Report of the Working Group on Ecosystem Assessment of Western European Shelf Seas (WGEAWESS)

ICES WGEAWESS REPORT 2011

SCICOM STEERING GROUP ON REGIONAL SEA PROGRAMMES

ICES CM 2011/SSGRSP:05

REF. SCICOM

Report of the Working Group on Ecosystem Assessment of Western European Shelf Seas (WGEAWESS)

3–6 May 2011 Nantes, France

International Council for the Exploration of the Sea Conseil International pour l’Exploration de la Mer

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ICES. 2011. Report of the Working Group on Ecosystem Assessment of Western European Shelf Seas (WGEAWESS), 3–6 May 2011, Nantes, France. ICES CM 2011/SSGRSP:05. 175 pp.

For permission to reproduce material from this publication, please apply to the Gen- eral Secretary.

The document is a report of an Expert Group under the auspices of the International Council for the Exploration of the Sea and does not necessarily represent the views of the Council.

ICES WGEAWESS REPORT 2011 | i

Contents

Executive summary ...... 1

1 Opening of the meeting ...... 2

2 WGEAWESS Terms of Reference 2011 ...... 2

3 Adoption of agenda ...... 2

4 Introduction ...... 2 4.1 General context ...... 2 4.2 Definition of the region covered by WGEAWESS ...... 3 4.3 WGEAWESS specificities ...... 4 4.4 About integrated Ecosystem Assessments ...... 7 4.5 Linkage with others ICES groups, review and sources of information ...... 9 4.6 Participant to the WGEAWESS group and/or the report ...... 9

5 Components relevance as compared to “some” Management Objectives / IEA / MSFD / ...... 11

6 WGEAWESS Ecosystem(s) description ...... 12 6.1 Natural Components ...... 12 6.2 Main Anthropogenic pressures ...... 14

7 Ecosystem description by subregion ...... 14 7.1 Gulf of Cadiz (GC, Region A) ...... 14 7.1.1 Definition/validation of subregions frontiers (Frontier A/B) ...... 14 7.1.2 Geography and Climate ...... 14 7.1.3 Bathymetry and substrates ...... 18 7.1.4 Hydrography and circulation ...... 21 7.1.5 Biological ecosystem components ...... 22 7.1.6 References ...... 35 7.1.7 Anthropogenic relative data: pressures and economics ...... 50 7.2 Process and models ...... 51 7.3 South Western Iberia (SWI, Region B) ...... 51 7.3.1 Subregion boundaries ...... 51 7.3.2 Geology ...... 51 7.3.3 Circulation ...... 53 7.3.4 Zooplankton ...... 54 7.3.5 Fish community...... 55 7.3.6 References ...... 57 7.4 North Western Iberia (NWI, Region C) ...... 63 7.4.1 Geography, bottom topography and climate ...... 63 7.4.2 Hydrography and circulation ...... 64 7.4.3 Biological ecosystem components ...... 65

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7.4.4 References ...... 71 7.5 South Bay of Biscay (SBoB, Region D) ...... 79 7.5.1 Geography and climate ...... 79 7.5.2 Hydrography and circulation ...... 79 7.5.3 Biological Ecosystem components ...... 80 7.5.4 References ...... 87 7.6 Inner Bay of Biscay (IBoB, Region E) ...... 103 7.6.1 Geography and climate ...... 103 7.6.2 Hydrography and circulation ...... 105 7.6.3 Ecosystem components ...... 108 7.6.4 References ...... 115 7.7 Western Bay of Biscay (WBoB, Region F) ...... 120 7.7.1 Geography and bottom topography ...... 120 7.7.2 Hydrography, circulation and climate ...... 121 7.7.3 Biological Ecosystem components ...... 124 7.8 Celtic Sea (CS, Region G) ...... 138 7.8.1 Celtic Sea boundaries ...... 138 7.8.2 Geography and climate ...... 138 7.8.3 Bathymetry ...... 139 7.8.4 Substrates ...... 140 7.8.5 Climate ...... 140 7.8.6 Hydrography and circulation ...... 141 7.8.7 Biological Ecosystem components ...... 145 7.8.8 Pressures on the ecosystem ...... 162 7.8.9 References ...... 163 7.9 English Channel (EC, Region H) ...... 165 7.9.1 The English Channel ecosystem ...... 165 7.9.2 Bathymetry ...... 166 7.9.3 Bedrock geology ...... 166 7.9.4 Sedimentology ...... 166 7.9.5 Hydrography ...... 167 7.9.6 Habitats ...... 167 7.9.7 Biological Ecosystem Components ...... 168

8 Recommendations to WGEAWESS ...... 171

Annex 1: List of participants ...... 172

Annex 2: WGEAWESS resolution for the next meeting ...... 174

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Executive summary

This first meeting of WGEAWESS was planned to initiate the first stages of the development of an integrated ecosystem assessment (IEA) of the Western European Shelf Seas. To take onboard the approaches being followed the group reviewed the reports of other existing SSGRSP regional groups: Working Group ICES/HELCOM Working Group on Integrated Assessmentss of the Baltic Sea (WGIAB), Working Group on Integrated Assessments of the North Sea (WGINOSE) and the Working Group on the Northwest Atlantic Regional Sea (WGNARS). From this review it was understood that the first stages are to describe: a ) The marine ecosystem components from the physical environment and trophic levels including marine mammals and seabirds; b ) The antropogenic effects as integrated approach includes human populations in the ecosystem: fisheries, energy, shipping, coastal development. To address ToR a) Carry out review and metadata compilation about relevant ecosystem components and process at the regional scale and carry out preliminary evaluation of data and trends - the WG developed a table for data availability on ecosystem components from physics to apex species and antropogenic effects. To develop this table a review of MSFD pressures, descriptors and indicators was done addressing ToR c). The Regional Ecosystem of Western of Western European shelf Seas was geographically defined and divided in subregions according to the expertise of the group. Each subregion description was supported by the metadata table indi- cating the available data for further integration. The sub-divisions are intended to help on subsequent multi-scale data integration and will be revised according to further reviews.

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1 Opening of the meeting

The meeting was opened on 3 May 2011. The Co-Chair, Pascal Laffargue (PL), wel- comed the participants (Annex 1) and presented the Terms of Reference for the meeting.

2 WGEAWESS Terms of Reference 2011

The meeting has been given the following terms of References: The Working Group on Ecosystem Assessment of Western European Shelf Seas (WGEAWESS), chaired by Pascal Laffargue*, France; Dave Reid*, Ireland; Maria de Fátima Borges*, Portugal; and Enrique Nogueira*, Spain, will be established and will meet at Ifremer, Nantes, France, 3–6 May 2011 to: a ) Carry out data review and metadata compilation about relevant ecosystem components and process at the regional scale and carry out preliminary evaluation of data and trends; b ) Review Integrated Ecosystem Assessment methodology availability and relevance and propose appropriate IEA approaches for regional assessment: multi scales data integration, biology/physics interactions and modelling, ecosystem status indicators; c ) Based on MSFD pressures/descriptions/indicators combinations evaluate feasibility and relevance of each of these combinations. WGEAWESS will report (via SSGRSP) by 15 August 2011 for the attention of SCI- COM.

3 Adoption of agenda

PL introduced the agenda which was shortly discussed, adjusted and finally adopted by the participants.

4 Introduction

This first meeting of WGNARS was planned to initiate the development of an integrated ecosystem assessment (IEA) of the of Western European Shelf Seas covering the region from the Celtic Sea to the Gulf of Cadiz, under the strategic initiative of SCICOM Steering Group on Regional Sea Programmes (SSGRSP).

4.1 General context The group reviewed the reports of the others existing SSGRSP regional groups: Working Group ICES/HELCOM Working Group on Integrated Assessments of the Baltic Sea (WGIAB), Working Group on Integrated Assessments of the North Sea (WGINOSE) and the Working Group on the Northwest Atlantic Regional Sea (WGNARS). Dave Reid (DR) summarized ICES WGECO recent work in the context of Integrated Ecosystem Assessments (IEA). MFB reviewed the information of the 2008 and last report of the Working Group of Regional Ecosystem Description (WGRED) relatively to the regions of Bay of Biscay and Iberian Seas and well as 2007 report of the ICES/GLOBEC Workshop on Long-Term Variability in SW Europe (WKLTVSWE) covering the Iberian Regions.

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Regional assessment groups under ICES organization, ICES working groups and regional/ecosystem assessment process.

Integrated Ecosystem Assessment DATA / Observation Networks WG RED Working in SSGRSP Group for Regional (SCICOM SG on Regional Seas) IBI‐ROOS Ecosystem Description (Iberian Biscay Irish maritime area Regional Operational Oceanographic System) WG EAWESS WG IAB ICES‐GOOS (Global Ocean Observing System): Steering WG NARS (Integrated Assessments Group and Transition Group for the (Northwest Atlantic of the Baltic Sea) development of ecosystem surveys Regional Sea) SSGESST (SCICOM SG Ecosystem Surveys WG HAME Science and Technology) (Holistic Assessments of WG INOSE SSGSUE Regional Marine Ecosystems) (Integrated WG ISUR (SCICOM SG Sustainable REGNS Assessments of the (Working Group on Use of Ecosystems) North Sea) Integrating Surveys for (Regional Ecosystem Study the Ecosystem Approach WG OOFE Group for the North Sea) (Operational oceanographic products for fisheries and WK BEMIA environment) Workshop on benchmarking ACOM Integrated Ecosystem Assessments (Advisory Committee) (ICES headquarter November 2011) “Group“ MSFD WG ECO (SCICOM SG Ecosystem Surveys Science WG on Ecosystem Effects and Technology) of Fishing Activities ICES Task Group 6 (Development of ‘criteria and methodological standards for the GES descriptors’)

Figure 1. Regional assessment groups under ICES organization, ICES working groups and regional/ecosystem assessment process.

4.2 Definition of the region covered by WGEAWESS The group discussed the boundaries of the region and defined subregions to better address processes at the appropriate scale to evaluate data and trends. Figure 2 illus- trates the region and defined subregions. WGEAWESS geographic area of interest covers Atlantic shelf coast including the Ibe- rian shelf, bay of Biscay and Celtic sea (Figure 2): • Ecoregion: E (Celtic Seas) and G (south European Atlantic shelf) • Ospar zone: III (south part) and IV (shelf part) • ICES zone: IXa; VIIIa, b, c; VIIe, f, g, h, j2 WGEAWESS group will focus on continental shelves ecosystems at that regional scale. To organize work to be done in the whole geographic area covered by WGEAWESS, we divided the region in 8 subregions (Figure 2). Subregions frontiers are validated through natural components distribution (Physicals/Hydrological/habitat structures/communities), administrative frontiers (sub areas as compared to WFD and MSFD regions) and, at last but not the least, dataset homogeneity.

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H G

D E

B A I II

Figure 2. Region covered by WGEAWESS (I) and the 8 subregions (II), from south to North, Gulf of Cadiz (A), Western Iberia South (B), Western Iberia North (C), south BoB (D), Inner BoB (E), Western BoB (F), Celtic Sea (G), English Channel (H).

4.3 WGEAWESS specificities WGEAWESS encompasses some specificities as compared to the others regions covered in ICES regional working groups on ecosystem assessment. That large geographic area offers significant latitudinal gradients and possibility to underline communities modifications occurring at large spatial scale (e.g. modifications in copepods community linked to large climatic changes, Figure 5). Large latitudinal extension of the region makes it sensitive to large climatic changes as shown in the Figure 5. It shows a mosaic of habitats from shallow coast to deep margin open to ocean and offers a variety of essential habitats for various species: nursery or spawning grounds, migratory pathways (e.g. mammals, bluefin tuna …). Region scale relevance is enhanced by potential fish distribution over their entire life cycle within the whole WESS area. Among them, we can found some of the main commercial European demersal fish species (e.g. hake, megrims, monkfishes or sole) and as well as pelagic ones (sardine, anchovy, blue whiting) . Western waters region show a relatively high level of diversity of species as compared to European seas (e.g. more than 576 fish species, high fish species richness explained by the co-occurrence of sub-tropical, temperate and boreal species).

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Figure 3. Distribution of Hake (Merluccius merluccius) as derived from ground fish survey data (Ifremer/SIH, 2009).

Many sensitive/vulnerable benthic habitats occur in the region (e.g. biogenic habitats such coral reefs, or specific assemblages like burrowers & seapens of the bay of Bis- cay ‘grande vasière’ area). VME's like CWC habitats are widespread all over the region covered by WGEAWESS (Figure 4).

Figure 4. CWC (Lophelia pertusa/Madrepora oculata) occurrence records adapted from Reveillaud 2008 and OSPAR database).

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Figure 5. Biogeographical changes in four plankton assemblages (calanoid copepod communities) based on three periods (adapted from {Beaugrand, 2005 #2527}).

Economic status • Region includes major European fisheries, N% of landings in European marine ecosystems coming from "Western Waters" region (Figure 6) that induce high fishing pressures. • Maritime transportation (e.g. 70% of the total oil consumed in the EU is transported through the English Channel and the WESS region).

Figure 6. Landings of main commercial species in European Large Marine Ecosystem.

From coast to margin : WGEAWESS region ecosystems are under heavy anthropogenic pressure (e.g. synthesis for the bay of Biscay in Lorance et al. 2009)

. Continental shelf under major fisheries impacts

o Biological effects from biomass extraction

o Physical effects from bottom trawling impact

. Marine transport (e.g. oil spill) . Waste dumping and increasing mineral resources extraction

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. Coastal physical and chemical modifications and pollution due to industry, urbanization …

4.4 About integrated Ecosystem Assessments - Ecosystem Assessment (EA) : An assessment that includes at least two trophic levels and often more than two species may be aggregated, and there are usually, but not necessarily more than one species/aggregate, in at least some trophic levels. Assessments that are called “ecosystem assessments” may or may not include abiotic influences on some or all of the biotic components being assessed. It is important to always differentiate whether an ecosystem assessment being reviewed or reported did or did not include abiotic forcing (WGECO, 2007/2010)

- Integrated Ecosystem Assessment (IEA) : Formal synthesis and quantitative analysis of information on relevant natural and socioeconomic factors, in relation to specified ecosystem management objectives (Levin et al. 2009). An integrated ecosystem assessment has all major trophic levels represented and linked, although the level of aggregation of species at each level can be high or low, and may differ among levels. Integrated Ecosystem Assessments must have major abiotic forcers included dynamically. The hydrographic model may be part of the analytical tool used for the integrated ecosystem assessment, or may be run separately from the biological one, and provide drivers for a dynamic biological model. In addition to State attributes of ecosystems, Integrated Ecosystem Assessments should either estimate directly or produce outputs adequate to estimate the status and trends of the dominant Pressures and Impacts as well (WGECO, 2007/2010)

In accordance with guidance from the UN Assessment of Assessments report (UNEP and IOC-UNESCO 2009) and the Working Group on the Ecosystem Effects of Fishing Activities (WGECO; ICES 2009b) is that successful IEA requires an initial decision on the extent of integration: 1 ) The marine ecosystem: the physical environment and trophic levels. Some forms of IEA integrate physics to fish. Others include seabirds and marine mammals. 2 ) Anthropogenic effects: a more integrated approach includes human populations in the ecosystem, including all human sectors (e.g., fisheries, energy, shipping, coastal development). The degree of integration of advice can be either sector by sector or integrated among sectors. 3 ) Socioeconomic aspects: the most integrated form includes costs, benefits and societal objectives. The form of integration should guide the choice of indicators or factors to consider for IEA. The WG decided that each Subregion Atlantic ecosystem will be considered, from the physical environment to apex predators. Following WGNARS approach (ICES, 2010), advice to manage human activities will be considered separately by sector (because governance structures are not currently in place to provide integrated advice), and socioeconomic aspects will be incorporated to promote the definition of ecosystem objectives.

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To address the ToR a) the WG developed a table of ecosystem components, from physics to apex species. This table is based on MSFD pressures/descriptions/indicators addressing ToR c). When describing each subregion ecosystem and filling the table ToR b) is intended to be addressed.

Figure 7. EA and EBM processes in Levin PS, Fogarty MJ, Murawski SA, Fluharty D (2009) Inte- grated Ecosystem Assessments: Developing the Scientific Basis for Ecosystem-Based Manage- ment of the Ocean. PLoS Biol 7:e1000014

The Five-Step Process of Integrated Ecosystem Assessment (IEA, e.g. from Levin et al. 2009, Figure 7): 1 ) Scoping process to identify key management objectives and constraints 2 ) Identification of appropriate indicators and management thresholds 3 ) Determination of the risk that indicators will fall below management tar- gets 4 ) Combination of risk assessments of individuals indicators into a determination of overall ecosystem status 5 ) Evaluation of the potential of different management strategies to alter ecosystem status That framework has to be done in a repetitive and adaptive process with implementation of management actions and monitoring of their effectiveness.

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PRELIMINARY STEPS FOR WGEAWESS: 1 Scoping process to identify key management objectives and constraints. 2 Identification of appropriate indicators and management thresholds

MAIN GOAL FOR WGEAWESS first meeting and report:

• To establish geographic context and validate WGEAWESS extension in an ecosystem assessment framework; • Conduct extensive reviews on ecosystems structures, functions, monitoring (data availability) and modelling activities for the WESS area; • To establish hotpoints of ecosystem assessment at a regional point of view (ecosystems structures, functions and variability, biodiversity, main natural components, main natural drivers, main anthropogenic threats, ...).

4.5 Linkage with others ICES groups, review and sources of information

4.6 Participant to the WGEAWESS group and/or the report

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Maria de Fátima Borges Portugal IPIMAR Western Iberia / X X [email protected] Fish Stock assessment, ground fish surveys … eco model Maria Manuel Angélico Portugal IPIMAR Western Iberia X [email protected] Miriam Guerra Portugal IPIMAR X [email protected] Diego Macías Spain CSIC Gulf of Cádiz / Xp X [email protected] biophys coupling IBM Eider Andonegui Spain AZTI inner part of Xp X [email protected] the Bay of Biscay /Assessment model, Multi/single species Enrique Nogueira Spain IEO Galicia and Xp X [email protected] Cantabrian Sea Javier Ruíz Spain CSIC Gulf of Cádiz Xp X [email protected] Marcos Llope Spain IEO Gulf of Cádiz X X [email protected] Maria Begoña Santos Spain IEO X [email protected] Miguel Bernal Spain IEO X [email protected] Rafael González-Quirós Spain IEO Xp X [email protected] Sven Kupschus UK CEFAS English Xp X [email protected] Channel

[email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], Pi- [email protected], [email protected]

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5 Components relevance as compared to “some” Management Objectives / IEA / MSFD /

Verena Trenkel and Pascal Lorance

Table 1. Refer to a Management Objectives / Indicators / Ecosystems components linkages

Qualitative descriptor Introduced Commercial Food Eutrophi- Sea Hydro- Contam - Sea food Ecosystem component Biodiversity species species web cation floor graphy inants Litter Disturbance Environmental features Substrate D D Estuarine & coastal habitats D D D D  River runoff D Water circulation D Upwelling and stratification D Physical parameters D Detritus, bacteria & micro-organisms  D D  D D D Primary producers Macrophytes  D  D D Phytoplankton  D  D   Zooplankton     Benthos Offshore benthos D   D  Coastal benthos D D  D D  D Fragile benthos D   Vertebrates Fish community D D D  Fish species D D    Marine mammals D    Birds D   D  Turtles D  D  Number of components relevant to the descriptor 12 7 1 12 6 7 4 5 4 7 5 Number of components with data 7 5 1 2 4 6 4 1 2 5 0

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Table 2. Scoring for membership to good environmental status (=1) for human impact assessment categories and spatial extent of human impacts for ecosystem components. Uncertainty 0 < ε <0.5. In the case of lack of data, membership is 0.5 (from Trenkel and Lorance, unpublished working document).

a) all components except exploited species

Category Spatial extent no impact likely possible impact (p) documented impact (d) (n) Local (L) 1−ε 0.9−ε 0.8−ε2 Widespread (W) 1−ε 0.5−ε ε2

b) exploited species

Quality Category Unreliable Intermediate Reliable IUCN*: cd, VU, EN, CR ε3 IUCN*: nt ε2 IUCN*: lc 1−ε over exploited 0.5 0.5−ε ε2 fully or under exploited 0.5 0.9−ε 1−ε

*IUCN categories: cd conservation dependent, VU vulnerable, EN endangered, CR critically endangered, nt near threatened, lc least concerned.

6 WGEAWESS Ecosystem(s) description

6.1 Natural Components First step for WGEAWESS is an extensive review of main natural components and available data.

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1.1-Thermal regime 1.4.1-Tidal regime Environmental (marnage) 1.2-Salinity regime Constraints 1.4.2-Currents 1.3-Oxygen 1.4.3-Waves 1.4-pH 2.2.3.1-open Bay 2.2.1-Estuarine 1-Water Physico- 1.5-Nutrients 2.2.3.2-semi-enclosed Chimie / 2.2.2-Coastal Bay Hydrology 1.6-Turbidity 2.2.3-Bay 1.7-Hydrodynamics 2.1.2-Intertidal 2.2.3-C. shelf break 2.1.2-Subtidal 1.8-River Runoff 1.9-Upwelling 2.3-Mudflats / Stratification 2.1.2-Supra/Infralittoral 2.6-Rocky 2.1.2-Circalittoral 2.1.1-Haploops 2.1-Bathymetry 2.1.2-Maërl 2.2-Coastal morphology 2.1.3-Corals 2-Habitat Type 2.3-Substrat I-Natural Geomorphology 3.2.1-Phytoplancton Components 2.4-Biogenic 3.2.1-Phytobenthos

3.2.1-Macrophyte 3.1-Detritus /Bacterials 3.3.1-Zooplankton 3.2-Primary producers 3.3.1-Nekton 3.3-Water column Invertebrate 3.4.1-Epibenthic

3.4-Benthic 3.4.1-Endobenthic Invertebrate 3-Biology (species / 3.5-Vertebrate 3.5.1-Fish population / community) 3.5.1-Mammals 3.6-Rem. species 3.5.1-Birds

3.6.1- Exploited species

3.6.2- Sensitive species

3.6.3- Widely distributed and migratory stocks

Figure 8. Ecosystem main components (A) from Lorance et al. 2009 (B) in a more detailed version.

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6.2 Main Anthropogenic pressures

Environmental Constraints

II-Anthropogenic Pressure

1.1.1-Mussel culture

1.1-Aquaculture 1.1.2-Oyster culture

1-Biological 1.1.3-Fish Culture resources Exploitation 1.2.1-Bottom Trawl (otter trawl, dredge) 1.2-Fishing activity 1.2.2-Fixed gear pot, nets...

2.1-Dredges

2-Mineral/various 2.2-Artificial structure resources (e.g. harbour Exploitation embankment, seawall)

2.3-Boats circulation

3.1-Atmospheric / terrestrial pollution 3-Pollution / wastes drop

3.2-dump site

7 Ecosystem description by subregion

7.1 Gulf of Cadiz (GC, Region A) PDF format files = GulfCadiz_WGEAWESS_JRuiz_DMacias.pdf Javier Ruiz and Diego Macías Instituto de Ciencias Marinas de Andalucía (ICMAN-CSIC); 11519 Puerto Real Cádiz (Spain).

7.1.1 Definition/validation of subregions frontiers (Frontier A/B) As extensively explained below, there are solid reasons to split the northern shelf at the Gulf of Cádiz into two dynamically distinct regions. West of Cape Santa María the shelf is narrow and the dynamics controlled by large scale processes of the eastern boundary current at the Atlantic and its interaction with Cape San Vicente. East of Cape Santa Maria the shelf is wide and has a dynamics very strongly influenced by the Guadalquivir river discharges.

7.1.2 Geography and Climate

Overall boundaries The Gulf of Cádiz (Figure 1) is the basin that connects the North Atlantic Ocean and the Mediterranean Sea. The north, east and south boundaries of the basin are the Ibe- rian Peninsula and Northwest African coasts whereas the west boundary is not well

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defined. The 9oW meridian running through Cape San Vicente would be a good choice for delimiting the Gulf of Cádiz to the west. Cape San Vicente is a sharp topographic feature where the shoreline changes orientation from north to east at almost right angle, separating the oceanographic regime west of Portugal from the more peculiar regime of the Gulf of Cádiz. The prominent cape Beddouzza, close to Cape San Vicente longitude, could be considered a nominal southern limit. This text focuses on the northern Gulf of Cádiz, roughly speaking the area north of 36oN (the latitude of the Strait of Gibraltar). In addition to Cape San Vicente, this area has two other noticeable capes, Santa María and Trafalgar. Cape Santa María is an abrupt break off where continental shelf hardly exists. The continental shelf extends offshore to depths of around 100 m where the shelf slopes down and the continental slope begins. It is divided by Cape Santa María in two different portions with distinct characteristics. West of the cape, the continental shelf is narrow (around 15 km), it is cut by the pronounced Portimao submarine canyon and there are hardly any inputs of continental freshwater. East of the cape, on the contrary, the shelf widens (around 50 km) and important rivers like Guadiana, Guadalquivir, Tinto and Odiel feed it with freshwater and other dissolved or suspended substances from the continent. East of Cape Trafalgar the shelf narrows again as the Gulf of Cádiz faces its eastern limit at the strait of Gibraltar.

Figure 1. Overall boundaries and bathymetry features of the Gulf of Cádiz. CSV, CSM and CT stands respectively for capes San Vicente, Santa María and Trafalgar. PC stands for Portimao Canyon.

Climate

Seasonality In broad terms the climate in the Gulf of Cádiz follows the Mediterranean pattern with hot and dry summers and mild and rainy winters. Nevertheless, the Atlantic influence softens this pattern towards milder and less dry summer and more rainy winters. Figure 2 shows this seasonal signal for historical data (from 1971 to present) at the meteorological station in Jerez airport.

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35 85 120

80 30 100

25 75 80

20 70 60 15 65 40 Montly Rainfall (mm) Montly 10 60 Temperature(ºC) Relative Humidity (%) Humidity Relative

20 5 55

0 50 0 May July May July April June April June March March August August January October January October Fabruary Fabruary December November December November September September

Figure 2. On the left are the climatological mean and the mean of maxima and minima monthly temperatures at Jerez airport. To the left the monthly rainfall (bars) and the mean of relative humidity (line).

Climatic oscillations The mid-latitude and eastern Atlantic location of the Gulf of Cádiz makes this basin very sensitive to the North Atlantic Oscillation (NAO). NAO conditions the precipitation in the region (Figure 3) and, therefore, the river run off with its subsequent impacts on the circulation, fertilization and nursery dynamics of the

Figure 3. Relation between the NAO index and the annual accumulated precipitation (mm/year) in the area of the Gulf of Cadiz for the period 1870–2007. The precipitation data were registered in the Real Observatorio de la Armada(ROA), situated in San Fernando (Cadiz,Spain). From Prieto et al. (2009).

The Strait of Gibraltar influence Wind regime at the Gulf of Cádiz seems less connected to NAO and more influenced by the local control exerted by the strait of Gibraltar. An increasing zonal component and stronger winds are observed as we approach the Strait as exemplified by the

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probability density of winds at the meteorological stations of Huelva and Cádiz (Fig- ure 5). The magnifying effect of the strait on the wind regime is more clearly seen on the power spectra of the wind velocity (Figure 4). Wind variance in Huelva noticea- bly accumulates at annual frequencies, corresponding to the seasonal cycle, whereas variances at frequencies in the interval between 1 week and 1 month (synoptic winds) are much lower. In contrast, the seasonal cycle signal in Cadiz is lower compared to Huelva and the accumulated variance corresponding to synoptic winds is remarka- bly high. This amplified effect has a significant effect on the coastal circulation and production of the basin, particularly at the shelf east of Cape Santa María.

Figure 4. Probability density of winds at Cádiz and Huelva meteorological stations. Cádiz is located east of Huelva and much closer to the Strait of Gibraltar. From Prieto et al. (2009).

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Figure 5. Power spectra for the distribution of variance in different time scales in the wind recorded at the Cadiz (upper) and Huelva (lower) meteorological stations. In both figures is dis- played the different significance of seasonal versus synoptic (of days to weeks). From Prieto et al. (2009).

7.1.3 Bathymetry and substrates Although the Gulf of Cádiz continental margin is located within the context of the eastern sector of the central North Atlantic (Figure 6), it shows unique morphological, structural and sedimentary features. The presence of unstable substrata and the predominance of along-shore processes have resulted in a distinctive broad slope and slope terrace morphology (Hernández-Molina et al., 2006). Following the overall highly dynamical nature of a basin that connects two seas (Atlantic and Mediterra- nean) and two continents (Africa and Europe), the sedimentary system has generated a highly heterogeneous and complex pattern as can be seen in Figure 7. A very singular feature of the Gulf of Cádiz bottoms is the abundance of mud volcanoes at the continental margin (Figure 8), that are receiving increasing environmental focus owing to the need for protecting such singular ecosystems from deep-sea trawling activities.

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Figure 6. 3D regional bathymetric map of the Gulf of Cádiz in the context of the North-East Atlan- tic. Legend of the physiographic reference points, in alphabetical order: ASM = Ampere Sea- mount; BH = Barbate high; DSM = Dragon Seamount; GB = Guadalquivir Bank; JSM = Josephine Seamount; HSM = Hirondelle Seamount; LSM = Lion Seamount; MTR = Madeira Torre Rise; SSM = Sea Seamount; USM = Unicorn Seamount. Legend of the morphostructural zones: SM = Sudiberic Margin; GM = Guadalquivir Margin, BM = Betic domain Margin. From Hernández- Molina et al. (2006).

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Figure 7. Morphosedimentary map of the Contourite Depositional System of the Gulf of Cádiz. From Hernández-Molina et al. (2006).

Figure 8. 3D multi-beam bathymetric image of the Gulf of Cádiz showing a landscape of structures related to gas seepages: numerous crater-like pockmarks, mud volcanoes and carbonate mounds. The view covers an area of approximately 8500km2 with water depths ranging from 600 to 1500 m. From Leon et al. (2006).

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7.1.4 Hydrography and circulation The surface circulation in the Gulf of Cádiz is affected by the seasonal fluctuations of the North Atlantic subtropical gyre. The size and position of this gyre follows the displacements of the Azores atmospheric high, which extends northwards in summer and reduces its size in winter. Following these fluctuations, the eastward-flowing Azores current would flow at a latitude greater than the Gulf of Cádiz latitude when the North Atlantic subtropical gyre is large, whereas it would be displaced to the south when the subtropical gyre diminishes the size. This seasonality is mirrored by the circulation along the eastern boundary of the mid-latitude North Atlantic. An example is the winter appearance of the Poleward Current flowing northwards at the surface along the Portuguese coast (Frouin et al., 1990; Haynes and Barton, 1990), which is replaced by the equatorward upwelling jet during the upwelling season from May to October (Wooster et al., 1976; Fiúza et al., 1982; Haynes et al., 1990; Peliz and Fiúza, 1999). The Gulf of Cádiz circulation is sensitive to these large-scale variations. Relvas and Barton (2002) suggest that, when the upwelling jet formed in summer reaches Cape San Vicente, it spreads preferably to the east along the shelf break and slope of the northern part of the Gulf of Cádiz, providing a generalized anticyclonic circulation in the basin. Figure 9 shows an acoustic Doppler snapshot of this situation as diagnosed in May 2001 (García-Lafuente and Ruiz, 2007). The figure shows a pattern of the large scale circulation in the Gulf of Cádiz that seems to be anticyclonic in summer, a pattern that might switch to cyclonic in winter according to García-Lafuente and Ruiz (2007). As figure 9 already suggest this overall pattern is modified at its northern shelf by smaller (mesoscale) features generated by the influence of the capes and the run off of major rivers. The schematic circulation model for the area by García- Lafuente and Ruiz (2007) is shown in figure 10. It comprises the overall anticyclonic circulation of the basin plus two mesoscale cyclonic features at the shelf east and west of Cape Santa Maria.

Figure 9. Summer overall circulation at the Gulf of Cádiz. Acoustic doppler current profiler (ADCP) velocities at 18 m depth during May 2001 (from García-Lafuente and Ruiz, 2007).

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Figure 10. Schematic circulation features at the Gulf of Cádiz. N1 and N2 stand for eastward circulation currents whereas CCC and SVE for a coastal counter current and a cyclonic gyre. From Gar- cía-Lafuente and Ruiz (2007).

Physical Environment Subregions Both from a geographic and a circulation standpoint, the information presented above indicates two distinct sub regions in the northern shelf of the Gulf of Cadiz, delimited by the Cape of Santa María. The western shelf is narrow and dynamically controlled by features associated to the boundary current of the eastern Atlantic in its interaction with the Portuguese coast. The eastern shelf is wide and with a dynamics which is mainly connected to the impact exerted on it by the Guadiana and Gua- dalquivir rivers, the major freshwater sources at the southern Iberian Peninsula, discharges as well as heavily influenced by the strong winds nearby the Strait of Gibraltar. Both of these areas are under the influence of cyclonic gyres (isolated from each other by Cape Santa Maria) differentiated from the overall anticyclonic circulation of the basin.

7.1.5 Biological ecosystem components

7.1.5.1 Phytoplankton and the physical environment An exhaustive regionalization of the Gulf of Cádiz through the use of colour signals from SeaWiFS also differentiates these two shelf sections among the different ecoregions of the Gulf of Cádiz (Navarro and Ruiz, 2006). The different regions recognized by Empirical Orthogonal Decomposition of SeaWiFS data for the area identified a close connection between the physical forcings and the biological responses for the ecological units at the Gulf of Cádiz. The set of regions are presented in Figure 11. The open ocean (deep blue in Figure 11) occupies an area of a bathymetry deeper than 1000 m; thereby the topography factor is not expected to greatly influence the physical and biological features. It shows only the occurrence of one winter chlorophyll maxima in its monthly climatology (Figure 12). Shelf waters west of Cape Santa María (light blue in Figure 11) have temperatures and chlorophyll values that are re- markably different to the oceanic zone. Monthly thermal variations are not as smooth and anomalies are higher owing to the influence of oceanographic instabilities in a narrow shelf with a square angle shape (Figure 13). Minimum and maximum values of temperature are reached during the same months as in open waters although the magnitude of the maxima is lower. Thermal anomalies are particular high during summer time, when the presence of the upwelling in Cape San Vicente injects cold waters to the surface (Fiúza, 1983). Chlorophyll climatology has two maxima throughout the year. The first one in spring is related to the development of spring

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blooms in these latitudes (Navarro and Ruiz, 2006). However, the highest chlorophyll values are found for the second peak in summer. The fact that the highest chlorophyll concentrations occur in summer, when the radiation is maximal, indicates that this zone is not strongly limited by nutrients during this period of the annual cycle. Therefore, due to the upwelling occurring in the zone, nutrients do not limit the production during the months of maximum stratification and minimum production in the deep waters. Oceanographic instabilities associated to the sharp slope of Cape Santa María (traditionally known as the Huelva Front, green color in Figure 11). Monthly climatologies (Figure 14) result in a thermal regime whose maxima are intermediate between the values observed in deep waters and in Cape San Vicente area. Chlorophyll peaks in February, and a second maximum of a smaller intensity appears in September, although the interannual variability of the maximum in winter is very high. The shelf east of Cape Santa María (marked red in Figure 11) shows the highest climatological values of temperature of all the areas (August in Figure 15). In addition, it also shows the lowest temperature value compared to the other regions (January in Figure 15). In contrast to this large rage of variation, anomalies are comparatively low. Both elements evidence a persistent forcing connected with the influence exerted by land on these waters, mainly through Guadalquivir river estuary (Prieto et al., 2009). Guadalquivir influence is also very neat on the chlorophyll concentration whose maxima are reached in April and have the highest records of all regions. A second phytoplankton bloom in fall coincides with the relaxation of thermal stratification in October. Chlorophyll anomalies are a high proportion of the average value of chlorophyll (>30%), which indicates a high interannual variability. This variability is tightly connected to Guadalquivir forcing as manifested by both the time coherence of chlorophyll and runoff signals (see for instance Navarro and Ruiz, 2006) as well as by the spatial distribution of nutrients in the shelf (Figure 16). Clima- tologies at Cape Trafalgar (marked yellow in Figure 11) are conditioned by vertical mixing nearby the Strait of Gibraltar where sharp changes of batimetry occur (García- Lafuente et al., 2007). Thermal and chlorophyll patterns are similar to the Huelva front or the shelf west of Cape Santa María whose climatologies are also driven by oceanographic instabilities (Figure 17).

Figure 11. Gulf of Cadiz Eco-Regions. Regionalization based on EOF analysis of colour satellite imagery (modified from Navarro and Ruiz, DSR-II 2006). Light blue: Cape San Vicente region. Green: Huelva Front region. Red: continental shelf under the Guadalquivir influence. Yellow: Cape Trafalgar region. Dark blue: open sea region. From Navarro and Ruiz (2006).

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1.5 23 1 22 0.5 21 0 20 -0.5 19 -1 18 Anomaly SST Anomaly

-1.5 17 SST Climatology

6 60 3 50 0 40 -3 30

Anomaly PAR Anomaly -6 1998 20

1999 PAR Climatology 2000 0.2 2001 0.35 2002 0.1 0.3 0 0.25 -0.1 0.2

Anomaly CHL Anomaly -0.2 0.15 Climatology CHL Climatology

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 12. Monthly averages and anomalies of sea surface temperature (SST), photosynthetic available radiation (PAR) and satellite chlorophyll (CHL) for open ocean waters in the Gulf of Cádiz. From Navarro and Ruiz (2006).

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2 19 C) o C) o 1 18

0 17

-1 16 Anomaly SST ( Anomaly

-2 1998 15 SST ( Climatology 1999 2000 2001 2002 ) -3 )

-3 1 2

0.5 1.75

0 1.5

-0.5 1.25

-1 1 Anomaly CHL (mg m Anomaly Climatology CHL (mg m Climatology

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 13. Monthly averages and anomalies of sea surface temperature (SST) and satellite chlorophyll (CHL) for the shelf west of Cape Santa Maria in the Gulf of Cádiz. From Navarro and Ruiz (2006).

2.25 22 C) o

C) 1.5 21 o 0.75 20 0 19 -0.75 18 -1.5 17 Anomaly SST ( Anomaly -2.25 1998 16 SST ( Climatology 1999 2000 2001

2002 ) -3 )

-3 1 1.6

0.5 1.4

0 1.2

-0.5 1

-1 0.8 Anomaly CHL (mg m Anomaly Climatology CHL (mg m Climatology

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 14. Monthly averages and anomalies of sea surface temperature (SST) and satellite chlorophyll (CHL) for slope waters (Huelva front) in the Gulf of Cádiz. From Navarro and Ruiz (2006).

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2 23 C) o C) o 1 21

0 19

-1 17

Anomaly SST ( Anomaly 1998 -2 1999 15 SST ( Climatology 2000 2001 2002 )

) 1.5 4.5 -3 -3 1 4.2 0.5 3.9 0 3.6 -0.5 3.3 -1 3

Anomaly CHL (mg m Anomaly -1.5 2.7 Climatology CHL (mg m Climatology

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 15. Monthly averages and anomalies of sea surface temperature (SST) and satellite chlorophyll (CHL) for the shelf east of Cape Santa Maria in the Gulf of Cádiz. From Navarro and Ruiz (2006).

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Figure 16. Spatial distribution of nutrients in the shelf west of Cape Santa María.

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2 20 C) o C) o 1 19

0 18

-1 17 Anomaly SST ( Anomaly

-2 1998 16 SST ( Climatology 1999 2000 2001

2002 ) -3 )

-3 1 1.3

0.5 1.2

0 1.1

-0.5 1

-1 0.9 Anomaly CHL (mg m Anomaly Climatology CHL (mg m Climatology

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 17. Monthly averages and anomalies of sea surface temperature (SST) and satellite chlorophyll (CHL) for Trafalgar shallows in the Gulf of Cádiz. From Navarro and Ruiz (2006).

7.1.5.2 Bacteria Prieto et al. (1999) made a comparative analysis of bacterioplankton distribution in the Alboran Sea, Strait of Gibraltrar and GoC. They found higher bacterial abundance in productive regions while lower overall biomass was present in the open-ocean regions (Figure 18). In this work a positive and significant correlation was found between bacterial abundance and chlorophyll concentration.

Figure 18. Bacterial abundances (x106 cells ml-1) at the Deep Chlorophyll Maximum (From Prieto et al., 1999).

Also, chemosynthetic bacteria have been reported to significantly contribute to the nutrition of deep-waters bivalves in the mud volcanoes of the GoC (e.g., Rodrigues et al., 2010).

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7.1.5.3 Zooplankton Information on zooplankton and especially for meroplankton (decapod and cephalo- pod larvae) for the northern sector of the GoC is scarce. In the off-shore region, around the Josephine Bank (southwest off Portugal), one study on zooplankton by Vives (1970) considered that in June, the most abundant copepods species are Calanus helgolandicus and Neocalanus gracilis with the copepod community composed by around 122 species. The copepods perform vertical daily migrations and can be separated by two group of species, one group that usually live above the 300 m depth and a second group that inhabit below the 500 m deep. The first group (e. g. Calanus helgolandicus, Neocalanus gracilis, Euaetideus giesbrechti) usually ascends to the upper layers (100 m depth to surface) during the night whereas the second group (e.g. Metridia lucens, M. brevicauda) do not rise above 300 m depth. Another study on zooplankton by Vives (1972), performed during June and July that includes information on coastal and open-sea regions, has concluded that Neocalanus gracilis, Nannocalanus minor and Calanus helgolandicus are the most abundant copepods in that areas. He also analyzed the composition of the copepods community in the vicinity of Cape San Vincente and concluded that they are of mixed character. According to the Mediterranean water flow in the area, the composition of species are all typical from the Atlantic Ocean in the first 300 m of the water column, and never found in Mediterranean Sea, as e.g. Chirudina streetsi, Undenchaeta plumosa, Scaphoca- lanus echinatus, Metridia lucens, M. venusta, Phyllopus helgae and Conaca rapax. Finally, it was considered that copepods populations in the area were mainly composed of neritic species. Neto and Paiva (1984) in a study along the south coast of Portugal for March, June and October 1979 and 1980, using a WP2 net with 200 µm mesh size had found that Acartia clausi, Oncaea curta, Oithona helgolandica, Euterpina acutifrons, Centropages chierchiae, Temora longicornis, Calanus helgolandicus, Clausocalanus lividus and C. arcuicornis represented 92.4% for all copepods. With the exception of Temora longicornis all the above species are neritic ones. Regarding other groups, Villa et al. (1997) found Penilia avirostris is the most abundant species on an area near the Cape S. Vicente (P2) and Neto and Paiva (1984) considered that this species together with Evadne spinifer are the most abundant of the cladocerans for all the south coast of Portugal. Oceanic species more common in the area are Muggia atlantica, Agalma elegans, Sagitta frederici, Thalia democratica and Salpa fusiformis, the first three all year around and the last two species only present during the winter months (Neto and Paiva, 1984, Villa et al. 1997). Considering the seasonal zooplankton abundance for Cape San Vicente area, Villa et al. (1997) found maximum abundances in July, August and September (Figure 19).

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Figure 19. Seasonal variation of phytoplankton biomass and zooplankton abundance (from Villa et al. 1997) for the NW GoC.

However Cunha (1993) using a Bongo net with 60 cm diameter aperture and mesh sizes of 335 µm and 505 µm collected zooplankton in a transect of 4 stations in the south coast off Portugal (Long. 08º35’W; Lat. 37º05’, 37º00’, 36º55’ and 36º50’ N) consider that the zooplankton biomass is minimum during the winter months rising during the spring time and sustaining high values until autumn (Table 1). The high values of zooplankton biomass during all spring and summer is considered to be caused by the upwelling events occurring during this time of the year that enrich the superficial coastal waters with nutrients (Cunha, 1993).

Table 1. Monthly mean values for zooplankton biovolumes (LN [(ml.1000m-3)+1]), SD and number of samples examined (extracted from Cunha, 1993).

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Net of 505 µm mesh size Mean 3.5 2.5 5.0 5.2 5.1 4.2 5.0 5.5 4.3 5.2 3.8 4.0 SD 0.7 1.2 1.1 0.7 0.3 0.5 0.8 0.3 0.0 0.7 1.1 0.5 N 8 4 8 8 4 4 8 7 2 4 12 8 Net of 335 µm mesh size Mean 4.1 3.6 5.4 5.3 5.7 5.5 5.5 5.7 5.2 5.9 4.3 4.2 SD 0.5 1.1 0.7 0.7 0.4 0.8 0.7 0.7 0.2 0.8 1.2 0.8 N 8 4 8 7 4 4 8 7 2 4 12 8

On the other hand, the western entrance of the Strait of Gibraltar has been defined as a zooplankton ‘hot-spot’ by Macías et al. (2010). The primary production triggered by the mixing events and the redistribution of planktonic biomass by the concomitant undulatory process create periodic accumulations of zooplankton biomass over the main sill of the Strait. Both, zooplankton community composition and size structure, seems to be controlled by the intense hydrological processes happening in this region.

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7.1.5.4 Small pelagic fish The main target species to the east of Cape Santa María is European anchovy (Engrau- lis encrasicolus) being sardine (Sardine pilchardus) a much less targeted species for its comparatively low market prices and much less abundance. European anchovy is the main economic resource of the fishing fleet in the Gulf of Cádiz. Being a short living species, anchovy recruitment and landing largely fluctuate with environmental variability (Nakata et al., 2000; Lloret et al., 2001; Erzini, 2005; Basilone et al., 2006). The sensitivity to the physical environment is particularly acute at the Gulf of Cádiz. The severe mortality imposed by the fishery avoids adults to survive from one year to the next. Without sustain of adults, the population totally relies on recruits to persist between years. Owing to the vulnerability that early stages have to ocean processes, the stock is, then, totally controlled in a BOTTOP fashion (mixed bottom-up and top-down; Ruiz et al., 2007) with the human pressure making the stock extremely exposed to environmental oscillations. As shown above, bathymetry and coastline create a cyclonic circulation segregated from the energetic currents nearby the Strait of Gibraltar (Figure 10). Salt marshes and river input respectively heat and fertilize the shelf during summer, generating a large pool of warm and chlorophyll-rich water (Navarro and Ruiz, 2006; García- Lafuente and Ruiz, 2007). At that time of year the concentration of anchovy eggs and larvae is very high (see an example at Figure 20). Besides favourable conditions for planktonic stages, the shelf is connected to the lower reaches of the Guadalquivir River, a nursery area for post-larvae of anchovy (Baldó and Drake, 2002; Drake et al., 2007). Favourable conditions for anchovy recruitment are distorted under specific meteorological regimes at the southern Iberian Peninsula. Shelf currents are highly sensitive to the intense zonal winds nearby the Strait of Gibraltar (Figure 4). Persis- tent easterlies cause the offshore spilling of waters from the shelf through Capes Santa María and San Vicente (Relvas and Barton, 2002). Westward advection of fish larvae under this regime has been documented (Catalán et al., 2006a). In addition, latent heat fluxes during easterlies cool shelf waters and hamper anchovy spawning (Ruiz et al., 2006). As explained above, rain at the south of the Iberian Peninsula fertil- izes the shelf through freshwater discharges from the Guadalquivir River (Navarro and Ruiz, 2006). A dam, 110 km upstream from Guadalquivir mouth, tightly regu- lates discharges, which are dramatically reduced during years of severe drought. Be- sides lowering the primary production of the shelf, the agriculture management of the dam during dry years modifies the seasonal pattern of discharges and negatively impacts the anchovy nursery within the estuary (Drake et al., 2002). Low recruitment under adverse meteorology, intense easterlies and low precipitation, can create stock collapses at the Gulf of Cádiz (see for instance Figure 21 for a dramatic collapse in mid nineties). The neat transfer of environmental signals into recruitment fluctuations have facilitated the implementation of modelling tools (Ruiz et al., 2009) showing some predictive capacity with a time spam of several months ahead (Figure 22).

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Figure 20. Anchovy larvae concentration (# larvae/100m3, contour lines) and zooplankton bio- volume (ml/100m3) in the Gulf Cádiz shelf to the east of Cape Santa María.

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Figure 21. Anchovy catches (black circles) in the Gulf of Cádiz (sub-division IX.a South) and CPUE in Barbate by a single purpose pursue-seine fleet. Bars represent the cumulative sum of days from March to September with easterlies stronger than 30 km h-1 in Cádiz meteorological observatory. From Ruiz et al. (2006).

Figure 22. Predictive capacity of European anchovy recruitment at the Gulf of Cádiz. Bars are real- ized CPUE at a certain year and lines are ∑ Bq, a proxy for CPUE. This proxy is estimated by a Bayesian model after assimilating all process and information controlling anchovy recruitment previous to the year when the prediction is made. From Ruiz et al. (2009).

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7.1.5.5 Demersal and benthic fish The Gulf of Cadiz is a highly suitable habitat for the reproduction of many commercially important marine species (e.g., Jiménez et al., 1998; Millán, 1999) being the Guadalquivir River a key player in providing suitable spawning and nursery conditions from many fish species (García-Isarch et al., 2003; Ruiz et al., 2006). The fisheries at the Gulf of Cadiz (included in ICES region IXa) have traditionally represented an important socio-economic activity for the coastal population of SW Spain. An important multispecies–multigear artisanal fishery exploits the coastal fringe of the Gulf (Sobrino et al., 1994; Silva et al., 2002), extending off-shore in the central region of the Gulf, between the Guadalquivir and Guadiana estuaries (Figure 23). Bottom trawling is forbidden at the first 10km offshore, which embraces a shallow area of a maximum depth of ca. 30 m. Species catches vary greatly in space and time in association with the highly diverse environmental traits encountered in the shelf and the species life cycles (Sobrino et al., 1994; Ramos et al., 1996). Some commercially important benthic and demersal species in the area include hake (Merluccius merluccius), several Sparidae, wedge sole (Di- cologoglossa cuneata) cephalopods like octopus (Octopus vulgaris) or cuttlefish (Sepia officinalis), and crustaceans like Squilla mantis or Melicertus kerathurus. This fishery represents 49% of the total catches in the GoC region with hake and octopus as the main captured species. Catalan et al. (2006b) found a strong spatial gradient of the structure of demersal assemblages of the Gulf related to depth, sediment type, and bottom temperature (all related to the distance from the Guadalquivir River mouth) that was responsible for most of the explained variability in global values and demersal species structure. The shallowest stations, also close to the Guadalquivir River mouth, showed higher numerical abundance and biomass values but lower diversity and number of species. Typical or abundant species from those stations included fishes from the families Sparidae (particularly Diplodus bellottii), Haemulidae, Soleidae or the stomatopod Squilla mantis. Deeper stations were defined by higher relative densities of cephalopods and several pleuronectiform fish. Significant seasonal differences in the abundance of several species also were observed at most stations, mainly between summer and winter. Species like Merluccius merluccius were particularly abundant in winter, whereas Arnoglossus laterna was more abundant in summer

Figure 23. Main fishing grounds (green areas) within the Gulf of Cádiz.

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7.1.5.6 Top predators – Marine mammals

Figure 24. Sperm whale density (black lines) and fin whale observations (blue lines) overlapping with large vessels nearby the Strait of Gibraltar. Figure from CIRCE web page.

The Spanish Society for Marine Mamals has evidenced, through the Life program LIFE02NAT/E/8610, the presence of harbour porpoise (Phocoena phocoena) and the bottlenose dolphin (Tursiops trunctus) in the north sector of the Gulf of Cádiz. Exten- sive observations have also been conducted in the context of their migration through the Strait of Gibraltar by the non-governmental organization CIRCE (http://www.circe.biz/). They evidence the significance of the Strait of Gibraltar as a migratory route as well as the threatens they face as a consequence of increasing marine traffic through the Strait. As an example, Figure 24 shows the great overlap between the density of fin and sperm whales (Balaenoptera physalus and Physeter catodon) with the presence of large (cargo and ferry) vessels in the area nearby the Strait. These studies also point at the importance of the oceanographic singularities of the area for other marine mammals like killer whales (Orcinus orca) or common and stripped dolphins (Delphinus delphis and Stenella coeruleoalba). These species are included in the Spanish National and the Andalusian Regional Catalogues of threaten species. In addition, harbour porpoise and bottlenose dolphin are in Annex II of the Habitat Directive whereas for killer whales both the International Union for the Con- servation of Nature (IUCN) and the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and contiguous Atlantic area (ACCOBAMS) consider this as a species under critical extinction threat.

7.1.6 References Baldó , F., Drake, P., 2002. A multivariate approach to the feeding habits of small fishes in the Guadalquivir Estuary. Journal of Fish Biology 61 (Suppl. A), 21–32.

Basilone, G., Guisande, C., Patti, B. et al. (2006) Effect of habitat conditions on reproduction of the European anchovy (Engraulis encrasicolus) in the Strait of Sicily. Fisheries Oceanogra- phy, 15:271–280.

Catalán, I., Rubín, J.P., Navarro, G., Prieto. L., 2006a. Larval fish distribution in two different hydrographic situations in the Gulf of Cádiz. Deep-Sea Research II, 53: 1377-1390.

Catalán, I., Jiménez, M.T., Alconchel, J.I., Prieto, L., Muñoz, J.L., 2006b. Spatial and temporal changes of coastal demersal assemblages in the Gulf of Cadiz (SW Spain) in relation to environmental conditions. Deep-Sea Research II, 53: 1402-1419.

Cunha, M.E., 1993. Variabilidade estacional do zooplâncton na plataforma continental portuguesa. Bol UCA 1:229-241.

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Drake, P., Arias, A.M., Baldó, F., Cuesta, J.A., Rodriguez, A., Silva-García, A., Sobrino, I., Gar- cía-González, D., Fernández- Delgado, C., 2002. Spatial and temporal variation of the nekton and hyperbenthos from a temperate European estuary with a regulated freshwater inflow. Estuaries 25, 451–468.

Drake, P., Borlan, A., González-Ortegón, E., Baldó, F., Vilas, C. and Fernández, C. (2007) Spa- tio-temporal distribution of early life stages of the European anchovy Engraulis encrasicolus L. within a European temperate estuary with regulated freshwater inflow: effects of environmental variables. Journal of Fish Biology, 70:1689–1709.

Erzini, K., 2005. Trends in NE Atlantic landings (southern Portugal): identifying the relative importance of fisheries and environmental variables. Fisheries Oceanography, 14:195–209.

Fiúza, A.F.G., de Macedo, M.E., Guerreiro, M.R., 1982. Climatological space and time variations of the Portuguese coastal upwelling. Oceanologica Acta, 5: 31–40

Fiúza, A.F.G., 1983. Upwelling patterns off Portugal. In: Suess, E., Thiede, J. (Eds.), Coastal Upwelling: Its Sediment Records, Part A. Plenum, New York, pp. 85–98.

Frouin, R., Fiúza, A.F.G., Ambar, I., Boyd, T.J., 1990. Observations of a poleward surface current off the coasts of Portugal and Spain during winter. Journal of Geophysical Research 95, 679–691.

García-Isarch, E., García, A., Silva, L., Sobrino, I., 2003. Spatial and temporal characterisation of the fish spawning habitat off the Guadalquivir River mouth (Gulf of Cadiz, SW Spain). In: 3rd International Zooplankton Production symposium. The role of zooplankton in global ecosystem dynamics: comparative studies from the world oceans, Gijón, Spain, May 20– 23, 2003, pp. 64–65.

García-Lafuente, J., Ruiz, J., 2007. The Gulf of Cádiz pelagic ecosystem. Progress in Oceanogra- phy, 74: 228-251.

Haynes, R., Barton, E.D., 1990. A poleward flow along the Atlantic coast of the Iberian Penin- sula. Journal of Geophysical Research 95, 11425–11442.

Haynes, R., Barton, E.D., Piling, I., 1990. Development, persistence and variability of upwelling filaments off the Atlantic coast of the Iberian Peninsula. Journal of Geophysical Research 98, 22681–22692.

Hernández-Molina, F.J., Llave, E., Stow, D.A.V., García, M., Somoza, L., Vázquez, J.T., Lobo, F.J., Maestro, A., Díaz del Río, V., León, R., Medialdea, T., Gardner, J., 2006. The contourite depositional system of the Gulf of Cádiz: A sedimentary model related to the bottom current activity of the Mediterranean outflow water and its interaction with the continental margin. Deep-Sea Research II 53, 1420–1463

Jiménez, M.P., Sobrino, I., Ramos, F., 1998. Distribution pattern, reproductive biology and fishery of the wedge sole Dicologoglossa cuneata in the Gulf of Cadiz, south-west Spain. Ma- rine Biology 131, 173–187.

León, R., Somoza, L., Medialdea, T., Maestro, A., Díaz-del-Río, V., Fernández-Puga, M.C., 2006. Classification of sea-floor features associated with methane sepes along the Gulf of Cádiz continental margin. Deep-Sea Research II 53, 1464–1481.

Lloret, J., Lleonart, J., Solé, I., Fromentin, J.M., 2001. Fluctuations of landings and environmental conditions in the North-Western Mediterranean Sea. Fisheries Oceanography 10, 33–50.

Macías, D., Somavilla, R., González-Gordillo, I., Echevarría, F., 2010. Physical control of zooplankton distribution at the Strait of Gibraltar during an episode of internal wave generation. Marine Ecology Progress Series, 408: 79-95.

Millán, M., 1999. Reproductive characteristics and condition status of anchovy Engraulis encrasicolus L. from the Bay of Cadiz (SW Spain). Fisheries Research 41, 73–86.

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Navarro, G., Ruiz, J., 2006b. Spatial and temporal variability of phytoplankton in the Gulf of Cádiz through remote sensing images. Deep-Sea Research II, 53

Nakata, H., Funakoshi, S. and Nakamura, M., 2000. Alternating dominance of postlarval sardine and anchovy caught by coastal fishery in relation to the Kuroshio meander in the En- shu-nada Sea. Fisheries Oceanography, 9:248–258.

Neto, T., Paiva, I. 1984. Algumas considerações sobre zooplâncton da costa algarvia. 3º Con- gresso sobre o Algarve – textos das comunicações. 1(57): 433-441.

Peliz, A.J., Fiúza, A.F.G., 1999. Temporal and spatial variability of CZCS-derived phytoplankton pigment concentrations off the western Iberian Peninsula. International Journal of Remote Sensing 20 (7), 1363–1403.

Prieto, L., García, C.M., Corzo, A., Ruíz, J., Echevarría, F., 1999. Phytoplankton, bacterioplankton and nitrate reductase activity distribution in relation to physical structure in the southern Alborán Sea and Gulf of Cádiz (southern Iberian Peninsula). Bol. Inst. Esp. Oceanogr., 14(1-4): 401-411.

Prieto, L., Navarro, G., Rodríguez-Galvez, S., Huertas, I.E., Naranjo, J.M., Ruiz, J., 2009. Oceanographic and meteorological forcing of the pelagic ecosystem on the Gulf of Cadiz shelf (SW Iberian Peninsula). Continental Shelf Research, 29: 2122-2137

Ramos, F., Sobrino, I., Jiménez, M.P., 1996. Cartografía temática de caladeros de la flota de ar- rastre en el Golfo de Cadiz. Inf. Tecn. 45/96. Consejería de Agricultura y pesca. Junta de Andalucía, 29pp.

Relvas, P., Barton, E.D., 2002. Mesoscale patterns in the Cape Sao Vicente (Iberian Peninsula) upwelling region. Journal of Geophysical Research, 107 (C10), 3164. doi:10.1029/2000JC00045.

Rodrigues, C.F., Webster, G., Cunha, M.R., Duperron, S., Weightman, A.J., 2010. FEMS Micro- bial Ecology, 73, 486-499.

Ruiz, J., García-Isarch, E., Huertas, I.E., Prieto, L., Juarez, A., Muñoz, J.L., Sánchez-Lamadrid, A., Rodríguez-Gálvez, S., Naranjo, J.M., Baldó, F., 2006. Meterological forcing and ocean dynamics controlling Engraulis encrasicolus early life stages and catches in the Gulf of Cádiz. Deep-Sea Research II, 53: 1363-1376.

Ruiz, J., Gonzalez-Quirós, R., Prieto, L., García-Lafuente, J., 2007. Anchovy in the Gulf of Cádiz: a case of BOTTOP control. Globec International Newsletter, 13(2): 22-24.

Ruiz, J., Gonzalez-Quirós, R., Prieto, L., Navarro, G., 2009. A Bayesian model for anchovy (En- graulis encrasicolus): the combined forcing of man and environment. Fisheries Oceanog- raphy, 18(1): 62-76.

Silva, L., Gil, J., Sobrino, I., 2002. Definition of fleet components in the Spanish artisanal fishery of the Gulf of Cadiz. Fisheries Research 1367, 1–12.

Sobrino, I., Jiménez, M. P., Ramos, F., Baro, J., 1994. Descripción de las pesquerías demersales de la región suratlántica española. Informes Técnicos del instituto Español de Oceanogra- fía 151, 79pp.

Villa, H., Quintela, J., Coelho, M.L., Icely, J.D., Andrade, J.P. 1997. Phytoplankton biomass and zooplankton abundance on the south coast of Portugal (Sagres), with special reference to spawning of Loligo vulgaris. Scientia Marina 61(2):123-129

Vives, F. 1970. Distribución y migración vertical de los copépodos planctónicos (calanoida) del SO. de Portugal. Inv. Pesq. 34(2):529-564

Vives, F. 1972. Los copépodos del SW. de Portugal en junio y julio de 1967. Inv. Pesq. 36(2):201- 240.

Wooster, W.S., Bakun, A., McLain, D.R., 1976. The seasonal upwelling cycle along the eastern boundary of the North Atlantic. Journal of Marine Research 34, 131–141.

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Table 2. WGEAWESS Natural Components/process for Gulf of Cadiz (GC, Region A).

TEMPORAL SPATIAL CONTACT COMMENTS

…

Components/Variables Platforms Methods (CTD, Data Type UNITS Extent (year) Resolution Extent Resolution satellite …) (Models or Ob- servations)

Physico-

Chemical / Hydrology

Temperature Surveys (Regional CTD O °C 2002-2007 Monthly Continental See Figure 25 ICMAN/CSIC Series, National shelf east of Fall 2000 Single Research Program, Cape Santa GOLFO, P3A2) Fall 2008 Single Maria

Satellite AVHRR O °C 1985-onwards Daily Global ICMAN/CSIC

Estuarine moorings Temperature sen- O °C 2008-2011 Continuous Point ICMAN/CSIC sors

Coastal moorings Temperature sen- O °C 2000-2010 Continuous Point ICMAN/CSIC sor, chain of ter-

mistors

Off-shore moorings Temperature sen- O °C 1996-present Continuous Point Puertos del sors Estado

ICES WGEAWESS REPORT 2011 | 39

TEMPORAL SPATIAL CONTACT COMMENTS

…

Components/Variables Platforms Methods (CTD, Data Type UNITS Extent (year) Resolution Extent Resolution satellite …) (Models or Ob- servations)

ROMS3D MODEL M °C 1998-2008 Continous Cape San 1 or 5 km square ICMAN/CSIC Vicente to (see Figure 24) University western Medi- Lisbon terranean

Salinity Surveys (Regional CTD O 2002-2007 Monthly Continental See Figure 25 ICMAN/CSIC Series, National shelf east of Fall 2000 Single Research Program, Cape Santa GOLFO, P3A2) Fall 2008 Single Maria

Satellite AVHRR O 1985-onwards Daily Global ICMAN/CSIC

Estuarine moorings Conductivity sen- O 2008-2011 Continuous Point ICMAN/CSIC sors

Off-shore moorings Conductivity sen- O 1996-present Continuous Point Puertos del sors Estado

ROMS3D MODEL M 1998-2008 Continous Cape San 1 or 5 km square ICMAN/CSIC Vicente to (see Figure 24) University western Medi- Lisbon terranean

40 | ICES WGEAWESS REPORT 2011

TEMPORAL SPATIAL CONTACT COMMENTS

…

Components/Variables Platforms Methods (CTD, Data Type UNITS Extent (year) Resolution Extent Resolution satellite …) (Models or Ob- servations)

Turbidity Estuarine moorings Turbidimeter O NTU 2008-2011 Continuous Point ICMAN/CSIC

Nutrient Surveys (Regional Chenical methods O uM 2002-2007 Monthly Continental See Figure 25 ICMAN/CSIC Series, National shelf east of Fall 2000 Single Research Program, Cape Santa GOLFO, P3A2) Fall 2008 Single Maria

Estuarine station Chemical methods O uM 1981-onwards Monthly Point CHG

Oxygen Surveys (Regional CTD O ugr/L 2002-2007 Monthly Continental See Figure 25 ICMAN/CSIC Series, National shelf east of Fall 2000 Single Research Program, Cape Santa GOLFO, P3A2) Fall 2008 Single Maria

Estuarine moorings Oxigen sensor O ugr/L 2008-2011 Continuous Point ICMAN/CSIC

Currents Surveys (Regional CTD O m/s 2002-2007 Monthly Continental See Figure 25 ICMAN/CSIC Series, National shelf east of Fall 2000 Single Research Program, Cape Santa GOLFO, P3A2) Fall 2008 Single Maria

ICES WGEAWESS REPORT 2011 | 41

TEMPORAL SPATIAL CONTACT COMMENTS

…

Components/Variables Platforms Methods (CTD, Data Type UNITS Extent (year) Resolution Extent Resolution satellite …) (Models or Ob- servations)

Estuarine moorings Current meters O m/s 2008-2011 Continuous Point ICMAN/CSIC

Coastal moorings Current meters O m/s 2000-2010 Continuous Point ICMAN/CSIC

Off-shore moorings Current meters O m/s 199X-present Continuous Point Puertos del Estado

ROMS3D MODEL M m/s 1998-2008 Continuous Cape San 1 or 5 km square ICMAN/CSIC Vicente to (see Figure 24) University western Medi- Lisbon terranean

Waves

River Runoff CHG (Confedera- Gauge station O m3/s 1941-2011 Daily Point CHG cion Hidrografica Guadalquivir)

Meteorology (winds, …) Metorological sta- various O Various Since early 1900s Hourly Several stations AEMT (Agen- tions along the coast cia Estatal de Meteorologia)

Meteo Model MODEL M Various Since mid 1950s Hourly Global 2.5ºX2.5º ECMWF

1ºX1º

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TEMPORAL SPATIAL CONTACT COMMENTS

…

Components/Variables Platforms Methods (CTD, Data Type UNITS Extent (year) Resolution Extent Resolution satellite …) (Models or Ob- servations)

Upwelling

/ Stratification

Bed shear stress

Geomorphology CMA has information but is unknown at the present mo- ment

Bathymetry Ad-hoc cruises Sonar O Unknown Unknown Unknown IHM (Instituto Some charts Hidrografico dates on the de la Marina) SXVIII

Coastal Aereal pictures Photograph O 1956-onwards Unknown Coastline CMA (Conse- jeria Medio morphology Ambiente)

Sediment Ad-hoc cruises Bottom sampling O Sediment To be found To be found Continental CMA There are type shelf published atlas on sediment types

Biogenic Substrat

Habitat classification

ICES WGEAWESS REPORT 2011 | 43

TEMPORAL SPATIAL CONTACT COMMENTS

…

Components/Variables Platforms Methods (CTD, Data Type UNITS Extent (year) Resolution Extent Resolution satellite …) (Models or Ob- servations) (Eunis …)

Biology

(species /

population /

community)

Detritus Surveys (Regional Analytical meth- O ugr/L 2002-2007 Monthly Continental See Figure 25 ICMAN/CSIC Series, National ods shelf east of /Bacterials Fall 2000 Single Research Program, Cape Santa GOLFO, P3A2) Fall 2008 Single Maria

ROMS3D MODEL M uM N 1998-2008 Continous Cape San 1 or 5 km square ICMAN/CSIC Vicente to (see Figure 24) University western Medi- Lisbon terranean

Phytoplancton Surveys (Regional Analytical meth- O ugr/L 2002-2007 Monthly Continental See Figure 25 ICMAN/CSIC Series, National ods shelf east of Fall 2000 Single Research Program, Cape Santa GOLFO, P3A2) Fall 2008 Single Maria

ROMS3D MODEL M uM N 1998-2008 Continous Cape San 1 or 5 km square ICMAN/CSIC

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TEMPORAL SPATIAL CONTACT COMMENTS

…

Components/Variables Platforms Methods (CTD, Data Type UNITS Extent (year) Resolution Extent Resolution satellite …) (Models or Ob- servations) Vicente to (see Figure 24) University western Medi- Lisbon terranean

Satellite SeaWiFS, MODIS, O ugr/L 1996-onwards Daily Global ICMAN/CSIC MERIS

Coastal toxic Microscopy O #/L 1999-onwards Monthly Coastal se- CAP (Conseje- phytoplankton lected sites ria Agricultura (per species) monitoring y Pesca)

Estuarine station Analytical meth- O ugr/L 1981-onwards Monthly Point CHG ods

Estuarine moorings Fluorescence O R.U. 2008-2011 Continuous Point ICMAN/CSIC

Benthic phytoplancton (µphytobenthos …)

Macrophyte

Zooplankton Surveys (Regional Bongo nets O #/m3 2002-2007 Monthly Continental See Figure 25 ICMAN/CSIC Series, National shelf east of Fall 2000 Single Research Program, Cape Santa

ICES WGEAWESS REPORT 2011 | 45

TEMPORAL SPATIAL CONTACT COMMENTS

…

Components/Variables Platforms Methods (CTD, Data Type UNITS Extent (year) Resolution Extent Resolution satellite …) (Models or Ob- servations) GOLFO, P3A2) Maria Fall 2008 Single

ROMS3D MODEL M uM N 1998-2008 Continous Cape San 1 or 5 km square ICMAN/CSIC Vicente to (see Figure 24) University western Medi- Lisbon terranean

Estuarine surveys Automatic image O #/m3 2008-2010 Monthly Guadalquivir ICMAN/CSIC processing estuary

Epibenthic fauna Survey Pelagic Trawls O # of indi- 1993-onwards Once or Twice a Spanish shelf IEO-Cadiz vidulas in (2003 lacking) year east to Cape taxons Trafalgar (soft bottom)

Endobenthic fauna Estuarine surveys Dredge O # of indi- 2008-2009 Four surveys Guadalquivir ICMAN/CSIC viduals in estuary taxons

Fish Surveys for demer- Bottom Trawls O # of indi- 1993-onwards Once or Twice a Spanish shelf IEO-Cadiz sals viduals in (2003 lacking) year east to Cape taxons Trafalgar (soft bottom)

Anchova Acoustic O tons 2004, 2006, 2007, Once each sur- Gulf of Cadiz IEO-Cadiz 2009, 2010 veyed year

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TEMPORAL SPATIAL CONTACT COMMENTS

…

Components/Variables Platforms Methods (CTD, Data Type UNITS Extent (year) Resolution Extent Resolution satellite …) (Models or Ob- servations)

anchova DEPM O tons 2005, 2008 Once each sur- Gulf of Cadiz IEO-Cadiz veyed year

anchova Bayesian Model M+O tons 1985-2004 Monthly Gulf of Cadiz ICMAN/CSIC

Ichtyoplankton Bongo tow O #/m3 per 2002-2007 Monthly Continental ICMAN/CSIC species shelf east of Cape Santa Maria

Sea Birds (that fly or not Census Standard methods O To be found Early XX cen- To be found Coastline of EBD-CSIC Details not e.g. penguins!!!) in bird quantifica- tury onwards Doñana Natu- fully known SEO (Sociedad tion ral Park now Española de Ornitología)

Mammals Census Standard methods O To be found Recent data (to To be found Spanish shelf CIRCE Details not in mammal quan- be found) fully known

tification now

Exploited species Landing by boat Fisheries statistics O Landing 1985-onwards Weekly Spanish waters CAP GPS systems and harbour in the Gulf of for fishing

Cádiz effort location

are being

implemented in ALL the fleet

Landing and sam- Size structure and O Depending 199X-onwards Monthly Spanish waters IEO-Cadiz

ICES WGEAWESS REPORT 2011 | 47

TEMPORAL SPATIAL CONTACT COMMENTS

…

Components/Variables Platforms Methods (CTD, Data Type UNITS Extent (year) Resolution Extent Resolution satellite …) (Models or Ob- servations) pling in harbours biological parame- on biological in the Gulf of ters (anchovy, parameters Cádiz sardine, hake, …)

inseveral harbours DCR

Sensitive/endangered spe- Birds migrating Migratory and cies (Corals,…) between Africa and reproduction Europe area for very sensitive species at large scales

Tuna, killer- whales,… migrating for reproduction between Atlantic and Mediterranean

Widely distributed stocks Blue fin Tuna Landings (al- O Tons SXVI onward Yearly Strait of Gibral- Casa Ducal de madraba) tar Medina-

Sidonia

ICATT

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TEMPORAL SPATIAL CONTACT COMMENTS

…

Components/Variables Platforms Methods (CTD, Data Type UNITS Extent (year) Resolution Extent Resolution satellite …) (Models or Ob- servations)

I: Irrelevant

ICES WGEAWESS REPORT 2011 | 49

Figure 25. Spatial domain of the ROMS-bio implemented for the Gulf of Cadiz and Alboran Sea. Climatologic sea surface temperature for May.

Figure 26. Sampling grid of the Regional Series cruises (from Prieto et al., CSR 2009). This grid was surveyed monthly during 2002–2007.

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7.1.7 Anthropogenic relative data: pressures and economics

7.1.7.1 Biological resources exploitation

7.1.7.1.1 Aquaculture The main aquaculture activity in the GoC region is performed within the salt marshes of the Cadiz Bay. Part of the exploitation is made by extensive methods (i.e., with no artificial food) with the rest being done in semi-intensive conditions (i.e., using natural water ponds and using limited food addition). Therefore, the impact of this activity (mainly excretion products from the fish farms) is very limited and only affects the nearby coastal areas.

7.1.7.1.2 Fisheries Fisheries are an economically important activity in the region, being a considerable percentage of the primary industry in the area. The fishing fleet is very heterogeneous from small, family-operated boats, to bigger industrial vessels. Also fishing techniques are diverse although the majorities of the catches are made by bottom trawl. The second more important fishing fleet is the purse seiners, mainly devoted to small pelagics (anchovy and sardine). Finally, in some harbors of the GoC, line-fishing is economically relevant as catches with this type of gear are highly valued. Fishing of eel-larvae with aggressive gear in the area of the Guadalquivir estuary is increasingly considered as a problematic issue because of the by-catch impact on many early life stages of economic and environmentally significant species.

7.1.7.2 Mineral/various resources exploitation: (dredges, artificial structures, boats circulation) There is very little miner activities in the GoC. Only some sandy bottoms are sporadi- cally dredged to use the sand for beaches regeneration. Past mining accidents like Aznalcollar seems to have produced little long-term impact on the nursery habitat of Guadalquivir river. New mining activities are being undertaken in this area whose impact is still to be considered. Boat circulation is very intense in the inner region of the GoC, close to the Strait of Gibraltar, as this is the unique connection of the Mediterranean Sea with the open ocean. Therefore, this area is highly polluted in terms of underwater noise levels and is also a potentially dangerous area for accidental spills from the numerous vessels.

7.1.7.3 Pollution and wastes drop There are some important chemical industries in the GoC coastline, especially on the salt marshes area near Huelva. Among this, there is also an oil refinery with a collec- tion buoy located in the continental shelf in front of Huelva. This has suffered different oil spills in the past and is now under consideration for increasing oil-flow capacity. Also, land-use in the Guadalquivir river vicinity (mainly rice-farming) pollutes the river runoff and controls the freshwater inputs to the estuary. These anthropogenic activities determine the environmental quality of the estuary and the nearby continental shelf area, which is the preferential spawning and nursery are for many fish species. Habitat fragmentation or, directly, habitat destruction by coastal urbanization and its subsequent transformation of the coastal territory where many species nurse is a very significant pressure on this ecosystem.

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7.2 Process and models The number of available model for the GoC region is rather limited but includes different levels of complexity, from hydrodynamics to high trophic levels. Also, the framework of each available model is quite different as there are some of them devoted to specifically resolve the dynamics of certain areas (such as the Bay of Cadiz or the Guadalquivir river runoff) while others covers the whole basin. The most integrated models are a hydrodynamic-biogeochemical coupled model developed for the entire GoC by the University of Lisbon (Peliz et al., in prep). This is a 3D model including low trophic levels (up to zooplankton), with a spatial resolution of 2km and forced by atmospheric patterns at the boundaries and within the model domain. In this model the Guadalquivir river influence is explicitly included and, in its actual state, is able to reproduce both the climatologic behaviour of the basin and its reaction to certain atmospheric forcings (for example winds or extreme temperature events). There is also an integrated model of the ecosystem developed in a Bayesian framework designed to simulate the behaviour of the anchovy population including the environmental effects (Ruiz et al., 2009). In this model, the conditions of the continental shelf (temperature and wind intensity and direction) and within the Guadalquivir estuary (freshwater inputs) are considered to influence the anchovy early-life stages survivorship. Predictions of this model fit very well with available catch data during a ten years period and are actually being refined to be used as a predictive tool for anchovy population dynamics.

7.3 South Western Iberia (SWI, Region B)

Maria de Fátima Borges

7.3.1 Subregion boundaries This subregion was defined as limited: • In the north by the Nazaré Canyon (ca. 39º 30’ N, 9º 55’W) bordered by Estremadura promontory and tipped by Cape Carvoeiro (ca. 39º 21’N, 9º 24’W). • in the south by the Cape Santa Maria (ca 36º 57’N, 7º 53’ W) 7º 53’ W) in the Algarve shelf of Portugal. The coastline runs in the zonal direction at approximately 36º 59º N.

7.3.2 Geology The Nazaré Canyon is one of the largest submarine canyons of the word extending for about 230km (140 miles) and completely cutting the W Portuguese shelf at 39.50 N. It has a maximum depth of at least 5 000 meters (16 000 ft) and was also named as Europe’s Grand Canyon (Tyler et. al., 2005). The width of the western Iberian continental shelf varies between 10 and 65 km along its approximate 700 km length. According to Physiographic features the western Iberia can be divided into three distinct segments, separated by the major canyons that cut across the shelf and descend into the abyssal domains (1) north of the Nazaré Canyon, (2) between the Nazaré and the Setúbal canyons, and (3) between the Setúbal and the Saint Vincent canyons (Vanney and Moguenot , 1981; Mougenot, 1988). The segment between the Nazaré and the Setúbal canyons is characterized by a relatively wide continental shelf (Mougenot, 1988). In this area, a ridge projects out

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from the continental slope, forming one of the most important physiographic features of the margin: the Estremadura Spur. This spur separates the Iberia Abyssal Plain in the north from the Tagus Abyssal Plain in the south, and extends nearly as far west as the Tore Seamount, at the northern end of the Madeira-Tore Rise. The origin of the spur is not clear, but it coincides partly with an alignment of small volcanic features, at least as far west as the 2000 m contour (Mougenot, 1988). Besides the Nazaré and the Setúbal canyons, the only other major canyons that dissect this segment of the margin are the Lisboa and Cascais canyons, both situated southwest of Lisboa (Van- ney and Mougenot, 1981). Small islands (Farilhões and Berlengas) occur close to the coast (10–15 km) to the northwest of Peniche. The segment between the Setúbal and the Saint Vincent canyons is characterized, in general, by a fairly narrow (10–20 km) continental shelf, although between 37°25'N and 38°N it is extended to the west by a platform (Vanney and Mougenot, 1981). Two large abyssal plains occur off western Iberia: the Tagus Abyssal Plain in the south, and the Iberia Abyssal Plain in the north. The Tagus Abyssal Plain is an enclosed, extremely flat-floored basin, bounded to the east by the irregular continental margin of Portugal, onto which sediments have been channelled through the Lisboa and Setúbal canyons. The abyssal plain is surrounded by three major ridges: the Ma- deira-Tore Rise in the west, the Estremadura Spur in the north, and Gorringe Bank in the south. Gorringe Bank separates the Tagus Abyssal Plain from the Horseshoe Abyssal Plain.

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Figure 1. Geography of the Western Iberian Ecosystem, showing the main features referred to in the text. The 200 m bathymetric contour, that roughly delimits the continental shelf, is represented. From north to south: CO, Cape Ortegal; CF, Cape Finisterre; OC, Oporto Canyon; AC, Aveiro Canyon; NC, Nazare´ Canyon; CC, Cape Carvoeiro; CR, Cape Roca; CE, Cape Espichel; SB, Setu´bal Bay; CS, Cape Sines; CSV, Cape São Vicente; PC, Portimão Canyon; CSM, Cape Santa Maria. (Adapted from Relvas et. al., 2007)

7.3.3 Circulation The circulation of the west coast of the Iberian Peninsula is characterized by a complex current system subject to strong seasonality and mesoscale variability, showing reversing patterns between summer and winter in the upper layers of the shelf and slope (e.g., Barton, 1998; Peliz et al., 2005, Ruiz Villareal et al., 2006). During spring and summer northerly winds along the coast are dominant causing coastal upwelling and producing a southward current at the surface and a northward undercurrent at the slope (Fiúza et al., 1982; Haynes and Barton, 1990; Peliz et al., 2005, Mason et al., 2005). The intermediate layers are mainly occupied by a poleward flow of Mediterranean Water (MW), which tends to contour the southwestern slope of the Iberia (Ambar and Howe, 1979), generating mesoscale features called Meddies (e.g., Serra and Am- bar, 2002), which can transport salty and warm MW over great distance. The poleward flow observed along the west coast of the Iberian Peninsula is characterized by

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a transport of warm and salty water (typical surface anomalies, 1–1.5 _C and 0.1–0.3 in salinity) with velocities up to some 0.2–0.3 m s_1 reported by Haynes and Barton (1990) and Frouin et al. (1990). From the point of view of hydrological fields, this current, recently reviewed by Peliz et al. (2005), is characterized by a coastal downwelling of the isopycnal field of up to 200 m in an across-shore distance of about 40 km. The predominantly equatorward winds observed in summer off West Iberia, drive an offshore Ekman transport and force the upwelling of colder, nutrient-rich, subsurface waters along coast. Satellite-derived sea surface temperature (SST), have been used in the past decades to describe the upwelling patterns in the region, owing to the clear thermal contrast between the cold, vertically mixed, upwelled waters, typically found over the shelf, and the thermally stratified oceanic waters. As recently reviewed by Relvas et al. (2007) when equatorward winds start to prevail (late spring/early summer), a narrow band of cold water of relatively uniform width is observed along the coast, and small scale (20–30 km) perturbations are usually seen along the thermal front. Approximately one month after the beginning of upwelling favourable winds, major filament structures start to develop, associated with offshore currents reaching 0.5 m s_1, leading to the classical picture of what is usually called ‘‘fully developed upwelling’’ where several cold water filaments are seen to extend more than 200 km offshore. The new production of an entire upwelling season could be entirely exported to the open ocean by upwelling filaments (Arístegui et al., 2006) and organic matter sedimentation could take place far away from the upwelling source. However, the results of observations made by Barton et al. (2001) showed that a portion of the water transported off shelf recirculated back to the shelf on time scales of about 1 month, and this could have implications for the retention of biological material on the shelf (e.g. fish larvae). According to Relvas et al. (2007) the frontal band extending along all the Algarve coast indicates that the eastward advection of the cold water around Cape São Vicente may be linked to a larger water inflow into the Gulf of Cadiz, i.e., the eastern branch of the Azores Current. During winter the prevailing winds in the west coast of Iberian Peninsula are mainly south-westerlies, and the atmospheric circulation is dominated by the eastward displacement of cyclonic perturbations and their associated frontal systems (Relvas et al., 2007). However, in some years the presence of episodic atmospheric anticyclonic circulation (the Azores High) could give rise to northerly wind events during winter (Borges et al., 2003). The exchange of water masses through the Gibraltar Straits is driven by the deep highly saline (S>37) and warm Mediterranean Outflow Water (MOW) that flows into the Gulf of Cadiz and the less saline, cool water mass of the Atlantic Intermediate Water (AIW) at the surface.

7.3.4 Zooplankton The Portuguese continental shelf is under the influence of a summer upwelling, particularly active between June and September (Fiuza, 1982). The upwelling is likely the most important driving force of seasonally patterned oceanographic and biological processes on the shelf. In the spring, there is an increase in zooplankton biomass, in response to the supply of phytoplankton driven by upwelled nutrients, reaching biomass maximums in late spring and early summer (Cunha, 2001).

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7.3.5 Fish community Gomes et al. (2001) analyzed catch data from five bottom trawl surveys (four in the autumn and one in the spring) conducted off Portugal between 1985 and 1988 and the results indicated the existence of five spatially distinct fish assemblages. The sharpest biological transition on the Portuguese shelf takes place as one moves from areas shallower than 120 m (‘‘Shallow Groups’’) towards deeper locations offshore (‘‘Deep Groups’’). Beyond the 150 m isobath, the biomass was dominated by blue whiting, whereas inshore variability in assemblage composition was much greater. Within the shallow and deep clusters of stations, the major separation was associated with latitude. More recently Sousa et al. (2007) continued this work analyzing subsequent 22 surveys (1989–1999) conducted off Portugal (36–710 m depth) and confirmed the existence of five spatially distinct fish assemblages: shallow and intermediate (northern and southern), and deep assemblages. Depth and latitude correlated with major directions of biological turnover on the shelf, and accordingly, determined the geographical location of the assemblage boundaries. These did not change significantly between the summer and fall surveys, but there were seasonal changes in relative species composition within assemblages, which are discussed in light of known patterns of planktonic production associated with the seasonal upwelling. On the shelf plateau (<150 m), horse mackerel (Trachu- rus trachurus) was more important in autumn assemblages, whereas the pelagic crab (Polybius henslowii), and boarfish (Capros aper) dominated summer assemblages to the north and south, respectively. On the upper slope, the fish community was dominated by blue whiting (Micromesistius poutassou). Most species were confined to certain depth and latitudinal ranges, and in ubiquitous species (European hake, Merluccius merluccius, horse mackerel), mean body size increased from the shallower to the deeper assemblages. Southern groups extended deeper than northern groups. In particular, the depth range of the southern intermediate group was almost twice that of the northern intermediate group, both having an upper limit around 100 m. These differences are probably related to bottom topography, as the shelf is much steeper and less regular to the south than in the north, where it is relatively flat and shallow. The second gradient observed in the Portuguese marine community was associated with latitude. In most surveys, both the shallow and intermediate groups subdivided into groups of stations aligned with latitude. The latitudinal boundary appears to be located around the Nazaré Canyon (39◦30_N), a sharp physical discontinuity on the shelf and slope the biggest in Europe as explained above. According to Sousa et al. (2005) the north–south biological discontinuity is not exclusively due to this canyon, but rather to differences in shelf and coastal morphology, bathymetry, river runoff, and ocean currents along the north and southern parts of the shelf.

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Figure 2. Map of the demersal assemblages in the summer of: (a) 1990 and (b) 1995. Two intermediate assemblages are observed in the summer of 1990, whereas one single overall intermediate group is present in the summer of 1995 (adapted from Sousa et al., 2005).

Based on 11 groundfish surveys from 1989 to 1999 analyzed by Sousa et al. (2005), in the shallow southern assemblage the most abundant species was boarfish and the second most abundant was horse mackerel. There were six additional species, which recurred in at least 25% of the surveys: hake, bogue, axillary seabream (Pagellus acarne), Atlantic mackerel, blue jack mackerel, and pelagic crab. Species richness was the highest among the assemblages. The sparids (including bogue andaxillary seabream) were a distinct feature of this assemblage as they were rare in catches elsewhere. Other distinct species in the assemblage were blue jack mackerel and At- lantic mackerel. In the intermediate northern, five species persisted: blue whiting, hake, pelagic crab, Atlantic mackerel, and squids. In the deep assemblage blue whiting dominated and deepwater shrimps were the most important species next to the blue whiting, and these included white glass shrimp, golden shrimp, deepwater rose shrimp (Parapenaeus longirostris) and blue and red shrimp (Aristeus antennatus). The number of assemblages identified and their main characteristics did not differ much from a previous study by Gomes et al. (2001) that used data from only four demersal autumn surveys (1985–1988) and described five autumn assemblages along similar gradients of depth and latitude. The results of multivariate techniques indicated that these assemblages were associated primarily with a depth gradient, a pattern already reported for other parts of the Atlantic (Mahon et al., 1984; Overholtz and Tyler, 1985; Bianchi, 1992; Gomes et al., 1992; Fariña et al., 1997).

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7.3.6 References Arístegui, X.A. Álvarez-Salgado, E.D. Barton, F.G. Figueiras, S. Hernández-León, C. Roy and A.M.P. Santos, 2006. Oceanography and fisheries of the Canary current/Iberian region of the eastern North Atlantic, A.R. Robinson, K.H. Brink, Editors The Sea, vol. 14b. The Global Coastal Ocean: Regional Studies and Syntheses, Harvard University Press, Cam- bridge, MA (2006), pp. 877–931.

Barton, E.D., 1998. Eastern boundary of the North Atlantic: Northwest Africa and Iberia coastal segment. In: The Sea (Ed. By A.R. Robinson & K.H. Brink). John Wiley & Sons, Inc., pp. 633-658.

Barton, E.D., Arístegui, J., Tett, P., Canton, M., Garcia-Braun, J., Hernandez-Leon, S., Nykjaer, L., Almeida, C., Almunia, J., Ballesteros, S., Basterretxea, G., Escanez, J., Garcia-Weill, L., Hernández-Guerra, A., Lopez-Laatzen, F., Molina, R., Montero, M.F., Navarro-Pérez, E., Rodriguez, J.M., Van Lenning, K., Velez, H. and K. Wild, 1998. The transition zone of the Canary Current upwelling region. Progress in Oceanography, 41: 455-504.

Bianchi, G., 1992. Demersal assemblages of the continental shelf and upper slope of Angola. Marine Ecology Progress Series, 81: 101–120.

Borges, M.F., Santos, M., Crato, N., Mendes, H., Mota, B., 2003. Sardine regime shifts off Portu- gal: a time series analysis of catches and wind conditions. Scientia Marina, 67 (Suppl. 1): 235-244.

Fariña, A.C., Freire, J., and E. González-Gurriarán, 1997. Demersal fish assemblages in the Galician continental shelf and upper slope (NW Spain): Spatial structure and long-term changes. Estuarine Coastal and Shelf Science, 44: 435-454.

Fiúza, A.F.G., Macedo, M.E. and R. Guerreiro, 1982. Climatological space and time variations of the Portuguese coastal upwelling. Oceanol. Acta, 5: 31-40.

Frouin, R., Fiúza, A.F.G., Ambar, I. and T.J. Boyd, 1990. Observations of a poleward surface current off the coast of Portugal and Spain during winter. Journal of Geophysical Re- search, 95: 679-691.

Gomes, M.C., Serrão, E., and M.F. Borges, 2001. Spatial patterns of groundfish assemblages on the continental shelf of Portugal. ICES Journal of Marine Science, 58: 633-647.

Haynes, R. and E.D. Barton, 1990. A poleward flow along the Atlantic coast of the Iberian Pen- insula. J. Geophys. Res., 95: 11425-11441.

Mahon, R., Smith, R. W., Bernstein, B., and Scott, J. S., 1984. Spatial and temporal patterns of groundfish distribution on the Scotian Shelf and in the Bay of Fundy, 1970–1981. Canadian Technical Report of Fishery and Aquatic Science, 1300.

Mason, E., Coombs, S., Oliveira, P.B., 2006. An overview of the literature concerning the oceanography of the eastern North Atlantic region. Relat. Cient. Téc. IPIMAR Série digital (http://ipimar-iniap.ipimar.pt) nº 33, 58 pp.

Mougenot, D., 1989. Geologia da margem Portuguesa. Docs. Tecnicos Inst. Hidrografico, 32, 259 pp.

Mougenot, D., 1985. Progradation on the Portuguese Continental Margin: interpretation of seismic facies, Marine Geol., vol. 69, nº 1/2, pp. 113-130.

Mougenot, D., 1988. Geologia da Margem Portuguesa, in Pub. (G)-IH-192-DT, Tese, Univ. Pier- re et Marie Curie, Paris VI, 259 p.

Mougenot, D., & Vanney, J. R., 1982. Les rides de contourites plio-quaternaires de la pente continentale sud-portugaise. Coll. Intern. CNRS, Bull. Inst. Géol. Bassin d'Aquitaine, Bor- deaux, vol. 31, pp. 131-139.

Overholtz, W. J., and Tyler, A. V., 1985. Long-term responses of the demersal fish assemblages of Georges Bank. Fishery Bulletin, 83: 507–520.

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Peliz, A., Dubert, J., Haidvogel, D. B., and Le Cann, B., 2003. Generation and unstable evolution of a density-driven eastern poleward current: The Iberian poleward current. Journal of Geophysical Research. C. Oceans, 108, C8.

Peliz, A.J., Dubert, J., Santos, A.M.P., Oliveira, P.B. and B. Le Cann, 2005. Winter upper ocean circulation in the Western Iberian Basin - Fronts, Eddies and Poleward Flows: an overview. Deep-Sea Research Part I-Oceanographic Research Papers, 52: 621-646.

Relvas, P., E. Barton, J. Dubert, P. Oliveira, A. Peliz, J. da Silva, and A. Santos, 2007. Physical oceanography of the western Iberia, ecosystem: Latest views and challenges, Prog. Ocean- ogr., 74, 149–173.

Ruiz-Villarreal, M., Gonzalez-Pola, C, Diaz del Rio, G., Lavin, A., Otero, P, Piedracoba, S., and J.M. Cabanas, 2006. Oceanographic conditions in North and Northwest Iberia and their influence on the Prestige oil spill. Mar. Pollut. Bull., 53: 220-238.

Sousa, P., Azevedo, M., Gomes, M.C., 2006. Species-richness patterns in space, depth, and time (1989-1999) of the Portuguese fauna sampled by bottom trawl. Aquat. Living Resour. 19, 93-103.

Sousa, P., Azevedo, M., Gomes, M.C., 2005. Demersal assemblages off Portugal: Mapping, seasonal, and temporal patterns Fisheries Research 75, 120-137.

Tyler, P., Amaro, T., Arzola, R., Cunha, M.R., de Stigter, H., Gooday, A., Huvenne, V., Ingels, J., Kiriakoulakis, K., Lastras, G., Masson, D., Oliveira, A., Pattenden, A., Vanreusel, A., Van Weering, T., Vitorino, J., Witte, U. and Wolff, G., 2009. Europe’s Grand Canyon: Nazaré Submarine Canyon. Oceanography, 22, (1), 46-57.

Vanney J-R, Mougenot D., 1981. La Plateforme continentale du Portugal et les Provinces adja- centes: analyse géomorphologique. Memórias dos Serviços Geológicos de Portugal, Lis- boa, 28: 86 p (+ 41 fig.).

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Table 2. WGEAWESS Natural Components/process for South Western Iberia (B) - From Nazaré Canyon (39º 30’ N, 9º 55’W) - to Saint Maria Cape (36º 57’N, 7º 53’ W).

TEMPORAL SPATIAL CONTACT Component/Variables Platform Method DataType UNITS Extent (year) Resolution Extent Resolution (CTD, (Models satellite …) Observations) Physico- ICESData Chemical / Hydrology base ?? Temperature Surveys Nansen O °C 1979s- Annual/ Portugal shelf/ IPIMAR (acoustics, CTD present season slope demersal) Satellite SST O ºC ?? Plymouth NOAA Buoys O IH

Models ? M ºC ?? ? ? UALG

Salinity Surveys Nansen O 1979s- Annual (spring, Portugal IPIMAR (acoustics, CTD present summer shelf/slope demersal) autumn) Surveys CTD O ?? IH Satellite Satellite O 1982 Day/month global Plymouth NOAA Buoys O ? ? IH Oxygen Surveys Nansen O 1979s-?? Portugal shelf IPIMAR

pH Surveys Nansen O 1979 -?? Portugal shelf IPIMAR

Turbidity

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Currents Buoys O ? IH Waves wavemeters O ? IH River Runoff ??? ???? ??? INAG Meteorology (winds, IM IPIMAR …) Upwelling surveys CTD O IPIMAR / Stratification satellite SST M IPIMAR gradients O Geomorphology Bathymetry M Portugal 250m grid IH shelf/slope Coastal M Portugal 250m grid IH morphology shelf/slope Sediment Survey O Portugal 250m grid IH dregde shelf/slope Biogenic Substrat Water energy at Mesh M Portugal 250m grid IPIMAR+UA+UAlg seabed Atlantic shelf/slope Project Habitat classification Mesh Acoustics; O m; µm; 2010-2013 Annual Portugal shelf 250m grid IPIMAR+UA+UAlg IPIMAR (Eunis …) Atlantic grab no.0.1m-2; (Sines area) Project sampling others Mesh M Portugal 250m grid IPIMAR+UA+UAlg Atlantic shelf/slope Project Biology (species /

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population / community) Detritus /Bacterials Phytoplancton satellite Remote mg/m3 1996 NOAA Plymouth sensing Station O ??? ??? IPIMAR grids

Benthic phytoplancton (µphytobenthos …) Macrophyte Zooplankton Station O ??? ???? IPIMAR grids

Epibenthic fauna Benthic Grab O No.0.1m-2. Historical Annual ; Shelf. IPIMAR surveys; sampling; Qualitative 2006/2010 seasonal ; Estuarine others others ocasional Endobenthic fauna Benthic Grab O No.0.1m-2 Historical Annual ;seasonal ; Shelf. IPIMAR surveys sampling 2006/2010 ocasional Estuarine Fish RV Surveys Acoustics O 1979- IPIMAR present Bottom O 1979- IPIMAR trawl present Egg O 1992-present IPIMAR surveys Sea Birds surveys Acoustics O number sporadic ICN Mammals surveys Onboard O number sporadic ICN

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records

Exploited species Harbour Landings O 1896-present IPIMAR DGPA, INE, census Sampling Discards O 1990- IPIMAR

Sensitive/endangered RV Surveys O 1979- IPIMAR species (Corals,…) present

Widely distributed RV Surveys O 1979- IPIMAR stocks present

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7.4 North Western Iberia (NWI, Region C)

Enrique Nogueira and Rafael González-Quirós 1

7.4.1 Geography, bottom topography and climate The North Western Iberia (NWI) subregion lies between Cape Estaca de Bares (ca. 43°48’N, 7°41’W) and Cabo Carvoeiro (ca. 39°21’N, 9°24’W). The NWI continental shelf runs south-westward between Cape Estaca de Bares and Cape Finisterre (ca. 42°53’N, 9°16’W) and then approximately in a meridional direction along ca. 9ºW (Figure 1). The coastal margin in Galicia, between Cape Estaca de Bares and the mouth of the river Miño (at ca. 41°52’N), is the most irregular section of the Iberian Peninsula and contains numerous ria-type estuaries. Rocky shores in Galicia predominate over sandy beaches, which represent ca. 14% of the coast. Between the mouth of the river Miño and approximately the 41°N the coastline is mostly rocky. Southward from the 41°N down to just north of the Nazaré Canyon, the coastline is mostly rectilinear and sandy (OSPAR, 2000). The continental shelf is narrow in Galicia (ca. between 30–40 km) and relatively wide between the river Miño and the Nazaré Canyon (ca. between 50–70 km). The continental slope is steep with a slope around 10%. Contourite sediments, which are mainly of continental origin, predominate in the continental margin. The substrate at the slope and outer shelf is mainly muddy, whereas the inner shelf (depth < 100 m) has predominantly rocky or sandy substrate. Inside and off the Galicia rias (see below), the sediments are muddy with high content of organic matter. A series of large topographic features (i.e. marine landscapes) can be distinguished on the shelf. The Galician coast is indented by numerous rias, flooded tectonic valleys that behave as partially mixed estuaries with a two-layered positive residual circulation pattern. The Rias Altas, those comprised between Cape Estaca de Bares and Cape Finisterre, are smaller and more exposed to the oceanic influence than the Rías Baixas, those between Cape Finisterre and the river Miño. Fine sediments with high organic content predominate in the inner part of the rias, the estuarine proper, while sand and gravel predominate in the central and outer parts. At ca. 42°40’N and 200 km off the Iberian coastal margin lies the Galicia Bank, a plain originated as a frag- ment of the continental shelf which rises to depths around 500 m, being an important fishing ground. The Nazaré Canyon is located In the southern part of the NWI . The climate at the NWI can be classified as oceanic (Cfb in the Köppen climate classification system) in the northernmost part (e.g. Rias Altas), characterised by relatively cool summer and warm winters, with a narrow annual temperature range (ca. 10 °C) and precipitations evenly dispersed around the year. Southward from Cape Finis- terre, the climate is still oceanic but with increasing Mediterranean character (Csb), characterized by warm to hot, dry summers and mild to cool, wet winters. The mean of the total annual precipitation varied from 1200 mm•year-1 in Vigo to less than 800 mm•year-1 in the southernmost part of the subregion. The wind pattern is governed by the position of the two main centres of activity in the North Atlantic: the anticy- clone south of 40°N (the Azores High) and the low pressure area centred around 60°N (Iceland Low). Between these two areas, the prevailing winds are relatively

1 Instituto Español de Oceanografía. Centro Oceanográfico de Gijón. Avda. Príncipe de Astu- rias 70-bis, 33212-Gijón

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strong from the west and southwest in winter. In summer, the northward displacement and reinforcement of the Azores High give rise to a predominance of equatorward coastal winds that promote coastal upwelling. Besides, the development of thermal lows in the Iberian Peninsula reinforce northerly winds, which can sometimes reach near gale force during the afternoon as a result of the intense heating over the continent (OSPAR 2010).

7.4.2 Hydrography and circulation The NWI lies in the inter-gyre region that separates the subpolar and subtropical oceanic gyres, bounded to the north by the south-eastern branch of the North Atlantic Current (NAC) and to the south by the Azores Current (AC ) (Maillard, 1986). Sur- face currents across this region are weak (1–2 cm•s-1) and run south-westward (Krauss, 1986, Pollard et al., 1996) seeding the equatorward Portugal Current (PC) (Maillard, 1986). At the slope and outer part of the shelf, a poleward-flowing slope current (Iberian Poleward Current, IPC) occur due to the geostrophic adjustment of the cross-shore density gradient. The IPC is as a narrow (25–40 km wide), weak (5–30 cm•s-1), sub-surface current (core about 200 m deep) bounded to the shelf-break zone off the Western Iberian margin (Frouin et al., 1990; Haynes and Barton, 1990). Pingree and Le Cann (1990, 1992a, b, 1993) described the poleward flowing slope currents along the northern Iberian shelf and slope and the Bay of Biscay as an intercon- nected circulation process. Currents in the shelf are then governed by the combined effects of the IPC, tides, low-density buoyancy structures due to continental runoff and coastal upwelling / downwelling events promoted by equatorward / poleward winds (OSPAR, 2000). Hydrodynamic processes show a strong seasonality, characteristic of temperate mid- latitudes. Minimum sea surface temperature (SST) of ca. 13 ºC is observed in winter. Thermal stratification begins in early spring and increases towards the summer, when SST reaches values around 17 ºC in August. In autumn, atmospheric cooling and increased frequency and intensity of storms associated to the passage of low pressure systems progressively increase the mixed layer depth towards winter conditions. The relatively narrow range of the seasonal oscillation of SST, compared for instance to that observed in the adjacent SBoB subregion, is due to the occurrence of upwelling, which reaches maximum intensity in summer. Several atmospheric and hydrodynamic processes induce noticeable spatial-temporal variability. The most conspicuous is the occurrence of coastal upwelling between March and October, with maximum intensity around the summer. The northward displacement and intensification of the Azores High during the summer and the development of thermal lows over the Iberian Peninsula favours equatorward winds that provoke intense and frequent coastal upwelling and associated filaments, and induce the ascent up to the surface of sub-surface cold, nutrient-rich waters along the NWI subregion. Coastal upwelling processes have important consequences on the characteristics and dynamics of the marine ecosystem, for instance, on primary production and on the distribution of certain species (see below). The Iberian Poleward Current (IPC) develops and presents its higher intensity in autumn (i.e. development phase of the IPC), flowing northward along the NWI shelf break and penetrating into the Bay of Biscay along the Cantabrian coast with decreasing intensity (Pingree and Le Cann, 1990). The IPC is characterized by higher temperature and salinity, generating fronts between coastal and offshore waters that modify the homogeneity pattern of winter hydrography. Those frontal structures af-

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fect plankton distribution, and differences in plankton communities are observed between the IPC and coastal water masses (Cabal et al., 2008). Low-density buoyant structures are of considerable importance due to runoff from the Rias Baixas and river discharges from Miño and Douro. Runoff shows marked seasonality, with maximum values from late-autumn to early-spring and minimum values during the summer. During winter, the confluence of maximum development of the IPC, predominant downwelling favourable westerly and south-westerly winds and intense runoff promote the incidence of a persistent low-density buoyant structure between Cape Finisterre and the outflow from the river Douro, which is named the Winter Buoyant Iberian Plume (WBIP). This structure generates a haline front parallel to the coastline approximately located over the mid-shelf, acting as a barrier that diminishes the intensity of across-shelf exchange.

7.4.3 Biological ecosystem components

7.4.3.1 Bacteria The abundance of benthic bacteria is related to the content of organic matter in the sediments. Along the NWI, the highest concentrations of benthic bacteria (ca. between 108 to 109 cells/g dry weight of sediment) occur close to urban areas and inside the rias, especially in the Rias Baixas that support intensive mussel culture and other aquaculture activities. The concentration decreases offshore where the amount of organic matter in the sediments is lower. The abundance of autotrophic picoplancton (organisms between 0.2 to 2 µm in size), mainly due to bacteria of the genus Prochlorococcus and Synechococcus, shows a marked seasonality, with maximum values of ca. 108 cells•L-1 in summer and minimum around ca. 106 cells•L-1 during the winter-spring transition (Morán et al., 2011). The abundance of autotrophic nano-flagellates ranges between 106 and 107 cells•L-1 (OSPAR, 2000). The abundance in the NWI is significantly lower than that in the SBoB, which can be related to a relatively higher abundance of total phytoplankton (with chlorophyll concentration as a proxy) and higher contribution of larger size- classes (nano- and micro-phytoplankton) in the NWI than in the SBoB (Bode et al., 1994). This difference in the structure of the phytoplankton community can be a consequence of the outsized relevance of fertilisation processes linked to a relatively higher intensity of runoff and coastal upwelling in the former of these subregions. The abundance of pelagic heterotrophic bacteria shows also a marked seasonality, with maximum values of ca. 108 cells•L-1 in summer and minimum of ca. 109 cells•L-1 in winter (Morán et al. 2011). The abundance is generally higher in the NWI than in the SBoB probably due, as mentioned above, to differences in the trophic conditions in both subregions, with imply lower availability of inorganic nutrients and dissolved organic matter during summer in the SBoB than in the NWI (Bode et al., 2001).

7.4.3.2 Phytoplankton The seasonal pattern of phytoplankton biomass in the NWI is characteristic of a temperate ecosystem under the influence of recurrent episodes of coastal upwelling. Sea- sonality is mostly governed by the mixing/stratification cycle of the water column and the consequences that it has on the availability of nutrients and light (OSPAR, 2000), giving rise to the occurrence of characteristic spring and autumn blooms of phytoplankton during the period of transient thermoclines (progression of stratification and de-stratification in spring and autumn respectively). The oligotrophic condi-

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tion characteristic of the stratified period is, however, frequently relaxed by the input of nutrients to the surface layer associated to the occurrence of coastal upwelling events between March and October. The occurrence of phytoplankton blooms, as deduced from SeaWiFS satellite images, are frequent during most of the year south of Cape Finisterre and also, although less intense and recurrent, in the northern part of the NWI (Bode et al., 2011). This seasonal pattern of phytoplankton biomass, and consequently of primary production, contrasts with that observed in the adjacent SBoB subregion. The chlorophyll concentration (subrogate of phytoplankton biomass) integrated in the euphotic zone (i.e. between surface and a maximum of 40 m depth) in shelf waters at the northern part of the NWI varied between ca. 15 and 70 mg Chl•m- 2 during the winter minimum and the spring bloom maximum. During summer, in stratified conditions the concentration is around 35 mg Chl•m-2, ascending to ca. 60 mg Chl•m-2 during upwelling events. South of Cape Finisterre, integrated chlorophyll during the winter minimum and in summer stratified conditions are similar to those observed in the northern part of the NWI, while values during the spring bloom and under upwelling are significantly higher, ca. 80 and 65 mg Chl•m-2 respectively (OSPAR, 2000). Diatoms predominate during the spring and autumn blooms, while dinoflagellates do so during summer when the water column is stratified (Fernández & Bode, 1994). The phytoplankton assemblages in the NWI are similar to those in the SBoB. Domi- nant diatoms species during the seasonal blooms are Chaetoceros socials, Ch. dydimus, Lauderia borealis, Thalassiosira fallax, Schroderella delicatula and Rhizosolenia setigera. During the stratification period, the phytoplankton assemblage is composed by diatoms such as Leptocyclindrus danicus, Chaeoceros affinis and Rhizososlenia delicatula and dinoflagellates such as Dinophysis acuminata, D. acuta, Gyrodinium spirale, Protoperidinium bipes and several species from the genus Ceratium (OSPAR 2000). During the winter period, the assemblage is composed by perennial species and small diatoms (e.g. Skeletonema costatum, Nitzschia longis- sima, Pseudo-nitzschia spp.), dinoflagellates (Gyrodinium glaucum, G. spirale), microflagellates and re-suspended phytobenthos (Paralia sulcata). During summer upwelling events, the phytoplankton assemblage is composed mainly by small-sized, chain-forming diatoms such as Chaetoceros socialis, Rhizosolenia delicatula and Pseudo-nitzschia spp. During the development phase of the IPC, from late-autumn to early-spring, the IPC domain has lower phytoplankton biomass than the coastal and mid-shelf domain, which at this time of the year is generally occupied by the low-density structure associated with the WIBP, and relatively higher proportion of small flagellates and dinoflagellates (Álvarez-Salgado et al., 2003). Toxic dinoflagellates and diatoms are also regular components of the phytoplankton community. These harmful algal bloom (HAB) species can cause shellfish toxicity at concentrations as low as 102-103 cells•L-1. For instance, the dinoflagellates Gymno- dinium catenatum and Alexandrium minutum (=lusitanicum) can provoke PSP (Paralytic Shellfish Poisoning) outbreaks, while species from the genus Dinophysis such as Dinophysis sacculus, D. acuminata, D. caudata and D. tripos can provoke DSP (Diarrheic Shellfish Poisoning) outbreaks. AMP (Amnesic Shellfish Poisoning) can be produced by the diatom Pseudo-nitzzchia australis. Cape Finisterre seems to be a biogeographic boundary for the proliferation of HAB species such as G. catenatum, D. acuta, D. acumunita.

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7.4.3.3 Zooplankton The zooplankton community in the NWI is comparatively less diverse than that encountered in the adjacent SWI and BoB subregions. The number of species found in the NWI is around 85, accounting for ca. 60% of the total zooplankton abundance, while the number of species (and its contribution to total zooplankton abundance) is ca. 140 (ca. 30% of abundance) and ca. 95 (ca. 70% of abundance) in the adjacent SWI and SBoB subregions respectively (OSPAR, 2000). The main groups of meroplankton are Cirripeda, Gastropoda, Decapoda and Bivalvia with percentages of relative abundance around 60, 10, 10 and 5% respectively. These groups show, however, a marked seasonality, characterised by peaks in abundance during the spawning and breeding season of the species concerned (OSPAR, 2000). Their spatial distribution is also highly variable, although the abundance tend to be higher in coastal than oceanic environments. Due to the intense shellfish culture carried out mainly in the Rías Baixas, the contribution of Bivalvia, mainly larval stages from Mytillus galloprovincialis, could outnumbered that of other meroplankton groups in certain times of the year. Within the holoplankton component, Copepoda is the most important group in terms of species richness, persistence, abundance and ecological significance (Valdés et al., 2007). The percentage of relative abundance of copepods represents on average nearly 70% of the holoplankton, although its contribution could rise to nearly 90% during peaks of zooplankton abundance. Other relevant groups are Cladocera and Appendiculata, which can represent 10% each. The seasonal pattern of mesozooplankton biomass is conspicuous, but differs notably between the northern and southern parts of the NWI (Bode et al., 2011). In the northern part, for instances off the Ría de A Coruña, average seasonal values of dry weight are around 35 mg•m-3 in spring and autumn, decrease slightly during summer (ca. 30 mg•m-3), and reach minimum values during winter (ca. 5 mg•m-3). To the south of Cape Finisterre, for instances off the Ría de Vigo, the seasonal cycle of mesozooplankton biomass shows a single summer peak of ca. 50 mg•m-3 on average. This contrasting pattern could be linked to a higher frequency and intensity of upwelling south of Cape Finisterre. The long-term average and the maximum values of biomass are also generally higher south of Cape Finisterre. For instances, these values are ca. 29 and 23 mg•m-3, with peaks of ca. 150 and 100 mg•m-3, off the rias de Vigo and A Coruña respectively. These values are also higher than those estimated for the adjacent SBoB subregion (ca. 20 and 50 mg•m-3 off Cape Peñas, in the central part of the SBoB subregion). In the oceanic part, abundance and biomass tend to be lower than in the neritic and coastal environments. Despite the high diversity of copepods, the major contribution to total biomass is due to a relatively reduced number of species. For instances off Vigo, only six species account for ca. 80% of the total biomass of copepods (Bode et al., 2011): Calanus helgolandicus (V-VI) (ca. 28%), Acartia clausi (ca. 23%), Centropages chierchiae (ca. 9%), Pseudocalanus elogantus (ca. 8%), Clausocalanus spp. (ca. 11%), Paraeuchaeta hebes (5%). For some species, such as C. helgolandicus and A. clausi, the spring peak tends to occur later in the NWI than in the adjacent SBoB subregion (Bode et al., 2011), presumably due to the lower temperatures reached in the former subregion due to the frequent occurrence of upwelling, which could slow down the development of eggs and initial stages of these species in the NWI relative to the SBoB subregions. How- ever, other species such as Clausocalanus spp. may show a contrasting pattern, with

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peaks occurring earlier south than north of Cape Finisterre, and in these zones earlier than in the SBoB subregion. The seasonal pattern of total copepod abundance and of the abundance of the main species varies, however, associated to topographic and hydrodynamic features. The main deviations of the average seasonal pattern occur in estuaries and shallow coastal areas where buoyancy structures associated to runoff pulses and coastal upwelling events alter fertilization and water column structure (OSPAR, 2000).

7.4.3.4 Small pelagic fishes The main small pelagic fish species in the NWI are sardine (Sardina pilchardus) and mackerel (Scomber scombrus). The rest of the small pelagic community is conformed by other less abundant species more common to subtropical waters, such as chub mackerel (S. colias), Mediterranean horse mackerel (T. mediterraneus) and blue jack mackerel (T. picturatus).

7.4.3.4.1 Sardine Sardine (Sardina pilchardus) in the NWI belongs to the Iberian-Atlantic population. Recruitment occurs nearby the western Bay of Biscay subregion (WBoB) and mainly on the western Iberian Peninsula (which includes the southern and northern subregions –SWI and NWI respectively). Sardine presents a protracted spawning season from autumn to spring. The autumn and spring peaks are not as differentiated as in the SBoB, because spawning in winter is relatively high compared to the SBoB, where it is negligible (Stratoudakis et al., 2007). Furthermore, in the NWI spawning intensity can be of the same magnitude, or even higher, than during the spring period, whereas in the SBoB the spring peak is markedly higher than the autumn peak (Solá et al., 1990). Spawning takes place close to the bottom around dusk along the shelf in coastal waters, although the spawning area may extend over the entire shelf, particularly in years of high spawning intensity. Areas of intense and recurrent upwelling prone to strong offshore transport, like the northern part of the NWI, are generally avoided. Sardine is an important resource for local purse-seiners in the NWI.

7.4.3.4.2 Mackerel Mackerel (Scomber scombrus) show a large distribution area, covering the North At- lantic and the Mediterranean. It is an active migratory species which forms schools, sometimes of large densities. It is a serial spawner whose spawning area in the North East Atlantic extends from the west of the British Isles to Western Iberian Peninsula. In the NWI subregion, spawning is mostly from January to May in the Spanish- Portuguese border (Solá et al., 1990; Rodriguez, 2008). Maximum spawning intensity progressively moves northward along the West European Shelf in relation with the development of the spring phytoplankton bloom (Coombs et al., 1990). Once spawning is over, it keeps migrating to the feeding grounds at the north of the North Sea, where overwintering between November and February occurs. After overwintenring, mackerel migrates southward, towards the spawning grounds (Uriarte and Lucio, 2001; Uriarte et al., 2001). This migratory behaviour seems to be associated with slope currents (such as the IPC) (Reid, 2001). These migrations are the cause of the seasonality seen in the mackerel fishery in the NWI and SBoB subregion (Villamor et al., 1997). Events of strong local wind and/or offshore Ekman transport during the spawning season may have an effect on mackerel larval survival and thus recruitment in the NWI and SBoB subregions (Villamor et al., 2004a; Villamor et al., submitted).

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7.4.3.5 Demersal and benthic fish The diversity of demersal and benthic fish species is relatively high in the NWI due to the co-occurrence of sub-tropical, temperate and boreal species. Species richness, distribution and abundance are determined, however, by the narrowness and topography of the continental shelf. Five types of communities characterise the area, corresponding to species inhabiting the shallow coastal waters, mid shelf, outer shelf, shelf break and slope (OSPAR, 2000). About 75% of the total biomass of demersal fish species in the NWI (and SWI) is accounted for: snipefish (Macroramphosus scolopax), boarfish (Capros aper), blue whiting (Micromesistus potassou), horse mackerel (Trachu- rus trachurus), mackerel (Trachurus picturatus), chub mackerel (Scomber japonicus), dogfish (mainly the lesser-spoted dogfish, Scyliorhinus canicula), hake (Merluccius merluccius), and seabream (Pagellus acarne). Other exploited species are anglerfish (Lo- phius piscatorius and L. budegassa) and megrim (Lepidorhombus boscii and L. whiffiagonis).

7.4.3.5.1 Blue whiting Blue whiting (Micromesistus potassou) is the most abundant demersal species in the North Atlantic. It is a migratory species distributed near the bottom, between 200 and 500 m depth, which perform diurnal vertical migrations. Larger individuals (>25 cm) tend to concentrate at deeper layers, between 500–700 m depth. It is the main prey for larger predators. The biomass located in the NWI is a relatively minor component (<10%) of the total biomass of the North Atlantic stock, and is integrated mainly by juveniles that come into the subregion from northern locations (Sánchez & Olaso, 2004).

7.4.3.5.2 Horse mackerel Horse mackerel (Trachurus trachurus) in the Atlantic is distributed from the coasts of Cape Verde up to the northern North Sea. The adults are considered a demersal species, whereas the juveniles behave as pelagic. It is a serial spawner whose spawning area stretches from the British Isles towards the south throughout its area of distribution. In the NWI it has a longer spawning season from March to August (Solá et al., 1990; González-Quirós, 1999; Rodriguez, 2008). It performs spawning and feeding migrations, but these are less evident than those of mackerel. Three stocks are currently recognized in the northeast Atlantic: Southern stock, North Sea stock and Western stock. Recently, horse mackerel in the NWI and SBoB has been included within the Western stock, which extends from Galicia northwards throughout the western European coast (ICES, 2005).

7.4.3.5.3 Dogfish and rays The lesser-spotted dogfish (Scyliorhinus canicula) constitutes 80% of the dogfish that inhabits the shelf (Sánchez & Olaso, 2004). Other species which belong to this group are small sharks that inhabit the outer shelf and slope, such as Galeus melastomus and Etmopterus spinax. At least eight species of rays inhabit the area, being the most abundant Raja clavata, which represent 50% of the biomass of this group.

7.4.3.5.4 Hake European hake (Merluccius merluccius) is the most important demersal fishery resource in the NWI and SBoB. Spawning occurs preferentially at the shelf break, and it is particularly intense during the first quarter of the year in the SBoB. Young fish remain in the nursery grounds during one year after spawning, scattering afterwards over the continental shelf.

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7.4.3.5.5 Anglerfish Two species of anglerfish are present in the NWI (Lophius pescatorious and L. budegassa), distributed from shallow to deep waters up to 800 m depth. Younger fish live in shallow waters moving to deep waters as they grow. Spawning occurs between October and March and the age of first maturity is around 8 years old (OSPAR, 2000). It is estimated that the biomass of anglerfish in the NWI subregion is about 50% of the spawning southern stock biomass (Sánchez & Olaso, 2004).

7.4.3.5.6 Megrim Two megrim species of the genus Lepidorhombus inhabit in the NWI, L. boscii and L. whiffiagonis. These species are distributed in sandy or muddy sea floor between 100 and 700 m depth.

7.4.3.6 Macrophytobenthos communities The occurrence of estuaries and rias in the northern part of the NWI provide the most diverse, rich and complex of the habitats for macrophytes along the Iberian Penin- sula. This area is characterised by a mixture of sub-tropical, temperate and boreal species, with a relatively high proportion of Fucales and other brown algae. The infralittoral zone is dominated by Gelidium sesquipedale. The occurrence of coastal upwelling favours the settlement of boreal species. Fucales are particularly abundant in the inner part of the Rías Baixas, although the intense aquaculture activities, the most important of which is mussel culture, facilitate the proliferation of other algae such as those from the genera Ulvales.

7.4.3.7 Benthic invertebrates Macrofauna (> 1 mm in size) on hard substrates in the upper intertidal zones is dominated by sessile or slow moving species comprising barnacles, limpets, lit- torinids and topshells. The dogwhelk (Nucella lapillus) and large patches of mussels (Mytilus galloprovincialis) are common species in the NWI. Lower intertidal and subtidal zones are dominated by dense stands of macrophytobenthos communities interspersed with barren areas dominated by sea urchins (Paracentrotus lividus and Echinus esculentus). Macrofauna on soft substrates is strongly related to grain size, depth and organic matter content of the sediment (OSPAR, 2000). In the intertidal and shallow sub-tidal zones two major communities predominate: Macomama which occurs on intertidal muddy sediments and Tellina, a Lusitanian-boreal community that occurs at medium to low tidal levels on fine to medium sandy sediments. In the inner subtidal sediments of the rias, which are muddy and occasionally hypoxic, very dense populations of Thyasira flexuosa predominate. Fine sand in the mid and outer parts of the rias favours the development of communities dominated by Tellina fabula and Paradoneis armata. Coastal upwelling results in benthic enrichment which favour the development of small surface-feeding and fast growing polychaetes. Meiofauna (1– 0.06 mm in size) is an important component in relation to the trophodynamics of the benthos. In the Galician rias, nematodes dominate followed by harpaticoid copepods. In those rias where sediments have a high content of organic matter, such as the Ria de Arousa, Comesomatidae species, such as Sebatatieria pulchra and Metacomesoma punc- tuatum, dominate, while in other rias with lower organic matter, such as the Ria de Muros, the Desmodoridae are the dominant family. On the continental shelf, with high oxygen levels and low bioturbation, densities of meiofauna are 10 to 100 times greater than in the rias. Nematodes predominate, representing 78% of total biomass, with Sabateria pulchra and S. ornate the most abundant species.

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7.4.3.8 Top predators The waters of the NIW are home to a wide variety of cetaceans and seabirds. A total of 20 species of cetaceans have been recorded in Galicia (López et al., 2004) of which the most abundant are the common dolphin (Delphinus delphis) in shelf waters and the bottlenose dolphins (Tursiops truncatus) in the rías. Other species found in the area include the harbour porpoise (Phocoena phocoena), the Iberian population of which is genetically distinct (Fontaine et al., 2007). This area is important for the win- tering of seabirds and there have been recorded also breeding colonies of some species including the Cory´s shearwater (Calonectris diomedea), European shag (Phalacrocorax aristotelis), the storm petrel (Hydrobates pelagicus) and seagulls (Larus spp.).

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Villamor, B., C. Gonzalez-Pola, A. Lavín, L. Valdés, A. Lago de Lanzós, C. Franco, J.M. Ca- banas, M. Bernal, C. Hernandez, M. Iglesias, P. Carrera and C. Porteiro. 2011 Environ- mental control of North East Atlantic mackerel (Scomber scombrus) recruitment in the Southern Bay of Biscay: Study case of the failure of year 2000. Fisheries Oceanography.

Villamor, B., P. Abaunza, P. Lucio and C. Porteiro. 1997. Distribution and age structure of mackerel (Scomber scombrus, L.) and horse mackerel (Trachurus trachurus, L.) in the northern coast of Spain, 1989-1994. Sci. Mar., 61(3):345-366.

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Table 1. WGEAWESS Natural Components/process for Western Iberia North (C).

TEMPORAL SPATIAL CONTACT Component/Variables Platform Method (CTD, DataType (Models UNITS Extent (year) Resolution Extent Resolution satellite …) Observations) Physico- ICESData Chemical / Hydrology base ?? Temperature Surveys Nansen O °C 1979s-present Annual/ Portugal IPIMAR (acoustics, CTD season shelf/ demersal) slope Satellite SST O ºC ?? Plymouth NOAA Buoys O IH

Models ? M ºC ?? ? ? UALG

Salinity Surveys Nansen O 1979s-present Annual Portugal IPIMAR (acoustics, CTD (spring, shelf/slope demersal) summer autumn) Surveys CTD O ?? IH Satellite Satellite O 1982 Day/month global Plymouth NOAA Buoys O ? ? IH Oxygen Surveys Nansen O 1979s-?? Portugal shelf IPIMAR

pH Surveys Nansen O 1979 -?? Portugal shelf IPIMAR

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TEMPORAL SPATIAL CONTACT Component/Variables Platform Method (CTD, DataType (Models UNITS Extent (year) Resolution Extent Resolution satellite …) Observations) Turbidity Currents Buoys O ? IH Waves wavemeters O ? IH River Runoff ??? ???? ??? INAG Meteorology (winds, IM IPIMAR …) Upwelling surveys CTD O IPIMAR / Stratification satellite SST M IPIMAR gradients O Geomorphology Bathymetry M Portugal 250m grid IH shelf/slope Coastal M Portugal 250m grid IH morphology shelf/slope Sediment Survey O Portugal 250m grid IH dregde shelf/slope Biogenic Substrat Water energy at Mesh Atlantic M Portugal 250m grid IPIMAR+UA+U seabed Project shelf/slope Alg Habitat classification Mesh Atlantic Acoustics; grab O m; µm; 2010-2013 Annual Portugal shelf 250m grid IPIMAR+UA+U IPIMAR (Eunis …) Project sampling no.0.1m-2; (Sines area) Alg others

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TEMPORAL SPATIAL CONTACT Component/Variables Platform Method (CTD, DataType (Models UNITS Extent (year) Resolution Extent Resolution satellite …) Observations) Mesh Atlantic M Portugal 250m grid IPIMAR+UA+U Project shelf/slope Alg Biology (species / population / community) Detritus /Bacterials Phytoplancton satellite Remote sensing mg/m3 1996 NOAA Plymouth Station grids O ??? ??? IPIMAR

Benthic phytoplancton (µphytobenthos …) Macrophyte Zooplankton Station grids O ??? ???? IPIMAR

Epibenthic fauna Benthic Grab sampling; O No.0.1m-2. Historical Annual ; Shelf. IPIMAR surveys; others Qualitative 2006/2010 seasonal ; Estuarine others ocasional Endobenthic fauna Benthic Grab sampling O No.0.1m-2 Historical Annual ;seaso Shelf. IPIMAR surveys 2006/2010 nal ; ocasional Estuarine Fish RV Surveys Acoustics O 1979- present IPIMAR Bottom trawl O 1979- present IPIMAR

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TEMPORAL SPATIAL CONTACT Component/Variables Platform Method (CTD, DataType (Models UNITS Extent (year) Resolution Extent Resolution satellite …) Observations) Egg surveys O 1992-present IPIMAR Sea Birds surveys Acoustics O number sporadic ICN Mammals surveys Onboard O number sporadic ICN records

Exploited species Harbour Landings O 1900-present IPIMAR DGPA, census INE, Sampling Discards O 1990- IPIMAR

Sensitive/endangered RV Surveys O 1979- present IPIMAR species (Corals,…)

Widely distributed RV Surveys O 1979- present IPIMAR stocks

I: Irrelevant

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7.5 South Bay of Biscay (SBoB, Region D)

Rafael González-Quirós1 and Enrique Nogueira2

7.5.1 Geography and climate The Southern Bay of Biscay (SBoB) subregion lies between Cape Estaca de Bares (ca. 43°48’N, 7°41’W) and Cape of Ajo (ca. 43°30’N, 3°35’W). The coastline runs in the zonal direction at approximately 43º 30’N (Figure 1). Rocky shores represent around 90% of the coastal margin, predominating over a multitude of small sandy beaches with maximum lengths up to 4 km, and several small-sized shallow estuaries; only two of them (Ortigueira and Viveiro) in westernmost part of the SBoB are relatively large and deep. Inland, the Cantabrian mountain range runs parallel and close to the coastline (Figure 1). Consequently, numerous short water courses, which include streams and small rivers (annual average flow between 1–10 and 10–100 m3·s-1 respectively), drain along the coast. The Nalón river is the largest, with an annual average flow of 109.0 m3 s-1 corresponding to a basin surface of 4866 km2 (Prego and Vergara, 1989). The continental shelf is narrow (width ranging between 30–40 km on the West and 10–15 km on the East) and indented by several canyons. The continental slope is relatively steep with a slope around 10%. Thick turbidity sheet-fan deposits coexist with contourite sediments in the continental margin. Sediments in the shelf are mostly of continental origin; muddy substrates predominate at the slope and the outer shelf (depth > 100 m), whereas rocky or sandy substrates prevail at the inner shelf. Three large topographic features (i.e. marine landscapes) stand out on the shelf: the Avilés canyon system to the West of Cape Peñas (ca. 6°W), the Lastres canyon at ca. 5°W and Le Danois (or Cachucho) Bank, a plain with depths ranging between 450 and 600 m located at approximately 15 km (ca. 44°N) North of the continental shelf at 5º W that has been recently included in the OSPAR Network of Marine Protected Areas. The climate at the SBoB is oceanic (Cfb in the Köppen climate classification system). Monthly average temperatures range 10 ºC between summer maxima (ca. 20 ºC) and winter minima (ca. 10 ºC). The mean of the total annual precipitation ranges between ca. 800 and 1000 mm·year-1 in the western and easternmost part of the subregion. Pre- cipitation is distributed during the whole year although with a summer minimum. Winds tend to blow alongshore, predominantly from the west in winter and from the east in summer. The height and proximity of the Cantabrian range to the coast contribute to increased rainfall when westerly winds cause the adiabatic cooling of humid oceanic air.

7.5.2 Hydrography and circulation Hydrodynamic processes show a strong seasonality, characteristic of temperate mid- latitudes. Minimum sea surface temperature (SST) of ca. 13 ºC is observed in winter, when the mixed layer reaches 250 m depth on average (González-Pola et al., 2007). Thermal stratification begins in early spring and increases towards the summer, when SST exceeds 20 ºC. In autumn, atmospheric cooling and increased frequency and intensity of storms associated to low pressure systems progressively increase the mixed layer depth towards winter conditions.

2 Instituto Español de Oceanografía, Centro Oceanográfico de Gijón, Avda. Príncipe de Astu- rias 70-bis, 33212-Gijón. Spain.

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This general pattern is modulated by several atmospheric and hydrodynamic processes that induce noticeable spatial-temporal variability. The most conspicuous is the strong alongshore temperature gradient during the summer; coastal SST in Galicia, which is part of the North Western Iberia subregion (NWI), presents values below 15 ºC, whereas SST exceeds 25 ºC at the adjacent Inner Bay of Biscay subregion (IBoB). Hence, the SBoB presents an eastward increasing SST gradient of ca. 10 ºC. This gradient is the consequence of the spatial intensity pattern of upwelling along the north Iberian shelf (Botas, 1990; Valencia et al., 2004; Lavín et al., 2006). The northward displacement of the Azores high pressure during the summer favours northerly winds that provoke intense and frequent upwelling of sub-surface cold, nutrient-rich waters along the NWI subregion. Upwelling on the Cantabrian coast is associated with easterlies, and their frequency and intensity decrease towards the East. At the Inner Bay of Biscay (IBoB), during the summer, the lower wind intensity and the configuration of the coastline (S-N in France and W-E in Spain) facilitate the stagnation of surface waters within that area, which favours sea surface heating and stratification. This thermal gradient and the associated spatial pattern of upwelling intensity have important consequences on the characteristics and dynamics of the marine ecosystem, for instance, on primary production and on the distribution of certain species (see below). The Iberian Poleward Current (IPC), which is developed due to the geostrophic adjustment of the cross-shore density gradient during the summer, presents its higher intensity in fall and flows north along the western Iberian shelf break, penetrating into the Bay of Biscay along the Cantabrian coast with decreasing intensity (Pingree and Le Cann, 1990). The IPC is characterized by higher temperature and salinity, generating fronts between coastal and offshore waters that modify the homogeneity pattern of winter hydrography. Those frontal structures affect plankton distribution, and differences in plankton communities are observed between the IPC and coastal water masses (Fernández et al., 1991, 1993; Cabal et al., 2008). The dynamics of the IPC present high interannual variability, which has been related with the North Atlantic Oscillation (Llope et al., 2006). Cantabrian river plumes are small and very shallow. Even the plume of the river Nalón, the largest in the Cantabrian, usually affects less than 5 m of the water column. Only after occasional heavy or persistent rain episodes, these plumes may reach deeper and cover larger areas. Nevertheless, the numerous rivers and the moderate rainfall in the area contribute to lower salinity values of coastal waters and to gener- ate frontal structures, more apparent in winter in coherence with the rainfall pattern. The influence of discharges from the river Adour in the IBoB subregion is noticeable in the eastern part of the SBoB. Besides, since river discharges from the Adour are associated with the spring-summer melting of the snow accumulated in the Pyrenees in the preceding winter, the lower surface salinity values are recorded in the eastern part of the SBoB subregion during summer, contrasting with other parts of the SBoB where minimum surface salinity values are recorded during early-winter.

7.5.3 Biological Ecosystem components

7.5.3.1 Bacteria The abundance of autotrophic bacteria of the genus Prochlorococcus and Synechococcus is on average around 8x106 and 107 cells·L-1 respectively. The contribution of these cyanobacteria to the abundance of pico-phytoplankton (0.2–2 µm), which include also a high diversity of small eukaryotes of the genus Micromonas, Ostreococcus and Pelagomonas, is highly variable, ranging between 0.1 and 99% (Morán et al., 2011).

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Both groups of cyanobacteria show a strong seasonality. Prochlorococcus is present only from August–September, when it reaches maximum concentrations at the surface around 8x107 cells·L-1, until its complete disappearance in March possibly due to its low tolerance to low temperatures. Sub-surface maxima occurred from November to January (Calvo-Díaz and Morán, 2006). On the other hand, the group Synechococcus consistently outnumbered Prochlorochoccus except in November. Annual maximum around 1.5x108 cells·L-1 occur during summer above the nutrient cline, and minimum values <105 cells·L-1 are recorded during spring. Its vertical distribution is more ho- mogeneous than that of Prochlorococcus (Calvo-Díaz and Morán, 2006).

The average abundance of pelagic heterotrophic bacteria is about 5x108 cells·L-1 (Calvo-Díaz and Morán, 2006). Temporal variation shows a neat bi-modal seasonal pattern, with maximum values of the order of 109 cells·L-1 around April and October and minimum of the order of 108 cells·L-1 around February and August (Morán et al., 2011). Their vertical distribution was rather uniform, with a slight decrease with depth in summer (Calvo-Díaz and Morán, 2006). The percentage of bacteria with high DNA content, a subrogate of bacterial activity, shows a strong and recurrent seasonality, with maximum values in spring (representing ca. 75% of total bacterial abundance) and minimum contribution in summer (Morán et al., 2011).

7.5.3.2 Phytoplankton The seasonal pattern of phytoplankton biomass is mostly governed by the seasonal mixing/stratification cycle of the water column and the consequences that it has on the availability of nutrients and light. Maximum biomass concentrations are observed during the spring bloom, when surface high concentration of nutrients and incipient stratification set optimum growth conditions. As phytoplankton consumes nutrients in the surface layers and thermal stratification inhibits their replenishment, phytoplankton biomass decreases and deepens in the water column. A secondary phytoplankton bloom occurs in autumn when the water column starts mixing and nutrients become available again at the photic layer. Phytoplankton biomass presents minimum values in winter, when nutrient concentrations turn high again in surface layers but light becomes the limiting factor due to low solar irradiance and intense water column mixing. The chlorophyll concentration (subrogate of phytoplankton biomass) integrated for the euphotic layer (i.e. between the surface and ca. 40 m depth) varied in shelf waters from ca. 15 to 60 mg Chl-a·m-2 in winter and during upwelling events respectively (Bode et al., 1996). The average value of annual primary production is around 428 gC·m-2 (OSPAR, 2000). Diatoms predominate during spring and autumn blooms, while dinoflagellates do so during summer, when the water column is stratified (Fernández and Bode, 1994). Dominant diatoms species during the seasonal blooms are Chaetoceros socials, Ch. dydimus, Lauderia borealis, Tha- lassiosira fallax, Schroderella delicatula and Rhizosolenia setigera. During the stratification period, the phytoplankton assemblage is composed by diatoms such as Leptocyclin- drus danicus, Chaeoceros affinis and Rhizososlenia delicatula and dinoflagellates such as Dinophysis acuminata, D. acuta, Gyrodinium spirale, Protoperidinium bipes and several species from the genus Ceratium (OSPAR 2000). This seasonality is, however, strongly modulated by mesoscale hydrographic features. Coastal upwelling, although not as frequent and persistent as in the western Iberian Peninsula (SWI and NWI subregions), may cause occasional increases of phytoplankton biomass in surface layers during the summer (Botas et al., 1990). As the intensity of upwelling decreases towards the East, this process may cause only low increases of subsurface biomass (i.e. subsurface chlorophyll maximum), due to

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the mere uplift of the nutrient cline and the consequent increase of light availability. The IPC affects phytoplankton biomass and composition, with lower biomass (chlorophyll-a as subrogate) and predominance of small flagellates and dinoflagellates in the IPC domain (Álvarez-Salgado et al., 2003). Under a meteorological scenario of moderate-to-intense westerly winds and low runoff the IPC occupies the inner shelf and restricts the across-shelf exchange. Runoff from the small rivers in the Cantabrian Sea generates buoyancy structures that can fuel localised phytoplankton blooms due to the combined effect of nutrient fertilisation and increased water column stability.

7.5.3.3 Zooplankton The zooplankton community in the SBoB is highly diverse in terms of taxonomic groups and species due to the transitional character of the subregion between boreal and sub-tropical realms (Valdés et al., 2007). The main groups of meroplankton are Cirripeda, Gastropoda and Decapoda with percentages of relative abundance around 60, 10 and 10% respectively. An across-shelf gradient in meroplankton species occur in the SBoB subregion, with higher abundances in coastal than oceanic environments. Besides, these meroplankton groups show a neat seasonality, with higher abundances during the spawning and breeding season of the species concerned (OSPAR, 2000). Within the holoplankton, Copepoda is the most important group in terms of species richness, persistence, abundance and ecological significance (Valdés et al., 2007). The percentage of relative abundance of copepods represents nearly 70% of the holoplankton, followed by Cladocera and Appendicularia which represent 10% each. Nevertheless, despite the high diversity of copepods the major contribution to total biomass is due to a relatively reduced number of species. For instances off Santander, in the eastern part of the SBoB, seven species account for ca. 75% of the total biomass of copepods (Bode et al., 2011): Calanus helgolandicus (V-VI) (ca. 23%), Paracalanus par- vus (ca. 14%), Clausocalanus spp. (ca. 11%), Acartia clausi (ca. 9%), Calanoides carinatus (ca. 6%), Temora stylifera (ca. 6%) and Centropages chierchiae (ca. 5%). On the shelf, the main copepod species show a conspicuous seasonality, with a main maximum around spring and a secondary maximum in late-summer or autumn (Bode et al., 2011). For some species, such as C. helgolandicus and A. clausi, the spring peak tends to occur earlier in the eastern than in the western part of the subregion (Bode et al., 2011), presumably due to the higher temperatures reached in the inner part of the Bay of Biscay (IBoB subregion) which may favour a faster development of eggs and initial stages of these species in this area (Bonet et al., 2005). The seasonal pattern described is coincident with that of mesozooplankton biomass, which reaches maximum values of dry weight around 35 mg·m-3 at the main spring peak, around 20 mg·m-3 at the secondary autumn peak and minimum values around 5 mg·m-3 in winter (Valdés and Moral, 1998; Bode et al., 2011). In the oceanic part of the subregion, copepod diversity, abundance and biomass tend to be lower than in the neritic and coastal environments. The annual cycle of abundance and biomass is similar to that in oligotrophic environments, with slight variation through the year and a single annual peak around April. Superimposed to this seasonal pattern, topographic features and hydrodynamics in- troduce considerable variability. The main deviations occur in estuaries and shallow coastal areas where buoyancy structures and coastal upwelling alter the water column structure. Besides, these areas are prone to high nutrient inputs that fuel phytoplankton blooms and the concomitant pulses of zooplankton production (OSPAR, 2000).

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7.5.3.4 Small pelagic fish The main small pelagic fish species in the SBoB are sardine (Sardina pilchardus) and mackerel (Scomber scombrus). Anchovy (Engraulis encrasicolus) has only a residual presence in the SBoB, although it is an important fishing resource for the local fleet, which catches it in the IBoB and over the French shelf (i.e. western Bay of Biscay subregion -WBoB). The rest of the small pelagic community is conformed by other less abundant species more common to subtropical waters, such as chub mackerel (S. colias), Mediterranean horse mackerel (T. mediterraneus) and blue jack mackerel (T. picturatus).

7.5.3.4.1 Sardine Sardine (Sardina pilchardus) in the SBoB belongs to the Iberian-Atlantic population. They have a coastal distribution and mostly correspond to individuals of year class 2+ or older, which suggests that recruitment is very limited in this area. Recruitment occurs, however, nearby the western Bay of Biscay subregion (WBoB) and on the western Iberian Peninsula (which includes the southern and northern subregions – SWI and NWI respectively). It is not clear to what extent the sardines inhabiting the SBoB originate from each of these recruitment areas. This apparent absence of recruitment contrasts with the high spawning intensity observed in certain years; it can be of the same magnitude, or even higher, than over the western Iberian shelf. Sar- dine presents a protracted spawning season in the SBoB, with a peak in spring, from March to May, and a secondary, less intense peak in autumn. Spawning in winter and summer is negligible. Spawning usually occurs in coastal waters, although the spawning area may extend over the entire shelf, particularly in years of high spawning intensity. It is an important resource for local purse-seiners that fish sardines mainly in winter, when other alternative higher-priced species are not available, e.g. anchovy or albacore (Thunnus alalunga).

7.5.3.4.2 Mackerel Mackerel (Scomber scombrus) is distributed throughout the northeast Atlantic- Mediterranean Sea and in the northwest Atlantic. It is an active migratory species, forming schools which can sometimes reach large densities. It is a serial spawner whose spawning area in the North East Atlantic extends throughout the west of the British Isles, the Bay of Biscay and the North Sea. In the SBoB subregion, spawning is mostly from March to May (Solá et al., 1990; Rodriguez, 2008). Once spawning is over, it performs a feeding migration along the west of the British Isles to the north of the North Sea. From September to December mackerel is found in the Norwegian Sea and the north of the North Sea. During winter, mackerel migrates southward, towards spawning grounds, including the SBoB (Uriarte and Lucio, 2001; Uriarte et al., 2001). This migratory behaviour seems to be associated with slope currents (such as the IPC) (Reid, 2001). These migrations are the cause of the seasonality seen in the mackerel fishery of the Bay of Biscay (Villamor et al., 1997). Punzón and Villamor (2009) suggest that the timing and place of fishing is a good indicator of the timing of migration and they point to changes in the timing of mackerel migration by over one month in the SBoB between 2000 and 2006, which can be an example of change in phenology. Events of strong local wind and/or offshore Ekman transport around April in the Cantabrian shelf may have an effect on mackerel larval survival and thus recruitment in the Cantabrian shelf (Villamor et al., 2004a; Villamor et al., submitted).

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7.5.3.4.3 Anchovy The presence of anchovy (Engraulis encrasicolus) in the SBoB is residual and spawning is only associated with the small plumes of Cantabrian rivers; the main habitat of this species is the IBoB and the WBoB. Nevertheless, historical records of landings and canning industrial activity in the area indicate that the SBoB was an important habitat of the species in the 1960s. The presence of the stock progressively declined and the local fleets were almost exclusively fishing anchovies in the IBoB or in the WBoB be- fore the closure of the fishery in 2005. Since the recovery of the stock in the last years, the stock has progressively expended into the SBoB, although this expansion does not seem to be of the extent indicated by past landing records.

7.5.3.5 Large pelagic fish There are two tuna species, albacore (Thunnus alalunga) and bluefin (Thunnus thynnus) which are present in the SBoB subregion mainly in summer (Cort, 1995). The more abundant is the albacore, which belongs to the North Atlantic stock. Juveniles up to 5 years old migrate into the SBoB subregion from adjacent waters of the Azores during the summer. It is an important resource for local fleets. Bluefin tuna adults arrive to the SBoB after leaving the spawning areas in the Mediterranean Sea. Al- though relatively less important in terms of landings, bluefin tuna is also landed by local fleets mainly during the summer.

7.5.3.6 Demersal and benthic fish The diversity of demersal and benthic fish species is quite high in the SBoB due to the co-occurrence of sub-tropical, temperate and boreal species. Species richness, distribution and abundance are determined, however, by the narrowness and topography of the continental shelf. Five types of communities characterise the area, corresponding to species inhabiting the shallow coastal waters, mid shelf, outer shelf, shelf break and slope (OSPAR, 2000). More than 80% of the biomass of demersal species is accounted for by: blue whiting (Micromesistus potassou), horse mackerel (Trachurus trachurus), dogfish and rays (mainly the lesser-spoted dogfish, Scyliorhinus canicula), hake (Merluccius merluccius), anglerfish (Lophius piscatorius and L. budegassa), and megrim (Lepidorhombus boscii and L. whiffiagonis). Benthic fish present in the SBoB include medium-sized species such as Mullus surmuletus, Chelidonichthys gurnardus and the genus Callionymus and flatfish such as species of the genera Arnoglossus, Psetta, Bathysolea and Solea.

7.5.3.6.1 Blue whiting Blue whiting (Micromesistus potassou) is the most abundant demersal species in the North Atlantic. It is a migratory species distributed near the bottom, between 200 and 500 m depth, which perform diurnal vertical migrations. Larger individuals (>25 cm) tend to concentrate at deeper layers, between 500–700 m depth. It is the main prey for larger predators. It is estimated that ca. 10% of the biomass of the stock is located in the SBoB, mainly integrated by juveniles that come into the subregion from northern locations in the Western Bay of Biscay (WBoB) and Celtic Sea (CS) subregions (Sánchez & Olaso, 2004).

7.5.3.6.2 Horse mackerel Horse mackerel (Trachurus trachurus) is distributed from the coasts of Cape Verde up to the northern North Sea, as well as the Mediterranean. The adults are considered a demersal species, whereas the juveniles behave as pelagic and for that reason it is sometimes included in the group of small pelagic fishes. It is a serial spawner whose

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spawning area stretches from the British Isles towards the south throughout its area of distribution. In the SBoB it has a longer spawning season from March to August (Solá et al., 1990; González-Quirós, 1999; Rodriguez, 2008). It performs spawning and feeding migrations, but these are less evident than those of mackerel. Three stocks are currently recognized in the northeast Atlantic: Southern stock, North Sea stock and Western stock. Recently, the Bay of Biscay horse mackerel has been included within the Western stock, which extends from Galicia northwards throughout the western European coast (ICES, 2005).

7.5.3.6.3 Dogfish and rays The lesser-spotted dogfish (Scyliorhinus canicula) constitutes 80% of the dogfish that inhabits the whole shelf (Sánchez and Olaso, 2004). Other species which belong to this group are small sharks that inhabit the outer shelf and slope, such as Galeus melastomus and Etmopterus spinax. At least eight species of rays inhabit the area, being the most abundant Raja clavata, which represent 50% of the biomass of this group.

7.5.3.6.4 Hake European hake (Merluccius merluccius) is the most important demersal fishery resource in the SBoB. Spawning occurs preferentially at the shelf break, and it is particularly intense during the first quarter of the year in the SBoB. The largest nursery for the southern stock of this species is found in the SBoB and their variability has been associated with hydrographic anomalies in the area. Young fish remain in the nursery grounds during one year after spawning, scattering afterwards over the continental shelf.

7.5.3.6.5 Anglerfish Two species of anglerfish are present in the SBoB (Lophius piscatorious and L. budegassa), distributed from shallow to deep waters up to 800 m depth. Younger fish live in shallow waters moving to deep waters as they grow. Spawning occurs between October and March and the age of first maturity is around 8 years old (OSPAR, 2000). It is estimated that the biomass of anglerfish in the SBoB subregion is about 50% of the spawning southern stock biomass (Sánchez and Olaso, 2004).

7.5.3.6.6 Megrim Two megrim species of the genus Lepidorhombus inhabit in the SBoB, L. boscii and L. whiffiagonis. These species are distributed in sandy or muddy sea floor between 100 and 700 m depth.

7.5.3.7 Macrophytobenthos communities The biogeographical gradient of macroalgal communities along the coast of the SBoB is possibly the most conspicuous ecological pattern coherent with the hydrographic Western-Eastern gradient referred above. The most abundant and characteristic species in the SBoB are: Ascophyllum nodosum, Bifurcaria bifurcata, Codium tomentosum, Cystoseira spp., Chondrus crispus, Fucus serratus, Fucus vesiculosus, Fucus spiralis, Ge- lidium sesquipedale, Himanthalia elongata, Laminaria ochroleuca, Laminaria hyperborea, Pel- vetia canaliculata and Saccorhiza polischydes. Boreo-Atlantic species, abundant on the Atlantic coast in the North Western Iberian subregion (NWI) are progressively substituted by species with meridional affinity towards the Inner Bay of Biscay (IBoB) subregion (e.g. Fischer-Piette, 1957; van den Hoek, 1975; Anadón and Niell, 1981; Anadón, 1983; Luning, 1990). Several species of large brown algae have a distinct distributional boundary in a middle zone of the

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SBoB (around Cape Peñas, at ca. 6°W), including Fucus serratus, Laminaria ochroleuca, Himanthalia elongata and others (Anadón & Niell 1981, Anadón 1983, Luning 1990). Nevertheless, this biogeographical pattern has in turn evolved in time towards a pro- gressive substitution of Boreo-Atlantic species by a complex assemblage of small sized ephemeral species with southern affinities all over the SBoB, particularly conspicuous in the last years (Viejo et al., 2010).

7.5.3.8 Benthic invertebrates Macrofauna (> 1 mm in size) on hard substrates in the upper intertidal zones is dominated by sessile or slow moving species comprising barnacles, limpets, lit- torinids and topshells. Lower intertidal and subtidal zones are dominated by dense stands of macrophytobenthos communities interspersed with barren areas dominated by sea urchins (Paracentrotus lividus and Echinus esculentus) which are extensively exploited in the central part of the SBoB. Macrofauna on soft substrates is strongly related to grain size, depth and organic matter content of the sediment (OSPAR, 2000). In the SBoB two major communities predominate: Macoma which occurs on intertidal muddy sediments and Tellina, a Lusitanian-boreal community that occurs at medium to low tidal levels on fine to medium sandy sediments. Meiofauna (1–0.06 mm in size) is an important component in relation to the trophodynamics of the benthos. It is however the least studied benthic component. Nematodes predominate in areas highly oxygenated and with low bioturbation. Macroinvertebrate benthic communities are particularly diverse at the shelf break (Louzao et al., 2010) or at the Le Danois Bank (Sanchez et al., 2008). The presence of reef-forming cold corals in the Aviles canyon system (Louzao et al., 2010) is one of the main reasons in favour for considering this canyon system a Marine Protected Area to be included in the OSPAR Network.

7.5.3.9 Top predators The waters of the SBoB are home to a wide variety of cetaceans and seabirds. A total of 14 species of cetaceans have been recorded of which the most abundant are the common dolphin (Delphinus delphis) in shelf waters and the bottlenose dolphins (Tur- siops truncatus) in the coastal areas, as well as the striped dolphin (Stenella coeruleoalba) and the long-finned pilot whale (Globicephala melas) (Ruano et al. 2007). Other species found in the area include the harbour porpoise (Phocoena phocoena), the Iberian population of which is genetically distinct (Fontaine et al., 2007). This area is an important migration corridor for seabirds during late summer and autumn. More than a million of seabirds from at least 16 species have been recorded such as the black scoter (Melanitta nigra), the Cory’s shearwater (Calonectris diomedea), the great shearwater http://www.birdlife.org/datazone/speciesfactsheet.php?id=3932 (Puffinus gravis), the Sooty shearwater (Puffinus griseus), Manx shearwater (P. puffinus), Balearic shearwater (P. mauretanicus), Northern gannet (Morus bassanus), Great skua (Stercorarius skua), Arctic skua (S. parasiticus), Pomarine skua (S. pomarinus), Mediterranean gull (Larus melanocephalus), Lesser Black-backed gull (L. fuscus), Black-legged Kittiwake (Rissa tridactyla), Sandwich tern (Sterna sandvicensis), Larus Common tern (S. hirundo) and Little tern (S. albifrons) (Arcos et al. 2009). The western sector of SBoB (Estaca de Bares-Cabo Peñas) is especially important for certain species (e.g. Balearic and Manx shearwaters, Northern Gannet, Great skua, Sandwich tern) since a significant percentage of their global populations visit this area (Arcos et al. 2009). Due to this high concentration of seabirds, this biogeographic area also en- compass important bird areas in the pelagic realm, as well as marine extension of

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breeding colonies of several species such as the Cory´s shearwater, the European shag (Phalacrocorax aristotelis), the European storm-petrel (Hydrobates pelagicus), the common tern and the yellow-legged gull (Larus michahellis). This marine area is an especially important breeding area for the Atlantic subspecies of the European storm petrel in the Iberian Atlantic coast (Arcos et al. 2009).

7.5.4 References Álvarez-Salgado, .A., F. G., Figueiras, F. F., Pérez, S., Room, E., Nogueira, A. V., Borges, l., Chou, C.G., Castro, G., Moncoiffé, A. F., Ríos, A.E.J., Miller, M., Frankignoulle, G., Savidge, and R., Wollast (2003), The Portugal coastal counter current off NW Spain: new insights on its biogeochemical variability. Progress in Oceanography, 56, 281-321, doi:10.1016/S0079-6611(03)00007-7.

Anadón R and Niell J (1981). Distribución longitudinal de macrófitos en la costa asturiana (N. de España) Investigación Pesquera 45: 143-156.

Anadón, R (1983) Zonación en la costa asturiana: variación longitudinal de las comunidades de macrófitos en diferentes niveles de marea. Investigación Pesquera 47:125-141.

Botas JA, Fernández E, Bode A, Anadón R (1990) A persistant upwelling off the Central Can- tabrian Coast (Bay of Biscay). Estuarine, Coastal and Shelf Science 30: 185-199.

Calvo-Díaz, A. Morán, X.A.G. 2006. Seasonal dynamics of picoplankton in shelf waters of the southern Bay of Biscay. Aquatic Microbial Ecology, 42: 159-174.

Cort, J.L. 1995. Data on the bluefin fishery in the Cantabrian Sea. SCRS/94/91. ICCAT Collect. Vol. Sci. Pap. 44 (1), 289-292.

Fernández E, Bode A (1991) Seasonal patterns of primary production in the Central Cantabrian Sea (Bay of Biscay). Scientia Marina 55: 629-636.

Fernández E, Bode A (1994) Succession of phytoplankton assemblages in relation to the hydrography in the southern Bay of Biscay: A multivariate approach. Scientia Marina 58: 191- 205.

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González-Pola C, Fernández-Díaz JM, Lavín A (2007) Vertical structure of the upper ocean from profiles fitted to physically consistent functional forms. Deep-Sea Research I 54: 1985- 2004.

Lüning, K (1990) Seeweeds: their environment. Biogeography and ecophysiology. John Wiley & Sons, New York. 527pp.

Morán et al., 2011

OSPAR. 2000. Quality Status Report 2000. Region IV _ Bay of Biscay and Iberian coast.

Peliz, A., J., Dubert, and D. B., Haidvogel (2003), Subinertial Response of a Density-Driven Eastern Boundary Poleward Current to Wind Forcing, Journal of Physical Oceanography, 33, 1633-1650.

Pingree RD, Le Cann B (1990) Structure, strength and seasonality of the slope currents in the Bay of Biscay region. Journal of the Marine Biological Association of the United Kingdom 70: 857-885.

Pingree, R. D., and B., Le Cann (1990), Structure, strength and seasonality of the slope currents in the Bay of Biscay, Journal of Marine Biology Association. U. K., 70, 857-885.

Prego, R and Vergara, A R (1989) Nutrient fluxes to the Bay of Biscay from Cantabrian rivers (Spain) Oceanologica Acta 21: 271-278.

Reid, D.G. 2001. SEFOS: Shelf Edge Fisheries and Oceanography Studies: an overview. Fisher- ies Research, 50: 1-15.

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Rodríguez J.M. 2008. Temporal and across-shelf distribution of ichtioplankton in the central Cantabrian Sea. Estuarine, Coastal and Shelf Science 79, 496-506.

Sánchez, F., Olaso, I. 2004. Effects of fisheries on the Cantabrian Sea shelf ecosystem. Ecological Modelling, 172: 151-174.

van den Hoek C (1975) Phytogeograpnic provinces along the coasts of the northern Atlantic Ocean. Phycologia 14: 317-330.

Villamor, B., C. Gonzalez-Pola, A. lavín, L. Valdés, A. Lago de Lanzós, C. Franco, J.M. Ca- banas, M. Bernal, C. Hernandez, M. Iglesias, P. Carrera and C. Porteiro. 2011 Environ- mental control of North East Atlantic mackerel (Scomber scombrus) recruitment in the Southern Bay of Biscay: Study case of the failure of year 2000. Fisheries Oceanography

Villamor, B., C. González-Pola, A. lavín, L. Valdés, A. Lago de Lanzós, C. Franco, J.M. Ca- banas, M. Bernal, C. Hernandez, P. Carrera, C. Porteiro and E. Alvarez. 2004a. Distribution and survival of larvae of mackerel (Scomber scombrus) in the North and Northwest of the Iberian Peninsula, in relation to environmental conditions during spring 2000. ICES CM 2004/ J:0, ICES Annual Science Conference. Vigo 26-28/09/2004.

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Table S1. Chronogram of the cruises for the biomass assessment of small pelagic (shaded grey) and demersal (■) fishes carried out in the North Iberian Shelf (NIS), which include the SBoB and the northern part of the NWI subregions. Information for the characterisation of hydrographic conditions and plankton distribution was also acquired during these cruises.

Year Month E F M A M J J A S O N D 1983 ■ 1984 ■ 1985 ■ 1986 ■ 1987 ■ 1988 ■ 1990 ■ 1991 ■ 1992 ■ 1993 ■ 1994 ■ 1995 ■ 1996 ■ 1997 ■ 1998 ■ 1999 ■ 2000 ■ 2001 ■ 2002 ■ 2003 ■ 2004 ■ 2005 ■ 2006 ■ 2007 ■ 2008 ■ 2009 ■ 2010 ■ 2011 ■

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Table S2. Temporal coverage of the data available in the database coming from the time series monitoring program RADIALES (monthly sampling in an across-shelf array of hydrographic stations; Figure 3).

Section Sampling Variables period Physics (T, S, Biogeochemist Phytoplankto Zooplankto Ichthyoplankt PAR) ry (Nutrients & n n on Chlorophyll) Vigo 1987- 1994- 1994- 2002-2007 1994- 1990- Coruña 1989- 1991- 1989- 1989- 1993- 1990- Cudillero 1992- 1993- 1992- 1995- 1993- 1994- Gijón 2001- 2003- 2001- 2001- 2004- 2001- Santander 1990- 1991- 1991- 1994-2001 1991- 1990-

Figure S1. Sampling frequency in the NIS (which includes the northern part of the NWI and the SBoB subregions) from the surveys for biomass assessment of small pelagic fishes (‘PELACUS’ cruises) carried out since 1988.

Figure S2. Sampling frequency in the NIS (which includes the northern part of the NWI and the SBoB subregions) from the surveys for biomass assessment of demersal fishes (‘DEMERSALES’ cruises) carried out since 1988.

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Figure S3. Transects sampled in the frame of the time series monitoring programme RADIALES carried out along the NIS.

Figure S4. Location of buoys (managed by ‘Puertos del Estado’) at the NIS that provide meteorological and sea surface parameters (SST and velocity and direction of currents).

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Figure S5. ROMS circulation model operative in the NIS. Integration scheme and temperature output as an example.

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Table 2. Meta-data North Iberian Shelf (NIS; 42°-44.5°N, 10°-1° W), which includes the Spanish waters belonging to subregions North-Western Iberia (NWI) and Southern Bay of Biscay (SBoB).

Temporal Spatial Contact Insti- Comments tution

Components / Vari- Platform Methods (CTD, Data Type (Models / UNITS Extent (year) Resolution Extent Resolution ables satellite …) Observations)

ABIOTIC

Water Physical - Chemical / Hydrol- ogy

Temperature Surveys (‘Pe- CTD O °C 1987- Annual NIS1 ca. 5 nm IEO Figure S1 and Table lacus’) (spring) across shelf x S1

18 nm along- shelf. Verti- cal

Surveys CTD O °C 1992- Annual NIS Irregular IEO Figure S2 and Table grid. Vertical S1 (‘Demersales’) (autumn)

Time series CTD O °C 1990- Monthly NIS 5 sections IEO Figure S3 and Table (‘Radiales’) along NIS. S2 Vertical

Satellite Satellite O °C Daily Global NOAA

Surveys / Satel- Re-analysis O/M °C Weekly Global 2.5°x2.5° NCEP/NCAR lite Surface

Buoys TS O °C 2000- Daily NIS Discrete Puertos del Figure S4 locations. Estado Surface

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ROMS Numerical inte- M °C Daily NIS 3.5x3.5 km IEO Figure S5 gration Vertical (40 layers)

Salinity Surveys (‘Pe- CTD O usp 1987- Annual NIS ca. 5 nm IEO Figure 1 and Table 1 lacus’) (spring) across shelf x 18 nm along- shelf. Verti- cal

Surveys CTD O usp 1992- Annual NIS Irregular IEO Figure S2 and Table grid. Vertical S1 (‘Demersales’) (autumn)

Time series CTD O usp 1990- Monthly NIS 5 sections IEO Figure S3 and Table (‘Radiales’) along NIS S2

Buoys TS O usp 2000- Daily NIS Discrete Puertos del Figure S4 locations. Estado Surface

ROMS Numerical inte- M °C 2002- Daily NIS 3.5x3.5 km IEO Figure S5 gration Vertical (40 layers)

Currents Buoys Current-meter O cm·s-1 2000- Daily NIS Discrete Puertos del Figure S4 locations. Estado Surface

ROMS Numerical inte- M °C 2002- Daily NIS 3.5x3.5 km IEO Figure S5 gration Vertical (40 layers)

Inorganic nutrients Surveys (‘Pe- Colorimetry O µM 2000- Annual NIS ca. 5 nm IEO Figure S1 and Table (nitrate, silicate and lacus’) (segmented (spring) across shelf x S1 phosphate) flow) 18 nm along- shelf. Verti-

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cal

Time series Colorimetry O µM 1990- Monthly NIS 5 sections IEO Figure 3 and Table 2 (‘Radiales’) (segmented along NIS. flow) Discrete depths

Oxygen concentra- Surveys (‘Pe- Winkler and/or O %sat 2000- Annual NIS ca. 5 nm IEO Figure S1 and Table tion lacus’) oxygen sensor (spring) across shelf x S1 18 nm along- shelf. Verti- cal

River runoff Gauge stations O m3·s-1 1990 (at least) Daily Discrete Confed- locations eración hidrográfica

Meteorological Land-based Various sensor O 1990 (at least) Daily Agencia Esta- information (rain- meteorological tal de Meteo- fall, wind, air tem- stations rología perature...)

Habitat type

Geomorphology

Bathymetry

Coastal morphology

BIOTIC

Detritus / Bacteria / Picoplankton

Abundance Surveys (‘Pe- Niskin bottles O cells·ml-1 2002- Annual NIS ca. 5 nm IEO Figure S1 and Table lacus’) (spring) across shelf x S1 Flow citometry (by citomet-

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ric groups) 18 nm along- shelf. Dis- crete depths

Time series Niskin bottles O cells·ml-1 2002- Monthly NIS 2 sections IEO Figure S3 and Table (‘Radiales’) along NIS S2 Flow citometry (by citomet- (Coruña & ric groups) Gijón). Dis- crete depth

Phytoplankton

Standing Stock Surveys (‘Pe- Fluorescence O µg·l-1 (cali- 1987- Annual NIS ca. 5 nm IEO Figure S1 and Table Biomass lacus’) (Fluorometer) bration) (spring) across shelf x S1 18 nm along- shelf. Verti- cal

Time series Fluorescence O µg·l-1 (cali- 1990- Monthly NIS 5 sections IEO Figure S3 and Table (‘Radiales’) (Fluorometer) brated) along NIS. S2 Vertical

Time series Analytical chlo- O µg·l-1 1990- Monthly NIS 5 sections IEO Figure S3 and Table (‘Radiales’) rophyll along NIS. S2 Discrete depths

Satellite Satellite O µg·l-1 Weekly Global 9x9 km. Sur- NOAA face

CPR colour index CPR Survey CPR O Relative 1960 Monthly NA Underway CPR-Survey (SA F4 & E4) units (µg·l-1 continuum if cali- sampling. brated) Surface

Species composition Surveys (‘Pe- Plankton net O Cells·m-2 1990- Annual NIS ca. 5 nm IEO Figure S1 and Table lacus’) Üthermol (spring) across shelf x S1 18 nm along-

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shelf. Dis- crete depths

Surveys (‘Pe- Niskin bottles O Cells·ml-1 2005- Annual NIS ca. 5 nm IEO Figure S1 and Table lacus’) (spring) across shelf x S1 FlowCAM 18 nm along- shelf. Dis- crete depths

Time series Niskin bottles O Cells·ml-1 1990- Monthly NIS 5 sections IEO Figure S3 and Table (‘Radiales’) along NIS. S2 Üthermol Discrete depths

CPR Survey CPR O Cells·m-3 1960 Monthly NA Underway CPR-Survey continuum sampling. Surface

Phytobenthos

Abundance / species composition / distribution

Macrophytes

Abundance / species composition / distribution

Zooplankton

Biomass Surveys (‘Pe- WP2 nets O mg·m-2 1990- Annual NIS ca. 5 nm IEO Figure S1 and Table lacus’) (spring) across shelf x S1 Dry-weigh bio- 18 nm along- mass (size- shelf. Depth fractionated) integrated

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Time series WP2 nets O mg·m-2 1990- Monthly NIS 5 sections IEO Figure S3 and Table (‘Radiales’) along NIS. S2 Dry-weigh bio- Depth inte- mass (size- grated fractionated)

Species composition Time series WP2 nets O Ind·m-3 1992- Monthly NIS 5 sections IEO Figure S3 and Table (‘Radiales’) along NIS. S2 Depth integrated

CPR Survey CPR O Cells·m-3 1960 Monthly NA Underway CPR-Survey continuum sampling. Surface

Size-structure Surveys (‘Pe- WP2 nets O NBSS 2005- Annual NIS ca. 5 nm IEO Figure S1 and Table lacus’) (spring) across shelf x S1. ZooScan 18 nm along- Re-analysis of stored shelf. Depth samples in progress integrated

Time series WP2 nets O NBSS 2005- Monthly NIS 5 sections IEO Figure S3 and Table (‘Radiales’) along NIS. S2. ZooScan Depth inte- Re-analysis of stored grated samples in progress

Epi-benthic Inver- tebrate

Abundance Surveys Bottom Trawl O 2000- Annual (au- NIS IEO Figure S2 and Table (‘Demersales’) tumn) S1

Endo-benthic In- vertebrate

Abundance

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Fish

Eggs Surveys (‘Pe- CUFES, Calvet O ind·m-3 2002- Annual NIS Surface con- IEO Figure S1 and Table lacus’) and Bongo nets (spring) tinuous un- S1. derway and discrete depth integrated

Ichthyoplankton Time series Bongo nets O ind·m-3 1990- Monthly NIS 5 sections IEO Figure S3 and Table (eggs & larvae fro (‘Radiales’) along NIS. S2. sardine, anchovy, Depth inte- mackerel and horse grated mackerel)

Abundance of Surveys (‘Pe- Acoustic O Tons 1990- For sardine since adults pelagic lacus’) 1990. For mackerel and horse mackerel since 2000. The whole pelagic community since 2007. Re-analysis of echo- grams in progress.

Biological informa- Surveys (‘Pe- Biological sam- O 1990- Annual NIS Opportunis- IEO For sardine, an- tion of pelagic fishes lacus’) pling of the (spring) tic hauls chovy and mackerel (e.g. sex ratio, age, catch depending of since 1990. For horse size-structure, echo-traces mackerel since 2002. weight-length...)

Abundance / distri- Surveys Bottom trawl O 1990- Annual (au- NIS Random IEO bution of adults tumn) stratified (5 (‘Demersales’) demersal strata and geographic sectors)

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Biological informa- Surveys Bottom trawl O 1988- Annual (au- NIS Random IEO Hake, monkfish, tion of pelagic fishes tumn) stratified (5 megrim (‘Demersales’) (e.g. sex ratio, age, strata and size-structure, geographic weight-length...) sectors)

Birds

Abundance / spe- Surveys (‘Pe- Observation O Number 2007- Annual NIS IEO In autumn only for cies composition lacus’) ind. (spring and 2007-2009 and distribution autumn)

Census Surveys Observation O Number 2003- Annual (au- NIS Attraction IEO ind. tumn) during fish- (‘Demersales’) ing haul operations

Abundance / spe- Time series Observation O Number 2007-2009 Monthly Central UIOVI-IEO cies composition (‘Radiales’) ind. Can- tabrian Sea

Mammals

Abundance / spe- Surveys SCANS- Observation O Number 1994 (I) & NEA Several part- cies composition I and II ind. 2005 (II) ners

Abundance / spe- Surveys (‘Pe- Observation O Number 2007- Annual NIS IEO In autumn only for cies composition lacus’) ind. (spring and 2007-2009 and distribution autumn)

Abundance / spe- Coastal observa- Observation O Number 2004-2007 Monthly Galician IEO cies composition tions ind. coast

Biological informa- Stranded indi- Observation O 1990- Opportunis- Galician IEO tion (pregnancy viduals tic coast rate, stomach content, age and matur-

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ity)

Exploited species

Landings By harbour, Observation O 1983- Monthly NIS IEO fishing gear and species

Landings By harbour, Observation O 1990- Monthly NIS IEO fishing gear and species

Size-structure of Selected har- Observation O Monthly NIS IEO landings bours and species

Stock abundance Annual NEA ICES ICES assessment depend- groups ing of the species

Sensitive species

Cold water corals

Widely distributed and migratory stocks

Mackerel

Horse mackerel

Blue whiting

European eel 1) NIS: North Iberian Shelf, 42°-44.5°N, 10°-1° W

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7.6 Inner Bay of Biscay (IBoB, Region E)

Eider Andonegi

AZTI-Tecnalia. Txatxarramendi ugartea z/g. 48395 Sukarrieta (Bizkaia). Spain

7.6.1 Geography and climate The Inner Bay of Biscay (IBoB) subregion lies between Cape of Ajo (ca. 43°30’N, 3°35’W) and Cape Ferret (ca. 44°47′N 1°8′W). This area is located between two different countries (Spain and France) as part of the Atlantic Ocean. It corresponds biogeo- graphically to a subtropical/boreal transition zone, as classified by the OSPAR Commission for the Protection of the Marine Environment of the North East Atlantic (OSPAR, 2000). Its topographical diversity is reflected in the ecological richness of the area, containing a wide distribution of fish species, some of them with commercial relevance for the surrounding countries. Compared to other parts of the Bay of Bis- cay, there is a warming period during the summer in these waters, at the same time an upwelling takes place in Galician and Brittany coasts. All these characteristics make this area a very interesting zone in terms of marine diversity. The Cape Breton Canyon could be considered as a natural barrier between these two sub-areas: the Basque and the French shelves. Below a water depth of 4500 m, there is an abyssal plan, which constitutes the real oceanic section of the bay. Some submarine mountains rise in this area, often aligned in an east-west direction (Pascual et al., 2004). Bordering this abyssal plain, the Basque continental shelf appears to the south, located within the eastern section of the northern Iberian Peninsula shelf. As the whole Cantabrian shelf, it is characterized by its narrowness, ranging from 7 km in front of the Matxitxako Cape to 20 km in front of Orio. Beyond 200 m water depth, there is a steep slope with submarine canyons (Pascual et al., 2004). The Basque inner shelf is covered by an almost continuous belt of rocks, interrupted regularly by the presence of sandy sediments caused by the of river mouths, rias, etc. (Rey and Me- dialdea, 1988). A particular characteristic of these sandy areas is that they lie to the east of the rivers, probably caused by the orientation of the coast to the predominant wave climate in the area (Uriarte et al., 2004). On the eastern limit of the abyssal plain is the Aquitaine Basin, which extends 330 km northward from the point where the Pyrenees reach the Atlantic Ocean. Structurally the Aquitaine Basin can be divided into two provinces separated by a prominent fault zone, the so-called North Aquitaine Flexure. This fault zone extends from Arcachon to Carcassonne and represents the continuation of the continental slope onshore. All the French part of this sub-area is comprised inside this basin, corresponding to the Southern Province of Aquitaine. Compared to the neighbouring shelf of the Basque coast, this shelf is quite wider, ranging from 60 to over 200 km (Figure 1).

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Figure 1. Morphology of the bay of Biscay (from Pascual et al., 2004).

This area is highly influenced by the Gulf Stream and the atmospheric westerlies, in the middle and upper troposphere. So, the annual mean temperature is higher than 10ºC. The climate is temperate, oceanic with moderate winters and warm summers. It is therefore associated with a Cfb climate (marine west coast-mild) according to the Köppen climate classification system (Usabiaga et al., 2004). The average yearly precipitation during the period 1928–2001 was 1559 mm. The maximum and minumum values over the same period are 2200 mm·yr-1and 1038 mm·yr-1. On average, it rains during about 200 days in a single year, occurring more frequently during autumn and with another relative maximum in March-April (Usabiaga et al., 2004; see Figure 2).

Figure 2. Seasonal cycle of monthly mean precipitation in Igeldo from 1928 to 2001 (from Usabi- aga et al., 2004).

On the other hand, the distribution of the winds is relatively is very different from season to season, and some special atmospheric events occur over the area: the so-

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called galernas (mesoscale storms), which appear mainly in summer, and the Foehn Effect (Barry and Chorley, 1998; Usabiaga et al., 2004).

7.6.2 Hydrography and circulation The Bay of Biscay is located between the eastern part of the subpolar and subtropical Atlantic gyres. The region is affected by both gyres, depending upon latitude. How- ever, the general water circulation in the area follows mainly the subtropical anticyclonic gyre, in a relatively weak manner (1–2 cm·s−1) (Koutsikopoulos and Le Cann, 1996).

Figure 3. Scheme of the main oceanographic processes in the Bay of Biscay (OSPAR 2000, from Koutsikopoulus and Le Cann 1996).

In the southeastern Bay of Biscay, the Basque coast is orientated east–west, whilst the French coast is orientated north–south. Over the area, onshore Ekman transport dominates in autumn and winter, in response to westerly and southerly winds. In spring and summer, easterly winds create weak coastal upwelling events, which compensate partly the convergence and downwelling (Borja et al., 1996; ICES, 2006; Fontán et al., 2008).

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Figure 4. Monthly mean upwelling–downwelling balance (m3·s-1·km-1) in waters of the Basque continental shelf, for the period 2001–2005, in comparison with the mean± standard deviation for the period 1986–2005 (from Fontán et al., 2008). Data Courtesy of NOAA (FNMOC: Fleet Numeri- cal Oceanographic Centre; and PFEG: Pacific Fisheries Environmental Group)

The Basque coast is a marginal area of the northeastern Atlantic and the Bay of Bis- cay; it has distinctive climatic and geographic characteristics. The concavity of the southeastern corner of the Bay of Biscay results in a strong continental influence over the region. Consequently, the continental shelf waters are less saline, colder in winter and warmer in summer, than waters of western areas at equivalent latitudes (Valen- cia et al., 2003; 2004). Convergence and downwelling lead to the accumulation of surface waters of oceanic origin in the southeastern Bay of Biscay; this mechanism modulates, to some extent, the “overcontinentalisaton”. This term expresses the influence of the land climate and inputs on the adjacent ocean; this is related to the degree of enclosure of the sea by the surrounding land (Valencia et al., 2004). Within this context, the southeastern Bay of Biscay can be considered as being less continental- ised than enclosed or semienclosed embayments; nonetheless, it is more continental- ised than other typically open sea areas. The synergy (of two concave right-angled coastlines) is enhanced by the active land and river runoff throughout the coastlines (Fontán et al., 2008).

Figure 5. Seasonal accumulated anomalies of: the Gironde River flow; salinity in the upper 100 m of the water column off the Basque coast; and precipitation in San Sebastián (from Fontán et al., 2008).

In spite of the marginal geographical location of the Basque coast, the trends over the area are consistent with the anomaly patterns described for the northeastern Atlantic

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Ocean. Sea surface temperatures at San Sebastián show the same anomalies described for the North Atlantic in the 1970s, coinciding with the “Great Salinity Anomaly” (Dickson et al., 1988; Usabiaga et al., 2004; Fontán et al., 2008). Some particular periods (e.g. the transition from the late 1980s to early 1990s) show increased temperature and salinity, related to mild and dry winters in the intergyre area of the northeastern Atlantic (Pérez et al., 1995; Valencia et al., 1996; Pérez et al., 2000; Valencia et al., 2003). This pattern was related to the dominance of the southerly and westerly winds, coinciding with an atmospheric regime which increases the occurrence of ENACW (East- ern North Atlantic Central Water) in the southern Bay of Biscay (Pingree and Le Cann, 1992a,b; Pingree, 1994) and over the continental shelf of the Basque coast (Va- lencia, 1993; Fontán et al., 2008). The annual cycle of the shelf waters of the Basque coast can be characterised by changes in the relative prevalence of downwelling and upwelling mechanisms (Va- lencia et al., 2004). In autumn and winter, southerly and westerly winds prevail in the southeastern corner of the Bay of Biscay; their average speeds are the highest throughout the year (Usabiaga et al., 2004). This regime causes currents directed towards the north and east and, as such, the dominance of downwelling in the shelf waters of the Basque coast. A combination of winter cooling, downwelling and turbu- lent mixing enhances the homogeneity of the water column. In spring, the reduction in wind stress and a change of the wind direction, to prevailing northwesterly winds, generates currents towards the west–southwest. This regime initiates the relaxation of downwelling and turbulence together with some phases of upwelling prevailing. Consequently, these factors, together with the warming of the surface layers, cause stratification of the water column; this continues throughout the summer and early autumn (Valencia et al., 2004). In general, the distribution patterns, trends and anomalies in oceano-meteorological time-series data sets are highly dependent on spatial and temporal scales. Frequently, it is possible to observe opposing trends, when different time periods are considered. Thus, the SST data series in San Sebastián, for the period 1947–2001, indicates a decreasing trend in the mean annual temperature; this is in response to warm periods at the end of the 1940s and the 1960s (Borja et al., 2000). However, Koutsikopoulos et al. (1998), investigating a SST series commencing in the 1970s cool period and extending from 1972 to 1993, define an increasing temperature trend for the southeastern Bay of Biscay. The monthly and seasonal analysis undertaken, of several SST time-series, indicate increasing trends for 1971–1998, or for some specific sub-periods such as 1991–1995 (Lavín et al., 1998), 1986–1990 (Valencia, 1993) and the most recent periods (1986–2003) (ICES, 2004c). This pattern shows that increasing trends are related more with mild winter SST periods, than with very high summer SST values (Koutsi- kopoulos et al., 1998; Borja et al., 2000). With regard to the geographical location of the observations, Koutsikopoulos et al. (1998) found that the southeastern part of the Bay of Biscay showed the strongest warming trend, for the period 1972–1993. The oceanographic conditions were hind- casted (1972–2009) using IFREMER’s coupled physical-biogeochemical model of the Bay of Biscay. This revealed a warming trend over the Bay of Biscay continental shelf, with a trend of ~+0.3°C per decade since the eighties (Huret et al., 2009), similar to the SST trend analysed from in-situ and satellite data over the whole Bay of Biscay (Mi- chel et al., 2009). This trend shows a seasonal dependence with higher values in summer (Gómez-Gesteira et al., 2008; Michel et al., 2009). Also this fast warming trend followed a cooling period, so the trend is slower (0.2°C per decade) looking at the period 1965–2005 (Michel et al., 2009).

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7.6.3 Ecosystem components

7.6.3.1 Bacterioplankton and phytoplankton communities Heterotrophic bacteria are recognized to be the major consumers of organic matter and nutrient regenerators, as well as an important means for the re-entry of carbon into microbial food webs (Azam, 1998; Rivkin and Legendre, 2001; Hoope et al., 2002; Orive et al., 2004). Average abundance and production of these bacteria along the Basque and the Aquitanian shelf increases when moving from marine shelf waters to estuaries and coastal plumes (see Table 1 below). As the salinity decreases, higher values of bacterial abundance and production are generally found. The high bacterial density and activity normally observed in most estuaries elsewhere, have been explained as a consequence of the elevated primary production levels driven by nutrient enrichment (Ducklow and Shiah, 1993). Specific growth rates, as indicators of the capacity of the population to replace its biomass, do not show any trend related to salinity gradients, and therefore, to nutrient availability.

Table 1. Range of bacterial abundance and production in mean values, from different shelf areas in the Inner Bay of Biscay. Some of these data have been provided by various authors and are not available in reports (see Orive et al., 2004).

Abundance (109 cells · l-1) Production (mgC·m-3·day-1) Location Basque shelf French shelf Basque shelf French shelf

Marine shelf waters 0.3-2.4 0.4-1.8 1.0-49.0 - Estuaries and coastal 0.8-14.7 0.8-9.1 2.0-694.0 - plumes

Most of the studies about the phytoplankton communities in the Bay of Biscay have been undertaken on estuaries, where the river discharge and water turbidity seem to be the main controlling factors. Phytoplankton growth and accumulation is limited to the periods of low river flow and, hence, by low turbidity and relatively large resi- dence time of the water (Orive et al., 2004). This pattern occurs typically in summer, always depending on the annual river flow regime. Generally, small centric dyatoms such as Cyclotella atomus, C. meneghiniana and Thalassiosira weissflogii form extensive blooms at these sites, accompanied by different species of chlorophytes and the dinoflagellate Peridinium foliaceum during the warmer periods (Franco, 1994; Trigue- ros and Orive, 2001; Orive et al., 2002; 2004).These assemblages reach higher densities in the estuaries than in rivers (due mainly to the shallowness of the rivers). Other species that can be found in these waters are: Skeletonema costatum, Chaetoceros salsugineum, Rhodomonas marina, Peridinium quinquecorne, Heterosigma akasiwo, Hemislemis virescens, Teleaulax acuta, Nephroselmis minuta, Tetraselmis gracilis and Apidinella spinifera. On the other hand, marine water dominate the seaward end of these systems, and there, the phytoplankton assemblages reflect well the seasonel cycle observed in coastal waters (Estrada, 1982; Reguera, 1987; Fernández and Bode, 1992; Varela, 1996). The onset of the phytoplanktom bloom may start in the late winter (water temperature around 12ºC) and nutrients are still present (Revilla et al., 2002; Ansotegui et al., 2003). Large diatoms are characteristic of theis winter-spring bloom, such as Aste- rionallopsis glacialis, Lauderia annulata, Detonula pumilla, Leptocylindrus danicus and several species of Pseudo-nitzschia, Rhizosolenia and Chaetoceros (Trigueros and Orive, 2001; Orive et al., 2002; Ansotegui et al., 2003).

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Chlorophyll a concentrations in continental shelf waters in autumn-winter are normally lower that 1 µg·l-1, whereas it presents a maximum peak (around 2–6 µg·l-1) within the sub-surface layers (10–30 m depth) (Orive et al., 2004). Within the estuaries, the chlorophyll a concentrations are at their maxima in spring- summer and minima in autumn-winter. Concentrations higher than 100 µg·l-1 have been detected in some Basque estuaries during blooms (Villate et al., 1991; Franco, 1994; Madariaga et al., 1994; Borja et al., 2000; Ansotegui et al., 2001; Revilla et al., 2002), whereas in autumn-winter periods, these concentrations are generally lower than 5 µg·l-1 (Orive et al., 2004). The contribution of heterotrophic bacteria to the total biomass production and miner- alization within the microplankton can be used to evaluate the relative importance of bacteria in the pelagic food webs and the carbon cycle. This information also indicates the dominant trophic pathway. Different studies showed that bacterial biomass was generally lower than phytoplankton biomass (Revilla, 2001; Orive et al., 2004).

7.6.3.2 Zooplankton Copepods are the dominant group of the zooplankton community in the IBoB subregion (Villate et al., 2004). However, their contribution to the total zooplankton is higher in the shelf and coastal areas (60–70%) than in the estuaries (40–60%). Clado- cerans, appendicularians or cnidatians are other representative groups of the meta- zoan holoplankton in the mesozooplankton community, and their abundance increase from the shelf to the estuaries. Gastropods and echinoderms are the principal meroplanktonic groups in meroplanktonic community on the shelf, whereas the coastal and estuarine communities are dominated by cirripeds. In the microzooplank- ton, polychaetes are dominant, constituting more than 5% of the zooplankton bigger than 45 µm (Villate et al., 2004). Protozoans are also a very relevant group, being species like Noctiluca scintillans and some acantharians very important. In addition to that, doliolids are important constituents of the neritic holoplankton in the Basque coasts, usually representing more than 1% of the total mesozooplankton. Ichthyoplankton assemblages are also a component part of the plankton community. Valencia et al. (1988) described the seasonal fluctuations in the abundance of fish eggs and larvae in the Basque shelf. Pelagic species eggs were the most abundant, the higher densities corresponding to sardine eggs (Sardina pilchardus). A significant negative relationship was found between total egg abundance and water surface temperature, due to the abundance of species which spawn mainly in cold waters, such as sardine and mackerel (Scomber scombrus). Some other commercial species were found in lower densities, such as Merluccius merluccius, Dicentrarchus labrax and Solea vulgaris. The results for the sampled larvae were quite similar, but several taxa with demersal spawning appeared only at the larval stages, such as Gobidae and Blennidae. In both cases (fish eggs and larvae), abundance in the study area showed their highest densities in early spring, decreasing sharply in mid-autumn (Valencia, 1988; Mo- tos et al., 2004).

7.6.3.3 Benthic communities

Macroalgae Within the Bay of Biscay, the Basque coast presents some unique biogeographical characteristics (Borja et al., 2004), which could cause the differences existing between

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the vegetation of the Basque coast and the neighbouring areas (Bornet, 1982; Sau- vageau, 1897; Beauchamp, 1907). These differences are mainly based upon the scar- city or absence of several large brown algae (fucoids and laminarians) in the Basque coast (Ibáñez, 1989; Borja et al., 2004). Hence, the dominance of several war-temperate red algae, together with a minor presence of large brown algae typical of cooler waters, shapes a particular zonation and enforces the meridional character of the flora, which has been corroborated by several phycologists (Borja et al., 2004). This area could be then considered as a refuge for some Mediterranean species (Gorostiaga and Limia, 1985).

Macrozoobenthos Several species considered endemic of the Mediterranean, the Moroccan Atlantic or more southern coast, have been found in the study area, due to the biogeographical peculiarities of this coast. The main causes of this peculiarity are both, the abnormal warming of surface waters and the cooling of the waters of Galicia (Díez et al., 2000), which limits the distribution and development of several flora and fauna species. The small snail Melaraphe neritoides is for instance, very frequent, always related to the presence of typical Mediterranean algae. Other species as Littorina obtusata are also associated to these algae (Borja et al., 2004). Holoturia belleri (Ibáñez and Salo, 1975; Rield, 1986), Blennius pilicornis (Motos and Ibáñez, 1977) and Blennius ponticus (Borja et al., 2004) are also found in the eastern part of this coast. Ophiura ophiura, Mar- thasterias glaciaris, Psilaster Andromeda and Pagurus alatus are also very typical invertebrates of this coast (Quincoces et al., 2011). Some of the species that appear along the intertidal zone of this coast, present different population dynamics, due to the special characteristics of the area (i.e. Gibbula umbilicalis, Patella vulgata (Peña, 1995) or Hydrobia ulvae, Scrobicularia plana, Hediste diverrsicolor (Sola, 1994)). Macoma balthica is cannot be found in the southeast of the Bay of Biscay, non in polluted areas, neither in the non-polluted ones.

7.6.3.4 Fish species Within the fish community, European hake (Merluccius merluccius), anchovy (Engrau- lis encrasicolus), and tunas (Thunnus alalunga and Thunnus thynnus) are presently the most important commercial fish species in the Bay of Biscay. Whilst tunas are a large- scale migratory species, European hake and anchovy can be considered as the main fisheries, restricted to the Bay of Biscay ecosystem (considering the ecosystem and the use by the human communities). Other fish species are also present in these waters, like horse mackerel (Trachurus trachurus), mackerel (Scomber scombrus), sardine (Sardina pilchardus) and blue whiting (Micromesistius poutassou). Raja clavata seems to be a very relevant species in this ecosystem too, along with Scyliorhinus canicula (Quincoces et al., 2011).

Small pelagic fish The main pelagic species in the Bay of Biscay are sardine and anchovy (small pelagic) and mackerel and horse mackerel (middle-size pelagic). These species form the basis of important fisheries that represent an important source of income for local econo- mies.

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Anchovy The distribution of anchovy (Engraulis encrasicolus) in Atlantic European waters is nowadays mainly concentrated in two well defined areas: the Bay of Biscay and the Gulf of Cádiz (Uriarte et al., 1996; ICES, 2008). Some residual coastal populations exist also along the Iberian coast, English Channel, Celtic Sea and North Sea (Beare et al., 2004; ICES, 2007b). Anchovy in the Bay of Biscay may grow to >20 cm and live span rarely goes beyond three years. It forms large schools located between 5 and 15 meters above the bottom during the day (Massé, 1996), although change in the schooling pattern of anchovy have been described since the beginning of the 2000s (ICES, 2008). It is a serial spawner (several spawns per year) and reproduces in spring. The spawning area is located southward of 47° N and eastward of 5° W. Most spawning takes place over the continental shelf in areas influenced by the river plumes of the Gironde, Adour and Cantabrian rivers (Motos et al., 1996). Recent studies have suggested that anchovy in the Bay of Biscay may recruit partially offshore (Irigoien et al., 2007). How- ever it is no clear to what extent individuals recruited off the shelf contribute to the total population (Irigoien et al., 2008), partly because modelling studies have suggested that off-shelf waters do not fulfill the conditions for larvae survival (Allain et al., 2007a; Allain et al., 2007b) As spring and summer progresses, anchovy migrates from the interior of the Bay of Biscay towards the north along the French coast and towards the east along the Cantabrian Sea, where it spends the autumn. In winter it migrates in the opposite direction towards the east and southeast of the Bay of Biscay (Prouzet et al., 1994). It has a high and very variable natural mortality. Mesoscale processes in relation to the vertical structure of the water column (stratification, upwelling and river plume extent) appear to have a great influence on the survival of larvae (Allain et al., 2001). However they may only act as limiting factors (Planque and Buffaz, 2008), and the mechanisms through which these physical processes impact biological oceanography and recruitment are still to be better understood. As all short lived species, anchovy stock is very dependent on recruitment, and therefore these recruitment failures lead to the low biomass levels observed in recent years. A reduction of the distribution of anchovy in the Bay of Biscay has been observed both in the acoustic and egg production survey (ICES, 2007b) and changes in the school composition have also been described (Massé and Gerlotto, 2003). In the past century, the anchovy population has almost disappeared from the Spanish coast and spawning grounds have been lost (ICES, 2004b). Based on circulation models, larval drift reveals that the larvae born in the French spawning grounds move towards Spanish coasts but fail to re-colonize there (Vaz and Petitgas, 2002). Although anchovy juvenile research surveys show that early juveniles are found alone, separated from the adults, in the oceanic area and along Spanish coasts (Uriarte et al., 2001; ICES, 2008), afterwards juveniles are found together with the adults along the French coasts (Petitgas et al., 2004; ICES, 2008). According to previous studies (Motos et al., 1996; Uriarte et al., 1996), anchovy populations appear to have density-dependent strategies of spawning area selection. Dif- ferent hypotheses have been suggested to explain interannual and long-term variations in anchovy abundance which are often attributed to important variability in recruitment levels, and are ultimately linked to variations in ocean processes. Changes in global and local environmental indexes have also been described for the Bay of Biscay, such as North Atlantic Oscillation index and Polar Eurasia and East Atlantic patterns (ICES, 2007a; Borja et al., 2008) and upwelling and stratification index (Borja et al., 1998; Allain et al., 2001; ICES, 2007c).

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In the last decade the spatial distribution of anchovy eggs in spring has expanded northward compared with the distribution of the anchovy eggs in the 1960s and 1970s (Bellier et al., 2007). Anchovy populations in the northern areas seem to have increased in recent years (Beare et al., 2004; ICES, 2004a).

Sardine Sardine (Sardina pilchardus) in the IBoB belongs to the Iberian-Atlantic population. In general, sardines present in this area are larger and longer than the ones of the western Bay of Biscay. More information regarding this species has been provided in the WBoB case study report.

Mackerel Mackerel (Scomber scombrus) belongs to the so-called North East Altantic mackerel population, which extends all along the western margin of Europe, from Portugal to Norway. More information regarding this species has been provided in the WBoB case study report.

Horse mackerel Horse mackerel (Trachurus trachurus) is distributed all along the European coasts, and the population found in the IBoB belongs mainly to the European southern stock. This species may be considered as benthopelagic as it is around over sandy bottom, at 100–200 m depth, but also at near-surface. Horse mackerel is distributed in large shoals near the coast in the warmest months of the year; it moves to deeper waters in the winter. This species lives around 15 years on average, but may live up to more than 20 years and can reach about 60 cm fork length, with common sizes ranging from 15 to 30 cm (Arregi et al., 2004).

Large pelagic fish Tuna species, albacore (Thunnus alalunga) and bluefin (Thunnus thynnus), cannot be considered as species inhabiting the Bay of Biscay, as they visit the IBoB waters in their trophic migration routes (Cort, 1995). The individuals that go into this area are immature individual that migrate from the African coast (bluefin tuna) or Azores (albacore) to the feeding areas during the summer months, and they return to the original areas during the autumn.

Demersal and benthic fish European hake (Merluccius merluccius) is one of the most important demersal species in the IBoB waters. Anyway, many other species exist in this ecosystem, blue whiting (Micromesistus potassou), dogfish and rays (mainly the lesser-spoted dogfish, Scylio- rhinus canicula and Raja clavata), monkfish (Lophius piscatorius and L. budegassa), and megrim (Lepidorhombus boscii and L. whiffiagonis). Red mullet (Mullus surmuletus), white bream (Diplodus sargus) dragonet (Callionymus maculatus) and scaldfishes (Ar- noglossus spp.) are common benthic fishes that inhabit the IBoB waters, being bass (Dicentrarchus labrax) and sole (Solea vulgaris) the most relevant (Arregi et al., 2004; Quincoces et al., 2011).

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Blue whiting Blue whiting (Micromesistus potassou) is the most abundant demersal species in the North Atlantic. It is a migratory species distributed near the bottom, between 200 and 500 m depth, which perform diurnal vertical migrations. In the IBoB ecosystem, this species constitutes a very important prey for large predators, like European hake (Mahe et al., 2007).

Dogfish and rays The lesser-spotted dogfish (Scyliorhinus canicula) and the ray (Raja clavata) are the most relevant species of this group in the study area, constituting also a very important biomass of the whole ichthyofauna.

Hake European hake is distributed widely throughout the Northeast Atlantic, from Nor- way in the north to the Guinea Gulf in the south and in the Mediterranean and Black Sea, being more abundant from the British Isles to the south of Spain (Casey and Pereiro, 1995). The population in the IBoB belongs to the so-called northern stock of European Hake. The boundary between the northern and the southern population, Cap Breton Canyon, was anyhow defined mainly based on management considera- tions. It is a demersal and benthopelagic species, found mainly between 70–370 m waters depth; however, it occurs also from inshore waters (30 m), to depths of 1000 m. Euro- pean hake lives close to the bottom during daytime but, during the night, moves up and down in the water column (Cohen et al., 1990). The juvenile and small European hake lives usually on muddy beds on the continental shelf, whereas large adult individuals are found on the shelf/slope, where the bottom is rough and is associated with canyons and cliffs. Different studies have indicated that this species spawns several times within the reproductive season, i.e. it is a batch-spawner, or a fractional spawner, species (Andreu, 1955; Pérez and Pereiro, 1985; Sarano, 1986). The transportation of early life stages, from spawning grounds to coastward juvenile recruitment areas, can be foreseen in relation to the general water mass circulation, as postulated by Koutsikopoulos and Le Cann (1996). In fact, Álvarez et al. (2004) inferred a north and northeast dispersion of eggs and larvae due to the main patterns of oceanographic processes such as wind induced currents and geostrophic flow.

Anglerfish Two species of anglerfish are present in the IBoB (Lophius piscatorious and L. budegassa; Quincoces et al., 2011).

Megrim Two megrim species of the genus Lepidorhombus inhabit in the IBoB, L. boscii and L. whiffiagonis (Quincoces et al., 2011). These species are distributed in sandy or muddy sea floor between 100 and 700 m depth.

7.6.3.5 Top predators Several cetacean and seabird species inhabit the IBoB waters.

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Marine mammals Historically, one of the most relevant sea mammals in this area has been the northern right whale (Eubalaena glacialis), known nowadays as the “Basque whale”. This species disappeared from the region long time ago. Information available on the different marine mammals species of the IBoB is some- what scarce. It is mainly obtained from opportunistic (fishermen, divers…) or systematic (researchers and volunteers of the Centre de Recherche sur les Mammifères Marins, the Biscay Dolphin Research Project and the non-governmental body: Ambar) observations. Cetacea are the most abundant marine mammals in the Bay of Biscay five whales (Mysticety) and fifteen toothed whales (Odontocety) have been recorded and cata- logued. The fin whale (Balaenoptera physalus) is the commonest large whale occurring in the area, along with the minke whale (Balaenoptera acutorostrata) and the sei whale (Balaenoptera borealis), the humpback whale (Megaptera novaenglidae) and the blue whale (Balaenoptera musculus). The other species (Odontocety) are: the sperm whale (Physeter catodon) and pygmy sperm whale (Kogia simus), the Cuvier’s beaked whale (Ziphius cavirostris), the Sowerby’s (Mesoplodon bidens) and northern bottlenose whale (Hyperoodon ampullatus), the common dophin (Delphinus delphis), the striped dolphin (Stenella coeruleoalba), the bottlenose dolphin (Tursiops truncatus), the white-beaked dolphin (Lagenorhynchus alboristris), the killer whale (Orcinus orca), the false killer whale (Pseudorca crassidens), the Risso’s dolphin (Grampus griseus), the long-fined pilot whale (Globicephala melas), the pygmy killer whale (Feresa attenuata) and the harbour porpoise (Phocoena phocoena) (Castro et al., 2004).

Seabirds The nesting seabird community of the IBoB sub-region is very poor in comparison with other European Atlantic areas, in terms of abundance and species diversity. The two most limiting factors for breeding seabird populations are prey abundance and availability close to breeding areas and availability of good nesting places (Franco et al., 2004). In spite of this limitation, some important breeding colonies exist within the area. Four seabird species can be considered as regular breeders on this area: the European storm-petrel (Hydrobates pelagicus), the European shag (Phalacrocorax aristotelis), the yellow-legged gull (Larus michahellis) and the black-backed gull (Larus graellsii) (Franco et al., 2004). The Basque coast is located on the migratory routes of many European birds, whilst the Bay of Biscay is an important area for some species during winter. During this period, seabirds take advantage of the presence of small-to-medium-size pelagic fishes (anchovy, sardine, mackerel and horse mackerel). More than 30 species can be considered seabird migrants along this coast. The most abundant one are northern gannets (Morus bassanus), auks (Alcidae; specially the common guillemot (Uria aalge) and the razorbill (Alca torda)), black-headed gulls (Larus ridibundus), Yelkouan shearwaters (Puffinus yelkouan), lesser black-backed gulls (Larus graellsii) and kittiwakes (Risa thidactyla). The Atlantic puffin (Fratercula arctica) is also a regular winter visitor to the Bay of Biscay; however, this species clearly prefers the more open waters. Great cormorant (Phalacrocorax carbo) arrives to the study area from in the end of August (Franco et al., 2004)

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7.6.4 References Allain G.,Petitgas, P. and Lazure, P. 2001. The influence of mesoscale ocean processes on anchovy (Engraulis encrasicolus) recruitment in the Bay of Biscay, estimated with a three- dimensional hydrodynamic model. Fisheries Oceanography, 10: 151-163.

Allain, G., Petitgas P. and Lazure P. 2007a. The influence of environment and spawning distribution on the survival of anchovy (Engraulis encrasicolus) larvae in the Bay of Biscay (NE Atlantic) investigated by biophysical simulations. Fisheries Oceanography 16, 506-514.

Allain, G., Petitgas, P., Lazure. P. and Grellier, P. 2007b. Biophysical modelling of larval drift, growth and survival for the prediction of anchovy recruitment in the Bay of Biscay (NE Atlantic). Fisheries Oceanography 16:489−505.

Álvarez, P., Fives, J., Motos, L. and Santos, M. 2004. Distribution and abundance of European hake Merluccius merluccius (L.), eggs and larvae in the North East Atlantic water in 1995 and 1998 in relation to hydrographic conditions. Journal of Plankton Research 25 (6), 1-16.

Andreu, B. 1955. Observaciones sobre el ovario de Merluza, Merluccius merluccius, y carac- terísticas de la puesta. Investigación Pesquera. Tomo 4, 49-56.

Ansotegui, A., Sarobe, A., Trigueros, J.M., Urrutxurtu, I. and Orive, E. 2003. Size distribution of algal pigments and phytoplankton assemblages in a coastal-estuarine environment: contribution of small eukaryotic algae. Journal of Plankton Research 25: 341-355.

Ansotegui, A., Trigueros, J.M. and Orive, E. 2001. The use of pigment signatures to assess phytoplankton assemblage structure in estuarine waters. Estuarine, Coastal anc Shelf Sci- ence, 52: 689-703.

Arregi, L., Puente, E., Lucio, P., Sagarminaga, Y., Castro, R. and Uriarte, A. 2004. Coastal Fish- eries and Demersal Estuarine Fauna. In: Borja, A. and Collins, M. (Eds.), Oceanography and Marine Environment of the Basque Country. Elsevier Oceanography Series, vol 70. Elsevier, Amsterdam, pp 493-513.

Azam, F. 1998. Microbial control of oceanic carbon flux: the plot thickness. Science, 280: 694-696

Barry, R.G. and Chorley, R.J. 1998. Classification, seasonality and persistence of low-frequency circulation patterns. Monthly Weather Revue, 115: 1083-1126.

Beare, D., Burns, F., Jones, E., Peach, K., Enrique Portilla, E., Greig, T., McKenzie, E. and Reid, D. 2004. An increase in the abundance of anchovies and sardines in the north-western North Sea since 1995. Global Change Biology 10 (7): 1209–1213

Beauchamp, P. 1907. Quelques observations sur les conditions d’existence d’êtres dans la Bahie de Saint-Jean-de-Luz et sur le côte avoisinante. Archives de Zoologie Expérimentale et Génerale 4 sér. 7: 4-16.

Bellier, E., Planque, B. and Petitgas, P. 2007. Historical fluctuations in spawning location of anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) in the Bay of Biscay during 1967-73 and 2000-2004. Fisheries Oceanography, 16(1): 1-15.

Borja, A. Fontán, A., Saez, J. and Valencia, V. 2008: Climate, oceanography, and recruitment: the case of the Bay of Biscay anchovy (Engraulis encrasicolus). Fisheries Oceanography, 17:6, 477–493.

Borja, A. Uriarte, A., Egana, J., Motos, L. and Valencia, V. 1998. Relationships between anchovy (Engraulis encrasicolus) recruitment and environment in the Bay of Biscay (1967-1996). Fisheries Oceanography, 7(3-4), 375-380.

Borja, A., Aguirrezabalaga, F., Martínez, J., Sola, J.C., García-Arberas, L. and Gorostiaga, J.M. 2004. Benthic communities, biogeography and resources management. In: Borja, A. and Collins, M. (Eds.), Oceanography and Marine Environment of the Basque Country. Elsevier Oceanography Series, vol 70. Elsevier, Amsterdam, pp 455-492.

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Borja, A., Belzunce, M.J., Castro, R., Franco, J., Villate, F. and Pérez, V. 2000. Seguimiento am- biental de los estuarios del Nervión, Barbadún y Butrón durante 1999. Consorcio de Aguas de Bilbao Bizkaia. 256 pp + annexes. Unpublished report.

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7.7 Western Bay of Biscay (WBoB, Region F) Many review already describes the western BoB natural components and processes. A "90's initial state" review of bay of Biscay main components have been elaborated in 2009 ({Lorance, 2009 #1896}), it summarizes natural components, processes and main impacts coming from anthropogenic activities. Ices group (WGRED) have recently conducted an extensive review for demersal and benthic ecosystems. Extensive review of knowledge and available data has been made for the french EEZ in the MSFD context. Most of the description and bibliographic references comes from works down as contribution to the Initial state evaluation realised for the french implementation of the European MFSD. Reports will be available on-line and gives a large overview of each ecosystems components (geology, hydrology, biology) and main anthropogenic threats (http://wwz.ifremer.fr/dcsmm).

7.7.1 Geography and bottom topography Bay of Biscay is characterized by a continental shelf extending from the coast to about 180 m deep. Continental shelf enlarged along french part of the BoB (from south-east to north-east), as large as about 200 km in its northern part and about 5 km only in the southern part near spanish border. Shelf shows globally a gently slope (less than 0.5%). Coastal morphology is more diverse in its northern part where rocky and

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sandy "coast" as well as "pointes, baies et îles alternent". Regarding area located south to Gironde river, coast is characterized by a monotonous linear sandy coast about 250km long followed by the "falaises" of the "basque" country. Continental break shows a slope varying from 10 to 12% and is mostly constitued by muds and crossed by deeper canyons. Infralittoral BoB habitats are characterized by the large mudflat "Grande Vasière", occupying the "north-central" part of the shelf between 70 and 110 m deep. Between that mud flat and the coast we can distinguish 3 main "ensembles": (1) Britanny region where behind an "island belt" where sedimentations processes accumulate fine particules coming from many estuaries and « form pre-littoral mudflats »; (2) Loire- Gironde region, caractérisés, en dehors des vasières littorales adossées aux îles, par d’immenses plaines de gravelle et (3) Aquitaine region, où de la côte vers le large, se succèdent des sables fins dunaires, des sables grossiers, des graviers puis des sables fins gris jouxtant les sables fins envasés de la grande vasière. Main hydrological processes acting upon sediment disposals are: • the residual north-south coastal current that makes littoral mudflats and fine particules from estuaries accumulating in the northern part of the BoB. • permanent action of waves at depth above 20m and only few days a year at deeper locations on the whole continental shelf.

A B

Figure 9. Residual currents (A) and sediment distribution (B) (from DCSMM initial status synthesis, Thierry Garland 2011).

7.7.2 Hydrography, circulation and climate Bay of Biscay coastal areas are under high "swell" level (maximal mean annual size about 9.5 m). In circalittoral area, effects of wind dominate over tidal process on water masses circulation. Winter residual currents are orientated from south-east to north-east whereas, at Summer, water masses flows from north-west down to southeast part of the bay of Biscay. Bay of Biscay circalittoral waters can be distinguished between "coastal" vs shelf waters. The first one are characterized by lower salinity and relatively high turbidity mostly at rivers mouths (mean turbidity from 5 to 10 mg.l-1) as well as highest seasonal variability. The second one, display marine salinity features and lower turbidity (from 1 to 5 mg.l-1). In the whole bay of Biscay, communities located above

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70 m deep are inside a "cold water cover" all year long with mean temperature oscillating from 10.8 to 11.9°C. Beyond measured hydrological variables from surveys, satellites, hydrodynamic modeling framework MARS3D (Ifremer) developed in bay of Biscay region offers 3 dimensional simulated dataset at relatively high spatial (4 km2) and temporal resolutions (3 minutes time step from 1971 to 2008).

Figure 10. (A) Equivalent height of fresh-water and (B) gyres (Okubo-weiss indices expressed in s- 2) as derived from MARS3D simulation platform (in {Huret, 2009 #1859}).

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Figure 11. Time series from 1972 to 2008 of mean sea surface (A) temperature and (B) salinity gyres (Okubo-weiss indices expressed in s-2) as derived from MARS3D simulation platform (in {Huret, 2009 #1859}).

Integrated analysis of those indices gives maps of hydrological landscape in the bay of Biscay area (e.g. Figure 12), main hydrological regions are thus described from indices values as well as from their variability. In Spring, 6 to 8 main hydrological regions have been described ({Planque, 2006 #1780;Planque, 2004 #1781}).

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Figure 12. 8 hydrological landscapes as derived from combination of 3D hydrodynamic model in the bay of Biscay ({Planque, 2004 #1781})

7.7.3 Biological Ecosystem components

7.7.3.1 Zooplankton Few Zooplankton data are available at BoB scale. Some results on large spatial and temporal scales showed high biomass and diversity levels at continental shelf break (Sourisseau, M. & Carlotti, F. Spatial distribution of zooplankton size spectra on the French continental shelf of the Bay of Biscay during spring 2000 and 2001; J. Geophys. Res. 111, (2006); Beaudouin, J. Zooplancton du golfe de Gascogne (plateau continental) en 1972. In part II. Plankton. Annales Biologiques, Copenhagen 29, 61-63 (1974); Irigoien, X., Fernandes J.A., Grosjean P., Denis, K. Albaina A. & Santos, M. Spring zooplankton distribution in the Bay of Biscay from 1998 to 2006 in relation with anchovy recruitment. Journal of Plankton Research 31, 1-17 (2008). Available data and already done analysis failed to establish a clear seasonal pattern at the BoB continental shelf scale. However, results obtained from coastal waters in restricted areas showed typical seasonal pattern for temperate North Atlantic area. From Continuous Plankton recorder Survey, Beaugrand et al. ({Beaugrand, 2000 #2534}) failed to link zooplancktonic community fluctuations in the offshore area of the Bay of Biscay with large climatic indices (e.g. Beaugrand, G., Ibanez, F. & Reid, P.C. Spatial, seasonal and long-term fluctuations of plankton in relation to hydrocli- matic features in the English Channel, Celtic Sea and Bay of Biscay. Marine Ecology Progress Series 200, 93-102 (2000).

7.7.3.2 Small pelagic fishes In the Bay of Biscay, from 2000 onwards, acoustic survey (PELGAS, Figure 13) gives a picture of small pelagic species distribution all over the continental shelf during the spring period. During 2000 to 2005 period, five species represented 95% of pelagic fish biomass (mean biomass about 1.2x106 tonnes): Sardina pilchardus (300x103 tonnes), Engraulis encrasicolus (80x103 tonnes), Scomber scombrus (about 700x103 tonnes), and Sprattus sprattus (50x103 tonnes).

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Their spring distributions show 3 main geographic areas in the bay of Biscay: • at the mouth of Gironde estuary around 60m deep where smaller-sized individuals of S.sprattus, S.pilchardus and E.encrasicolus are dominating. That area represents a spawning area for E.encrasicolus; • near the shelf break (north to 45°20N) where bigger individuals concentrate; • centre of the shelf almost free of small aggregating pelagic fishes. Among those main species, only one of them (S.sprattus) spend its entire life cycle in the bay of Biscay and most of it for E.encrasicolus.

Figure 13. Tracks surveyed by PELAGO (Portuguese acoustic survey), PELACUS (Spanish acoustic survey) and PELGAS (French acoustic survey) during spring 2009 ({ICES, 2010 #2535}).

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7.7.3.3 Anchovy

7.7.3.4 Sardine

Figure 14. Sardine general: Distribution of sardine as observed during the French acoustic survey PELGAS08 {ICES, 2008 #2536}.

Figure 15. Sardine general: Sardine length distribution in numbers of fish for divisions VIIIa+VIIIb in the French acoustic survey PELGAS08{ICES, 2008 #2536}.

7.7.3.5 Large pelagic species Quantitative available data in the bay of Biscay for large pelagic species are those coming from fisheries catches statistics only (1952–2009 time series). Among them, 6 species are dominating: Thunnus alalunga, Thunnus thynnus, Xiphias gladius, Sarda sarda, Thunnus obesus, Prionace glauca and others pelagic sharks.

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7.7.3.6 Demersal and benthic fish Benthic demersal fish communities in the bay of Biscay are organized along depth and latitude gradients as well as sediment types characterized by a large "mudflat" ("Grande vasière") located in the northern part of the bay of Biscay. Bay of Biscay demersal fishes are characterized by a relatively high species richness with about 576 potential species (i.e. observed at the same latitude in Atlantic region, Quero 2003). However, among the about 200 species captured during standardized bottom trawl surveys (Ifremer EVHOE), 5 species only (Trisopterus luscus, Trisopterus minutus, Capros aper, Argentina silus, Merluccius merluccius) represent almost 50% of total abundance and biomass of demersal fishes. Small pelagic fishes also occurred in demersal fish community and they spatially or temporally represent dominant species in biomass. It is the case for species like Engraulis encrasicolus, Trachurus trachurus, Sardina pilchardus and Scomber scombrus that are regularly captured in demersal habitats but show highly fluctuating abundance and biomass levels. On the external part and the slope of the bay of Biscay shelf, demersal fish community is dominated by blue whiting (Micromesistius poutassou). Among the largest demersal fish species, 8 species dominate the community: Merluc- cius merluccius, Scyliorhinus canicula, Conger conger, Merlangius merlangus, Lophius piscatorius, Lepidorhombus boscii, Lophius budegassa and Solea solea (distribution shown in Figure 16).

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Scyliorhinus canicula Merluccius merluccius Conger conger Merlangius merlangius

Lophius piscatorius Lophius budegassa Lepidorhombus boscii Solea solea

Figure 16. Principal areas where main "largest" bentho-demersal fish species are observed from Ifremer bottom trawl fish surveys in Autumn {Trenkel, 2009 #1992}.

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Main elasmobranches species occurring on the continental shelf (Figure 17) are rays Raja clavata, Raja montagui and Leucoraja naevus, and sharks Scyliorhinus canicula (from the coast to the slope), Galeus melastomus (mostly from external part of the shelf and the top of the slope) and Squalus acanthias (Figure 17). Some pelagic migratory sharks are encountered like Prionace glauca, Isurus oxyrhynchus and Galeorhinus galeus.

Raja clavata Raja montagui Leucoraja naevus Scyliorhinus canicula

Galeus melastomus Squalus acanthias

Figure 17. Principal area where main rays and sharks fish species are observed from Ifremer bottom trawl fish surveys in Autumn {Trenkel, 2009 #1992}.

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From the 54 demersal fish populations that are regularly monitored since 1990 (Ifre- mer bottom trawl survey, EVHOE, CGFS, NURSE), 38 species show stability features whereas 16 others show abundance and/or length increasing. However that short period of observation didn't emphasize the tendency of rarefaction during the 19th and 20th centuries for some of highly fished commercial species. Among them sharks and rays are highly impacted (Echinorhinus brucus, Squatina squatina, Raja batis, Raja brachyura, Dasyatis pastinaca, Myliobatis aquila, Galeorhinus galeus, Mustelus asterias, Raja c1avata) as well as some actynopterygian fishes like Trigla lyra or Eutrigla gurnardus. IUCN listed a total of 70 fish occurring in the bay of Biscay as sensitive species (…) with 28 of them that need to be particularly monitored (e.g. "amphihaline" species like Anguilla anguilla or Acipenser sturio, marine "Ostheitch.." species like Hippocampus spp. and "chondrich..." species including rays, Dipturus batis, D. oxyrinchus, Rostroraja alba and sharks like Cetorhinus maximus).

7.7.3.7 Macrophytobenthos communities

7.7.3.8 Benthic invertebrates Benthic invertebrate communities in the bay of Biscay are organized along depth and latitude gradients as well as sediment types characterized by a large "mudflat" ("Grande vasière") located in the northern part of the bay of Biscay. Historic dataset offer an overview of community distribution at the BoB scale but mainly restricted to the northern part (Figure 18). Few temporal series are available to evaluate tendencies of benthic invertebrates community at the BoB scale. Studies in "Grande Vasière" area comparing 1970 and 2008 status have shown a large modification of biological and sedimentary features suggesting combined climatic and anthropogenic (mainly trawls) effects ({Blanchard, 2004 #1762}{Hily, 2008 #1748;Le Loc'h, 2004 #1055;Le Loc'h, 2008 #1747}). Localised surveys in few BoB bays and mouths of estuaries offer opportunity to follow megafaunal epibenthic invertebrate community in sub-littoral area. Since 2008, fisheries bottom trawl surveys give a picture of megafaunal epibenthic invertebrate in the circalittoral area (Figure 19).

Figure 18. Bio-sediment map in the bay of Biscay from historical data (Ifremer, REBENT).

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Figure 19. Distribution of main megafaunal communities for some commercial (A) and sensitive species (B to F) as recorded from EVHOE bottom trawl surveys in the bay of Biscay.

A) Cumulated distribution of individual size B) 1987 to 2009 evolution of mean abundance

(Total length in cm)

Figure 20. Size spectrum (A) and temporal tendencies (B) of two commercial benthic crustacean species as derived from EVHOE bottom trawl survey on the bay of Biscay (CANCPAG=Cancer pagurus and NEPHNOR=Nephrops norvegicus).

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Figure 21. Cold Water Coral occurrence in the bay of Biscay (Lophelia pertusa/Madrepora oculata records adapted from Reveillaud and OSPAR).

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Table 3. Table of Metadata - WGEAWESS Natural Components/process for each of the regions - List of data offering spatial coverage at subregion scale and/or temporal series.

TEMPORAL SPATIAL CONTACT COMMENTS Components/Variables Platforms Methods Data Type UNITS Extent Resolution Extent Resolution (CTD, satel- (Models or (year) lite …) Observa- tions) Physico- Chemical / Hydrology Temperature Scientific Sur- CTD O °C 1987-present Annual BoB Conti- various Ifremer / … veys (spring, nental shelf Pelagic and autumn) demersal (Pelgas, Evhoe)

Satellite Satellite O °C Daily Global NOAA

BOBYCLIM Various O °C 1 century inte- Mean BoB, Celtic 1/10° Ifremer Integration of all available data grated data monthly Sea and square from the 20th century to draw a values English mean climatology of the BoB Channel

MARS3D MODEL M °C 1970s-present 3 days BoB Conti- 4km2 Ifremer / … Validity from surface to 200m nental deep. French shelf

Salinity Scientific Sur- CTD O 1987-present Annual BoB Conti- Ifremer / … veys (spring, nental shelf (Pelgas, Evhoe) autumn) MARS3D 3D MODEL M 1970s-present

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TEMPORAL SPATIAL CONTACT COMMENTS Components/Variables Platforms Methods Data Type UNITS Extent Resolution Extent Resolution (CTD, satel- (Models or (year) lite …) Observa- tions) pH NA Nutrients 0 MARS3D 3D MODEL M 1970s-present 3 days BoB Conti- 4km2 Ifremer / … Validity from surface to 200m nental deep. French shelf Turbidity MARS3D 3D MODEL M 1970s-present 3 days BoB Conti- 4km2 Ifremer / … Validity from surface to 200m nental deep. French shelf Currents Waves

Upwelling MARS3D 3D MODEL M 1970s-present 3 days BoB Conti- 4km2 Ifremer / … Validity from surface to 200m nental deep. / Stratification French shelf Bed shear stress NA River Runoff Fixed stations O French water agency Meteorology (winds, Fixed stations O French mete- …) orological agency Geomorphology Bathymetry Coastal morphology Sediment “Historic” data- BoB Conti- various

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TEMPORAL SPATIAL CONTACT COMMENTS Components/Variables Platforms Methods Data Type UNITS Extent Resolution Extent Resolution (CTD, satel- (Models or (year) lite …) Observa- tions) set nental French shelf Biogenic Substrat Biology (species / population / community) Bentho-demersal fish Bottom trawl GOV (4m O (bathy- Species 1990-present 1 season BoB and CS About 70 Ifremer / … http://www.ifremer.fr/SIH- and commercial crusta- survey "EVHOE" vertical open- metric and abundance per year continental stations in indices-campagnes/ ceans and cephalopods ing and 20mm latitudinal and biomass (autumn) shelf (cir- BoB and 70 codend mesh stratified calittoral stations in size) sampling area) CS strategy) NURSE Beam trawl O Species 1980-present 1 season Bay and abundance per year estuary (latitudinal and biomass (end of nurseries stratified summer) sampling strategy) Bentho-demersal mega- Bottom trawl GOV (4m O (bathy- Species 2008-present 1 season BoB and CS About 70 Ifremer / … epifaunal invertebrates survey "EVHOE" vertical open- metric and abundance per year continental stations in ing and 20mm latitudinal and biomass (autumn) shelf (cir- BoB and 70 codend mesh stratified calittoral stations in size) sampling area) CS strategy) NURSE Beam trawl O Species 1997-present 1 season Bay and abundance per year estuary (latitudinal and biomass (end of nurseries stratified

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TEMPORAL SPATIAL CONTACT COMMENTS Components/Variables Platforms Methods Data Type UNITS Extent Resolution Extent Resolution (CTD, satel- (Models or (year) lite …) Observa- tions) sampling summer) strategy) Small Pelagic fishes PELGAS Acoustic and O Species 2000-present 1 season BoB Conti- Nn stations Ifremer / … pelagic trawl abundance per year nental in BoB and (validation of (systematic and biomass (spring) French shelf nn stations acoustic re- transect (circalittoral in CS cords) sampling area) design) Detritus /Bacterials

Phytoplancton Satellite Satellite O Daily Global NOAA Satellite

Scientific Sur- O °C 1987- Annual (spring, BoB Conti- Ifremer / … veys present and autumn) nental shelf Pelagic and demersal (Pelgas, Evhoe) Benthic phytoplancton NA (µphytobenthos …) Pelagic zooplankton PELGAS Pe- Net (200 µm O Species irregular irregular Irregular lagic survey mesh size) abundance Pelagic survey Optical Plank- O Size spec- 2003-present 1 season BoB conti- N transect Meroplankton only "PELGAS" ton Recorder trum per year nental shelf from coast (spring) to slope CPR program CPR (Con- O Species 1958-1995 Monthly all Only one continuous onboard mer- tinuous plank- abundance over the transect chant ships ton recorder), year Offshore 7-8m deep, Bay of Bis- 270µm mesh cay from Le

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TEMPORAL SPATIAL CONTACT COMMENTS Components/Variables Platforms Methods Data Type UNITS Extent Resolution Extent Resolution (CTD, satel- (Models or (year) lite …) Observa- tions) size (on aver- Corona age) (Spain) to Brighton (England) Macrophyte Zooplankton Epibenthic meio to mac- Historic dataset Grabs and O Species 1970 ??? rofauna dredge abundance REBENT Endobenthic meio to Historic dataset Grabs and O Species 1970 ??? macrofauna dredge abundance REBENT Sea Birds Observers Mammals Observers

Exploited species Landings Discards Sensitive/endangered species (Corals,…) Widely distributed stocks I: Irrelevant

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7.8 Celtic Sea (CS, Region G)

7.8.1 Celtic Sea boundaries The Celtic Sea occupies the area to the south and south west of Ireland. It is bounded to the east by the entrance to the English Channel. We have taken this boundary to be defined by the approximate position of the Ushant Front (Le Boyer et al. 2009), this also broadly matches the boundary between the Greater North Sea and the Celtic Seas ecoregions used by OSPAR (OSPAR 2010). The International Hydrographic Or- ganization defines the limits of the English Channel on the west as a line joining Isle Vierge (48°38′N 4°34′W to Lands End (50°04′N 5°43′W). To the north east it is separated from the Irish Sea. The boundary here is taken as approximating to the Celtic Sea Front (Elliott et al. 1991. St David’s Head, Wales (51.9N, 5.32W) to Carnsore Point, Ireland (52.2N, 6.35W). To the North West, there is no obvious physical, oceanographic or biological boundary to define a border. The northern boundary of ICES subarea VIIj lies along the latitude of 52o 30’N (west from Dunmore Head) and this has been taken as an operational boundary. To the south west the Celtic Se has been taken as being bounded by latitude of 48oN. This was used as the boundary between the OSPAR Regions III and IV, based on the biogeographic provinces defined by Dinter (2001). This also represents the approximate boundary between Lusitanean- Boreal communities and Boreal-Lusitanean communities. The western boundary was taken as the shelf break, and for the purposes of this report we used the 200 m contour as a proxy.

7.8.2 Geography and climate The main coastline in the region lies along the Irish coast from Carnsore Point in the east to Dunmore Head in the west. The coastline is generally rocky and indented and becomes increasingly so to the west. Along the southern coast of Ireland, there are numerous small bays and estuaries and large, navigable estuaries at Cork Harbour and Waterford Harbour. The south coast is moderately sheltered from the prevailing west to south-west winds. The coast to the east has sandy beaches for more than half its length with rocky and muddy substrates comprising about 16% and 13% respectively. Westwards, the intertidal substrates become increasingly rocky with a corresponding reduction in sand and varying amounts of mud. The western part of the coast is a series of long, narrow inlets (i.e. rias) separated by mountainous peninsulas. The inlets support an important mariculture industry. The other main area of coast lies around the Severn estuary of the UK. On both the southern and northern shores of the estuary, the coast is generally rocky and exposed, particularly towards Lands End at the SW corner of the UK. The short section of coast along the northern shore of Brittany is also generally exposed and rocky. There are a large number of conservation sites along the southern Irish coast and also on the UK coast (Figure 1.1.2.1).

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Figure 1.1.2.1 Coastal conservation sites in Ireland and UK.

7.8.3 Bathymetry The Celtic Sea south of Ireland is an extended shelf within which most of the area is shallower than 100 m. It is limited to the west by the slope of the Porcupine seabight and the Goban Spur. The shelf break is generally quite sharp except in the inner part of the Sea Bight. A general map of the Celtic Sea bathymetry is presented in Figure 1.1.3.1.

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Figure 1.1.3.1. General bathymetric view of the Celtic Sea.

7.8.4 Substrates The seabed substrates and habitats are predominantly sands and muds. Not all of the area has been mapped in detail, and particularly for the western part, information is not very detailed – see Figure 1.1.4.1. The bulk of the area is made up of sand (EUNIS deep circalittoral sand – orange) in the northern part and courser sediments in the south (EUNIS circalittoral coarse sediment - yellow), with prominent areas of mud (green) through the middle of the Celtic Sea and in the Porcupine Sea Bight.

Figure 1.1.4.1 Seabed sediments and biotopes for the NWW area (Source: MESH; http://www.searchmesh.net).

7.8.5 Climate The climate of the general region is strongly influenced by a large-scale westerly air circulation which frequently contains low pressure systems. Storms and atmospheric depressions enter from offshore in the southwest of the region with no sheltering landmass for protection. A major factor in climate variability is the North Atlantic Oscillation (NAO). NAO effects are strongest in winter and account for more than a third of the total variance in sea level atmospheric pressure. A positive NAO leads to

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strong westerly winds and warmer and wetter conditions over the northeast Atlantic area and a negative NAO brings lighter westerlies and cooler weather. Recent decades have seen a shift towards a more dominant positive phase of the NAO since records began in the 1860s (Boelens et al., 2005). The North Atlantic Drift Current (NADC) is another influencing factor in the region. The NADC brings humid mild air to the region and is largely responsible for the temperate climate of Ireland and northwest Europe. The predominant winds over the open waters south and west of Ireland are from the west and southwest. In the open ocean winds of greater than 8 m/s (Beaufort Force 5) are experienced on 70–80% of occasions in winter (October to March) and 30–35% in summer (April to September), however the frequency of winds greater than 8 m/s is lowest in the southeast (Irish Coast Pilot, 2006). Gales (Beaufort Force 8 or above) occur on approximately 20–30% of winter days in the Celtic Sea and less than 2% of summer days (Irish Coast Pilot, 2006). Offshore precipitation in winter in the southeast of Ireland occurs with a frequency of 15% in winter and 10% in summer (Irish Coast Pilot, 2006). The amount and duration of precipitation can vary significantly from one period to the next, and averages around 50mm.month-1 in summer and 100mm.month-1 in winter. Nolan et al. (2009) report that Ireland has become meas- urably warmer in the past two decades. It is predicted that, warming will continue well into this century. The rate at which sea surface temperature in Irish waters has increased since 1994 (0.6°C per decade) is unprecedented in the last 150 year observational record. The warmest years in the 150 year observational record are 2005, 2006 and 2007 (Nolan et al., 2009).

7.8.6 Hydrography and circulation Figure 1.2.1 shows the seasonal variation in the water masses found in the area (Con- nor et al. 2006). The waters in the area are generally stratified in the summer and autumn and then mixed in winter and spring.

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Figure 1.2.1. Seasonal variation in water bodies in the vicinity of the Celtic Sea area (Source: Con- nor et al., 2006).

Figure 1.2.2. Main features of the oceanic circulation in the Celtic Sea and wider area.

The main features of the circulation are presented in Figure 1.2.2. The main features are the frontal regions at the entrances to the Irish Sea and English Channel (Celtic Sea and Ushant Fronts), and the Western Irish Shelf Front. The other main feature is

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the Irish Slope current, which is part of the wider European Shelf Edge Current. This is generally poleward in the winter and spring, but can reverse in the summer. There are also gyres found in the area of the Goban spur and Porcupine Bank. Sea surface trends in the area are shown in Figure 1.2.3. The main feature is the steady increase observed since the last years of the 20th century. The spatial temperature anomaly pattern is shown in Figure 1.2.4

Figure 1.2.3 Annual mean SST anomalies (green bars), averaged over the region [45°-60°N, 3°- 20°W], extracted from the HadSST2 dataset (Rayner et al., 2006) and overlain by a 5 year running mean (black line) for the period 1850–2008. AVHRR satellite derived SST anomalies for the period 1986–2006 are overlain in blue and the Malin Head coastal SST time series from 1958–2006 in red. Anomalies are calculated relative to the 1961–1990 mean for the case of HadSST2 and Malin Head datasets and relative to the time series climatology for the case of the AVHRR dataset (Fig- ure from Cannaby and Hüsrevoğlu, 2009).

Figure 1.2.4. Annual mean anomalies of SST (oC) derived from level-3 processed AVHRR satellite data and calculated relative to the 1985 to 2006 climatology. Data are presented at 7 year intervals from 1985 to 2006.

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Annual mean salinity anomalies on the Irish shelf (Figure1.2.5) exhibit a multi-annual variability which, when lagged by 7 years, significantly correlates to the NAO (Nolan 2009). No distinct salinity trends exist in deeper waters on the Irish continental shelf (i.e. water depths of ca. 200 m). Surface salinity anomalies on the Irish shelf also show variability from year to year, with evidence of freshening in coastal waters associated with increased winter rainfall. Coastal salinity records are significantly correlated to the Eastern Atlantic Pattern (EAP) (Fennell, 2008).

Figure 1.2.5. Annual mean bottom salinity anomalies on the Irish shelf (bars), overlain by a 5 year running mean (black line). Bottom salinity anomalies are overlain by a 5 year running mean of the NAO advanced 7 years in time (blue dashed). Salinity anomalies are calculated relative to the 1971–2007 climatology, and have been averaged over the region 48-58N, -15-3W

Several major rivers discharge freshwater into the region and influence the circulation patterns, these are notably the River Loire, the Severn and the Irish rivers Lee and Blackwater in the Celtic Sea (Figure.1.2.6). To the west of Ireland, fresh water discharges from Irish rivers (e.g. Shannon) and those further afield (e.g. Loire, Severn) interact with Eastern North Atlantic Water. (Nolan and Lyons, 2006).

Figure 1.2.6. Discharges from rivers affecting the western Irish Shelf, river Loire (upper panel) and rivers Shannon and Severn (lower panel). Note different scales on Y axes.

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7.8.7 Biological Ecosystem components

7.8.7.1 Bacteria Little research has been carried out on the bacteria community of the Celtic Sea. The main groups identified were ά-proteobacteria, related to Roseobacter spp., and a Cyto- phaga-Flavobacterium cluster (Zubkov et al. 2001).

7.8.7.2 Phytoplankton For most of the Celtic Seas productivity is reasonably strong on the shelf but drops rapidly west of the shelf break. Based on CPR greenness records for this area the spring bloom occurs around April and collapses by October, although in recent years has continued into December. CPR data also suggest that there has been a steady increase in phytoplankton colour index across the whole area over at least the last 20 years. Phytoplankton productivity and taxonomic composition in the Celtic Sea has been shown to depend on water column structure. Diatoms dominate well mixed areas with high nutrient content and display high rates of productivity, while dinoflagellates and microflagellates are found in stratified waters exhibiting lower rates of productivity (Raine et al. 2002). Certain oceanographic conditions can lead to the formation of toxic algal blooms around Irish Coasts with highest occurrence of them noted along the southwest of Ireland. Large harmful algal blooms recorded in 2005 were associated with the dinoflagellate Karenia mikimotoi and caused mortalities to benthic and pelagic marine organisms at a scale that has not previously been observed (Silke et al. 2006). Phytoplankton in the study area includethe large diatoms and dinoflagellates as well as some smaller microflagellates (often called pico or nanoplankton due to their small size) (Hartley Anderson, 2005). Seasonal and spatial changes in phytoplankton for the North East Atlantic have been analysed based on over 100 000 Continuous Plankton Recorder (CPR) samples. The diatom bloom peaks first during May, with a smaller peak in summer. Dinoflagel- lates abundance reaches a peak in August. The blooms of both species start in the North Sea and spread outwards across the North East Atlantic region (Figure 1.3.2.1.from McQuatters-Gollop et al. 2007) .

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Figure 1.3.2.1. Mean monthly spatial patterns of (a) diatoms, (b) dinoflagellates and (c) their relative community abundances (as percentage diatoms) in NE Atlantic between 1958–2003.

The seasonal pattern of phytoplankton abundance and year on year changes are presented in Figure 1.3.2.2. Showing a clear increase in diatom abundance since the late 1990s.

Figure 1.3.2.2. Average monthly and yearly abundance of the phytoplankton functional groups, diatoms (Bacillariophyceae) – left, and dinoflagellates (Dinophyceae) - right in Celtic Sea waters from 1990–2002 - X-axis = month; Y-axis = year; colour legend denotes numerical abundance.

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An increase in the intensity of colour throughout the year has been observed in the northern Celtic Sea since the late 1990s. This extension of the growth season (March– September) became most evident from 2000–2005. This means that an increase in phytoplankton colour was evident in the earlier and later months of the year (See Figure 1.3.2.3, taken from Nolan 2009).

Figure 1.3.2.3. Average monthly values for phytoplankton colour (biomass) in the Celtic Sea from 1960–2005. X-axis = month; Y-axis = year; colour legend denotes numerical abundance.

Harmful Algal Blooms (HABs) are also seen in the Celtic Sea and are considered to be mostly natural (Nolan 2009). Three species which can cause harmful algal events are Karenia mikimotoi (high biomass icthyotoxic spp.), Dinophysis acuminata and D. acuta (which can give rise to Diarrhetic Shellfish Poisoning (DSP)); these species exhibited large interannual variability. There was no obvious change in the interannual or seasonal variability of the genus Dinophysis. Since 2000, the dinoflagellate Karenia mikimotoi, typically present in bloom concentrations in thin layers in well stratified waters was present in a higher percentage of samples during the winter months (Figure 1.3.2.4). This indicates that the organism is able to withstand the harsh conditions of winter; winter temperatures have increased in recent years and this is most probably a symptom of these changes. An unusual event that occurred in recent years was a large Karenia mikimotoi bloom in 2005 (Silke et al., 2005). What was notable about this bloom was that it occurred in June, 1–2 months earlier than the species usually

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blooms. When the bloom decayed, it caused significant damage to the marine ecosystem all along the west coast of Ireland with mass mortalities of benthic communities (Silke et al., 2005).

Figure 1.3.2.4. Percentage of samples in which Karenia mikimotoi was recorded in between 1990– 2007 in Irish coastal waters.

7.8.7.3 Zooplankton The zooplankton community in the Celtic Sea is dominated in terms of biomass and abundance by copepods, particularly the large copepod species Calanus helgolandicus and C. finmarchicus. These two species exhibit a strong geographical divide, with C. finmarchicus more abundant in colder more northern waters and C. helgolandicus abundant in warmer more southerly waters. There has been a marked increase in the abundance of C. helgolandicus in the Celtic Sea in recent years (Figure 1.3.3.1.)

Figure 1.3.3.1. Left, mean annual abundance of Calanus helgolandicus in the Celtic Sea with smooth trend (green line). Right, mean abundance in March (squares). Black lines show significant (p < 0.05) linear trends through abundance values. NB mean values are calculated from measurements once corrected for time of day, seasonality and spatial location using a Generalised Additive Model (see Lynam et al., 2009).

In an investigation of the long term changes in zooplankton biomass concentration and mean size, based on CPR data from 1958–2003, Pitois & Fox (2006) noted a decline in total zooplankton biomass within the Celtic Sea and in general, within northwest European Shelf waters, a northward spread of temperate species (e.g. the copepods C. helgolandicus, Pseudocalanus elongatus, Pseudocalanus spp. and the cladocerans Evadne spp and Podon spp.) and a decline in boreal species (e.g. the copepods C. finmarchicus and Euchaeta norvegica). The change in zooplankton biogeographt is shown in Figure 1.3.3.2.

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Figure 1.3.3.2. Long-term (1958–2005) changes in the mean number of species per assemblage (col- umns). The period 1958–1981 (row 1) was a period of relative stability and the period 1982–1999 (row 2) was a period of rapid northward shifts. Average maximum values are rarely superior to row 1 because they include both daylight and dark periods over 2 month periods. Black dotted oval denotes areas where pronounced changes have been observed (Reproduced from Beaugrand et al., 2009).

7.8.7.4 Small pelagic fish The main small pelagic fish species in the Celtic Sea are herring (Clupea harengus), blue whiting (Micromesistus potassou), mackerel (Scomber scombrus), and horse mackerel (Trachurus trachurus). Also found are sprat (Sprattus sprattus) sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus).

7.8.7.5 Herring Herring is found mainly in the Irish part of the Celtic Sea, and supports a commercial fishery (See Figure 1.3.4.1.1. – source HAWG ICES 2011a). The stock had been declining until recently, but has now recovered above Bpa Figure 1.3.4.1.2. It is generally considered as an important forage fish species in this area. Herring in the Celtic Sea is at the south end of its range, but there is no evidence of the warming trend in the area affecting this stock. The stock is not substantially migratory and spawns in the Celtic Sea.

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Figure 1.3.4.1.1. Herring in the Celtic Sea. Irish official herring catches by statistical rectangle in 2010/2011.

Figure 1.3.4.1.2. Celtic Sea herring stock trajectory.

7.8.7.6 Blue whiting Blue whiting is a wide ranging and migratory gadoid species and is generally considered as pelagic. It is found widely from Spain to Norway, however, it is also common in the Celtic Sea, both as adults and juveniles – see Figure 1.3.4.2.1 (Persohn et al. 2009), although there is no evidence that it spawns in this area (Ibaibarriaga et al. 2007).

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Figure 1.3.4.2.1. Catch rates for blue whiting adults and juveniles in the French EVHOE bottom trawl survey 1992–2006.

The recent stock trends have been declining, and the species is currently considered as being below Bpa see figure 1.3.4.2.2.

Figure 1.3.4.2.2. NEA Blue whiting stock trajectory (ICES 2010a).

Blue whiting is another important forage fish species in this area (Trenkel et al. 2005).

7.8.7.7 Mackerel Mackerel is another wide ranging migratory species, found from Portugal to Norway. While mackerel spawns over a wide area, the centre of gravity of spawning is found in the Celtic Sea on the shelf edge south-west of Ireland (Figure 1.3.4.3.1.).

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64N

62N

60N

58N

56N

54N

52N

50N

48N

46N

44N

42N

40N 20W 18W 16W 14W 12W 10W 8W 6W 4W 2W 0W

Figure 1.3.4.3.1. Mackerel spawning distribution in 2010.

The Celtic Sea is also an important nursery area for this species. In particular in their first winter after hatching (see Figure 1.3.4.3.2 from Petitgas 2010).

Figure 1.3.4.3.2. Distribution of mean catch rates of mackerel in bottom‐trawl surveys carried out in the fourth quarter (1985–2006): (left) age 0 and (right) age 1. Circles are scaled to the maximum, showing the key nursery areas off Portugal, in Biscay, the southwest and northwest of Ireland, and off the Hebrides.

The stock is currently healthy and the biomass is above Bpa – see Figure 1.3.4.3.3.

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Figure 1.3.4.3.3. NEA Mackerel stock trajectory (ICES 2010a).

7.8.7.8 Horse Mackerel Horse mackerel is yet another wide ranging migratory species, found from Portugal to Norway. Like mackerel it spawns over a similar wide area, the centre of gravity of spawning is found in the Celtic Sea on the shelf edge south-west of Ireland (Figure 1.3.4.4.1. - taken from ICES 2011b).

Figure 1.3.4.4.1. Horse mackerel spawning distribution in May 2010.

The Celtic Sea is also a nursery area for juvenile horse mackerel. Current stock levels are around 2 million tonnes and have been relatively stable for some years.

7.8.7.9 Other small pelagics Sprat is fished in the Celtic Sea, but there is no assessment. Landings from the area show strong annual variation, but have been between 400 and 4000 tonnes for some years. Surveys (ICES 2010b) suggest that sprat are generally only found north of 50oN. Sprat was identified as an important forage fish in the Celtic Sea by Trenkel et al. (2005). Sardine (Sardina pilchardus) is generally considered as a southern species, and the bulk of the population are found in Biscay and further south. It is not fished commercially in the Celtic Sea. Analysis of egg surveys (Ibaibarriaga et al. 2007) show spawning by this species in the Celtic Sea (Figure 1.3.4.5.1). Anchovy is also generally seen

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as a more southern species, and again there is no major commercial fishery in the Celtic Sea. No eggs or larvae of this species were reported by Ibaibarriaga et al. 2007.

Figure 1.3.4.5.1. Abundance of sardine eggs in the mackerel egg surveys.

7.8.7.10 Demersal and benthic fish There is a large and diverse community of demersal fish in the Celtic Sea. Surveys have shown the presence of 140–160 different species. The main commercial species are cod (Gadus morhua), haddock (Melanogrammus aeglefinus), whiting (Merlangus merlangius), hake (Merluccius merluccius), monkfish (2 species: Lophius piscatorius & L. budegassa), megrim (2 species: Lepidorhombus whiffiagonis & L. boscii), plaice (Pleuronec- tes platessa), sole (Solea solea) and Pollack (Pollachius pollachius). Surveys (ICES 2010b) suggest that many of these species are concentrated in the area of the Celtic Sea north of 50oN and running along the Irish coast, e.g. cod, haddock, whiting, hake and plaice. However, both haddock and hake are also found south of 50oN in water deeper than 100 m. Monkfish are found broadly across the area, although L. budegassa is restricted to water deeper than 100 m. Megrim are also found in deeper water across the area, although Lepidorhombus whiffiagonis also extends into the NE of the Celtic Sea, and L. boscii is restricted to the deep water edge.

7.8.7.10.1 Dogfish and rays Surveys (ICES 2010b) show that most of the elasmobranch species are concentrated in the NE corner of the Celtic Sea, some exclusively, e.g. tope (Galeorhinus galeus), thornback ray (Raja clavata), painted small eyed ray (R. microocellata), spotted ray (R. montagui) and nurse hound (Scyliorhnus stellaris). In addition, some species are also found in deeper water >100m in the western part of the Celtic Sea e.g. lesser spotted dogfish (Scyliorhinus canicula), starry smooth hound (Mustelus asterias), and cuckoo ray (Leu- coraja naevus). Spurdog (Squalus acanthias) are found scattered across the area, though still concentrated in the NE. Other sharks reported by the Irish Elasmobranch Group (http://www.irishelasmobranchgroup.org/) include: Greater spotted dogfish (Scyliorhinus stellaris) Blackmouth dogfish (Galeus melastomus)

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Basking shark (Cetorhinus maximus) Angel shark (Squatina squatina) Blue shark (Prionace glauca) Porbeagle (Lamna nasus) Shortfin mako (Isurus oxyrincus) Thresher shark (Alopias vulpinas)

7.8.7.11 Celtic Sea demersal fish community Information from surveys has also been used to study the trends in the fish community in the Celtic Sea, and in particular the relative abundance of large fish – the Large Fish Indicator (Shephard et al. 2011). In the Celtic Sea, the threshold for large fish has been taken as those over 50cm, and the trends in the index are presented in Figure 1.3.6.1.1., which shows a general decline in the LFI since the start of the 1990s.

Figure 1.3.6.1.1. LFI series for eastern and western subregions of the Celtic Sea.

The main species contributing to the large and small fish components of the Celtic Sea fish community are presented in Figure 1.3.6.1.2. Blue whiting have been included as a demersal species in this analysis.

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Figure 1.3.6.1.2. Trends in biomass of (a) the six small fish species, and (b) the six large fish species for which greatest biomass was observed in the Celtic Sea WCGFS.

7.8.7.12 Benthic Communities There is relatively little information available on the benthic fauna of the Celtic Sea. A recent study linked to oil and gas exploration (The Fourth Strategic Environmental Assessment for Oil and Gas Activity in Ireland’s Offshore Waters: IOSEA4 Irish and Celtic Seas http://www.dcenr.gov.ie/Natural/Petroleum+Affairs+Division/Irish+Offshore+Strateg ic+Environmental+Assessment+(IOSEA+4)/IOSEA+4+-++Irish+and+Celtic+Seas.htm) reported a study in preperation by Cabioch et al. (in prep - Cabioch, L., Amoureux, L., Gentil, F., Glacon, R. Retiere, C., O’Connor, B., McGrath, D., Könnecker, G., Dineen, P. & B. Keegan (in prep). Macrofaunal communities of the Celtic Sea). Biotope communities from this are presented in Figure 1.3.7.1. One of the main features on the map is the Nephrops based community which is likely to be representative of the other muddy areas to the east of this study. The BIOMÔR 1 study (Mackie et al., 1995) reported the bivalves Abra alba, Abra nitida, the polychaete Levinsenia sp. and Nemertea as the most abundant along with Nephrops norvegicus and the cumacean Diastylis lucifera.

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Figure 1.3.7.1. Schematic representation of the major macrofaunal benthic assemblages in the Celtic Sea (after Cabioch et al. in prep).

Ellis et al. (2001) identified two macro-epibenthic assemblages. The first was dominated by the anemone Actinauge richardii and occurred along the shelf edge in waters 132–350 m deep on deep sea sand or deep sea muddy sand – EUNIS. Other dominant species in this assemblage included the Devonshire cup-coral (Caryophyllia smithii), the hermit crab Pagurus variabilis, the swimming crab Macropipus tuberculatus and the brittlestar Ophiothrix lütkeni. The second macro-epibenthic assemblage was more widespread in the Celtic Sea (depth range 66–232 m) and was dominated by Pagurus prideaux and its commensal anemone Adamsia carciniopados. Other dominant species in this assemblage were the shrimps Crangon allmani and Processa caniliculata, the swimming crabs Liocarcinus depurator and L. holsatusand the brittle star Ophiura ophiura. Cold water corals and other biogenic reef forming organisms ar not widespread in the Celtic Sea. The main protected feature being the Belgica mounds off the SW of Irelland on the edge of the Porcupine Sea bight (Figure 1.3.7.2.)

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Figure 1.3.7.2. Location of Belgica mounds protected area.

7.8.7.13 Cetaceans Many cetacean species are found in the Celtic Sea. Common species sighted include Common dolphin (Delphinus delphis), harbour porpoise (Phocoena phocoena), and Minke whale (Balaenoptera acutorostrata). Distribution maps for these are shown in Figures 1.3.8.1–3. These data are taken from the SCANS-II report (SCANS 2003). Un- der the Irish Whale Fisheries Act 1937 the hunting of all whale species, including dolphins and porpoises, is totally banned within the fisheries limits out to 200 miles from the Irish coast.

Figure 1.3.8.1. Harbour porpoise distribution.

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Figure 1.3.8.2. Minke whale distribution.

Figure 1.3.8.3. Common Dolphin distribution.

Other fairly common species include; Bottlenose (Tursiops truncatus), white sided (La- genorhynchus acutus), and striped dolphins (Stenella coeruleoalba), as well as Killer whales (Orcinus orca) and Cuviers beaked whale (Ziphius cavirostris). Many other species of cetacean have also been recorded in the Celtic Sea off Ireland (source: Irish Whale and Dolphin Group (http://www.iwdg.ie).

7.8.7.14 Seals There are two common species of seal found in the Celtic Sea, grey seal (Halichoerus grypus), and harbour seal (Phoca vitulina). Grey seals are common along the southern shore of Ireland, with large breeding colonies at the NE and SW ends of coast (Cronin et al. 2010). There also major colonies on the SW tip of Wales in the UK, and reports of an isolated colony on the Molène archipelago in Brittany (Gerondeau et al. 2007). Harbour seals are also common along the Irish coast, and particularly in the bays of the extreme south west of Ireland (Cronin et al. 2010), but there are no reports of them on the UK or Brittany Celtic Sea coasts.

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7.8.7.15 Seabirds The Celtic Sea is an important foraging area for many breeding seabird species. Twelve species in particular breed along the coastline of the Celtic Sea and are relatively common in the area. • Northern Fulmar Fulmarus glacialis • Manx Shearwater Puffinus puffinus • European Storm-petrel Hydrobates pelagicus • Northern Gannet Morus bassanus • Great Skua Stercorarius skua • Lesser Black-backed Gull Larus fuscus • Herring Gull Larus argentatus • Great Blacked-backed Gull Larus marinus • Black-legged Kittiwake Rissa tridactyla • Common Guillemot Uria aalge • Razorbill Alca torda • Atlantic Puffin Fratercula arctica At-sea distribution maps of some common seabirds during the breeding season are presented in figure 1.3.10.1. and all data are taken from Mackay & Giménez 2004. Great Cormorant Phalacrocorax carbo, European Shag Phalacrocorax aristotelis,, and Black-headed Gull Larus ridibundus, are also quite common along the coast and have good breeding numbers, but tend to forage inland or close inshore, making them uncommon offshore in the Celtic Sea (Mark Jessop CMRC pers. comm.). Ten other species are shown as breeding in the area but are relatively uncommon. Great Shearwater Puffinus gravis, Sooty Shearwater Puffinus griseus, Leach's Storm-petrel Oceanodroma leucorhoa, Pomarine Skua Stercorarius pomarinus, Arctic Skua Stercorarius parasiticus, Long-tailed Skua Stercorarius longicaudus, Mew Gull Larus canus, Common Tern Sterna hirundo,Arctic Tern Sterna paradisaea, Black Guillemot Cepphus grille.

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Figure 1.3.10.1. Breeding distributions of 6 species of seabird common in the Celtic Sea. Top Left: Northern fulmar. Top Right: Manx shearwater. Middle left: European Storm-petrel. Middle right: Northern gannet. Bottom right: Great skua. Bottom right: Herring gull.

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Figure 1.3.10.1 (cont.) Breeding distributions of 6 species of seabird common in the Celtic Sea. Top Left: Lesser Black-backed Gull. Top Right: Great Black-backed Gull. Middle left: Black-legged Kittiwake. Middle right: Common Guillemot. Bottom right: Razorbill. Bottom right: Atlantic puffin.

7.8.8 Pressures on the ecosystem The Celtic Sea region addressed in this report is major component of the OSPAR „Celtic Seas Ecoregion“ – Region III. An extensive study was made of the human and other pressures on the Celtic Seas ecosystem within the 2010 Quality Status Report. The report addressed 22 different pressures, and evaluated these against eight ecosystem components. Four of these were species based; fish, cetacean, seals, and Seabirds. The other four were habitat based; Rock and biological reef habitats, shallow sediment habitats, shelf sediment habitats, and deep sea habitats – the last of these was not addressed for this ecoregion. The results of this analysis are presented in figure 1.4.1. Based on the OSPAR QSR report, the most important pressures were identified as; habitat damage (in areas of soft sediment), introduction of non-indigenous species, and removal of species. The ecosystem components that faced the highest level of impact were the two soft sediment categories.

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Region III Fish Seals Shallow Shallow habitats habitats habitats Seabirds sediment sediment Deep-sea Deep-sea Cetaceans reef habitats reef Shelf sediment sediment Shelf Rock & biogenic biogenic & Rock

Climate change L - N L - L L - M L - L L - N L - L L - N - change Climate Climate

Temperature changes (local) - - - - - L - H - -

Salinity changes (local) - - - - - L - H - -

Changes in water flow, wave Hydrological Hydrological - - - - - L - H - - pressures (local) pressures action & emergence regime (inshore/local) Contamination by hazardous L - L L - L L - L L - M L - M L - L L - L - substances

Radionuclide contamination - - - - - L - - -

De-oxygenation - L - M L - M - - L - M L - L - pressures Nitrogen & phosphorus enrichment - L - M L - M - L - M L - M - -

Pollution & other chemical other & Pollution Organic enrichment L - M - - - L - H L - M L - L -

Electromagnetic changes - L - - - - L - H L - H -

Litter L - H L - L L - L - - - L - L -

Underwater noise L - H L - H L - H - - L - H - -

Barrier to species movement - L - H L - N L - H - - - - Other physical pressures physical Other Death or injury by collision - L - L L - L L - H - - - -

Siltation rate changes L - H L - L - N - L - M L - M - -

Habitat damage L - L L - M L - L L - M L - L M - M M - L -

Habitat changes Habitat Habitat loss L - N L - L L - L L - N L - N L - N L - L -

Visual disturbance ------

Genetic modification ------L - -

Introduction of microbial - L - L - M - - - L - - pathogens Introduction of non-indigenous L - H - - M - L L - M L - N L - - species & translocations Biological pressures Biological Removal of species (target & non- M - L L - L L - M L - M L - M M - M M - L - target)

Total impact 12 14 13 10 9 20 16 0

Not Moderate Moderate Good Moderate Moderate Moderate Moderate Overall assessment present

Confidence in overall High Very low High High High High High assessment Not Deep sea present >1000m

Figure 1.4.1. Summary results from pressures assessments for Region III – Celtic Seas – (OSPAR 2010).

While the OSPAR analysis was for a wider region, the conclusions are probably reasonably applicable to the Celtic Sea region addressed in this report. The Celtic Sea is broadly similar to the wider Ecoregion III. The main human pressures are likely to be linked to fishing activity, which is extensive in the Celtic Sea. Much of the Celtic Sea margins have low population densities and few large cities. On the Irish coast the main cities would be Cork and Waterford. On the UK coast the main cities would those along the Severn estuary, principally; Bristol, Cardiff, Newport and Swansea. There is little oil and gas extraction in the area, apart from the Kinsale Gas field off the Irish coast. Sand extraction is conducted off Dunmore head on the Irish coast at the border to the Irish Sea. The Celtic Sea is also one of the major shipping routes in the world with traffic passing through it and into the Irish Sea and the English channel.

7.8.9 References Beaugrand, G., Luczak C. and Edwards M. 2009: Rapid biogeographical plankton shifts in the North Atlantic Ocean. Global Change Biology 2009 Vol. 15 No. 7 pp. 1790-1803

Boelens, R., Minchin, D. & O’Sullivan, G. (2005). Climate change. Implications for Irelands Ma- rine and Environment Resources, Marine Foresight Series no 2. Marine Institute

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Cannaby, H., and Hüsrevoğlu, Y. S. 2009. The influence of low-frequency variability and long- term trends in North Atlantic sea surface temperature on Irish waters. ICES Journal of Ma- rine Science, 66: 1480–1489.

Connor, D.W., Gilliland, P.M., Golding, N, Robinson, P., Todd, D., & Verling. E. (2006). UK- SeaMap: the mapping of seabed and water column features of UK seas. Joint Nature Con- servation Committee, Peterborough.

Cronin, M, Jessopp, M & D. Reid. 2010. Seals and Fish Stocks in Irish Waters Briefing note to European Parliament Directorate General for Internal Policies 58 pp.

Dinter, W. P. 2001. Biogeography of the OSPAR Maritime Area. A synopsis and synthesis of biogeographical distribution patterns described for the North-East Atlantic. Bundesamt für Naturschutz, Bonn, Germany. 167 pp.

Elliott, S.A.J., Clarke, T. & Z. Li. (1991). Monthly distribution of surface and bottom temperatures in the northwest European shelf sea. Contential Shelf Research. 11(5): 453-466.)

Ellis, J.R., Lancaster, J.E., Cadman, P.S. & S.I. Rogers. (2001). The marine fauna of the CelticSea. In: Marine biodiversity in Ireland and adjacent waters. Proceedings of a conference 26-27 April2001 (Ed: J.D. Nunn). Ulster Museum Belfast 2001.

Fennell, S. 2007. A study of the behaviour and interannual variability of surface salinity and temperature at the M3 weather buoy off the southwest coast of Ireland MSc 2007.

Gerondeau, M., Barbraud, C., Ridoux, V., and Vincent, C. 2007. Abundance estimate and seasonal patterns of grey seal (Halichoerus grypus) occurrence in Brittany, France, as assessed by photo-identification and capture–mark–recapture. J. Mar. Biol. Ass. U.K., 87, 365–372

Hartley Anderson (2005). Deep Water Environment to the West of Ireland. Report to the Irish Shelf Petroleum Studies Group. Project ISO3/21. Draft report, December 2005.

Ibaibarriaga, L., X. Irigoien et al. (2007). "Egg and larval distributions of seven fish species in north-east Atlantic waters." Fisheries Oceanography 16(3): 284-293

ICES. 2010a. Report of the Working Group on Widely Distributed Stocks (WGWIDE), 28 Au- gust - 3 September 2010, Vigo, Spain. ICES CM 2010/ACOM:15: 612 pp.

ICES. 2010b. Report of the International Bottom Trawl Survey Working Group (IBTSWG), 22– 26 March 2010, Lisbon, Portugal. ICES CM 2010/SSGESST:06. 267 pp.

ICES. 2011a. Report of the Herring Assessment Working Group for the area South of 62 deg N (HAWG), 16 - 24 March 2011, ICES Headquarters, Copenhagen. ICES CM 2011/ACOM:06 .749 pp.

ICES. 2011b. Report of the Working Group on Mackerel and Horse Mackerel Egg Surveys (WGMEGS), 11–15 April 2011, San Sebastian, Spain. ICES CM 2011/SSGESST:07. 109 pp.

Irish Coast Pilot (2006). Offshore and Coastal Waters Round Ireland and including routes to the Irish Sea from the Atlantic Ocean landfalls. Seventeenth Edition. United Kingdom Hy- drographic Office.

Le Boyer, A., Cambon, A.G., Daniault, N., Herbette, S., Le Cann, B., Marié, L., and Morin, P. 2007. Observations of the Ushant tidal front in September. Continental Shelf Research. 29/8, 1026-1037

Lynam, C.P, Lordan C. and Edwards M. 2009: ICES Working Document 2 presented at WKROUND, Copenhagen 18-23 Jan 2009.

Mackey, M. and Gimenez, D.P. , 2004, SEA 6,7, 8 Data Report for Offshore Seabird Populations. Report of the Coastal and Marine Resources Centre, University College Cork, to the UK Department of Trade and Industry

Mackie, A.S.Y., Oliver, P.G. & E.I.S. Rees. (1995). Benthic biodiversity in the southern Irish Sea. Studies in Marine Biodiversity and Systematics from the National Museum of Wales. BIOMÔR Reports 1: 263pp.

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McQuatters-Gollop, A., Raitsos, D.E., Edwards, M. and Attrill, M.J., 2007. Spatial patterns of diatom and dinoflagellate seasonal cycles in the NE Atlantic Ocean. Marine Ecology Pro- gress Series 339: 301-306

Nolan, G., Gillooly, M. & Whelan, K. (2009). Irish Ocean Climate and Ecosystems Status Report 2009. Marine Institute

Nolan, G.D. and Lyons,K. (2006) Ocean climate variability on the western Irish Shelf, an emerg- ing time series ICES CM 2006/C:28.

OSPAR 2010. Quality Status Report. OSPAR Commision, London. 176 pp.

Persohn, C., P. Lorance et al. (2009). "Habitat preferences of selected demersal fish species in the Bay of Biscay and Celtic Sea, North-East Atlantic." Fisheries Oceanography 18(4): 268-285

Petitgas, P. (Ed.) 2010. Life cycle spatial patterns of small pelagic fish in the Northeast Atlantic. ICES Cooperative Research Report No. 306. 93 pp.

Pitois, S.G. & C.J. Fox (2006). Long-term changes in zooplankton biomass concentration and mean size over the Northwest European shelf inferred from Continuous Plankton Re- corder data. ICES Journal of Marine Science 63:785–798

Raine, R; White, M; Dodge, JD, (2002) The summer distribution of net plankton dinoflagellates and their relation to water movements in the NE Atlantic Ocean, west of Ireland, Journal of Plankton Research. 24: (11) 1131-1147.

Rayner N. A. et al. 2006: Global analysis of sea surface temperature, sea ice and night marine air temperature since the late nineteenth century. Journal of Geophysical Research, 108: 4407, doi: 10. 1029/2002JD002670

Shephard, S., Reid, D. G., and Greenstreet, S. P. R. Interpreting the large fish indicator for the Celtic Sea. – ICES Journal of Marine Science, doi:10.1093/icesjms/fsr144.

SCANS (2006) Small Cetaceans in the European Atlantic and North Sea - (SCANS-II). Available at http://biology.st-andrews.ac.uk/scans2/documents/final/SCANS-II_final_report.pdf.

Silke J., O Beirn F., Cronin M (2005). Karenia Mikimotoi: An Exceptional Dinoflagellate Bloom in Western Irish Waters - Summer 2005" Marine Environment and Health Series, No 21, 2005.

Trenkel, V. M., J. K. Pinnegar et al. (2005). Spatial and temporal structure of predator-prey relationships in the Celtic Sea fish community. Marine Ecology Progress Series 299: 257-268.

Zubkov, M.V., Fuchs, B.M., Burkill, P.H. & Amann, R. 2001. Comparison of Cellular and Bio- mass Specific Activities of Dominant Bacterioplankton Groups in Stratified Waters of the Celtic Sea. Applied and Environmental Microbiology, 67/11, 5210–5218.

7.9 English Channel (EC, Region H)

7.9.1 The English Channel ecosystem Typically the English Channel is considered the area between the Celtic Sea and the North Sea in the west and east respectively, and delimited by landmasses in the form of England to the north and the coast of France, Belgium and the Netherlands in the south. The area is funnel like, generally wide and deep in the west, narrowing and becoming increasingly shallower in the east. Hydrodynamically and biologically the Channel represents a transition zone structured according to a number of physical gradients with depth and temperature being amongst the most important. Because of these gradients the eastern and western extent of what WGEAWSS terms the English Channel ecosystem is poorly defined biologically and unlikely to be well isolated from the physical and biological processes that occur in the adjacent ecosystems. WGEAWESS has taken the decision to include the areas of greatest transition in a single unit called the English Channel ecosystem. In the west it is bounded by the

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Celtic Sea ecosystem (WGEAWESS) with the boundary running approximately north to south at 3.5° west and the North Sea (WGINOSE) by an east to west border around the 51.5° north mark (both borders being generally further east than the oceanographic definition of the English Channel).

7.9.2 Bathymetry The English Channel is characterized by waters less than 100 m in depth, and the area as defined here is in fact largely less than 70 m in depth. The shallow coastal strip (< 30 m) on the UK side of the channel is generally narrow so that deeper water is found close to shore particularly in the regions of headlands. On the French side the shallow waters extend out further interspersed by numerous shoals and islands east of the Contentin Peninsula with a more uniform depth distribution from the Baie de Seine eastwards. The rest of the area represents a shallow basin with a rather flat base at around 65 m although at its centre there is a central deep channel culminating at the western end in the Hurd deep at roughly 170 m, much deeper than its surroundings.

7.9.3 Bedrock geology The bed rock geology of the English Channel is one dominated by Cretaceous sedimentary rock formations deposited during a time when the local environment was very much more tropically marine. Few igneous rock formations are present apart from small patches in the western part of the French coast around the Channel Is- lands. Most of the northern part of the channel is underlain by relatively homogenous and tectonically undisturbed Cretaceous chalk deposits while further south Gault- Greensand and some tertiary sediments are evident. Parts of the original depression that now forms the Channel were created during the Alpine orogeny, but the movements here were much more subtle so that the differences in the age of rocks exposed are mainly due to erosional processes rather than tectonic movements. In its current form the Channel is a very recent marine environment only being fully submerged in the last 5000 years or so as sea level rose following the last ice age. The area however has not been impacted directly by glacial activity and all of the recent estimates of ice cover suggest that permanent ice was located further north despite considerable uncertainty as to the exact location. Consequently, almost all current sediments in the area are marine in origin and are scarce in most parts with large areas only covered by a thin veneer of mobile sediment and even exposed bedrock in places (ca. 5%). The origins of the deep channel cut into the bedrock named the Hurd Deep at its western terminus is in fact part of an extensive network of channels predominantly found in the east with a confluence to the east of the Isle of Wight. The exact origin of these channels is still being debated with some theories suggesting these represent old river channels, catastrophic outburst of a glacial lake or a combination of the two, but almost certainly terrestrial in nature. Some of these channels, particularly in the southern area are filled with sub-recent sediments while deeper and more northern ones are generally still open due to high current velocities and a paucity of available sediments

7.9.4 Sedimentology Sediments in the offshore area are sparse particularly in the central part of the channel. Where present they are marine in nature and are largely the result of erosive processes of the local bedrock. Fine sands and muds are highly mobile due to the tidal currents and are quickly removed in suspension from the erosive areas of the channel, while coarser sands are predominantly moved as bedloads. There are two

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bedload parting zones in the Channel ecosystem, one large one located between the Isle of Wight and the Cotentin Peninsular, the other north of the Dover Straits in the southern North Sea. Lager particles such as gravel are too heavy to be moved appre- ciable distances by tidal currents but remain mobile rolling with the tide or are moved by strong storm surges with some sediment sorting. The two main deposition areas are located on the French coast southwest of the Dover Strait and on the UK coast east of Start Point. Deposits are mainly of sand and even here the sediments remain highly mobile forming fields of sand waves and intricate networks of mega ripples with an asymmetrical orientation. In inshore areas tidal influences though still strong wanes, particularly in the west on the UK coast and in the east on the French coast. Here in bays and estuaries local terrestrial influences increase so that sedimentation of finer particles is possible and muddy sand mixes dominate on the UK coast with cleaner sand found on the eastern French coast, but even here areas of muddy sediments are rare and limited to areas immediately influenced rivers such as the So- lent, the Seine and the Exe.

7.9.5 Hydrography With few large rivers and substantial protection from climatic forces by the landmasses to the north and south the hydrography of the channel is dominated by tidal forces. These also produce substantial tidal flushing in an easterly direction despite the constrictive nature of the Dover Straits in the eastern part of the area. Tidal currents are strongest in the area south of the Isle of Wight and at the Dover Straits with the area around the Channel Islands exposed to the strongest currents due to a combination of the restrictions in width caused by the Cotentin Peninsular and the shallow nature of the French coast. The tidal currents ensure that the waters of the shallower eastern Channel remain fully mixed year round and the overall conditions can be likened to coastal conditions. Even in the fully mixed part there remains an east west gradient in temperature, with the west and offshore warmer in winter and cooler in summer as well as a seasonal disparity between the difference between bottom and surface temperatures during summer being larger in the west than in the east and further offshore. This feature is an artifact of the tidal flushing dragging the Celtic Sea influences into the Channel in the form of a tongue, the extent of which is limited overall by the bathymetry restricting it to the deeper waters with inter annual variations largely govern by climatic conditions such as storms and seasonal temperature fluctuations. Salinity conditions are decidedly marine with the effect of the relatively small volume of fresh water entering the system being dissipated rapidly by the tidal flushing in conjunction with a fully mixed system so that low salinity conditions are strongly localised.

7.9.6 Habitats On the basis of the physical conditions the English Channel ecosystem can be divided into several habitats according to the EUNIS habitat classification (Habitat map Cog- gan Diesing). The greatest proportion of the area is covered by circalitoral coarse sediment (A5.14) with large parts of the remainder being classified as infralittoral and deep circalittoral coarse sediment habitats (A5.13 and A5.15), underlining the dominance of coarse mixed sediments in the area. Infralittoral sandy mud (A5.33) is restricted small patches in bays and near rivers, with slightly larger areas found in the Baie de Seinne and Lyme Bay. An extensive area of exposed high-energy circalittoral rock (A4.1) is located just north of the central channel and south of the Isle of Wight

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where some of the strongest currents have scoured the chalk bedrock. Due to the characteristic homogeneity in hardness of the chalk the area has remained essentially flat with little localized relief except where other rock types are exposed. Immediately to the east, south of Poole Bay a sizeable area of circalittoral and deep mixed sediments (A5.44 , 5.45) persists, while the main bedload convergence zone in the west provides circalittoral and deep circalittoral sand (A5.27, A5.25) and infralittoral fine sand (A5.23) in the eastern bedload convergence zone. The area aound the Cotentin Peninsular and the Channel Islands exhibits a wide spattering of moderate energy infralittoral rock near the coast.

7.9.7 Biological Ecosystem Components

7.9.7.1 Small pelagic By far the most abundant small pelagic in the English Channel ecosystem are Sprat they are widely distributed in the coastal bays but also further offshore feeding on zooplankton. They in turn are preyed upon by a large number of pelagic and demersal predatory fish, but also a sizeable avian population found in the Channel, particularly the western end. Mackerel and horse mackerel are also common small palagics in the area, but concentrations, particularly of mackerel appear to be higher in shore in the summer particularly in the north western part of the channel an area also covered by the mackerel box, a protective area designed to conserve juvenile and summer feeding mackerel from heavy exploitation by trawled gears. Also during the summer large schools of bass congregate in the channel for spawning and feeding. Although decidedly demersal in behaviour during much of the year the species does school up and is exploited by a number of fishing activities such as pair trawling when feeding on other small pelagic during the summer months. Historically the species has migrated from around the UK to the English Channel top spawn, with the Solent and the Seine estuary forming major nursery areas for the species. Recent in- vestigations have shown that spawning now occurs also in other areas around the UK coast possibly in response to increasing winter temperatures so the degree to which the migrations still occur is uncertain. Pilchard or sardine are common in the Celtic Sea and their distribution extends into the western portion of the Channel usually as far west as Lyme Bay only, but in some years migrations continue to go further east possibly related to water temperature differences. Anchovie are also known to utilize the Channel habitat for spawning and nursery and feeding ground of the species are typically associated with low salinity environments and indeed the Somme on the French coast is known to harbour a sizeable population of the species. However in this ecosystem where such habitats are rare they tend to utilize inshore areas and bays on the UK and Fernch coast in addition to the more usual conditions. Herring, sandeel are also present in the English channel, but in contrast to the anchovie which occur predominantly in the western part these are found mainly in the eastern section probably forming extensions of North Sea populations. Herring are present mainly seasonally, while sandeels are known to utilize year round small and very specific areas of deep sand in the bedload convergence zone south west of the Dover Strait where the preferred sandy habitat can reach sediment depths of up to 25m.

7.9.7.2 Large pelagic The Channel ecosystem is relatively depauperate of large pelagic fish species. The shallow nature and the decidedly coastal characteristic mean that few open ocean

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species wander here. Blue sharks are occasionally found during the summer months around the Ushant front and Baskiig sharks have been seen with some frequency in the Hurd deep during the same period, but generally these species should be considered visitors rather than part of the ecosystem. The most common residents are the tope but predominantly found in the eastern part of the system, while porbeagle tend to have their centre of distribution further westwards. Thresher sharks also regularly encountered in small numbers throughout the area in association with schools of small pelagic, presumably feeding on the relative high abundance of these in the system.

7.9.7.3 Demersal benthic Demersal fish species communities in the area are highly diverse in the system as a whole, but there is a distinct discontinuity in species distribution long recognized between the western and eastern part of the system with the east on its own being less diverse than the west. Flatfish species are surprisingly abundant and diverse, given the coarse nature of the sediment frequently thought to be unsuitable for flatfish. As expected though, numerically these species tend to be most abundant in bays and in the other sediment deposition zones. However species such as sole (Solea solea) is almost ubiquitous throughout the system outside the immediate central bedload divergence zone. Plaice are less uniformly distributed with aggregations found mainly in the bedload convergences in the east and the west as well as around bays and estuaries where sizeable deposits of sand are evident particularly on the eastern French coast and to a lesser degree in Lyme Bay. Juvenile plaice are largely restricted to the eastern part of the area where the sandy short habitat used as nursery grounds is more abundant. The distribution of dab is virtually identical to that of plaice. Lemon Sole are found in coastal areas throughout the region, but tend to be more abundant on the UK coast. Other species of less or no commercial interest are the sol- lonette highly abundant on the finer inshore sediments particularly in Lyme Bay and the south eastern coast of the channel. Marginally further offshore and in sandy sediment scaldfish are abundant progressively replaced by imperial scaldfish further out. Numerically the most abundant demersal fish species in the area particularly in the west are poor cod, known to be associated with deeper channels and strong tidal currents elsewhere. Other gadids such as cod and whiting are also present, but these represent mostly juveniles and in much lower numbers around the central part of the channel. Adult cod and Pollack are encountered infrequently in the area except on wrecks, despite sizeable areas of exposed bedrock known to attract these species elsewhere. The likely cause is the lack of relief in these areas. Haddock are only found in the west and predominantly small or juvenile fish with adults likely to migrate out towards the Celtic Sea. Gurnards are present in large numbers in the western portion of the system with a generally north south progression from grey gurnards, tub gurnards, red gurnards and streaky gurnards. However, it appears at least superficially that these are habitat affinities rather than a latitudinal gradient in species preference. Other large contributions to the fish biomass in the channel from commercially un- important species are dragonets, lesser spotted dogfish and pout. These are found almost ubiquitously in sizeable quantities in all but the deepest waters. Their respec- tive roles in the ecosystem are not very clear, but the size of the biomass component and the amount of carbon and nitrogen tied up in each does suggest that they must play an important role in the structure.

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Rays also represent an important fisheries resource locally within the area, particularly around the Channel Islands. Thornback ray and Blond Ray make up the major- ity of batid survey catches in the east( Martin et al. 2010), while in the western portion of the area undulate and spotted ray also contribute significantly too the catches. However most individuals encountered are young of the year with only very few mature individuals seen.

7.9.7.4 Charismatic mega fauna The cetacean fauna (whales, dolphins and porpoises) of the eastern channel is low, both in terms of species diversity and total abundance. Around 15 species have been recorded, but only three of these are residents or regular visitors on annual migrations. None of these are abundant, with mostly the common dolphin (Delphinus delphis) found offshore in small groups or as individuals, while inshore the bottlenose dolphin (Tursiops truncatus) tend to be sighted more regularly particularly in bays. These two species also have a decidedly westerly distribution with frequent probably transient visits to the eastern part of the channel. Harbour porpoise (Phocoena phocoena) are also sighted annually in the eastern part of the channel, but considerably less frequently than the other two species. Other marine mammals including whales have been irregularly recorded from the waters of the channel, these include killer whales, minke whales and even humpback whales, with records of sighting of even less frequent visitors to some degree uncertain as it is not clear to which degree these are associated with potential strandings. For geographical comparisons of sightings rates for various cetacean species in UK waters, see Evans (1990, 1992) and Northridge et al. (1995).

7.9.7.5 Anthropogenic activity and effects The English Channel is one of the busiest shipping channels in the world. Almost the entire northern European international trade landing in important cities in the industrial heartland of Europe such as Hamburg, Rotterdam Folkstone as well as many smaller ports travel through the English channel to deliver and discharge their cargo. Shipping is so intense in certain areas that traffic separation schemes are necessary to ensure the safety of shipping and to avoid environmental accidents. This is particularly important given the quantities of oil and chemical imports into Europe. Recently a number of collisions have occurred, but these fortuitously have not had major ecological effects due to the nature of the cargo, but underline the substantial risks. Less immediately catastrophic, but more frequent and ultimately of higher risk is the potential for introductions of alien species. Aquaculture plays a very minor role in the English Channel perse and is almost entirely limited to Oyster ranching. However the impact of this has been incredibly heavy due to the introduction of the American slipper limpet (Crepidula fornicata) which now persists in large parts of the ecosystem. This filter feeding gastropod is usually found in shallow coastal waters, but here also persists in large abundance in deeper areas frequently disturbed by mobile fishing gear which also serves to increase the spatial distribution of this alien invader. It is thought to lower oyster production by competition for food, but more recently has also been shown to affect the production of sole and other flatfish largely as a response to the unsuitability of the shell remains as a habitat (Kostecki et al., 2011) but in the English Channel the American slipper limpet although of less risk, fishing has probably had the highest sustained impact on the ecosystem.

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8 Recommendations to WGEAWESS

• Comparative exercises between ecosystems / subregions • Define Main objectives for integrative analysis • Methods to Analyse dataset : . Propose a list of methods to be applied at the regional scales like: Regime shifts detection, empirical orthogonal functions (EOF), spatial clustering, PCA, “traffic light”, qualitative analysis, spatial and temporal signal detection, etc.

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Annex 1: List of participants

Name Country Institute WGEAWESS WGEAWESS Nantes topics/region member Meeting (Chair, Official or Invited) Pascal Laffargue France Ifremer Benthic habitats X X [email protected] / Bay of Biscay and Celtic Sea Pascal Lorance France Ifremer Bay of Biscay X partial [email protected] and Celtic Sea Pierre Petitgas France Ifremer Bay of Biscay X [email protected] and Celtic Sea Verena Trenkel France Ifremer Bay of Biscay X partial [email protected] and Celtic Sea David Reid Ireland Marine Celtic Sea X X [email protected] Institute Hugo Mendes Portugal IPIMAR X [email protected] Maria de Fátima Borges Portugal IPIMAR Western Iberia / X X [email protected] Fish Stock assessment, ground fish surveys … eco model Maria Manuel Angélico Portugal IPIMAR Western Iberia X [email protected] Miriam Guerra Portugal IPIMAR X [email protected] Diego Macías Spain CSIC Gulf of Cádiz / Xp X [email protected] biophys coupling IBM Eider Andonegui Spain AZTI inner part of Xp X [email protected] the Bay of Biscay /Assessment model, Multi/single species Enrique Nogueira Spain IEO Galicia and Xp X [email protected] Cantabrian Sea Javier Ruíz Spain CSIC Gulf of Cádiz Xp X [email protected] Marcos Llope Spain IEO Gulf of Cádiz X X [email protected] Maria Begoña Santos Spain IEO X [email protected] Miguel Bernal Spain IEO X [email protected] Rafael González-Quirós Spain IEO Xp X [email protected]

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Sven Kupschus UK CEFAS English Xp X [email protected] Channel

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Annex 2: WGEAWESS resolution for the next meeting

The Working Group on Ecosystem Assessment of Western European Shelf Seas (WGEAWESS), chaired by Maria de Fátima Borges, Portugal; Dave Reid, Ireland; Pascal Laffargue, France, and Enrique Nogueira, Spain, will meet in Lisbon, Portugal, 24–27 April 2012 to: a ) Carry out data review and metadata compilation about relevant ecosystem components and process at the regional scale and carry out preliminary evaluation of data and trends; b ) Review Integrated Ecosystem Assessment methodology availability and relevance and propose appropriate IEA approaches for regional assessment: multi scales data integration, biology/physics interactions and modelling, ecosystem status indicators; c ) Based on MSFD pressures/descriptions/indicators combinations evaluate feasibility and relevance of each of these combinations. WGEAWESS will report (via SSGRSP) by 15 June 2012 for the attention of SCICOM.

Supporting information

Priority Heavy pressure on shelf seas (biodiversity loss, climate changes, fisheries), lack in understanding of large marine ecosystem functioning and the context of ecosystem health indicators development for the Marine Strategy Framework Directive require to address those research topics at the relevant scale i.e. the regional approach. Scientific justification Topics at ecosystem/regional scale need interdisciplinary work dealing with physics and biology coupling to develop descriptive framework and models and to establish functional connexions from smallest to largest scales. Each relevant spatial and temporal observation scales requires developing and sharing observation tools and data sources, ensure data storage and management, specific methodology for data aggregation and use in modelling and indicators developments. Such regional and ecosystemic approaches are needed to study differential, hierarchical and synergetic effects of natural vs human pressure on marine ecosystem. The EAWESS working group will focus on North Atlantic European continental shelf. Regional area of interest includes the Celtic sea, bay of Biscay and Western Iberia, involving five countries (Ireland, UK, France, Spain and Portugal). The choice of such limits is justified by : - bio-geographical (transitional region between sub-tropical and sub-arctic gyres) - chemo-physical continuum: large opened and connected areas dominated by soft bottom, closely linked by regional ocean circulation process, offering ‘coast-shelf-slope’ and latitudinal environmental gradient - management unit (ICES, OSPAR) - already existing scientific networks (e.g. IBI-ROOS) Resource requirements There is no resource implication for ICES. Working group program is based on synthesis of data and results from existing scientific program, and coordination of surveys and observations networks. However, involvement of ICES data center would useful to help with sharing and harmonizing data. Participants 20-25 members Secretariat facilities Preparation and dissemination of annual and specific/thematic reports Financial No financial implications.

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Linkages to advisory Initially there will be no direct linkages with advisory committees, but committees the integrated approach is expected to support development of ecosystem health indicators and therefore advices on Northeast Atlantic seas management. The group will maintain communication with ACOM vice- chairs for ecosystems. Linkages to other Natural and strong links will developed with a number of ICES working committees or groups groups. First of them under the Steering Group on Regional Seas in order to share an harmonize data and methodology : WGIAB ( Integrated Assessments of the Baltic Sea) WGNARS (Working Group on the Northwest Atlantic Regional Sea) Others links within ICES are expected Observation Networks: IBI-ROOS (Iberian Biscay Irish maritime area – Regional Operational Oceanographic System): Operational oceanography network, real time data products and services ICES-GOOS (Global Ocean Observing System): Steering Group and Transition Group for the development of ecosystem surveys Steering Group on Ecosystem Surveys and Sampling Technology. Global/integrated ecosystem assessment: WGINOSE (Working Group on Integrated Assessments of the North Sea): multi scales integration, data review in North Atlantic area, quantification of natural vs human pressure WGECO WGOOFE Linkages to other OSPAR organizations EEA