 160g 90g 36g x1 520g 1510g Crangon (Brown shrimp) + x5 11g 11g 2g 54g 63g x4 200g 48g Harbour crab (Liocarcinus ) x1 x5 Spider crab (small) x1 x1 Hermit crab x1 x1 Pea crab + Crab indet x1 x3 Palaemon shrimp 11g Anenomes spp. + ++ x6 x10 Brittlestars 6g ++/+ 4g + Starfish (Asterias) 100g Feather star (Antedon) x2 +/+ + + Bryozoans (Nemertisia -like) ++ 4g Sponge 8g 1g Peacock worms (Sabella pavonina) +/+ ++/+ ++ x4 Sea squirts (Ascidians) x1 950g 1810g Coweries (Trivia) x3 Whelks (Buccinum) x4 Sea slug x1 Dab x1 x6 x4 x6 x6 x7 x2 x1? Flounder x1 x2 x1 Plaice x1 x3 x1 Hooknose (Pogge) x1 x4 x1 Sand Goby x2 x8 x1 x4 x1 x1 Black Goby x5 x1 Pipefish (Nilsson's) X2 X1 15-spined stickleback x1 x1 Dragonet x2 x1 x1 Grey Gurnard x1 Green seaweed (mainly Ulva) +++ Kelp (mainly L. saccharina) +/+ ++ ++++ Shell gravel +++ +++ Red Algae ++ +++ Mud +++ +++ +++ +++ Mud with Gravel ++++ ++++ ++++ Table A4 1.5m trawl results for Areas 1-4 and Rossmore. February 28th and March 1st 2012. Trawl tracks in Figures A6-A8 below. 135

Figure A6 Lough Mahon Trawls February 28th 2012 (1.5m beam trawl – from the Port of Cork vessel – ‘Denis Murphy’. 136

Figure A7 Area 1 and Area 2 Trawls – March 1st 2012 137

Figure A8 Rossmore Trawls – March 1st 2012 138

May 29th 2012 May 31st 2012 Trawls (1.5m beam) 2012 Trawl 1 Trawl 3 Trawl 4 Trawl 5 Trawl 6 Trawl 7 Trawl 1 Trawl 2 Trawl 3 Trawl 4 Trawl 1 Trawl 2 Trawl 3 Trawl 4 A1 A1 A2 A2 A2 A2 A2 A2 A2 A2 A3 A3 A3 A3 Green Crab (Carcinus maenas) 100 (g) 110 (g) + + 425 (g) 150 (g) x1 x2 x2 43g 60g 500g 875g Crangon (Brown shrimp) 9.39 (g) 58.94 (g) 30.6 (g) x2 x11 x6 42g x23 200g 280g Barnacles (Balanus crenatus) + + +++ Palaemon + x1 x2 Anenomes + x2 x1 Starfish (Asterias) + x1 Mussel + Dab x2 x3 Flounder x1 x1 x1 Plaice x2 x2 x7 Hooknose (Pogge) x1 x1 Sand goby x2 x2 x1 Spratt x1 Cod 97mm Green seaweed (mainly Ulva) + + + ++ +++ + +++ +++ Kelp (mainly L. saccharina) + + + +++ + +++ +++ Leaf Litter ++ ++ Can & Bottles + +

Table A5 1.5m Trawl results for Areas A1-A3 May 29th and 31st 2012. Trawl tracks given in Figures A9 and A10 below

139

May 30th 2012 June 1st 2012 Trawls (1.5m beam) 2012 Trawl 1 Trawl 2 Trawl 4 Trawl 1 Trawl 2 Trawl 3 Seine 1 Seine 2 A4 A4 A4 Rossmore Rossmore Rossmore Rossmore Rossmore Green Crab (Carcinus maenas) 1550g 550g 300g 1200g 1180g 1400g 200g + Crangon (Brown shrimp) 54g 425g 600g 4.5g x10 Hermit crab x4 x2 Edible crab x1 Spider crab (small) x1 Palaemon shrimp x8 x10 76g x7 x15 Shrimp indet x1 x1 Mysids ++/+ ++ Anenomes +/+ ++ Brittlestars ++ + Starfish (Asterias) x1 Peacock worms (Sabella pavonina)x1 +/+ Sea squirts (Ascidians) 400g + 1000g Colonial sea squirt 1 Sea slug 1 Sponges (3-4 species) + Whelk x1 Butterfish x1 x1 Dab x1 x1 x4 Common Goby ++/+ +/+ Sand Goby x2 x3 Spratt x2 Black Goby x3 x7 Flounder x1 Pipefish (Greater) x1 x1 Plaice x6 x3 x2 x3 Pollack x1 X1 5-bearded Rockling x1 Dragonet x2 x3 Wrasse (Corkwing) x1 Green seaweed (mainly Ulva) + ++/+ +++ Kelp (mainly L. saccharina) ++ ++/+ +++ Red Algae ++ ++ ++ Shell gravel +++ ++ +++

Table A6 1.5m beam trawl results for Area 4 and Rossemore (May 30th and June 1st, 2012) Figures A11 and A12 show the trawl tracks

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Trawls (2m beam trawl) 2012 Trawl 1 Trawl 1 (Rep 3) Trawl 2 Trawl 1 Trawl 2 Trawl 1 Trawl 2 June 18th 2012 A4 A4 A4 A3 A3 A2 A2 Green Crab (Carcinus maenas) 615g 250g 380g 21g 650g 4.16 5.8 Crangon (Brown shrimp) 125g 150g 61g 500g 484 123g Edible crab + Spider crab (small) x3 x2 Palaemon shrimp 175g 10g 21g Gammarid amphipods +++ Mysids +++ Anenomes +/+ ++ Starfish (Asterias) 125g 180g Feather star (Antedon) + +/+ X1 Peacock worms + + +/+ Bryozoans (Nemertisia -like) + Sepiola atlantica 1 Sea slug x1 x1 Sea squirts (Ascidians) + Sponge + Pipefish (Nilsson's) x1 x21 x7 x2 Pipefish (Greater) x1 Dab x1 x3 x1 Flounder 102mm Plaice x3 x16 x7 x1 Sole x1 x2 x2 Hooknose (Pogge) x1 x1 Sand Goby x2 x4 x10 Black Goby Transparent Goby x1 x1 Cod 57mm Pollack x1 Saithe x1 Whiting x1 5-bearded rockling x1 Conger eel larva x1 Thornback ray (Raja clavata) 41.5cm Green seaweed (mainly Ulva) +++ +++ +++ Kelp (mainly L. saccharina) +++ +++ +++ Red Algae +/+ ++ Leaf litter Shell gravel ++ ++ Mud +++ +++

Table A7 2m trawl results for Areas 2, 3 and 4 (June 18th, 2012). Trawl tracks shown in Figure A13 below.

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Figure A9 May 29th 2012 Area 1 & 2 Trawls (1.5m beam trawl)

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Figure A10 May 31st 2012 Area 2 & 3 Trawls (1.5m beam) 143

Figure A11 May 30th 2012 Area 4 Trawls (1.5m beam) 144

Figure A12 June 1st 2012 Control Site (Rossmore) Trawl and Beach Seine locations. 145

Figure A13 June 18th 2012 Area 2, 3 and 4 trawl locations. (2m beam trawl – from the Denis Murphy) Note that ‘blue’ positions are approximate based on the same waypoints as Feb 28th 2012

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Marine Institute Dredge spoil analytical requirements

1.0 Sample location and analyses required:

This sampling plan has been based on the information supplied by Port of Cork in drawing no. FM/11/1a, with regard to a dredging campaign for 2011, and on the results of the last batch of sediment chemistry in 2008. The following surface samples should be taken. Sample locations are shown on the charts in Figures 1 – 3 at the end of this document.

Further sampling and analysis, at depth if necessary, may be required in the event that problem areas of heavy contamination are identified as a result of the initial testing.

Sample Depth Description Parameters for analysis No. 1 Surface Middle of Kennedy Quay - 1m from quay wall 1, 2, 3, 4a, 4b, 4c, 4d, 4e, 4f, 4g

2 Surface Middle of Horgan’s Quay – 3m from quay wall 1, 2, 3, 4a, 4b, 4c, 4e, 4f, 4g

3 Surface Mid channel, north of power station outfall 1, 2, 3, 4a, 4b, 4c, 4e, 4f, 4g

4 Surface Off Quigley’s Quay, Tivoli 1, 2, 3, 4a, 4b, 4c, 4e, 4f, 4g

5 Surface North side of channel, Lough Mahon at R11 1, 2, 3, 4a, 4b, 4c, 4d, 4e, 4f, 4g

6 Surface South side of channel, Lough Mahon at R7 1, 2, 3, 4a, 4b, 4c, 4e, 4f

7 Surface South side of channel, Lough Mahon at R3 1, 2, 3, 4a, 4b, 4c, 4e, 4f

8 Surface Passage West, Haulbowline Industries ~ 2m off berth 1, 2, 3, 4a, 4b, 4c, 4e, 4f, 4g

Overlap of turning circle and shipping channel, 9 Surface 1, 2, 3, 4a, 4b, 4c, 4d, 4e, 4f Ringaskiddy

10 Surface Ringaskiddy Basin 1, 2, 3, 4a, 4b, 4c, 4d, 4e, 4f, 4g

Ringaskiddy Deepwater Berth ~50m from Northwest 11 Surface 1, 2, 3, 4a, 4b, 4c, 4e, 4f end, ~ 3m off ┴ to berth.

Ringaskiddy Deepwater Berth ~50m from Southeast 12 Surface 1, 2, 3, 4a, 4b, 4c, 4d, 4e, 4f, 4g end, ~ 3m off ┴ to berth.

13 Surface Ringaskiddy RoRo berth - middle 1, 2, 3, 4a, 4b, 4c, 4e, 4f

2.0 Parameter Code:

1. Visual inspection, to include colour, texture, odour, presence of animals etc 2. Water content, density (taking into account sample collection and handling) 3. Granulometry including % gravel (> 2mm fraction), % sand (< 2mm fraction) and % mud (< 63μm fraction). 4. The following determinants in the sand-mud (< 2mm) fraction * : a) total organic carbon b) carbonate c) mercury, arsenic, cadmium, copper, lead, zinc, chromium, nickel, lithium, aluminium.

Port of Cork May 2011

Marine Institute Dredge spoil analytical requirements

d) organochlorines including γ-HCH (Lindane), and PCBs (to be reported as the 7 individual CB congeners: 28, 52, 101, 118, 138, 153, 180). e) total extractable hydrocarbons. f) tributyltin (TBT) and dibutyltin (DBT) g) Polycyclic aromatic hydrocarbons (PAH) - Acenaphthene, Acenaphthylene, Anthracene, Benzo (a) anthracene, Benzo (a) pyrene, Benzo (b) fluoranthene, Benzo (ghi) perylene, Benzo (k) fluoranthene, Chrysene, Dibenz (a,h) anthracene, Flourene, Fluoranthene, Indeno 1,2,3 – cd pyrene, Naphthalene, Phenanthrene, Pyrene. h) Toxicity tests (Microtox or whole sediment bioassay) using appropriate representative aquatic species. (This requirement will depend on the results of the chemical analyses.)

*where the gravel fraction (> 2mm) constitutes a significant part of the total sediment, this should be taken into account in the calculation of the concentrations.

3.0 Important notes: 3.1 Details of the methodologies used must be furnished with the results. This should include sampling, sub sampling and analytical methods used for each determinant 3.2 Appropriate marine CRM are to be analysed during each batch of analyses and the results to be reported along with sample results. 3.3 The required detection limits for the various determinants are given below.

Contaminant Concentrati Units (dry on wt) Mercury 0.05 mg kg-1 Arsenic 1.0 mg kg-1 Cadmium 0.1 mg kg-1 Copper 5.0 mg kg-1 Lead 5.0 mg kg-1 Zinc 10 mg kg-1 Chromium 5.0 mg kg-1 Nickel 15 mg kg-1

Total extractable 10.0 mg kg-1 hydrocarbons TBT and DBT (not 0.01 mg kg-1 organotin)

PCB – individual congener 1.0 μg kg-1 OCP – individual 1.0 μg kg-1 compound

PAH – individual 20 μg kg-1 compound

Port of Cork May 2011

Marine Institute Dredge spoil analytical requirements

4.0 Reporting requirements Reports should include the following information 4.1 Date of sampling 4.2 Location of samples eg ING or lat/long. 4.3 Treatment of samples and indication of sub sampling, compositing etc. 4.4 Tabulated geophysical and chemical test results 4.5 Completed excel spreadsheet for results 4.6 Summary method details 4.7 Method performance specifications: Limit of detection, Precision, Bias 4.8 Clear expression of units and indication of wet weight or dry weight basis 4.9 Blanks & in-house references to be run with each sample batch, and reported with sample results. 4.10 Appropriate Certified Reference Materials (CRM) to be run with each sample batch, and reported in full with sample results. 4.11 If determinant is not detected, report less than values, and indicate LoD/ LoQ used. Other quality assurance information (e.g. accreditation status)

Figure 1 – sampling locations City Quays.

Port of Cork May 2011

Marine Institute Dredge spoil analytical requirements

Figure 2 – sampling positions Lough Mahon to Passage West.

Figure 3 – sampling positions Ringaskiddy.

Port of Cork May 2011

Marine Institute Dredge spoil analytical requirements

Sample positions are listed in the table below, in WGS84.

Sample_No Longitude Latitude 1 -8.458790 51.899574 2 -8.458676 51.900487 3 -8.446202 51.902429 4 -8.420778 51.900860 5 -8.397606 51.901165 6 -8.380519 51.892836 7 -8.360465 51.883644 8 -8.332811 51.869230 9 -8.324568 51.838286 10 -8.328379 51.836855 11 -8.330504 51.835474 12 -8.327684 51.833164 13 -8.324971 51.832222

If you need clarification on anything, please don’t hesitate to contact me.

Best regards,

______Margot Cronin Marine Environment Chemist

Port of Cork May 2011

Instructions to Applicants

* Please complete all sheets. * Project ID will be assigned by Marine Institute so that cell can be left blank * Sample position to be entered as lat/long WGS84 in decimal degrees * Please do not alter the format of this spreadsheet by changing units, by moving columns or by inserting new columns amongst the existing used columns. * Please insert any other determinands as necessary, in the empty columns to the right of the existing columns used in results sheet. * Any comments should be inserted in column for comments/notes * A brief description of methodology (eg sample treatment, extraction method, method of detection) should be supplied in methodology sheet. * Measured value as well as certified value to be entered for Certified Reference material in QA sheet * If inhouse reference material is used, please insert measured value with range normally achieved. Project ID year_no. Dredge Quantity m3 Location Survey Company Date of Sampling Analysing Laboratory Sub Contract Lab Date of Analysis Port of Cork Aquatic Services Unit 27/06/2011 NLS (Leeds) 29/06/2011 Sample Position Latitude Position Longitude Number Depth M (decimal degrees) (decimal degrees) Visual appearance life signs eg worms? % Moisture % >2mm % <2mm >63um % <63um % TOC 1 10.4 51.89913 -8.45780 Black mud 72 3.9 46.3 49.8 6.2 2 12.1 51.90018 -8.45807 Black mud 75 0.0 49.3 50.7 5.7 3 9.2 51.90192 -8.44579 Grey/black mud 72 2.3 46.3 51.4 5.3 4 3.1 51.90078 -8.42049 Grey/black mud 68 0.0 33.9 66.1 4.6 5 7.1 5m east of buot R 11 62 0.0 39.8 60.2 4.1 6 9.6 51.89298 -8.37919 52 0.0 44.3 55.7 3.6 7 8.8 51.88354 -8.35958 Muddy sand 38 0.0 73.8 26.2 3.5 8 9.8 51.86824 -8.33180 58 0.0 42.0 58.0 4.2 9 14.8 51.83800 -8.32380 41 3.9 61.0 35.1 3.9 10 13.7 51.83651 -8.32724 57 0.0 31.0 69.0 4.2 11 13 51.87470 -8.32942 59 0.5 56.9 42.6 4.18 12 13.1 51.83261 -8.32664 63 0.0 40.1 59.9 4.39 13 11.7 51.83180 -8.32414 Black mud 53 0.0 15.9 84.1 3.9 Wet wt / dry METAL Li METAL Al METAL Cd METAL Hg mg METAL As mg METAL Cr mg METAL Cu mg METAL Pb METAL Ni mg METAL Zn mg ΣPAH9 ug wt? mg kg-1 mg kg-1 mg kg-1 kg-1 kg-1 kg-1 kg-1 mg kg-1 kg-1 kg-1 TEH g kg-1 kg-1 DW 37.0 40900 0.853 0.208 8.34 224 111 67.1 135 212 0.53 DW 37.3 44000 0.751 0.255 8.99 154 89.2 78.5 89.5 214 0.48 DW 42.7 44000 0.507 0.147 13.2 143 63.9 51 79.1 170 0.38 DW 43.8 48200 1.32 0.084 12 119 64.5 71.9 61.2 547 0.27 DW 41.0 45800 0.279 0.071 8.43 96.2 44.2 35.2 51.8 115 0.14 DW 38.4 43400 0.227 0.069 7.09 81.8 87.5 31.7 38.7 101 0.07 DW 38.0 43200 0.229 0.067 6.95 64 38.1 30.5 27.9 99.9 0.03 DW 44.2 46900 0.374 0.114 10.5 100 97.4 48 50.8 149 0.10 DW 41.1 44200 0.226 0.08 7.7 103 37.4 33.1 52.9 102 0.02 DW 41.9 45100 0.206 0.065 7.61 80.9 43.1 31.4 38.4 93.6 0.08 DW 40.4 44400 0.254 0.068 5.25 79.5 69.8 43.4 34.9 130 0.11 DW 45.7 50000 0.29 0.083 12 115 39.2 41.2 59.2 121 0.09 DW 47.6 52400 0.316 0.108 12.1 96.4 53.7 47.4 46.6 127 0.06 Total PAH ug kg- PCB Σ 7 PCB ug 1 PCB 028 ug kg-1 PCB 052 ug kg-1 PCB 101 ug kg-1 PCB 118 ug kg-1 PCB 138 ug kg-1 PCB 153 ug kg-1 PCB 180 ug kg-1 kg-1 Total CB 3690 0.44 0.32 0.6 0.6 0.76 0.56 0.28 3.56 <4500 0 3790 0 <1820 0 1210 0.28 <0.1 0.28 0.32 0.32 0.28 <0.1 <1.68 0 0 0 0 2060 0 0 <0.1 0.16 0.16 0.16 0.16 0.2 <0.1 <1.04 <802 0.28 0.24 0.28 0.24 0.32 0.28 <0.1 <1.74 0 0 1040 0.32 0.28 0.28 0.4 0.36 0.32 <0.1 <2.06 0 0 PAH PAH PAH PAH Benzo a PAH Benzo PAH Benzo b OCP HCB ug kg- OCP HCH Total DDT ug OT TBT mg OT DBT mg Acenaphthen Acenaphthylen Anthracene anthracene ug (a) pyrene fluoranthene 1 Gamma ug kg-1 kg-1 kg-1 kg-1 Notes e ug kg-1 e ug kg-1 ug kg-1 kg-1 ug kg-1 ug kg-1 0.04 <0.01 60.1 53 110 300 332 332 0.09 0.0458 73.1 <30 149 373 392 408 0.01 <0.009 22.2 19 85.1 383 447 432 0.02 <0.006 14.4 13.1 41.8 172 212 245 0.01 <0.005 9.32 7.76 28.5 109 141 184 <0.003 <0.004 0.007 <0.003 0.02 <0.006 10.4 22 68.1 214 256 280 0.007 <0.003 0.006 <0.004 9.63 9.5 22.4 65.5 73.6 117 0.01 <0.006 0.01 0.0191 11.5 10.5 25.2 86.4 102 156 0.008 <0.004 PAH Benzo PAH Benzo k PAH PAH Dibenz PAH PAH Indeno PAH ghi perylene fluoranthene Chrysene a,h anthracene PAH Flourene ug kg- Fluoranthene 1,2,3 – cd PAH Naphthalene ug Phenanthre PAH Pyrene ug PAH Σ 13 ug ug kg-1 ug kg-1 ug kg-1 ug kg-1 1 ug kg-1 pyrene ug kg-1 kg-1 ne ug kg-1 kg-1 kg-1 159 107 331 34 110 600 137 187 462 515 171 117 409 38.9 179 696 158 <200 610 656 171 137 361 37.9 45 698 179 101 246 608 95 72.7 172 21.7 31.1 273 93.2 <50 134 272 64.9 52 115 16.6 19.7 174 69.7 46.9 84.5 158

91 90 218 27.1 31.1 276 105 79.4 116 280

38.8 33.1 66.6 9.93 27.1 108 46.8 <50 84.5 86.8

53.9 42.8 92.4 13.7 26.4 149 61.9 47 103 124 Density (g/ml) Carbonate % Notes / comments: 1.23 7.3 1.2 5.6 1.29 8.2 1.26 9.2 This samples was taken on inner side of Jetty 1.37 11.9 1.56 11.6 South side of R7 1.68 11.6 20m south of R3 1.36 12.2 35m south of intended position just astern of moured vessel , 3m from quay 1.68 14.0 1.41 13.4 1.37 12.6 45m south of intended position, just astern of moored vessel 1.34 14.2 1.43 11.7 30m off this position on outer (northern) side of moored Swansea Cork ferry (Julia) Reference Type Reference Material % OC TEH g kg-1 METAL Cu mg kg-1 METAL Zn mg kg-1 METAL Cd mg kg-1 Certified reference material (meas) MESS-3 36.1 155 0.238 Certified reference material (certified value) MESS-3 33.9 [1.6] 159 [8] 0.24 [.01] Blank Certified reference material (meas) HIPA-1 Certified reference material (certified value) HIPA-1

Certified reference material (meas) IAEA-159 Certified reference material (certified value) IAEA-159 METAL Hg mg kg-1 METAL Pb mg kg-1 METAL As mg kg-1 METAL Cr mg kg-1 METAL Mn mg kg-1 METAL Ni mg kg-1 METAL Li mg kg-1 METAL Al mg kg-1 0.0855 21.3 20.6 90.4 42.8 65.9 68200 0.091 [.009] 21.1 [.7] 21.2 [1.1] 105 [4] 46.9 [2.2] 73.6 [5.2] 85900 [2300] PAH ΟΤ Σ TBT + PCB 028 PCB 052 ug PCB 101 ug PCB 138 ug PCB 153 ug PCB 180 ug PCB 118 ug Σ 7 PCB ug Acenaphthene OT DBT mg kg-1 OT TBT mg kg-1 DBT mg kg-1 ug kg-1 kg-1 kg-1 kg-1 kg-1 kg-1 kg-1 kg-1 ug kg-1

0.15 0.085 [.0091]

0.4 0.48 0.48 0.48 0.56 0.4 0.48 6.1 0.57 [.28] 0.67 [.25] 0.52 [.16] 0.60 [.31] 0.56 [.09] 0.26 [.1] 0.51 [.21] 6 [4] PAH PAH Acenaphthylene ug Anthracene PAH Benzo (a) PAH Benzo (a) pyrene PAH Benzo (b) PAH Benzo (ghi) PAH Benzo (k) PAH Chrysene kg-1 ug kg-1 anthracene ug kg-1 ug kg-1 fluoranthene ug kg-1 perylene ug kg-1 fluoranthene ug kg-1 ug kg-1

6.26 17.2 73.5 87 150 72.4 44.1 79.9 6.4 [5.4] 11 [5.1] 54 [20] 58 [26] 100 [42] 95 [45] 49 [14] 58 [26] PAH PAH PAH PAH PAH PAH Dibenz (a,h) Flourene ug Fluoranthene PAH Indeno (1,2,3 – Naphthalene ug Phenanthrene Pyrene ug PAH Σ 13 PAH OCP HCH Gamma OCP HCB Notes / anthracene ug kg-1 kg-1 ug kg-1 cd) pyrene ug kg-1 kg-1 ug kg-1 kg-1 ug kg-1 ug kg-1 ug kg-1 comments:

15.6 13.8 118 76.8 41.3 89.3 103 <2 25 [14] 13 [7.7] 110 [32] 120 [34] 23 [13] 59 [29] 100 [38] 0.21 [.18] Fraction Granulometry Methods of detection (metals & Organics extraction Project id analysed method OC method Metals extraction type mercury/arsenic) types Methods of detection (PCBs / PAHs / TBT / DBT) combusted, determined by TCD, Organic C - Dry sieved after acid pretreated to organics removal with remove inorganic <63µm Hydrogen Peroxide carbon Metals general (HF) ICPMS PCB - solvent extraction PCB - GCMS (SIM) Mercury (Aqua Regia and microwave) acidic SnCl2 reduced CV-AFS OCP - solvent extraction OCP - GCMS (SIM) PAH - solvent extraction PAH - GCMS (EI) Key Value Project ID year_no. ID to be filled in by MI Dredge Quantity m3 Amount of material proposed for dredging, including contingencies Location Area eg Cork Harbour / Dublin Bay Sampler / Contractor Company employed to take samples etc CRM Certified reference materials used in analyses for metals, organics & TBT Fraction analysed Which fraction of sediment was analysed? < 2mm is requested, but some labs use < 63um. Wet wt / dry wt? Were analyses carried out on wet or dry sediment? Analysing Laboratory Main laboratory where samples are sent to for analysis Sub Contract Lab Sub-contracted laboratory where samples are sent by Main Laboratory Sample Number Sample number assigned by sampler Depth M Depth at which sample was taken Position Latitude (decimal degrees) Position where sample was taken. To be reported in decimal degrees, WGS84 Position Longitude (decimal degrees) Position where sample was taken. To be reported in decimal degrees, WGS84 Visual appearance - colour, texture, signs of life?

% Moisture Water content of sample, reported as % (H 2O) % >2mm Grain size or granulometry % > 2mm % <2mm >63um Grain size or granulometry % > 63mm < 2mm % <63um Grain size or granulometry % < 63mm % TOC Total Organic Carbon (NOT organic matter) METAL Li mg kg-1 Lithium METAL Al mg kg-1 Aluminium METAL Cd mg kg-1 Cadmium METAL Hg mg kg-1 Mercury METAL As mg kg-1 Arsenic METAL Cr mg kg-1 Chromium METAL Cu mg kg-1 Copper METAL Pb mg kg-1 Lead METAL Ni mg kg-1 Nickel METAL Zn mg kg-1 Zinc TEH g kg-1 Total extractable hydrocarbons ΣPAH9 ug kg-1 Sum of 9 PAH (polycyclic aromatic hydrocarbons) Total PAH ug kg-1 Total all PAH PCB 028 ug kg-1 PCB 028 ug kg-1 PCB 052 ug kg-1 PCB 052 ug kg-1 PCB 101 ug kg-1 PCB 101 ug kg-1 PCB 118 ug kg-1 PCB 118 ug kg-1 PCB 138 ug kg-1 PCB 138 ug kg-1 PCB 153 ug kg-1 PCB 153 ug kg-1 PCB 180 ug kg-1 PCB 180 ug kg-1

PCB Σ 7 PCB ug kg-1 Sum of the 7 ICES PCB (polychlorinated biphenyls) previously listed OCP HCB ug kg-1 Hexachlorobenzene OCP HCH χ ug kg-1 1α,2α,3β,4α,5α,6β-hexachlorocyclohexane (Lindane) Total DDT ug kg-1 Sum of DDT compounds OT TBT mg kg-1 Tributyl tin OT DBT mg kg-1 Dibutyl tin Notes Any comments / irregularities / justifications to be inserted here PAH Acenaphthene ug kg-1 PAH Acenaphthene ug kg-1 PAH Acenaphthylene ug kg-1 PAH Acenaphthylene ug kg-1 PAH Anthracene ug kg-1 PAH Anthracene ug kg-1 PAH Benzo a anthracene ug kg-1 PAH Benzo a anthracene ug kg-1 PAH Benzo (a) pyrene ug kg-1 PAH Benzo (a) pyrene ug kg-1 PAH Benzo b fluoranthene ug kg-1 PAH Benzo b fluoranthene ug kg-1 PAH Benzo ghi perylene ug kg-1 PAH Benzo ghi perylene ug kg-1 PAH Benzo k fluoranthene ug kg-1 PAH Benzo k fluoranthene ug kg-1 PAH Chrysene ug kg-1 PAH Chrysene ug kg-1 PAH Dibenz a,h anthracene ug kg-1 PAH Dibenz a,h anthracene ug kg-1 PAH Flourene ug kg-1 PAH Flourene ug kg-1 PAH Fluoranthene ug kg-1 PAH Fluoranthene ug kg-1 PAH Indeno 1,2,3 – cd pyrene ug kg-1 PAH Indeno 1,2,3 – cd pyrene ug kg-1 PAH Naphthalene ug kg-1 PAH Naphthalene ug kg-1 PAH Phenanthrene ug kg-1 PAH Phenanthrene ug kg-1 PAH Pyrene ug kg-1 PAH Pyrene ug kg-1

-1 PAH Σ 13 ug kg Sum of 13 polycyclic aromatic hydrocarbons