# 6 Ecosystem/Environment Interactions

Lead by Myriam Callier, Sofia Gamito, Harkaitz Eguiraun, Iciar Martinez, Laura Ribeiro and Ramon Filgueira, Francis O'Beirn, Montse Perez, Bastien Sadoul, Fabrice Pernet, Fiz da Costa

Interactions between aquaculture and ecosystems are governed by the cultured species (type of species, production stage, trophic level, fed vs. unfed species), the method of culture (land-based vs. coastal, pond vs. open-water system), the location (intertidal vs. subtidal) and the type of production (fish cages/land-based/RAS and shellfish Longline/bouchot/parcs/bags/bateas). It also depends on farming practices, including the density of the production, the amount of feed provided (Intensive vs. semi-intensive vs. extensive culture) and the "receiving" ecosystems (Aubin et al., 2019). Throughout the BoBIC ecoregion, the main cultured species within the marine environments (see chapters 2 and 3) are bivalves (M. gigas, Mytilus edulis, Mytilus galloprovincialis, Ruditapes philippinarium, Ruditapes decussatus) and finfish (Scophtalmus maximus, Dicentrachus labrax, Gilthead sea bream and Sparus aurata).

The present chapter will not cover all aquaculture-ecosystems interactions as a number of reports have already considered these and provided a synthesis of aquaculture interactions (e.g. WGEIA 2022 report). This Chapter will focus on the interactions that we considered, as an expert group, as particularly relevant to the BoBIC region, considering farmed species and published studies. Interactions must be considered from two perspectives: the impact of the aquaculture on the environment (e.g. waste production). The impact of the environment on aquaculture (contaminant, welfare, disease, stress, among others).

## 6.1 Impact of aquaculture on ecosystems

### 6.1.1 Finfish farming

The impact of finfish farming at farm and ecosystem scales has been well documented and include the effects related to feed production, the release of nutrients into the environment (solid waste and dissolved nutrients) and, the release of treatments/pollutants, genetic introgression (from escapees). Finfish production in the BoBIC ecoregion is relatively small compared to other ecoregions. The total production of finfish is approximately 26 088 T per year (17 953 T in Spain in 2021, 7842 in Portugal in 2021 and 293 T in France in 2021). In comparison, the production is ten times higher in the Celtic Seas ecoregion (200 000 T) and 54 times higher in the Norwegian sea ecoregion (at 1.4 million T).

#### 6.1.1.1 Feed

On a global scale, main impacts of fish farming are linked to the ingredients needed for production of feed. Fish feed is composed of terrestrial and marine ingredients with impacts on ecosystems in other regions of the world. The production of marine ingredients (fishoil and fishmeal) typically involves harvesting large quantities of wild fish, which can lead to overfishing and depletion of some fish stocks (Corten et al., 2017). This is concerning for small, pelagic fish species, usually harvested for aquaculture feed, that are a critical part of the ocean's food chain. Also, most of these fish are of human-grade (Cashion et al., 2017), and therefore aquaculture feeding is in competition with direct human nutrition, especially in Africa, in sub-Saharan countries (Corten et al., 2017; Thiao and Bunting, 2022). Yet, increasing efforts are made to reduce pressure on wild stocks by improving feed composition and feed conversion ratio. The emblematic example of this reduction is the formulation of feed for salmon which used, in the 90s, 80% of marine
ingredients, it is now around 22% (Aas *et al.*, 2022). In parallel, fishmeal and oil are increasingly obtained from by-products of fisheries. As a consequence of all these efforts, the quantity of fish required to produce 1 kg of fed marine finfish is estimated at 0.94 kg (In supplementary table 3 of Koch *et al.* 2020) (NB: there is a variation in the percentage of each component (and/or the fish species and stock of harvested fish used to manufacture the feeds) depending on the prices of raw materials). Therefore, for the BoBIC ecoregion, it can be estimated that the annual production of approx. 26 000 tons of fish required 24 440 tons of wild fish. Yet, this is only a gross approximation, which can greatly vary depending on the species, the production practices, the environmental conditions, and the price of ingredients. For marine species, studies on the potential of alternative ingredients (including algae, insects, etc.) are in progress (see Le Gouvello and Simard, 2017). Concerning terrestrial ingredients, we can report general environmental impacts related to classic crop production such as land-use, freshwater use, and Greenhouse gas release. Terrestrial food ingredients represent the major source of these global scale impacts for fed marine finfish production (Gephart *et al.*, 2021). Since shellfish and algae productions are not fed, these environmental impacts do not apply. The vast majority of aquaculture production in the ecoregion is therefore not concerned by these impacts.

### 6.1.1.2 Nutrient wastes

At the farm level, the release of faeces, uneaten feed and dissolved waste may induce organic enrichment around finfish production and may decrease water quality and induce modification of benthic and pelagic ecosystems (Hargarve, 2005). Fish waste includes particulate organic matter (i.e. faeces, uneaten feed) and dissolved inorganic nutrients (fish excretion). Particulate organic matter may accumulate under fish cages and induce organic enrichment with local impact on the sediment biogeochemical characteristics of the sediment (anoxia, increase of H2S), and modification of the benthic community diversity, abundance and structure. Nearfield impacts have been well studied and are measurable, however far-field effects are less studied and more difficult to measure. In coastal areas under pressure from multiple activities, it is difficult to determine the contribution of nutrients from finfish farming to systems that are already nutrient enriched.

* In France, on the French Atlantic coast, the fish-farm production is low (see Chapter 2). Only four finfish farms are located in this ecoregion including 3 land-based systems: Environmental Impact Assessments are carried out although no publications are available.

* Few references are available regarding nutrient waste estimation and revalorization of wastes and sub-products in the Spanish Atlantic coast. Fraga-Corral *et al.*, (2022) selected the Galician coast as a case study. The authors analyse the production data and the generation of waste and by-products and, concluded that a bio-economy model should be adopted for their reuse and to reduce their negative environmental impact. As far as we know, aquaculture companies in Spain carry out Environmental Impact Assessments, but the results are confidential. In Galicia guides for the realization of environmental monitoring plans for marine cultures in floating cages and land-based fish farms installed on the coasts of Galicia are published (https://mar.xunta.gal/es/el-sector/acuicultura).

* In Portugal, along the Atlantic coast (western and south) the majority of marine finfish aquaculture is located in the ecoregion. There are several land-based finfish aquacultures in earth ponds within the lagoons (Ria de Aveiro, Sado Estuary, Ria de Alvor and Ria Formosa) under a semi-intensive regime. Two intensive land-based fish farms are located in Praia da Tocha and south of the Praia de Mira, responsible for 45% of the total marine fish production in 2021. Finfish production in cages also exists in Sines and in the South of Portugal. Fish farms in transitional waters are generally located close to areas of good water renewal, with high water exchange rates with oceanic water, to ensure an appropriate and healthy production. Furthermore, due to their privileged location, the
potential impact of the fish-farming effluents is reduced by dilution with clean coastal or oceanic waters.

### 6.1.1.3 Mitigation: fallowing, and Integrated multi-trophic aquaculture

The main strategies to mitigate the impact of fish waste on the environment are:

1. proper selection of production sites based on the evaluation of the carrying capacity of the ecosystem,

2. fallowing i.e. halting the production for a variable period of at least several months moving the farm to a different location (Zhulay *et al.*, 2015),

3. improving the feed conversion ratio (by improvement of feed composition, selection program) and

4. better management practices, such as the use and development of innovative farming systems such as recirculating aquaculture system (RAS) and integrated multi-trophic aquaculture (IMTA) to improve the treatment and valorisation of waste.

Fallowing is a practice to assist recovery of the environment and to protect the farmed specimens from potential pathogens by moving the farm somewhere else without the threat. It is obligatory in some countries such as Norway (Zhulay *et al.*, 2015), but it has not officially been implemented in the BoBIC area. In Spain for example, while the 2014 APROMAR report (APROMAR, 2014) recommended its implementation, it is not mentioned in the 2022 report (APROMAR, 2022). In Portugal, shellfish farmers themselves implement fallowing, especially for clams in certain lagoon areas with low water renewal and low oxygenation. The procedure consists of mixing new sand with the existing sediment and stop using that area for a couple of months. RAS could be a mitigation of many of these impacts – but may still present a risk (i.e. point source of pollution).

Integrated multi-trophic aquaculture (IMTA) refers to the combination of species from different trophic levels in the same culture system (Chopin and Robinson, 2004). IMTA, in addition to diversifying species in culture, can be designed to improve environmental sustainability of fish farming, increase profitability and be a source of employment in coastal regions. Few IMTA systems are commercially effective in the BoBIC region but, many projects are testing IMTA pilots both in open and inland waters (see chapter 9).

Some examples of commercial IMTA:

* In France (see Chapter 2):

* one marine finfish hatchery on-land uses a series of a dozen of downstream ponds to allow sedimentation of particulate waste and the culture of macroalgae that benefit from the dissolved waste. This system allows to effectively mitigate the waste of the hatchery.

* many producers of pacific oysters in ponds have diversified their production by adding Kuruma prawn (*Penaeus japonicus*) in the ponds in summer. The prawns eat the macrobenthos in the sediment and allow the resuspension of organic matter which can benefit the oysters. The association favours oyster's growth and allows the production of additional biomass, often without feeding the shrimps.

* A fishfarm producing fingerling including a system combining land-based finfish farm producing 50 million fingerlings in 2018: sea bass (*Dicentrarchus labrax*), sea bream (*Sparus aurata*) and meagre (*Argyrosomus regius*) (Ferme Marine du Douet in Oleron Islands) and 11 t of *Ullva rigida* in 13 lagoons of 500 m² and 1,8 m depth.

* In Spain (see trials described in Chapter 9)

* In Portugal: ALGAPLUS (see Chapter 2)
#### 6.1.1.4 Disease interactions

"Most, if not all, farmed fish diseases come from pathogens existing in wild populations. Aquaculture activities, however, create conditions (e.g. high stocking levels) conducive to pathogen transmission and disease. Stocking with hatchery-reared fish or aquaculture escapees can affect disease dynamics in wild populations. The close contact between farmed and wild fish may readily lead to pathogen exchange (Peeler and Murray, 2004)" (in a review Cidad et al., 2018, MEDAID). Many diseases in farmed fish are diseases initially found in wild populations. However, aquaculture practices, such as dense stocking, enhance the likelihood of diseases spreading. Interactions between farmed fish and wild animals can change the dynamics of disease among wild fish populations. Indeed, due to the close proximity between farmed and wild species or because of escapees, there is a high risk of exchanging pathogens between them (Peeler and Murray, 2004).

A viral epidemiological study of wild fish around the Gulf of Cadiz (southwestern Iberian Peninsula) by Moreno et al., 2014 focused on infectious pancreatic necrosis virus (IPNV), viral hemorrhagic septicemia virus (VHSV), and viral nervous necrosis virus (VNNV) and found isolated incidences in wild fish in the San Pedro River mouth and in near oceanic locations. Among the segmented viruses that most severely impact fish aquaculture, IPNV especially affects salmonid aquaculture, mainly Atlantic salmon (*Salmo salar*) and rainbow trout (*Oncorhynchus mykiss*) species, with lethality rates that can reach up to 90% in fry and postsmolt stock (Valero and Cuesta, 2022).

The critical incidence of fish NNV (family Nodaviridae, genus Betanodavirus) is expanding, with a wide range of farmed and wild affected species and a worldwide geographical distribution. One of the most affected regions is the Mediterranean area, where NNV affects two of the main aquaculture fish species, the European sea bass and the gilthead sea bream which are also farmed in the BoBIC region. Therefore, this virus is one of the most threatening and studied during the last three decades since it can reach complete losses of production at larval and juvenile stages (Valero and Cuesta, 2022).

Official disease surveillance in Spain is carried out by the competent authorities of the Autonomous Communities (CCAA). These have developed specific surveillance programs in accordance with the sampling plans and diagnostic methods established in the Commission Implementing Decision (EU) (2015/1554). Coordination is exercised by MAPA (Ministry of Agriculture, Fisheries and Food).

#### 6.1.1.5 Escapes and genetic impact

Fish escape events have been reported for a number of fish species cultured worldwide (Arechavala-Lopez et al., 2018). There are two forms of escapees: "fish escape" can be defined as a single or a group of fish that make their way out of the net-pen, "escape through spawning" refers to the release of viable, fertilized eggs spawned by farmed fish inside sea cages (Arechavala-Lopez et al., 2018).

The impact of escapees from aquaculture is of general concern for the sustainability of natural resources (Prado et al., 2018). Fish escaping from sea cage aquaculture may induce potential genetic effects through interbreeding with wild populations, ecological effects through predation, or competition and the transfer of diseases to wild fish. Escapes also represent an important economic loss for the sector. According to Arechavala-Lopez et al., (2018), knowledge of the effects of escaped fish on the ecosystem is limited to Atlantic salmon (*Salmo salar*) and Atlantic cod (*Gadus morhua*).

In the BoBICAO ecoregion, land-based aquaculture of turbot started 40 years ago with low risk of escapees but the use of farmed turbot to enhance wild stocks along the Northeast Atlantic coasts in the last decades will likely have increased the risk to wild populations (Prado et al.,
2018). In the framework of the EU project AquaTrace (The development of tools for tracing and evaluating the genetic impact of fish from aquaculture 2012–2016), the genetic introgression in wild populations of turbot Scophthalmus maximus has been studied. Prado *et al.*, (2018) developed Single nucleotide polymorphism tools to monitor turbot of farmed ancestry in the wild. The study reported a notable proportion of fish of farmed ancestry in the wild (15.5%), mainly in the North Sea, where restocking activities have taken place, determining genetic introgression in wild populations. Conversely, effects of land-based aquaculture appear negligible. The authors indicate that this introgression might represent a risk for the turbot population, considering the lower fitness of farmed individuals.

Genimpact, a European network (2006–2007) focused on the evaluation of the genetic impact of aquaculture activities on native populations, provided a summary of the genetic effects of domestication, culture and breeding of fish and shellfish, and their impacts on wild populations as well as the monitoring tools for evaluation of genetic impact of aquaculture activities on wild populations, predictive tools and management options. As for turbot, according to Danancher and García-Vázquez (2007), escapes are not common in land-based facilities (most companies produce turbot in this type of facility), but no further data are provided.

Prevent-Escape, a pan-European project funded by the EU carried out between 2009–2012, provided recommendations and guidelines for aquaculture technologies and operational strategies to reduce escape events, including indicators to differentiate between escaped and wild fish (external appearance, morphometry, fatty acids profiles and trace elements in scales). A project co-financed by the European Fisheries Fund and the Spanish Biodiversity Foundation, called ESCA-FEP, offered guidelines for prevention of fish escapes (Izquierdo-Gomez *et al.*, 2014a) and defined recapture plans to mitigate their impact and reduce the economic loss of aquaculture companies (Izquierdo-Gómez *et al.*, 2014b). Some of the outputs of the Prevent-Escape and ESCA-PEP are presented in the review by Arechavala-Lopez *et al*. (2018). In this paper, a review of the potential interactions, risks and consequences, of Sea Bream and Sea Bass escapes is provided in the Table below).

In addition, the project "Global change Resilience in Aquaculture" (GLORiA and GLORiA2) aims to provide solutions regarding the adaptation to climate change including extreme events that may cause damage to aquaculture facilities and increase the risk of escapees. In this project, methods are also developed to better identify the origin of the fish: farm-raised fish, wild or escapees (analysis of antibiotics in fish, deep learning image). To underpin the importance of this project it is noted that Storm Gloria (in January 2020), with waves up to 14 m high, ravaged most marine net-pen facilities and between 60 and 70% of Spanish finfish production was impacted (APROMAR, 2021; De Alfonso *et al.*, 2021). Millions of fish perished and/or escaped, with considerable socio-economic and ecological implications.
<table><caption>Table 6.1 Summary of the reviewed literature on the implications and risks of genetic, ecological and socio-economic interactions of sea bream (Br) and sea bass (Bs) escapees at different geographic areas. H: hypothesis; S: suggested; D: demonstrated</caption><thead><tr><th>Interactions</th><th>Implications and risks</th><th>Sps.</th><th>Geographic area/s</th><th>H</th><th>Author/s.</th></tr></thead><tbody><tr><td rowspan="20">Ecological</td><td rowspan="2">Dispersion, competition, predation</td><td>Br</td><td>W-Mediterranean</td><td>D/S</td><td>Arechavala-Lopez et al., 2012a</td></tr><tr><td>Br</td><td>C-Mediterranean</td><td>D/S</td><td>Segvić-Bubić et al., 2017b</td></tr><tr><td>Bs</td><td>W-Mediterranean</td><td>D/S</td><td>Arechavala-Lopez et al., 2014a</td></tr><tr><td rowspan="4">Establishment/local-absent sps.</td><td>Br</td><td>CE-Atlantic</td><td>D/S</td><td>González Lorenzo et al., 2005</td></tr><tr><td>Bs</td><td>CE-Atlantic</td><td>D/S</td><td>Toledo-Guedes et al., 2009,2012</td></tr><tr><td>Bs</td><td>CE-Atlantic</td><td>D</td><td>Toledo-Guedes et al., 2014a,b</td></tr><tr><td>Bs</td><td>CE-Atlantic</td><td>D/S</td><td>Ramirez et al., 2015</td></tr><tr><td rowspan="3">Pathogens transmission</td><td>Br</td><td>W-Mediterranean</td><td>S</td><td>Arechavala-Lopez et al., 2012a</td></tr><tr><td>Bs</td><td>W-Mediterranean</td><td>S</td><td>Arechavala-Lopez et al., 2011</td></tr><tr><td>Bs</td><td>CE-Atlantic</td><td>S</td><td>Toledo-Guedes et al., 2012</td></tr><tr><td rowspan="10">Interbreed, hybridization, etc.</td><td>Br, Bs</td><td>Mediterranean Sea</td><td>S</td><td>Arechavala-Lopez et al., 2013a</td></tr><tr><td>Br</td><td>C-Mediterranean</td><td>S</td><td>De Innocentiis et al., 2004</td></tr><tr><td>Br</td><td>Mediterranean and NE-Atlantic</td><td>S</td><td>Miggiano et al., 2005</td></tr><tr><td>Br</td><td>C-Mediterranean</td><td>S</td><td>Segvić-Bubić et al., 2011a</td></tr><tr><td>Br</td><td>C-Mediterranean and NE-Atlantic</td><td>S</td><td>Franchini et al., 2012</td></tr><tr><td>Br</td><td>C-Mediterranean</td><td>D</td><td>Segvić-Bubić et al., 2014</td></tr><tr><td>Bs</td><td>Mediterranean</td><td>S</td><td>Bahri-Sfar et al., 2005</td></tr><tr><td>Bs</td><td>Mediterranean and NE-Atlantic</td><td>S</td><td>Haffray et al., 2006</td></tr><tr><td>Bs</td><td>E-Mediterranean</td><td>S</td><td>Brown et al., 2015</td></tr><tr><td>Bs</td><td>C-Mediterranean</td><td>D</td><td>Segvić-Bubić et al., 2017a</td></tr><tr><td rowspan="5">Gametes/eggs escapes</td><td>Br</td><td>E-Mediterranean</td><td>S</td><td>Dimitriou et al., 2007</td></tr><tr><td>Br</td><td>C-Mediterranean</td><td>S</td><td>Segvić-Bubić et al., 2011a</td></tr><tr><td>Br</td><td>C-Mediterranean</td><td>S</td><td>Franchini et al., 2012</td></tr><tr><td>Br</td><td>E-Mediterranean</td><td>D</td><td>Somarakis et al., 2013</td></tr><tr><td>Br, Bs</td><td>Mediterranean</td><td>D</td><td>Jackson et al., 2014</td></tr><tr><td rowspan="10">Socioeconomic</td><td rowspan="2">Farm economic losses</td><td>Br</td><td>C-Mediterranean</td><td>D</td><td>Segvić-Bubić et al., 2011b</td></tr><tr><td>Br</td><td>E-Mediterranean</td><td>D</td><td>Dimitriou et al., 2007</td></tr><tr><td rowspan="5">Impacts on fish/mussel farms</td><td>Br</td><td>W-Mediterranean</td><td>D</td><td>Arechavala-Lopez et al., 2012a,2018</td></tr><tr><td>Br</td><td>W-Mediterranean</td><td>D</td><td>Izquierdo-Gómez et al., 2014,2017</td></tr><tr><td rowspan="3">Interactions with fisheries</td><td>Br</td><td>W-Mediterranean</td><td>S</td><td>Izquierdo-Gómez et al., 2016</td></tr><tr><td>Bs</td><td>W-Mediterranean</td><td>D</td><td>Arechavala-Lopez et al., 2011,2018</td></tr><tr><td>Bs</td><td>CE-Atlantic</td><td>D</td><td>Toledo-Guedes et al., 2014a,b</td></tr></tbody></table>

### 6.1.1.6 Changing of habitats /impacts of habitat uses

In Portugal, the expansion of semi-intensive fish farming in earthen ponds is usually carried out in old, abandoned salt pans (salinas), which impacts the natural capital and this priority habitat for the conservation of avifauna. It might have an important impact on wading birds that use the salt pans for feeding or refuge during high tides. Nevertheless, there are large areas abandoned and degraded in transitional waters and coastal lagoons (e.g. Sousa et al., 2020) that could be re-naturalised. Part of these areas could be reused for salt production or converted for fish production. The same happens in southern Spain where earthen pond culture is also common (see 2.2.1).

### 6.1.1.7 Ecological Carrying Capacity

The concept of carrying capacity has emerged as a flexible framework to operationalize the eco-system approach to aquaculture (Weitzman and Filgueira, 2019). Carrying capacity can be defined as the magnitude of aquaculture activity that can be supported without leading to “unacceptable changes” in ecological process, species, populations, or communities in the environment (Filgueira et al., 2015). The flexibility of the concept in the definition of metrics and thresholds to define “unacceptable changes” allows the inclusion of different perspectives in its application. While the most common application of carrying capacity in aquaculture is related to ecological aspects, the concept has also been applied to evaluate production, social, and physical carrying capacities (McKindsey et al., 2006). Further, other concepts commonly applied to aquaculture management, such as assimilative capacity, i.e. the capacity of the system to assimilate organic loading without compromising the delivery of goods and services (Tett et al., 2011), could fit within the general definition of carrying capacity, and it is particularly relevant to finfish aquaculture. The concept of carrying capacity becomes a powerful tool for bay-scale assessments of aquaculture sustainability as it can incorporate the potential cumulative effects of multiple farms. One farm can have a reduced impact on the environment, but several farms may have a significant impact, with eutrophication risk increased. For the evaluation of the impact of
additional farms in a restricted area long-term monitoring and ecosystem modelling are essen-
tial. The global carrying capacity of the system must be evaluated.

Despite the broader recognition of the concept in policies, the use of carrying capacity to grant aquaculture sites and to study broader ecological effects is limited for finfish aquaculture in the Bay of Biscay and the Iberian Coast ecoregion. The use of carrying capacity as a potential management tool is most prominent in the scientific literature rather than in policies and regulations for this region.

In Spain, the central government indicates that carrying capacity studies are needed for aquaculture planning; however, they defer to the precautionary principle and monitoring as an alternative due to the complexity of estimating carrying capacity (Fisher *et al.*, 2023). The relevance of the concept is recognized by provincial policies, e.g. Andalusia, Galicia (FOESA, 2015).

In France, the MOCAA project funded by Ifremer and the Ministry developed a modelling tool to evaluate the assimilative capacity of site for fish farming. Case studies on the BoBIC region are included in this study to validate the tool (Callier *et al.*, 2022).

In Portugal, the carrying capacity of semiartificial lagoons for extensive fish production, in Ria Formosa, has been estimated. Their carrying capacity can be increased by raising the water renewal and improving the environmental quality (Gamito, 1997). Later, using a trophic model, the carrying capacity of a similar semiartificial lagoon, a water reservoir of a sea bream farming pond, was estimated using a trophic model (Gamito and Erzini, 2005). Further trophic model exploration showed that the intensification of fish production increases the carrying capacity of the ponds, fuelled by the artificial feed introduced into the system, and the energy spent in water pumping for increasing water renewal and aeration (Gamito et al., 2020).

Ria Formosa was also modelled to explore the interactions of inshore and offshore aquaculture (Ferreira *et al.*, 2012, 2014). The authors used a set of joint models (hydrodynamic and ecological) to explore the potential spread of diseases and for optimization of stocking density, pointing to a better performance in IMTA with gilthead sea bream and mussel culture compared to mussel culture alone. The limited number of ecological carrying capacity studies and assessments for fish compared to bivalves (see below) is related to the reliance of bivalves on natural food resources at the bay-scale (Weitzman and Filgueira, 2019). Contrarily, one of the major ecological effects of finfish aquaculture is organic deposition at the farm-scale, which can be explored with local measurements or models.

The joint impact of several fish or bivalve farms in a restricted area such as an estuary or a coastal lagoon must be evaluated. One fish farm can have a low negative impact on the environment, but several farms may have a significant impact, with eutrophication risk increased. For the evaluation of the impact of an extra farm in a restricted area long-term monitoring and ecosystem modelling are essential, and the ecological carrying capacity of the global estuarine or coastal system must be evaluated. For example, Ferreira *et al*. (2014) highlights the need for an ecosystem approach to aquaculture and proposed an integrated model for aquaculture production, pathogen interaction, and environmental effects (Ferreira *et al.*, 2021).

6.1.2 Shellfish farming

At farm and ecosystem scale, shellfish farming may induce several pressures on the environ-
ment:

* Fall-off under structures - Longline and raft culture.

* Biodeposit production may increase sedimentation rates and modify benthic ecosystem characteristics (sediment, infaunal community) (McKindsey *et al.*, 2011).

* Hydrodynamic changes.
* Phytoplankton removal, top-down control of eutrophication.

* Zooplankton removal, top-down control of plankton.

* Pathogens.

* Overfishing of natural seed stocks.

* Interaction with wild species (Callier *et al.*, 2018).

* Effects on sensitive habitat/spawning areas.

* Treatment: chemical used to treat the structure, antifouling.

* plastic issue (impact on finfish +shellfish) and contribution of Aquaculture to plastic

* Biogenic acidification, shellfish emit CO² in the seawater through respiration and calcification and remove (bi)carbonate ions, potentially leading to seawater acidification and CO² degassing in the atmosphere. That is also true for finfish or any other animal production in the sea.

* Acidification / carbon removal. Through respiration, high density shellfish production may acidify the coastal waters while shellfish growth may remove carbonate from the system.

* Changes on habitat uses.

* Effect of antibiotics (hatcheries bivalve) leading to increased bacterial resistance near shellfish hatcheries. Shellfish hatcheries using antibiotics may act as a potential source of antibiotic residues and resistant bacteria to the aquatic environment (Dubert *et al.*, 2017).

* Chemical used in structures in shellfish culture.

* Aquaculture as a source of plastics and microplastics – some data from PT in relation to MP in shellfish and originating in land (run-off)- any publication/report).

* impacts on sensitive areas and habitats (seagrass).

* Shading, with effects particularly on photosensitive species.

Some specific pressures are more detailed below:

### 6.1.2.1 Effects on habitats

Some shellfish farms in the north of Portugal produce oysters in old salt ponds, contributing to their maintenance. There are, however, conflicts between extensive shellfish culture in intertidal bottoms and natural habitats, such as the destruction of seagrass beds and sandbanks (Mateus *et al.*, 2016). The shellfish farmers remove the seagrass, such as *Zostera noltii*, from the sediment and add gravel to improve oxygenation and water circulation in the sediment (Carvalho, 2006; Guimarães *et al.*, 2012). The farmers also change the natural sandy banks for shellfish culture, damaging the wild benthic invertebrate communities. The water circulation through the tidal channels might be changed due to the addition of coarse sediments in the clams' culture bed, reducing the lagoons' water renewal with oceanic water. To prevent erosion of the clams' beds borders, barriers of old nets, rests of oysters' bags and other plastic materials are placed along the tidal channels (Figure 6.1). These barriers function as artificial reefs for the settlement of hard substratum macroinvertebrates, such as mussels and oysters, increasing at the end the local biodiversity nearby the shellfish farm that, however, have reduced several ecosystem services provided by the *Zostera* beds and sandy banks.
<figure><img src="image_27.png" /><figcaption>**Figure 6.1** Ria Formosa lagoon (southern Portugal): Example of a clam's culture bed (right side of the image), protected by a barrier of old oyster bags and other debris from the tidal channel, to prevent erosion.</figcaption></figure>

In France, the presence of bouchots and trestles may prevent erosion by attenuating current (Sornin, 1982). The use of old salt ponds (Amanieu, 1973) for oyster production contribute to maintain and a good supply of salt water, essential to maintaining the lagoon habitat and anthropized marshes which are buffer zones in the event of submersion (e.g. Shepard *et al.*, 2011; Spalding *et al.*, 2014).

### 6.1.2.2 Production and Ecological Carrying capacity

The concept of carrying capacity has mainly been applied to study the environmental interactions of shellfish aquaculture, particularly in relation to the potential effects of the farmed biomass on phytoplankton populations.

In Spain, studies in the early 1970s pioneered the use of the trophic relationship between phytoplankton and filter-feeders to optimize mussel production in Galician Rías at the bay-scale; however, these studies focused on production rather than ecological carrying capacity (e.g. Tenore *et al.*, 1985). Similarly, the depletion of seston and phytoplankton at the raft-scale in Ría de Ares-Betanzos has been used to evaluate the potential effects of food depletion on bivalve performance but the findings were also contextualized around ecological carrying capacity (Duarte *et al.*, 2008; Cranford *et al.*, 2014). Trophic web modelling has been used to estimate the ecological and production carrying capacity of Ría de Arousa, an extensive mussel cultivation area (Outeiro *et al.*, 2018).

In France, carrying capacity studies were carried out in the Pertuis Charentais and Marennes Oléron Bay in the 90's (Bacher 1993, Raillard *et al.*, 1994, Bacher *et al.*, 1998) and resulted in the development of modelling tools to estimate the production carrying capacity of shellfish systems. More recently, ecosystem modelling to assess the impact of rearing density, environment variability and mortality on oyster production has been developed (Cugier *et al.*, 2022). In this paper, a three-dimensional hydrodynamic model, primary production and individual growth estimates are used to predict oyster growth and production in Bourgneuf Bay (French Atlantic coast). Scenarios were tested to compare the effects of aquaculture practices and environment variability and mortality (Cugier *et al.*, 2022).
In Portugal, bivalve production in intertidal areas and estuarine waters has been the focus of
several carrying capacity studies concerning bivalve aquaculture. Production might exceed the
carrying capacity of the system since the bivalves filter all the water and remove the available
phytoplankton and POM (Ferreira et al., 2018). Their feeding, therefore, can have an impact on
other filter-feeder wild organisms of the ecosystem, as well as a negative impact on the individ-
ual growth rates of the farmed bivalves themselves, as food availability could be the limiting
factor for maximizing growth of introduced organisms. Their growth might be reduced and, the
bivalves can become more fragile and susceptible to parasitic infections or other illnesses. Ria
Formosa in southern Portugal, is the main region for bivalve production, mainly clams (Ruditapes
decussata) and oysters (Magallana gigas). Recently, oyster production has been gaining ground in
the Ria Formosa, to the detriment of clam farmers, which are losing income, leading producers
to abandon clam production or convert the activity, or even produce both species together. The
joint production of oysters (in tables or bags above the sediment) and clams can have a negative
effect on clam growth since oysters might absorb the phytoplankton and POM available leaving
few for the clams that lay on the bottom. These interactions need to be investigated and tested
and the total carrying capacity of the ecosystem needs to be evaluated.

Similar to the studies in Spain, farm-scale models have been used to optimize bivalve production, in which the implications for ecological carrying capacity have been stated (Ferreira *et al.*, 2009). At the ecosystem-level, the effects of dredging and clam biomass on Ría de Formosa were simulated by mathematical modelling indicating that aquaculture was exploited close to the carrying capacity of the system (Duarte *et al.*, 2007). As stated above, a large modelling initiative was carried out to explore the aquaculture environment interactions of IMTA in Ría de Formosa, which included several bivalve species and types of culture, benthic and suspended (Ferreira *et al.*, 2012, 2014).

## 6.2 Impact of the environment on aquaculture (all species)

### 6.2.1 Water quality – Ecological status

Water bodies used for marine aquaculture production are subject to multiple sources of contamination, which may impact their microbiological or chemical quality. Sources of contamination can be of human origin: agriculture (livestock effluents, chemical treatments of crops), collective or individual sanitation, transport, and industries (contaminant discharges into water); or of natural origin: wildlife or natural soil erosion. Water quality might therefore vary according to environmental conditions, and human activities, and can alter the correct development of aquaculture activities. This is particularly true for shellfish, which filter water for nourishment, and therefore concentrate micro-organisms and certain chemical molecules present in the water.

* In Portugal, for transitional waters (TW - estuaries and coastal lagoons) a high percentage of Portugal's area was classified as being in moderate ecological status (76%), with only 18% of the area with good ecological status. In contrast, coastal areas presented 83% of the area in good or high ecological status<fnref n="25" />.

* For future consideration, similar assessment could be done for Spain and France. WFD status and aquaculture production could be linked for all three countries<fnref n="26" />.

<footnote n="25">²⁵ (https://water.europa.eu/marine/countries-and-regional-seas/country-profiles/portugal, assessed December 2023).</footnote>

<footnote n="26">²⁶ https://water.europa.eu/marine/countries-and-regional-seas/country-profiles.</footnote>
## 6.2.2 Impact of pathogens on shellfish farming

Shellfish production is regularly affected by degradation of water quality leading to regulation forbidding the selling of products. This is for example the case during norovirus outbreaks which tend to follow seasonal patterns, with a higher prevalence typically observed in colder months, particularly during winter and early spring. This coincides with peak times for norovirus infections among humans, increasing the likelihood of contamination entering marine and estuarine environments.

In France, since 2008, Pacific oyster has been affected by episodes of massive and recurrent mortality triggered by the presence of viral infectious agents (such as Herpes virus OsHV-1 μVar) in conjunction with environmental factors (i.e. rise in temperature). (Fleury et al., 2022) This viral infection induces a decrease in antimicrobial defences as well as a modification of its microbiota. This process leads to a secondary infection by potentially pathogenic opportunistic bacteria, which multiply rapidly causing irreversible tissue damage leading to the death of the animal. At the same time and although less documented, mortality also affects the numerous wild stocks present on the French coast. Oyster farming industry relies on natural spatfall collection and hatchery. This collect is practised in several oyster farming basins (Chapter 2), Bassin d'Arcachon was providing between 60 and 70% of the 4 billion needed for the production (e.g. Maurer et al., 2009a; Auby et al., 2012) followed by Pertuis Charentais (e.g. Geay and Bouquet, 2009). Now, oyster natural spatfall production has declined markedly with hatcheries now supplying 50-70% of the oyster spat production. Mussel production rely solely on natural spatfall production (https://agreste.agriculture.gouv.fr/agreste-web).

Natural spatfall recruitment is highly variable from year-to-year and therefore unpredictable. This context has motivated the implementation of monitoring networks at the national scale to measure the health status of cultivated and wild oyster populations, during the entire life cycle of the species (reproduction, larval ecology, recruitment, growth, survival) (Fleury et al., 2022).

In the 2022 ECOSCOPA report, authors were able to analyse the effect of an increased in temperature from climate change on a local scale. The main results obtained during this 2021 campaign indicate that, in terms of environmental factors, this year was part of the general trend of global warming, but in a more moderate way than in previous years (Fleury et al., 2022). At the level of the network sites, 2021 is a continuation of recent years with an average thermal anomaly higher than normal by +0.5°C, which results mainly from a strong anomaly from winter: temperatures of seawater exceeded normal levels, but late in summer. In terms of phytoplankton inputs, phytoplankton concentrations were fairly normal. The reproduction and egg-laying phases took place at a "normal" period, allowing a supply of larvae within normal limits, except for the Bourgneuf Bay site, for which concentrations of young larvae were low. Given the variable temperatures that were just within the norms in the different basins, the spat collection was relatively heterogeneous depending on the sectors, very good on certain sites, almost zero on others. After a long period of high mortality, the spat mortalities observed for 2021 were very low for the first time (except for the Bay of Veys and Marennes-Oléron sites).

## 6.2.3 Persistence of antibiotic resistant Vibrio spp. in shellfish hatcheries

The main supply of seed for farming bivalves comes from hatcheries. The main bottleneck in the bivalve production process are pathogenic species belonging to the genus Vibrio which may lead to disease outbreaks causing the entire loss of larval batches in hatcheries (Dubert et al., 2016a). Dubert et al. (2017) published an extensive review of the recently characterized Vibrio species associated with disease of bivalves during early stages of development. Antimicrobial agents
have routinely been applied to water to treat and prevent disease in hatcheries, particularly during the first stages of bivalve development (Prado *et al.*, 2014). Therefore, this extensive use of antibiotics may trigger the development of resistant bacteria, which can transmit quickly resistance genes in the hatchery environment by horizontal transfer mechanisms (Miranda *et al.*, 2013). Antibiotic treatments limit the bacterial diversity and promote the rapid development and persistence of resistant vibrio *spp.*, most of them with pathogenic potential, as observed with bacterial strains isolated from a Spanish bivalve hatchery (Dubert *et al.*, 2016b). In addition to that, those shellfish hatcheries using antibiotics may act as a potential source of antibiotic residues and resistant bacteria to the aquatic environment (Dubert *et al.*, 2017).

### 6.2.4 Predation

Predation is a major problem for some productions, especially in open water and in ponds. The most direct impact of predation on marine aquaculture is the loss of stock. Predators such as birds, fish, and crustaceans can consume a significant portion of the farmed species, leading to direct economic losses for producers. For example, birds like cormorants and herons are known to prey on fish in ponds and nets, while sea bream and sea stars can be a problem for bivalves' productions. They are known to prey on a variety of bivalves and can cause significant losses if they invade aquaculture areas. To prevent birds' predation in fish farms in earthen ponds, these are usually covered by nets. The culture of molluscs in bags also prevents or reduces predation by birds, fish, and larger crabs.

### 6.2.5 Effect of climate change on aquaculture

In the past years, the North Atlantic water temperature has risen to unprecedented values (Kuhlbrodt *et al.*, 2024). This temperature changes affects the aquaculture production. For example, in the EPPO experimental station (located in the Ria Formosa, in southern Portugal), summer temperature in fishponds rose to more than 28°C for several days. These temperatures might be a limiting factor for the majority of species produced in Portugal. In fact, for meagre (*Argyrosomus regius*) and sea bass (*Dicentrarchus labrax*) 28°C or above are temperatures out of the reproduction limit for the species (Mosqueira *et al.*, 2022). According to Mosqueira et al., the ideal temperature for the gilthead bream (*Sparus aurata*) lies between 22 and 26°C and higher temperatures are cause of stress. Furthermore, with temperature rise, the amount of dissolved oxygen decreases, and the degradation of the water quality accelerates, which imposes additional management measures to sustain the production, such as more aeration or even ejection of compressed air or oxygen. Although the ocean water temperature near the coast in southern Portugal usually does not exceed 24°C, the water temperature in earthen ponds of 1 or 2 m deep can exceed 30°C for several days. The situation can worsen during neap tides, when there is a lower water renewal rate inside the ponds and outside, in the shallow waters of the estuaries or coastal lagoons. Therefore, the outside water temperature can also remain too high, without the possibility of lowering the inside water temperature in the ponds.

### 6.2.6 Emerging issues and contaminants of concern

Well known and documented environmental pollutants that may influence aquaculture practices include heavy metals, fertilizers, pesticides, Persistent Organic Pollutants (POPs), micro- and nanoplastics, and the so-called emerging contaminants, which are being detected worldwide with increasing frequency and in higher amounts in aquatic systems, displaying strong spatial and temporal quantitative and qualitative variations (Deycard *et al.*, 2014; Laroche *et al.*, 2014;
Borja et al.; 2019, Mendoza et al., 2020; Masia et al., 2021; Solaun et al., 2021; Basurko et al., 2022; Rosas et al., 2022; Bilbao-Kareaga et al., 2023; Mauffret et al., 2023; Zorita et al., 2023).

These compounds will not only influence the wildlife but also the health and welfare of farmed
organisms bred in those waters. Emerging contaminants include human and veterinary medi-
cines (such as antibiotics, anti-inflammatory drugs, beta-blockers, hormones and antidepres-
sants), recreational drugs, caffeine, nicotine, hygienic products (scrubbings, soaps, triclosan) and
sun-blockers, among many others. They are relevant not only because they may influence the
health of aquatic organisms and induce resistances to some of the treatments, but also because
they influence their behaviour, including that of bivalves and fish. These are so marked that
behavioural modifications have been proposed as early biological warning systems for the pres-
ence of pollutants in the environment (Bae and Park, 2014, see also Laroche et al., 2014 for re-
sponses of European flounder in different waters of the Bay of Biscay) and in aquaculture
(Eguiraun et al., 2014; Eguiraun and Martinez, 2023 a, b). Furthermore, contaminant-induced be-
havioural modifications in aquaculture settings have the potential to influence the welfare and
yield in aquaculture settings (Eguiraun and Martinez, 2023 a, b).

The presence and quantity of heavy metals are regularly monitored in different zones of the Bay of Biscay through the Spanish Mussel Watch program (Besada *et al.*, 2014). Not surprisingly, the program identified industrial and the more densely populated areas both as primary sources of contaminants and the most polluted zones. Cu, Zn and as concentrations presented fairly uniform geographical distributions while Hg and Pb levels were higher in mussels from the Cantabrian Sea region as a result of historical anthropogenic activities. Cd, on the other hand, appeared to be more affected by natural processes on the Northwest Atlantic coast than by human activity.

Deycard et al. (2014) documented the contribution of urban wastewater of As, Cd, Cu, Cr, Ni, Pb and Zn to the Girone Estuary (France) and remarked the relevance of the weather, in particular, short, intense summer rainstorms, in increasing the levels of these elements. However, while heavy metal contamination of farmed shellfish and algae may be largely due to the environmental levels of the contaminants and may be severely affected by weather events, the levels in farmed finfish would be highly dependent on the composition of the feed, which is regulated by the European Food Law (EC,2002).

6.2.6.1 Microplastics and microfibers

Worldwide there is a rising awareness of plastic litter and the impacts it might have regarding food safety and aquatic environment. Global plastic production and use was over 320 million tonnes in 2015, and it is expected to exceed 1 billion tonnes by 2050 due to the growing market demand for plastic products.

Plastic is a general term for a range of polymer materials with different properties, when mixed with different additives to enhance their performance (e.g. plasticizers, ultraviolet stabilizers, antioxidants, flame retardants,) (FAO, 2017). The five types of plastics that dominate the global production are: polyethylene, polypropylene, polyvinylchloride, polystyrene, and polyethylene terephthalate (GESAMP, 2015).

Microplastics (MP), particles smaller than 5mm, can originate in manufacturing (e.g. cosmetics, calibration) or from the abrasion, degradation, and physical breakdown of macroplastics from different sectors of activity, including aquaculture itself given that the aquaculture sector uses different types of plastics in their daily routines. The resistance, durability, ease of moulding and lightness of plastic material are some of the characteristics that explain the strong and widespread implementation of this material in the sector, especially in marine aquaculture where the environment is more corrosive (e.g. sun exposure, salinity, hydrodynamics).
Identifying the contribution from the large variety of human activities to microplastic litter is extremely difficult, but estimates indicate that 74% of the 12.2 million tonnes of plastic ending in the marine environment annually have land-based origin (Eunomia, 2016). Scarce information exists regarding the contribution of the aquaculture sector to microplastic litter but estimates from a Norwegian study considers that microplastics generated from abrasion in an aquaculture unit to be in the range of few kilograms (Sundt et al., 2014, in Huntington, 2019). However, since the aquaculture sector is pressured to increase production, it is expected that the contribution will increase, thus monitoring and good practices to minimize plastic litter must be implemented.

The smaller size of these particles raises questions in regard to food safety, since these tiny particles (or even lower, nanoparticles <1 µm) can be ingested by different aquatic organisms in the foodweb, and if accumulated in tissues, present hazards for consumers.

When ingested MP accumulation in tissues have been described to affect cellular structures and interfere with biological pathways. Some authors indicate that MP induce physical disruption of an inert particle, and others highlight the adsorption potential of these small particles of aquatic pollutants.

Shellfish are filter-feeders therefore are more exposed to MP. Shellfish's whole-body soft tissue is totally ingested compared to fish, where muscle is the portion consumed, posing higher concerns for consumer's food safety.

Not only microplastics but also microfibers are relevant ubiquitous environmental pollutants (Mendoza et al., 2020; Basurko et al., 2022; Rosas et al., 2022; Bilbao-Kareaga et al., 2023) and have been found in edible species, including European hake (Cabanilles, 2022), eel (Menendez et al., 2022) and mussels (Reguera, 2019; Masia et al., 2022) whose physiological, particularly large-term, effects are still under investigation. Some authors, consider the southeast Bay of Biscay, particularly the French waters, a hot spot for plastic accumulations (see Basurko et al., 2022, who measured 28% microplastic, 26% mesoplastics and 46% macroplastics) that may originate in the southwest Iberia and extend (Rosas et al., 2022). In addition, Mendoza et al. (2020) identified maritime ports and areas related to fishing activities as sources of macroplastics and probably microplastics as well (Masia et al., 2011). As is the case for other contaminants, there is a strong spatial and temporal variability of the microplastic distribution in the Bay of Biscay. Some studies indicate that European shellfish consumers are expected to ingest up to 11 000 plastic particles per year (Barcelo and Knepper, 2019).

In Portugal, two studies assessed the incidence of MP (e.g. shape, size, colour) in different shellfish species, reared in different structures and from different areas of the country (Botelho et al., 2023, Ribeiro et al., 2023). One study carried out for one year in the Aveiro lagoon, mussels (*Mytilus galloprovincialis*) and cockles (*Cerastoderma edule*), respectively from rocky substratum and sandy sediments, were periodically collected. In mussels the concentrations varied between 0.77-4.3 MP g⁻¹, whereas for cockles varied between 0.81-5.1 MP g⁻¹ (Botelho et al., 2023). For both species lower values were observed in January, which according to authors is related to bivalves' lower filtering rate due to lower winter temperatures. The types of plastics and colours were a mixture that differed throughout the year.

The other study evaluated the concentration of MP in different species (*M. gigas*, *Ruditapes decussata*, *Mytilus galloprovincialis*) cultured under different systems along the Portuguese coast, both in spring and autumn (Ribeiro *et al.*, 2023). Oysters reared in tables at Ria de Aveiro Lagoon, Sado estuary and floating structures in earth pond (in IMTA - Integrated Multitrophic aquaculture - regime) exhibited values below 0.4 MP.g⁻¹ and below 0.1 MP.g⁻¹, respectively in spring and autumn. Clams reared in culture parks in Ria Formosa lagoon exhibited an increase in the number of MP between spring and autumn, from 0.2 MP.g⁻¹ in spring to -1 MP.g⁻¹ to 0.64 MP.
concentrations in mussels reared in longlines off the coast were 0.8 and 0.5 MP.g⁻¹, respectively in spring and autumn. Overall, concentrations were lower or equal to 1 MP. g⁻¹ soft tissue.

In addition to microplastics, microfiber pollution is also ubiquitous and found in shorelines all over the world Browne et al., (2011) whose work suggested that a significant source of microfibers comes from sewage waters as a consequence of cloth washing. Interestingly, Masia et al., (2019) found microfibers to be more abundant than microplastics in sand samples from the Bay of Biscay. The physiological effects of micro- and nano-plastics and fibres themselves are still under investigation, but it has been shown that microplastics can be carriers of micro-organisms including antibiotic-resistant pathogenic bacteria (Pham et al., 2021; Yang et al., 2023) and therefore constitute a serious hazard for farmed and wild organisms.

Regarding the presence of emerging chemical contaminants, the European Water Framework Directive (WFD; EC, 2000) establishes a list of chemicals that must be monitored and kept under certain established Environmental Quality Standards (EQS) to maintain a satisfactory surface water status. In addition, some substances have been listed as deserving further monitoring and regulation (EC, 2015, 2018). The "Watch List" includes hormones, antibiotics, anti-inflammatory drugs, pesticides, antioxidants and UV-filters. Their presence has been recorded in the waters of the Bay of Biscay (Mijangos et al., 2018; Solaun et al., 2021). The values detected by Mijangos et al. (2018) for the period February 2016 to February 2017 in wastewater treatment plants (WWTP) into estuaries of the Basque Country, were similar to those detected in Europe wide surveys of WWTPs and they displayed local, depth-related and seasonal variations. The latter could be related to seasonal mobility patterns of the population in the corresponding areas, for instance, in towns that significantly increase their population for the holiday seasons (i.e. Górliz-Plentzia, Spain). Harbour activities were also identified as a noteworthy source of contaminants. A more recent study limited to the presence of contaminants listed in the European watch list has been published by Solaun et al. (2021) who sampled three wastewater locations in the Basque country (Galindo, Gernika and Oiartzun) and 5 points associated with receiving waters. As in the study by Mijangos et al. (2018), the concentration in the wastewaters was higher than in the receiving waters and there were temporal variations. Six of the 19 compounds analysed exceeded their predicted no-effect concentrations in receiving waters.

#### 6.2.6.2 Effect of climate change on environmental pollutants

In addition to influencing the water temperature and salinity (Borja et al., 2019), climate change also affects the type and amounts of pollutants in the waters. Although increased water temperatures exerts a stress on wild and farmed aquatic species and the presence of faecal contaminants in the water jeopardize the safety of aquaculture products, we have not been able to find data on how the changing environmental conditions might have impacted the aquaculture production in 2023 and previous years; we believe the temperature-increase will influence the frequency and type of pathogenic micro-organisms that will challenge the farming industry. Borja et al. (2019) considered global warming and its unpredictable effects on the total ecosystem one of the factors that may compromise the status of the Bay of Biscay.

## 6.3 Ecosystem services

In the last 20 years, the Ecosystem Services (ES) concept has gained important visibility in environmental research and policymaking. ES has been defined as the "benefits that people obtain from ecosystems" (MEA, 2005) and the "direct and indirect contribution of ecosystems to human well-being" (TEEB, 2010), supporting all domains of human society, from individual survival to the development of the global economy.
In the EU context, aquaculture is one of the five maritime economic activities prioritized in the Blue Growth Strategy (European Commission, 2017) and linking marine/coastal ES with the different blue economy sectors is key to accomplish a sustainable blue growth (Lillebø et al., 2017). Furthermore, United Nations Sustainable Development Goals (SDG) for 2030 acknowledges that sustainable aquaculture can contribute to support the sustainable use and conservation of oceans, seas and marine resources (SDG 14 – life below water) and offer ample opportunities to reduce hunger and foster well-being (SDG 2 – zero hunger; SDG 3 – good health and well-being).

As any other human activity, aquaculture evolves within complex environmental, social, economic and cultural contexts, with each one of them having particular effects worth describing explicitly and systematically. Aquaculture is an interconnected part of the ecosystem in which it occurs and can provide ES far beyond the provision of food and recognizing the positive effects of certain modes of aquaculture is paramount (Custodio et al., 2021). Given aquaculture's rapid expansion and intensification worldwide, reframing aquaculture trade-offs analysis through the lens of an ES framework can provide a novel and comprehensive analytical matrix of interactions with its multidimensional context, stimulate science-based Ecosystem Based Management and promote sustainable solutions (Custodio et al., 2022).

<table><caption>Table 6.2. Examples of aquaculture Ecosystem Services.</caption><thead><tr><td>Type of ecosystem services</td><td>Examples of services</td></tr></thead><tbody><tr><td>Provisioning services</td><td>Direct food provision (e.g. aquatic plants and animals)<br/>Indirect food provision (e.g. boosts fisheries by providing habitat and organic enrichment for wild species)<br/>Other non-food products (e.g. agar, carrageenan, bivalve shells, ornamental fish)<br/>Medicinal resources (e.g. extracts from algae and marine invertebrates)</td></tr><tr><td>Regulation and maintenance services</td><td>Bioremediation and water filtration (e.g. filter-feeders, bottom feeders and algae)<br/>Wave attenuation/coastal protection (e.g. offshore mussel farms, oyster reefs)<br/>Carbon sequestration and storage (e.g. bivalves and algae)<br/>Buffer for ocean acidification (e.g. algae)<br/>Sediments stabilization (e.g. constructed wetlands)<br/>Habitat provision (e.g. pseudo-reserves around farms)</td></tr><tr><td>Cultural services</td><td>Spiritual and physical connection with marine/aquatic environments (e.g. coastal communities, natural reserves)<br/>Cultural symbols (e.g. Koi carp aquaculture)<br/>Sense of place (e.g. employment opportunities, gender equity)<br/>Livelihood (e.g. alternative activity for fishing communities)<br/>Tourism and recreation (e.g. ecotourism, food tourism, sport fishing)<br/>Education (e.g. education-oriented activities)<br/>Research (e.g. pilot-scale experiments)</td></tr></tbody></table>
A recent global review conducted by Custodio *et al.* (2021) found that, in general, it seems that certain types of aquaculture negatively impact overall ES delivery (e.g. intensive mangrove shrimp farming in Asia), yet certain modes of production (e.g. integrated multi-trophic aquaculture) and cultured species (e.g. algae and certain bivalves) can have a positive impact on ES, not only improving provisioning services but also regulation and maintenance services and, potentially, cultural services. Some types of aquaculture are potentially more impactful on the supply of ES than others due to their high energy needs and ecological risk. Both fish- and shrimp farming are usually on top of the list, as they are typically fed with artificial feeds, which promote externalities (e.g. sourcing fishmeal from fisheries) and nutrient pollution and pose greater a threat to local biodiversity due to, for example, escapees, disease and chemical inputs.

Regarding production systems design, Integrated Multi-Trophic Aquaculture (IMTA) has been endorsed by scientists as a more sustainable mode of aquaculture than intensive monocultures, as that practice is capable of enhancing multiple ES. In IMTA, nutrients wasted on artificially fed cultures (e.g. fish, shrimp), in both particulate and dissolved forms, are redirected to downstream trophic levels to nourish extractive species. Bottom feeders (e.g. sea cucumber, polychaeta) and filter-feeders (e.g. bivalves) feed on the wasted particulate fraction and other extractive species, such as seaweeds and macrophytes, utilize the dissolved nutrients for growth. Such system mimics natural trophic interactions, benefiting from ES supported by certain aquatic species to create a more sustainable and productive environment. Walton *et al.* (2015) assessed the potential ES delivered by sustainable aquaculture systems in wetlands from Doñana National Park, Spain, and concluded that properly designed dual-purpose farms could provide a suitable environment for ecological synergies. Moreover, a review on the status of semi-intensive and extensive aquaculture in Southern European countries suggested that developing IMTA in degraded wetlands would potentially benefit stakeholders and improve ES in those areas (Anras *et al.*, 2010).
# 7 Social and Economic Context

*Lead by Francis O'Beirn, Jorge Ramos, José Perez, Sebastian Villasante*

In 2020, the EU aquaculture sector received 1.2 million tonnes in sales volume and €3.9 billion in turnover. The importance of this ecoregion in terms of European aquaculture production is highlighted in STECF (2023) wherein the majority of the value of aquaculture production is identified as occurring in Spain (24%) and France (21%). In economic value, France had the highest turnover at 22%, followed by Spain at 15%. While some of these statistics might be derived from outside the Ecoregion, i.e. the northern coast of France and the Mediterranean coast of Spain, the ecoregion still likely accounts for a large proportion of these values. It is important to note that the majority of aquaculture output from this region is derived from marine-based ventures concentrated in inshore intertidal and shallow subtidal areas. Furthermore, the importance of the shellfish sector is considered high, especially as it primarily consists of small family owned enterprises with a strong historical connection to the specific areas which plays an important role in terms of social acceptance. This chapter discusses the structure of the aquaculture sector within various sectors and subregions (countries) and considers its importance in terms of employment, among other aspects.

## 7.1 Portugal

In 2021, total production from aquaculture in mainland Portugal represented just 1.6% of the total production in Europe. In that year, around 17 900 tonnes of live weight were produced. Aquaculture sales generated a revenue of 162.8 million euros (INE, 2022). The main taxa produced essentially belonged to bivalves and fish. Shellfish is the primary component of Portuguese aquaculture production, representing 57% of the total produced and 63% in terms of value (MRAG, 2021). Clams, mussels and oysters represent around 97.8% of the molluscs produced. When considering fish, there are essentially four main species: turbot, sea bream, and sea bass.

### 7.1.1 Economic context

**National importance of the aquaculture industry**

Most of the aquaculture sector in Portugal involves small producers, the vast majority related to the production of bivalves in viveiros (i.e. plots of sandy-muddy land located in tidal marshes). In these bivalve plots, producers pay an eventually renewable 10-year leasing fee to the state (i.e. a public domain occupancy fee). There are also small fish production companies on an extensive or semi-intensive basis, producing mainly sea bream and sea bass. These companies are essentially located in the Central region of the country, and south in the Sado River estuary and the Algarve region. Regarding the production of fish at sea - namely sea bass and sea bream -, there are several constraints that have not allowed large production (e.g. high hydrodynamic seawaters).

From 2009 until 2016 in the central area of the Portuguese mainland coast there was also production of turbot by a large company. Later, after 2017 the infrastructures have been considered a national interest project (PIN). The production is essentially to export to European countries (Spain, France, Italy, Netherlands, and Germany). In 2021 this firm produced 3 200 tons of turbot and obtained 28 million euros in revenue.
In the last 15 years, some other medium-sized companies have also emerged in the aquaculture sector. These companies are essentially involved in the production of fish and mussels in offshore systems.

Until 2011, Portuguese aquaculture production was less than 10 000 tons per year. From 2009 onwards, turbot began to be produced on a larger scale, almost quadrupling its quantity compared to 2008, and with production reaching a maximum of 4 406 tons in 2012. From 2013 onwards, mussel production increased considerably. In 2021 there were two species with production of more than 3 500 tons (clams and turbot) and two other species with production of more than 3 000 tons (bream and mussels).

### The value of the aquaculture industry

Clams and oysters are traditionally the main cultivated bivalves with records dating back to the 1950s. The main production areas are the Ria Formosa, Ria de Alvor, Ria de Aveiro, Sado Estuary and Lagoa de Albufeira. More recently, from 2008 onwards - when offshore production areas were delimited - mussels also began to be produced on a large-scale (Ramos *et al.*, 2015). During 2013 there was a large increase in mussel production (1 547 tons), almost exclusively offshore the Algarve region. Offshore the central area of the Algarve there were years of high production and was certified as sustainable for the mussel species (*Mytilus galloprovincialis*) in 2014. Offshore the westernmost part of the Algarve and Vicentine coast, mussel production continues at a steady state. In 2020, following proposals for new mussel aquaculture projects off the Sagres area, there was opposition from several stakeholders.

In general, there has been a gradual decrease in the number of establishments licensed for aquaculture production accompanied by a gradual increase in the quantity produced. This is a sign of new entrants with capacity to produce at a larger scale and a larger number of exits from small-scale producers (bivalve *viveiros* and extensive production fish farmers).

The estimated value of aquaculture production for the year 2014 was around 50.3 million euros. In 2018 this value almost doubled, reaching close to 100 million euros. Since then, this value has always been above that figure.

## 7.1.2 Employment

### Shellfish related jobs

Employment in aquaculture has been decreasing slightly in recent years. However, the importance of clam and oyster aquaculture is recognized as a generator of economic wealth and employment. Many jobs consist of bivalve plot producers (a.k.a. *viveiristas*) who lease their plot to the State for a period of 10 years. These *viveiros* are essentially located in areas such as the Ria Formosa, the Ria de Alvor and the Ria de Aveiro to produce clams and oysters. There are support infrastructures that help bivalve producers to yield high quality bivalves (purification plants locally known as *depuradoras*), and thus facilitate and open channels for the flow of their products to other markets (Spain and France essentially).

In the Tagus River estuary, Ria Formosa and other intertidal areas there is also informal employment linked to the capture of bivalves (clams and oysters). They are essentially people who collect in the saltmarsh areas that are open access. The harvesting of Japanese clams *Ruditapes philippinarum* in the Tagus estuary is prohibited (Mamede *et al.*, 2022). However, until May 2021 there were some informal shellfish farmers who had no difficulty selling to a few buyers. Japanese clams could yield 4–5 euros/kg for the gatherer under these circumstances. It was reported by authorities that the capture and dispatch of these bivalves without depuration for human consumption is a public health problem, as there is a high risk of contamination by toxins (de Pablo *et al.*, 2022).
## Regional impacts of the aquaculture industry

For jobs related to fish production, there are some semi-intensive or intensive production units in the centre and north of Portugal. These are the units that generate the most specialized jobs, some of them employing people with high academic qualifications. They essentially produce flatfish such as turbot and Senegalese sole. There are other small-scale production units that mainly produce sea bream and sea bass, in areas further along the coast. In the central and northern interior of the country there are family businesses (i.e. SMEs) producing trout. In 2020, the total number of employees in the aquaculture industry was estimated at 1 262 persons and 987 FTE, from which only 154 are women.

## Production units

At the end of 2021, there were 1 252 licensed aquaculture establishments for inland, marine and transitional waters, 20 fewer units than in 2020, a balance generated by the reduction of 14 tanks and nine nurseries, offset by the licensing of three additional floating ones. The number of hatchery units remained the same as in the previous year. In terms of total licensed area, there was an increase of 19.5%, which resulted in an increase in the average size of around 21%, reaching 2.40 hectares per aquaculture establishment (1.98 hectares in 2020) (EP-INE, 2022).

## 7.2 Spain

Spain is one of the most important producers of marine aquaculture species within the EU. Overall, the sector produced 276 600 Tonnes of product in 2020 with an estimated value of €517.4 million (STECF, 2023). The two sectors considered most important on the Atlantic coast of the ecoregion are shellfish sector (mostly raft culture of mussels) and the production of turbot in tanks on land.

### Production

The production in 2020 was mainly related to marine aquaculture (fish and shellfish), which together represent more than 94% of the quantities produced, while only 6% in freshwater aquaculture. Marine aquaculture is mainly represented by shellfish and around 18% of that total production is marine fish. The relevance to shellfish production total production has remained stable around 75-81% between 2017-2020 (STECF, 2023).

Within shellfish aquaculture, the species with the greatest activity in Spanish aquaculture in terms of production is the mussel (*Mytilus galloprovincialis*). Mussel production, which is very stable, is around 225 000 tonnes per year. Although more than 95% of Spanish mussel production is in Galicia, there are four other producing regions (Catalonia, Andalusia, Valencia and the Balearic Islands). This production, however, translates to only 18.4% of overall economic value. The production of mussels is influenced heavily by market prices but also by natural phenomena such as harmful algal blooms, poor growth rate and poor mussel recruitment. The potential impact on climate related factors will greatly influence performance of this sector, for example, the almost exclusive reliance on natural seed settlement in this sector is a major risk to future projections (Avdelas et al., 2021).

The second most relevant species in shellfish aquaculture is the oyster. Mainly two types of oysters are cultivated, the flat oyster (*Ostrea edulis*) and the Japanese oyster (*Magallana gigas*). Although their production is much lower than that of mussels, this species represents an important group of molluscs in economic terms. In addition to the others, clam culture is also a representative group within shellfish production. The most cultivated species are the fine clam (*Ruditapes decussatus*), the slimy clam (*Venerupis pullastra*) and the Japanese clam (*Ruditapes philippinarum*), which can be cultivated in cultivation parks or in natural beds.
The main species in marine fish production were sea bass, sea bream and turbot. While the production of sea bass and sea bream is concentrated in the Mediterranean area, that of turbot is only located in Galicia, since the turbot aquaculture companies in Cantabria and Asturias ceased their activity in previous years. When talking about marine fish, sea bass is the main harvested species in Spain, with 22 765 tonnes in 2020, with a total value of 144.1 million euros. Sea bream is the fourth marine fish cultivated in Spain, 6 458 tonnes in 2020, valued at 12.5 million euros. These two species represented more than 31% of the total aquaculture production value in 2020. Sea bream and sea bass production is concentrated in the Mediterranean coast, but these species are also produced in the Canary Islands and in the Atlantic coast of Andalusia (STECF, 2023).

Another important species is Atlantic bluefin tuna, with a total production in 2020 of 8913 tonnes, valued 133 million euros. This species has experienced a 73% growth in production between 2017 and 2020. Moreover, this is one of the species with the highest price per unit, representing 3% of the total volume of the total production of the industry, but accounting for 23% of the total value of production. Turbot, with 6 963 tonnes, is the third most important species for marine aquaculture in Spain. The impact of COVID-19 has had a negative effect on the production of this species, which has decreased its production by 15% with respect to 2019, after presenting a sustained trend in its production during the last four years. The rainbow trout is the main freshwater species in Spain. Its production takes place inland around all the regions of the country. Total production achieved 15 806 tonnes in 2020 with a value of 52 million euros (STECF, 2023).

Regarding aquatic plants, production has stagnated between 9–11 tonnes between 2017 and 2020. In Spain, production is evenly distributed between microalgae and macroalgae cultivation. Regarding microalgae cultivation, its production is carried out in companies, spread throughout the Spanish geography, dedicated to its production mainly using fotobioreactors.

## Industry structure and employment

Considering official data from the Spanish Government (MAPA), in 2020, 5 102 aquaculture establishments were in operation in Spain, meaning a reduction of 160 establishments compared to 2019. Currently, within the ecoregion, there are 3 979 aquaculture establishments listed as in operation (Aquaculture Viewer- Spain). In 2020, the total number of employees in the aquaculture industry was estimated at 12 500, of which approx. 9 800 (3 941 FTE) were located in the ecoregion. In 2017, the proportion of females in the workforce was 26 % with the majority (75%) over the age of 40 years. Furthermore, there was 3 030 were skilled workers, 1 846 unskilled workers, 639 technicians with higher or medium degrees, 263 administrative staff and 118 people with other professional categories. As for the distribution of work by gender, in 2020 the trend whereby men (74%) occupy most jobs and FTE (81%) continues.

## 7.3 France

### Main context of the French aquaculture (including this related area)

Marine aquaculture in France extends across all its maritime territories. While there's a diversity of production systems associated with shellfish farming and fish farming, the production relies on a limited number of cultivated species: oysters and mussels for shellfish farming, and sea bass, sea bream, turbot, meagre, salmon, sole, and sturgeon for fish farming. Nationally, shellfish farming represents 91% of the turnover and 95% of employment (full-time equivalent). In 2021, there were a total of 2 328 companies specialized in shellfish farming (2 294) and 34 in fish farming (Agreste Survey, 2023). That same year, the total production of French marine aquaculture animals amounted to nearly 157 000 tons, with around 5 600 related to fish farming and the rest composed of approximately 81 000 tons of oysters, 66 000 tons of mussels, and 2 200 tons of other shellfish (Agreste, 2020 and 2021). In terms of value added, shellfish farming is characterized by
higher value-added rates compared to fish farming. In 2020, the value added created by shellfish farming amounted to 390 million euros compared to 18.7 million euros for marine fish farming.

The shellfish farming sector in France is mainly composed of small businesses. 80% of the companies employ fewer than five full-time equivalent employees (FTE). In contrast, fish farming companies mostly involve larger enterprises with more than 20 FTE.

The overall dynamics of the sector show a downward production trend with a total loss of 20% in tonnage between 2008 and 2021. Shellfish-farming businesses have been impacted in recent years by episodes of increased mortality resulting in losses of marketable biomass in farming. The production levels of oysters and mussels have not been able to reach those recorded in the early 2000s, which were around 180 000 tons annually. Regarding fish farming, the stagnation of production around 5 000 tons per year (which is even a lower production level compared with the 6 000 tons produced in the mid-90s) (Dosdat et al., 1997), across all species, shows the sector's difficulties in growing within a context of competition and international market opening, conflicts over the use of maritime species, and limited social acceptability, which greatly restricts access to new production areas. With a total production of about 375 tons per year, seaweed farming remains a marginal branch of the sector in France but represents one of the main producers in Europe.

## 7.4 Global picture of aquaculture in the Bay of Biscay

The aquaculture landscape in the Bay of Biscay and the Iberian Coast ecoregion is a microcosm of the national industry, sharing common drivers and challenges with other ecoregions. Oyster farming remains a dominant activity. Innovation and technological advancements, particularly in fish farming, are leading to diversification, integrated multi-trophic aquaculture (IMTA), and exploration of new farming spaces. However, the sector is largely dominated by shellfish and mainly oyster farming. The small number of fish farms in the area means that detailed descriptive statistics are not possible due to confidentiality constraints.

The French shellfish activity is geographically segmented into "shellfish-farming regions", which are administrative subdivisions for the governance of the sector. The Bay of Biscay area is hosting four of them, corresponding to Southern Brittany, Pays de la Loire, Poitou Charente and Aquitaine. Although practices and métiers are homogeneous throughout the regions, they do have their own specific characteristics. The species cultivated are more varied in Southern Brittany, where in addition to pacific oysters (*Magallana gigas*) and mussels (*Mytilus edulis*), flat oysters, cockles and clams are also produced. This region is also diversified in terms of cultivation types, with oysters grown on the foreshore in bags put on fixed rafts, on the ground and also in deep water. Mussel production is dominated by bouchots. In the Loire Atlantique region, mussels are cultivated either on lines or in bouchots. Oysters are mainly produced in bags on rafts, as is also the case in Poitou Charente and Aquitaine regions.

Oyster farming is by far the dominant activity across the whole of the Bay of Biscay and is almost exclusive to Aquitaine. In Pays de la Loire, mussel farming is proportionally more important than in other regions. There are also more mixed enterprises producing both oysters and mussels in this region. In general, the métiers are rather segmented, as cultivation practices are specific to each species.

The production business is often combined with trading activities, which allows access to the final consumer market via sanitary certification for the sale of live animals' safety. For small and medium-sized companies, this allows them to sell directly to markets, thereby increasing their profit margins particularly in the event of economic difficulties (as in the case of mass mortality episodes). Large oyster companies and mussel growers mainly sell their products via large
distribution platforms or directly to supermarkets. Brittany is the region with the largest propor-
tion of pure producers who sell to other producers.

Marennes-Oléron, in the Poitou Charente region, is the largest oyster basin in France. It is re-
nowned for its spat collection, which, along with the Arcachon basin in Aquitaine, is used to
supply natural spat to a large number of local companies. Since the advent of hatcheries, the
supply of spat has been split half and half between natural and hatchery spat, mainly triploid.
In addition, this production basin is also important for the production of oysters matured in
marshes, which provides a significant adding value to the oyster production.

The sector is characterized by small family run shellfish businesses, highlighting the industry's socio-economic fabric. Environmental considerations are paramount, with a wide range of issues to address. Development expectations from both administrative bodies and professionals are high, often colliding with the hurdles of social acceptability and space scarcity. Offshore aquaculture emerges as a potential frontier, possibly synergizing with wind farms, embodying new opportunities and complexities.

Sector employment figures in the Bay of Biscay

The structure of the aquaculture sector in the Bay of Biscay follows the same pattern as at the national level, with a predominant weight of shellfish farming, primarily oyster farming. This ecoregion contains one of the largest oyster production and commercialization basins in Europe. The entire Bay of Biscay coastline hosted 1 355 shellfish-farming businesses in 2021, nearly half of which are located in the Marennes Oléron basin. They employ 12 216 workers, 60% of whom are temporary in 2021. This work is equivalent to a total of 5 081 FTE.

Sales of adult animals for consumption account for the bulk of the trade, with around 58 500 tons of oysters sold for a value of 303 million euros, 23 500 tons of mussels for a value of 53.5 million euros, and 1 500 tons of other shellfish for a value of 7.8 million euros, (Agreste). Nearly 25 000 tons of adult oysters produced by Bay of Biscay companies are sold to other professionals. This represents around 5 000 tons of mussels and 1 000 tons of other shellfish.
# 8 Interaction of environmental, economic and social drivers

Lead by Jose Perez and Sebastian Villasante

## 8.1 Interaction of environmental drivers

Aquaculture is intimately tied to environmental conditions and exhibits sensitivities to climate hazards. This relationship works both ways. Production systems are likely to have both positive and negative effects on ecosystems, and at the same time, products resulting from aquaculture depend on environmental quality.

Shellfish farmers grapple with deteriorating operating conditions linked to environmental issues which have consequences for cultured animals in terms of growth, mortality and recruitment. These environmental factors result from multiple factors including climate change leading to droughts, the increase of water temperature or water acidification, abrupt changes in salinity, microbiologic or chemical pollution and contamination from harmful algal blooms. Changes to local biodiversity equilibria can also cause new predation threats that lead to economic losses. All these disruptions are likely to bring about changes in production cycles, which are conditioned by seasonality processes and can modify economic risks. For instance, in oyster farming, income is highly concentrated during specific times of the year, such as Christmas and summer period since ecoregion has important touristic destinations.

Viral contamination of cultivated shellfish can also affect businesses, particularly in the case of heavy rainfall events likely to overflow sewage networks and treatment plants. The detection of noroviruses in shellfish, responsible for gastroenteritis, led to commercial bans in production basins along the Atlantic coast (Arcachon, Vendée, Loire Atlantique) at the end of 2023. This concern has also emerged in Galicia in recent decades (Polo et al., 2015; Romalde et al., 2018). These watershed contaminant processes also involve bacterial pathogens. Similar situations occurred in Portugal, although official reports are still not available.

Parasites are also responsible for production losses with significant socio-economic impacts. Besides leading to heavy mortalities *Perkinsus olensis*, can also affect the natural reproductive capacity of clams cultivated offshore, affecting recruitment.

Environmental impacts triggered by aquaculture production are significant, with waste management of metals, organics, and plastics being a concern, alongside the abandonment of oyster beds that can lead to ecological and economic repercussions. For example, a survey conducted in Charentes Maritimes, as part of the CODEMAR project, recently analysed the plastic pollution from marine aquaculture. The results indicated that three quarters of new entrants to the industry lose material at sea. Although the individual loss rate is low, the cumulative volume of plastic waste generated by the sector is substantial.

Unused or abandoned oyster beds may give rise to desolate habitats incurring considerable expenses for restoration. Beyond the financial implications for the shellfish sector, the challenge encompasses the need to monitor biomass levels concerning the trophic support capacity of shellfish ponds. The shellfish sector must also consider biomass monitoring relative to the carrying capacity of ponds. Contrasting regional approaches in places like Charente-Maritime, which suggests reducing stocking density, stand in sharp contrast to national plans aiming to increase production. At the same time there is growing pressure to consider ways to reduce carbon footprint in the production process.
Ensuring water quality remains critical, especially as the majority of shellfish areas are classified under category B (based on the Regulation (EU) No 2015/2285, this requires mandatory purification before the expedition for final markets), facing issues like harmful algal blooms and chemical pollutants from agriculture. This is also the case for the Spanish and Portuguese sector, mainly shellfish aquaculture which needs to be purified when shellfish comes from areas classified as B (the case for all Galician waters) and harmful algal blooms which impose the closure of harvesting for shellfish sector.

These issues reflect the delicate balance the aquaculture sector must maintain with the environment, highlighting the need for sustainable practices and careful management of resources to mitigate impacts and safeguard the industry's future.

## 8.2 Interaction of economic drivers

In the interplay of economic drivers within the aquaculture sector, the industry stands at the crossroads of societal expectations and economic ambitions. As it navigates the Blue Economy framework, its objective is to maintain high standards of economic and environmental performance. The sector seeks to balance growth with environmental stewardship and social responsibility, aiming to enhance the attractiveness of the profession. By increasing the added value of aquaculture products, it strives to remain competitive against imports from low-cost countries while ensuring the social acceptability of its products. For example, in France, the industry aims to rectify the structural deficit in the mussel market and return oyster production to pre-mortality crisis levels. Mussel culture in Galicia (NW Spain) has evolved over the last 40 years and among other adaptations producers has increased the proportion of small mussels to meet market demand affecting mussels culture cycles and profitability of the mussel industry (Labarta and Fernán-dez-Reiriz, 2019). Portugal aims to increase aquaculture production to 25 tonnes/year until 2030, based on offshore production and RAS production, as a result of the investments on R&D projects, technological innovations, and highly qualified human resources

## 8.3 Interaction of social drivers

The aquaculture sector navigates complex social dynamics. Public perception often challenges new projects, with the industry facing hurdles in gaining social acceptability. Conflicts over the use of marine and freshwater spaces and the difficulty in obtaining necessary production licenses, especially for fish farming, are prevalent issues. This necessitates strategic communication and awareness efforts to foster public understanding and support. Effective planning is crucial, including careful site selection and management of resource use conflicts, to align with social drivers and ensure the sustainable growth of aquaculture. In Spain, the level of social acceptance of aquaculture has been analysed from the point of view of carrying capacity (Ruiz-Chico et al., 2020) as a tool to achieve societal sustainability. The authors conducted surveys in six coastal provinces in Spain and respondents gave higher priority to socio-economic objectives than to environmental ones.

Strategies for aquaculture in the area are poised to tackle several key challenges. The simplification of administrative procedures is critical to facilitate smoother operations and encourage growth. Marine spatial planning is another priority, ensuring the sustainable use of maritime spaces, alongside social acceptability. Ensuring animal health and welfare is also high in the priority list, as is improving environmental performance, particularly in the face of climate change. Driving innovation, improving data collection, and fostering transparent communication are also strategic priorities to propel the industry forward sustainably.
Concerning social drivers and bottlenecks of aquaculture development, several works in the literature address the social dimensions of aquaculture particularly focusing on the conflicts with other different users in the ecoregion (Gesche et al., 2015, Pérez Agúndez et al., 2022). The nature of these conflicts is diverse. We can distinguish between conflicts associated with claims from third-party users against aquaculture. These conflicts generally involve: (1) competition for shared spaces with other activities; this is the case for interactions with fisheries, both professional and recreational, and with various recreational nautical and touristic activities, (2) opposition from environmental NGOs or local residents for various reasons, such as ecosystem and landscape preservation. A second type of conflictual interaction concerns aquaculture claims against other users. The origins of these disputes lie in the use of common resources, or concerns about water quality degradation.

The Bay of Biscay has witnessed several conflicts associated with these types listed. Examples include conflicts between shellfish farming and agriculture arising from the competition for freshwater resources in the Marennes-Oléron basin, particularly during summer period. Additionally, complaints from oyster farmers in the Arcachon basin have arisen due to deteriorating water quality, leading to sanitary closures or disruption of production cycles (Rivaud and Cazals, 2013). Numerous other conflicts have been documented along the French Atlantic coast in previous decades (Borel, 1997) involving fishers, recreational and tourist activities, environmental NGOs or local residents. However, this type of conflict can also be found in more recent times (Mille, D., and Blachier, P., 2009; Moulin, 2022). While the historic usage rights held by shellfish farmers are a guarantee of the sector's legitimacy among other users, tensions tend to escalate when expanding the areas accessible to shellfish companies or introducing new activities such as offshore aquaculture or fish cage culture systems.

Although no conflicts have been reported for Portugal until now, potential risk exists due to the larger number of users of maritime common space. It is expected that the plan developed for the National Maritime Spatial Planning Situation (PSOEM, 2019), contributes to minimize potential conflicts.

Even if aquaculture production systems based on low trophic levels could represent a better social perception due to lower environmental impact, issues of social acceptability are linked to various factors that are also economic and social in nature, including the questioning, by some citizens, of participatory democracy as deployed in the field (Kermagoret and Frangoudes, 2021).
# 9 Future projections and emerging threats and opportunities

Lead by Fabrice Pernet; contribution by Iciar Martinez and Harkaitz Eguiraun

## 9.1 Emerging threats

Climate change and other constraints will undoubtedly challenge future growth of marine aquaculture (Froehlich et al., 2018). The Bay of Biscay is no exception to this reality. Ocean warming, acidification and deoxygenation, shifts in precipitation regime, changing ocean productivity and circulation patterns and increasing occurrence of extreme climatic events are some of the stressors that will influence the potential of marine aquaculture production worldwide (FAO, 2018; IPCC, 2019; IPCC, 2023). The Bay of Biscay is no exception to this reality (Costoya et al., 2015; Borja et al., 2019; Chust et al., 2022). Here are some general impacts that are direct or indirect consequences of climate changes.

### Ocean warming and marine heatwaves

Climate change leads to an increase in sea surface temperatures and enhance the probabilities of marine heatwave, i.e. a prolonged period of unusually warm water temperatures in the ocean (Hobday et al., 2016). Sea surface temperatures in the Bay of Biscay have been warming at a rate of 0.26 ± 0.03°C per decade from 1982 to 2014, with the most pronounced warming during April-June and September-November (Costoya et al., 2015). Additionally, the warm season has lengthened by roughly one month over the past three decades, accompanied by a rise in the occurrence of extreme hot sea surface temperature (Costoya et al., 2015). This long-term trend will affect the distribution and behavior of marine species, including those targeted by aquaculture. Species indeed follow their thermal niche, and their performance (growth, survival, reproduction) depends on temperature. Seawater warming is already occurring and shifts in reproductive phenology or population distribution range have already been reported. One of the most striking examples is the case of the Pacific oyster *Crassostrea gigas*. Initially introduced to the southern coast of France in the 1970s, it has since expanded its range northward, reaching the southern coast of Norway thanks to global warming (Thomas et al., 2015). Beyond changes in the biogeographic distribution of aquaculture species, marine heatwave can also induce unusual stress, abnormal mortality and reduced growth rate.

### Ocean Acidification

As the oceans absorb more carbon dioxide from the atmosphere, they become more acidic. This can have detrimental effects on shell-forming organisms, such as molluscs and certain types of plankton, which are important components of the marine foodweb (Kroeker et al., 2013; Wittmann and Pörtner, 2013; Leung et al., 2022). This can disrupt the growth and development of shell-forming organisms like oysters and mussels, impacting their production in aquaculture systems (Gazeau et al., 2013).

Overall, ocean acidification is monitored worldwide since the late 1980s using a combination of ship-based measurements, buoy networks, coastal monitoring stations, and international collaborations to track changes in seawater chemistry and better understand the global implications of this phenomenon. The rate of acidification varies between regions and within each region. Overall, time-series show covering periods of more than 15 years show a decrease of around 0.017–0.027 pH units per decade (Kwiatkowski et al., 2020). There is currently no reliable estimate of
acidification trends for the Bay of Biscay. However, according to IPCC, future pH in the Bay of Biscay is expected to decrease of -0,0023 to -0,0035 yr⁻¹ under RCP 4.5 and RCP 8.5 respectively (McGovern *et al.*, 2022). Considering these trends, 60% of the bottom waters of shelf area of the Greater North Sea, Celtic Seas, Bay of Biscay and Iberian Coast (OSPAR Regions II, III and IV) will become undersaturated with respect to aragonite by 2100 under RCP 8.5, which may threaten shellfish aquaculture in these areas (McGovern *et al.*, 2022).

As part of the CocoriCO₂ research project supported by EMFF between 2020 to 2023, France established a comprehensive pH monitoring network across mollusc farming regions including 5 sites within the Bay of Biscay. This monitoring network revealed extreme and sporadic episodes of acidification within shellfish farms (Petton *et al.*, 2023). These occurrences already pose threats to shellfish populations, with potential exacerbation in future.

## Deoxygenation

Deoxygenation is on the rise across coastal and open oceanic regions, predominantly driven by ocean warming and nutrient run-off from land (Diaz and Rosenberg, 2008; Breitburg *et al.*, 2018). Projections indicate that this trend will persist, with the ocean experiencing ongoing oxygen depletion as global warming progresses. The ramifications of oxygen loss within marine environments are far-reaching, encompassing diminished biodiversity, alterations in species distributions, potential displacement or depletion of fisheries resources, shifts in biogeochemical cycling, and the likelihood of mass mortalities. Despite these potential effects on ecosystems supporting fisheries, the consequences of climate changes on dissolved oxygen in the coastal ocean are still poorly documented.

Model simulation suggested that several areas of the Northwest European continental shelves, including the Bay of Biscay, would be vulnerable to deoxygenation (Ciavatta *et al.*, 2016). A high frequency monitoring of the Vilaine Bay along the Atlantic coast of France revealed recurrent deoxygenations and even hypoxia in bottom waters (Ratmaya *et al.*, 2022) as also observed in the Gironde estuary (France) (Dubosq *et al.*, 2022). Deoxygenation is an emerging issue in this ecosystem of a great economic interest. A better understanding of dissolved oxygen dynamics though long-term and continuous *in situ* monitoring is required.

## Sea Level Rise

According to IPCC, global mean sea level increased by 0.20 m between 1901 and 2018. Global sea levels could further rise by about 0.63 to 1.01 meters by the end of the 21st century compared to 1995–2014 levels under SSP5/RCP8.5 with high regional variability (IPCC, 2023). (Chust *et al.*, 2010)

The impact of sea level rise on aquaculture is significant, with inundation of coastal facilities, damage to infrastructure such as ponds, cages, and hatcheries, disruption of production, and financial losses being among the most notable consequences. Rising sea levels can lead to the intrusion of saltwater into coastal aquifers, contaminating freshwater sources used in aquaculture operations. Elevated salinity levels can negatively affect the health and growth of aquatic species, particularly those adapted to lower salinity levels. As a consequence of the retreat of coastlines due to sea level rise, aquaculture farms may lose valuable land for expansion or relocation. This loss of space can limit the industry's ability to adapt to changing environmental conditions and meet growing demand for seafood. Higher sea levels can exacerbate coastal erosion, undermining aquaculture infrastructure and causing shoreline instability. This can necessitate the implementation of costly measures such as shoreline protection or relocation of facilities to more stable areas. Finally, changes in coastal habitats and water quality resulting from sea level rise can alter the distribution and abundance of aquaculture species. Some species may thrive in new conditions, while others may struggle to adapt, leading to shifts in farming practices and product availability. Overall, sea level rise poses significant challenges to the sustainability and
viability of coastal aquaculture operations, necessitating proactive adaptation strategies and careful management to mitigate its impacts.

## Change in precipitation level

Climate change is resulting in alterations to precipitation patterns, leading to longer and more frequent episodes of drought in Western Europe (Dai, 2011). The drought that occurred in France during summer of 2022 (which continues to the present in the south of the country) is a clear manifestation of ongoing climate change (Faranda et al., 2023). Drought has the effect of limiting the supply of nutrient salts (mainly nitrogen and phosphorus) and consequently primary production and the growth of primary consumers like shellfish.

## Disease outbreak

Climate change can promote the growth and spread of pathogens and parasites, increasing the risk of disease outbreaks among aquaculture stocks (Harvell et al., 1999; Burge et al., 2014; Lafferty et al., 2015). This can result in significant economic losses for aquaculture operations. Temperature is the most well-studied climate-related driver of marine disease because it profoundly influences host and pathogen metabolism. Although there are reports of the exacerbating effects of temperature on the risk of disease, it is difficult to attribute a causal link between climate change and the occurrence of disease. However, the general assumption that a warmer world is a sicker world is not always true. Disease outbreaks are influenced by complex interactions of factors involving hosts, pathogens and environmental conditions, some of which may overshadow the effects of climate change itself (Lafferty, 2009).

## Harmful algal blooms

Global climate change (warming, acidification and deoxygenation) can also contribute to the proliferation of harmful algal blooms (HABs) (Gobler, 2020). These blooms can produce toxins that are harmful to aquaculture species, posing health risks to both aquatic organisms and consumers.

## 9.2 Adaptation to climate change

To adapt to climate change, there are three main options available (Pernet and Browman, 2021). First, it's imperative to anticipate the biogeographical shifts in species distribution. Species are naturally distributed across geographic areas where environmental conditions align with their physiological requirements. Any alterations in these conditions due to climate change can potentially disrupt the suitability of certain areas for aquaculture production. As a result, it's anticipated that some production may relocate to environments that remain favourable for longer durations. For instance, the open sea, with its greater resilience and stability in terms of temperature and pH compared to the coastal zone, may become a more viable option for aquaculture. Additionally, there's growing interest in developing land-based recirculating aquaculture systems (RAS) where environmental parameters are tightly controlled. However, transitioning to these alternatives would necessitate significant industry-wide changes, likely appealing to only a minority of producers initially.

The second option is to select animals that are tolerant of climate change. It is therefore necessary to select traits of interest that are heritable, that is to say transmissible between generations, then develop genetic selection plans while maintaining genetic diversity (Reid et al., 2019). The foundations for such plans need further developments.

Finally, the third option is to promote ecosystem conservation, restoration or remediation strategies through nature-based solutions to foster resilience to climate change stressors. Among NBS, vegetation though seaweed aquaculture is a promising area (Duarte et al., 2017; Gattuso et al.,
2018). Through photosynthesis, seaweed decrease acidity, increase calcium carbonate saturation levels and oxygen concentration during the day, which, under future acidified/deoxygenated conditions, may provide a temporary refuge for shellfish. These three options are not mutually exclusive and should be considered together.

## 9.3 Reinforcing monitoring programs

Monitoring programs assist in the assessment of how climate change affects aquaculture systems, including changes in water temperature, acidity, oxygen levels, nutrient and phytoplankton, diseases and other anthropogenic stressors like contaminants. This understanding allows for the implementation of adaptive management practices to mitigate risks and enhance resilience.

Regular monitoring of environmental parameters allows aquaculture operators to detect changes at an early stage, such as shifts in water quality or disease outbreaks. This allows for timely responses to mitigate negative impacts. Monitoring data can inform aquaculture management decisions, such as adjusting stocking densities, feed formulations, or site selection, to optimize production efficiency and minimize environmental impacts.

Monitoring programs can help ensure compliance with environmental regulations and sustainability standards, providing evidence of responsible aquaculture practices and promoting consumer confidence in seafood products.

In conclusion, monitoring programs represent an invaluable instrument for the implementation of adaptive management in aquaculture. They facilitate the anticipation and response to the challenges posed by climate change, while simultaneously promoting the implementation of sustainable production practices.

## 9.4 Other anthropogenic stressors

The monitoring of heavy metals particularly, but not restricted to, Hg and Pb deserve continuing monitoring programs to assess their evolution in the Bay of Biscay, either using analytical biochemical methods (Borja *et al.*, 2019; Besada *et al.*, 2014) or by implementing Early Biological Warning Systems and monitoring the behaviour of selected species (Bae and Park, 2014; Eguiraun and Martinez, 2023 a, b).

Similarly, monitoring of emerging contaminants and their spatial and temporal variations should also be implemented by national and international plans. Solaun *et al.* (2021) recommend performing regular monitoring focusing on the most populated areas and removing from the list of compounds to monitor those whose concentration does not exceed their PNEC values. This recommendation is intended to spare screening expenses and efforts. However, the amount and type of compounds will vary spatial and temporarily and the fact that a given compound has not been detected for some time is not a predictor for its future levels. Therefore, they should not be completely eliminated from the list. Similarly, non-targeted screenings for unexpected compounds should be performed regularly. In addition, the locations to be monitored should not be limited to populated and industrial (harbours, refineries, gas platforms etc.) areas, but also rural areas where pesticides, fertilizers, purines and related compounds may originate.

In the managing of microplastics, the initiation of BlueWWater, a recently granted 3-year European project (https://cetmar.org/bluewwater/) is noteworthy. The project is aiming to reduce the emission of microplastics and pollutants to the marine environment in the waters between Galicia and Northern Portugal. The aim of the project is to improve the quality of Galician and Portuguese river, transition and coastal water masses through the control, monitoring and
evaluation of emissions of microplastics and emerging contaminants to the aquatic environment. Given the relevance of the aquaculture industry in this region, the results of this project will be of high value to evaluate and managing the influence of regular and emerging contaminants in the farmed organisms. In addition to the monitoring of microplastics and microfibers, antibiotic-resistant and pathogenic bacteria often carried by them (Pham et al., 2021; Yang et al., 2023) that therefore constitute a potential and serious health hazard for farmed organisms, should also be monitored.

In addition, the European project Nettag+ (https://nettagplus.eu/) is a three-year project aiming to PREVENT, AVOID and MITIGATE the environmentally harmful impacts of marine litter in European ports, actively contributing to the European Commission Mission "Restore our ocean and waters by 2030".

Finally, Rapid Alert and Contingency Systems following accidents should be strictly followed and, whenever necessary, improved.

## Recommendations

To ensure high quality aquaculture production, that is in agreement with the recommendations proposed by other authors (in particular those of Borja et al., 2019) we propose the following steps to be taken: (1) reducing/eliminating the sources of contaminants by using, whenever possible, alternative safer materials and medicines; (2) improving sewage and discharge water purification systems to eliminate contaminants from industrial, hospital, household and any other type of effluents; (3) the improved sewage systems must be able to cope with periods of unusually heavy rains; (4) efficient non-targeted and targeted (of the most relevant pollutants) monitoring programs; (5) respecting and improving the Rapid Alert Systems that the responsible authorities should follow quickly and strictly to minimize the dangers caused by undesirable spillages, (6) setting up of early biological warning systems to estimate the real effect of the naturally found mixtures of contaminants on selected and relevant model organisms, and (7) establish trustworthy, official channels to keep a close contact with aquaculture facilities to inform them about the status of the relevant waters.

## 9.5 IMTA systems as a strategy to improve environmental sustainability

Many projects tested IMTA pilots both in open and inland waters. Some examples of pilot IMTA:

* In Portugal, semi-intensive aquaculture in earthen ponds is common in coastal lagoons and estuaries, the impact of the effluents is reduced using settlement ponds (Hubert et al., 2006, Carvalho et al., 2009). The evolution from monoculture to Integrated Multi-Trophic Aquaculture (IMTA) has resulted in the removal of excess nutrients and detritus (Cunha et al., 2019, Gamito et al., 2020). In IMTA, extractive species such as macroalgae reduced the concentration of nutrients, while detritivore macroinvertebrates reduced the amount of POM in the sediment and in the effluents, improving the overall health of the ecosystem.

* As part of the Seacase project (2007–2010), 6 independent case studies were presented to demonstrate the feasibility for productivity enhancement in coastal extensive or/and semi-intensive aquaculture in Southern Europe under sound environmental conditions. These included production of juveniles in extensive or semi-extensive conditions, extensive and semi-intensive polyculture in earthen ponds, an intensive-extensive integrated land-based system, extensive production in valliculture, and integrated management of marine extensive ponds and lagoons for a sustainable eel fishery.
* IMTA-Effect (2016-2019) (Integrated Multi Trophic Aquaculture for EFFiciency and Environmental ConservaTion) was funded by EU ERANET COFASP (www.cofasp.eu) with partners from France and Portugal. "It associated nine partners from public research and private companies, in six countries. The project aimed to develop IMTA strategies for fish farmers to develop new production systems being efficient, economically attractive, robust, and environmentally friendly. For this purpose, the project aims to provide scientific references on the nutrient and energy efficiency gains generated by associating different aquatic species of different levels in the foodweb".

* In France, the EPURVAL2 project (2017-2021) (https://www.europe-en-france.gouv.fr/fr/projets/epurval-2-mise-en-place-de-sites-pilotes-pour-lepuration-et-la-valorisation-des-effluents-de) tested different IMTA systems including a system combining land-based finfish farm producing 50 million fingerlings in 2018: sea bass (*Dicentrarchus labrax*), sea bream (*Sparus aurata*) and meager (*Argyrosomus regius*) (Ferme Marine du Douet in Oleron Islands) and 11 t of *Ulva rigida* production in 13 lagoons of 500 m² and 1,8 m depth.

* In France, the European Integrate project extension (2022-2023) testing the association of flatoyster and sea cucumbers (*Holothuria forskali*) with exceptional growth of sea cucumbers.

* In France, the European SIMTAP project (2019-2022) tested the association in successive ponds, with one for the production of gilthead sea bream, followed by two of an association of oysters and shrimps, one with an association of clam and shrimps, and one with ulva.

* In Spain, a project funded by JACUMAR was launched in 2007. The overall objective was "to evaluate the application of integrated multi-trophic farming systems in aquaculture in Spain.". The goals were to improve the environmental management of farms and to promote the economic bolstering of companies by diversifying their production. Six regions with diverse conditions for farming were considered. A report is available for the Galician region (Guerrero and Cremades, 2012) and describe case studies in the BoBIC region including:

* Integrated farming of macroalgae in fish cages in the ria of Muros and Noia (A Coruña): The experiment was conducted in turbot rearing cages (MARCULTURA, S.A., company) located in the ria of Muros and Noia (A Coruña), farmed with the macroalgae *Saccharina latissima*. No significant benefit of the integration of macroalgae due to the high level of nutrients in the Galician rias was observed. The presence of macroalgae near fish could reduce light radiation while increasing sedimentation and recruitment processes that may lead to increase in fouling, which could be a problem. They also conclude that the benefit of these polycultures should be evaluated both in terms of the improvement in quality of the marine environment and the increase and diversification of total aquaculture production.

* Open sea farming of the edible seaweed *S. latissima* associated with floating mussel rafts was tested in the rias of Ares and Betanzos (A Coruña). The analysis of isotopic abundance (15N ratio) in *S. latissima* indicated that the macroalgae assimilate forms of nitrogen excreted by organisms at a greater trophic level, probably mussels (Pérez Camacho, 1992).

Biofiltration of solids from the effluent of a turbot farming plant, in a closed circuit, with filtering molluscs (clam and oyster), suspension feeding invertebrates (anemone) and food macroalgae (*S. latissima* and *Ulva spp.*) in O Grove (*Pontevedra*). This study indicated that the system was able to maintain various commercial species, and high ammonia concentration in fish and mussel tanks decreased as it passed through the algae. They measured the increase in the biomass of molluscs (from 2 to 29 kg in a period of 10 months) and algae (*S. latissima*, and *Ulva spp.*) and
concluded that it would be feasible to optimize an IMTA system on land, combining fish/anem-
one/polychaetes/molluscs/macroalgae, to generate a diversification of production and a substan-
tial improvement in the management of suspended solids and in the quality of effluent dis-
charged into the sea.
10 Reference list

Aas, T.S., Åsgård, T., Ytrestøyl, T. (2022) Utilization of feed resources in the production of Atlantic salmon (Salmo salar) in Norway: an update for 2022. Aquac. Rep. 26, https://doi.org/10.1016/j.agrep.2022.101316.

Agreste 2021, Recensement agricole 2021. https://agreste.agriculture.gouv.fr/agreste-web/download/publi-cation/publie/Chd2105/cd2021-5_Aqua2019.pdf.

Anras L, Boglione C, Cataudella S, Dinis MT, Livi S, Makridis P et al. (2010) The current status of extensive and semi-intensive aquaculture practices in Southern Europe. Aquaculture Europe 35: 12–16.

APROMAR (2014) La acuicultura en España. https://apromar.es/wp-content/uploads/2022/01/Informe-ACUICULTURA-2014.pdf.

APROMAR (2022) Aquaculture in Spain 2022. https://apromar.es/wp-content/uploads/2022/10/Aquacul-ture-in-Spain-2022_APREMAR.pdf.f.

APROMAR (2023) Aquaculture in Spain https://apromar.es/wp-content/uploads/2023/10/Aquacul-ture_in_Spain_2023_APREMAR.pdf.

AQUAREF - Opérations d'échantillonnage en milieu marin dans le cadre des programmes de surveillance DCE (matrices : eau, sédiment et biote) - Recommandations techniques – Edition 2015.

Aquaculture Viewer- Spain - https://servicio.pesca.mapama.es/acuivisor/.

Arechavala-Lopez P., Toledo-Guedes K., Izquierdo-Gomez D., Šegvić-Bubić T. & Sanchez-Jerez P. (2018) Implications of Sea Bream and Sea Bass Escapes for Sustainable Aquaculture Management: A Review of Interactions, Risks and Consequences, Reviews in Fisheries Science & Aquaculture, 26:2, 214-234, https://doi.org/10.1080/23308249.2017.1384789.

Aubin Joel, Callier Myriam, Rey-Valette Helene, Mathe Syndhia, Wilfart Aurelie, Legendre Marc, Slem-brouck Jacques, Caruso Domenico, Chia Eduardo, Masson Gerard, Blancheton Jean-Paul, Ediwarman, Haryadi Joni, Prihadi Tri Heru, Casaca Jorge De Matos, Tamassia Sergio T. J., Tocqueville Aurelien, Fontaine Pascal (2019). Implementing ecological intensification in fish farming: definition and princi-ples from contrasting experiences. Reviews In Aquaculture, 11(1), 149-167. Publisher's official version: https://doi.org/10.1111/raq.12231, Open Access version : https://archimer.ifremer.fr/doc/00484/59570/

Aubin Joël, Caroline Fontaine, Myriam Callier, Emmanuelle Roque d'Orbcastel. Blue mussel (Mytilus edu-lis) bouchot culture in Mont-St Michel Bay: potential mitigation effects on climate change and eutroph-ication. International Journal of Life Cycle Assessment, 2018, 23 (5), pp.1030-1041. 10.1007/s11367-017-1403-y.

Avdelas, L., Avdic-Mravlje, E., Borges Marques, A.C., Cano, S., Capelle, J.J., Carvalho, N., Cozzolino, M., Dennis, J., Ellis, T., Fernández Polanco, J.M., Guillen, J., Lasner, T., Le Bihan, V., Llorente, I., Mol, A., Nicheva, S., Nielsen, R., van Oostenbrugge, H., Villasante, S., Visnic, S., Zhelev, K. and Asche, F. (2021), The decline of mussel aquaculture in the European Union: causes, economic impacts and opportuni-ties. Rev. Aquacult., 13: 91-118. https://doi.org/10.1111/raq.12465.

Bacher C. (1993) Use of an ecosystem model for the assessment of the influence of cultivated oysters (M. gigas) of the nitrogen cycling in the Marennes-Oleron Bay (Ifremer report)

Bacher Cédric, Johanna Balle-Beganton, Julien Neveu, Harold Rethoret, Françoise Vernier, Paul Bordenave, Rémi Mongruel, José Perez (2010) Modeling freshwater uses in coastal areas – the case of Pertuis Cha-rentais (France). International Environmental Modelling and Software Society (iEMSs) 2010 Interna-tional Congress on Environmental Modelling and Software Modelling for Environment's Sake, Fifth Biennial Meeting, Ottawa, Canada.

Bacher, Duarte, Ferreira, Heral and O. Raillard (1998) Assessment and comparison of the Marennes Oleron Bay (France) and Carlingford Lough (Ireland) carrying capacity with ecosystem models. Aquatic Ecol-ogy 31: 379–394, 1998 Production Carrying capacity (model based on physical transport and deposited matter).
Bae, M.-J.; Park, Y.-S. (2014) Biological early warning system based on the responses of aquatic organisms to disturbances: A review. *Sci. Total. Environ.*, 466-467: 635-649. https://doi.org/10.1016/j.sci-totenv.2013.07.075.

Barcelo D., Knepper, T. (2019) Analysis, fate and effects of microplastics in the environment: Preface to article collection. *Trends in Analytical Chemistry* 121, 115671. https://doi.org/10.1016/j.trac.2019.115671.

Basurko, O.C., Ruiz, I., Rubio, A., Beldarrain, B., Kukul, D., Cózar, A., Galli, M., Destang, T., Larreta, J. (2022) The coastal waters of the south-east Bay of Biscay a dead-end for neustonic plastics. *Marine Pollution Bulletin*, 181, art. no. 113881. https://doi.org/10.1016/j.marpolbul.2022.113881.

Besada V, Sericano JL, Schultze F. (2014) An assessment of two decades of trace metals monitoring in wild mussels from the Northwest Atlantic and Cantabrian coastal areas of Spain, 1991-2011. Env. Int., 71: 1-12. doi: 10.1016/j.envint.2014.05.024.

Bhagat, J., Zang, L., Nishimura, N., Shimada, Y., (2022) Application of omics approaches for assessing mi-croplastic and nanoplastic toxicity in fish and seafood species, *Trends in Analytical Chemistry*, 154, 116674, https://doi.org/10.1016/j.trac.2022.116674.

Bilbao J., Muñiz O., Revilla M., Rodríguez J. G., Laza-Martínez A., Seoane S. (2020) Suitability of two areas of the Basque coast to sustain shellfish aquaculture according to both the presence of potentially toxic phytoplankton and the biotoxins regulated by the European Union. *Regional Studies in Marine Science* (36): 101279. https://doi.org/10.1016/j.rsma.2020.101279.

Bilbao-Kareaga, A., Menendez, D., Peón, P., Ardura, A., Garcia-Vazquez, E. (2023) Microplastics in jellifying algae in the Bay of Biscay. *Implications for consumers' health*. Algal Res., 72: 103080. http://dx.doi.org/10.1016/j.algal.2023.103080.

Borel, G. (1997). Les conflits d'usage liés aux mutations de l'aquaculture marine sur le littoral atlantique français: l'exemple du Finistère/Resource-use conflicts linked to changes in marine aquaculture on the French Atlantic coast: the example of Finistère. *Cahiers Nantais*, 47(1), 92-100.

Borja, A., Amouroux, D., Anschutz, P., Gómez-Gesteira, M., Uyarra, M.C., Valdés, L. (2019) Chapter 5 - The Bay of Biscay. In: *World Seas: An Environmental Evaluation*. 2nd Edition, Editor: Charles Sheppard, Academic Press. Pages 113-152. https://doi.org/10.1016/B978-0-12-805068-2.00006-1.

Botelho M.J., Vale C., Marques F., Moreirinha C., Costa S.T., Guilhermino L., Joaquim S., et al.), Rudnitskaya A. (2023) One-year variation in quantity and properties of microplastics in mussels (*Mytilus galloprovincialis*) and cockles (*Cerastoderma edule*) from Aveiro lagoon. *Environmental Pollution*, 333, art. no. 121949. https://doi.org/10.1016/j.envpol.2023.121949.

Braga, A.C.; Rodrigues, S.M.; Lourenço, H.M.; Costa, P.R.; Pedro, S. Bivalve Shellfish Safety in Portugal: Variability of Faecal Levels, Metal Contaminants and Marine Biotoxins during the Last Decade (2011–2020). *Toxins* 2023, 15, 91. https://doi.org/10.3390/toxins15020091.

Brausch, J.M.; Connors, K.A.; Brooks, B.W.; Rand, G.M. (2012) Human pharmaceuticals in the aquatic envi-ronment: A review of recent toxicological studies and considerations for toxicity testing. *Rev. Environ. Contam. Toxicol.*, 218: 1-99. https://doi.org/10.1007/978-1-4614-3137-4_1.

Breitburg, D., Levin, L. A., Oschlies, A., Grégoire, M., Chavez, F. P., Conley, D. J., Garçon, V., Gilbert, D., Gutiérrez, D., Isensee, K., Jacinto, G. S., Limburg, K. E., Montes, I., Naqvi, S. W. A., Pitcher, G. C., Ra-balais, N. N., Roman, M. R., Rose, K. A., Seibel, B. A., Telszewski, M., Yasuhara, M., and Zhang, J. 2018. Declining oxygen in the global ocean and coastal waters. *Science*, 359: eaam7240.doi:10.1126/sci-ence.aam7240

Browne, M.A., Crump, P., Niven, S.J., Teuten, E., Tonkin, A., Galloway, T., Thompson, R. (2011) Accumu-lation of microplastic on shorelines worldwide: Sources and Sinks. *Env. Sci. Technol*, 45: 9175-9179. https://doi.org/10.1021/es201811s.

Burge, C. A., Mark Eakin, C., Friedman, C. S., Froelich, B., Hershberger, P. K., Hofmann, E. E., Petes, L. E., Prager, K. C., Weil, E., Willis, B. L., Ford, S. E., and Harvell, C. D. 2014. Climate Change Influences on Marine Infectious Diseases: Implications for Management and Society. *Annual Review of Marine Sci-ence*, 6: 249-277.10.1146/annurev-marine-010213-135029.
Cabanilles, P., Acle, S., Arias, A., Masiá, P., Ardura, A., Garcia-Vazquez, E. (2022) Microplastics Risk into a Three-Link Food Chain Inside European Hake. Diversity, 14: 308. https://doi.org/10.3390/d14050308.

Callier Myriam, Byron Carrie J., Bengtson David A., Cranford Peter J., Cross Stephen F., Focken Ulfert, Jansen Henrice M., Kamermans Pauline, Kiessling Anders, Landry Thomas, O'Beirn Francis, Petersson Erik, Rheault Robert B., Strand Oivind, Sundell Kristina, Svasand Terje, Wikfors Gary H., McKindsey Christopher W. (2018). Attraction and repulsion of mobile wild organisms to finfish and shellfish aquaculture: a review. Reviews In Aquaculture, 10(4), 924-949. Publisher's official version: https://doi.org/10.1111/raq.12208

Callier Myriam, Fiandrino Annie, Laugier Thierry, Triplet Sebastien, Geoffroy Thibault, Le Grand Louis, Chary Killian, Falguiere Jean-Claude, Ubertini Martin, Merou Nicolas (2023). Modelling ecosystem assimilation capacity for a sustainable aquaculture in France: the MOCAA project. ASC 2023 - ICES Annual Science Conference 2023. 11-14 September 2023 Bilbao, Spain.

Cardoso C., Almeida J., Coelho I., Delgado I., Gomes R., Quintã R., Bandarra N.M., Afonso C. 2023. Farming a wild seaweed and changes to its composition, bioactivity, and bioaccessibility: The Saccorhiza polyschides case study. Aquaculture (566): 739217, https://doi.org/10.1016/j.aquaculture.2022.739217.

Carvalho, S; Falcão, M; et al 2009 Benthic dynamics within a land-based semi-intensive aquaculture fish farm The importance of settlement ponds. Aquacult Int 17: 571-587.

Carvalho, S; Moura, A; Sprung, M. 2006 Ecological implications of removing seagrass beds (Zostera noltii) for bivalve aquaculture in Southern Portugal. Cah. Biol. Mar. 47: 321-329.

Chapela Rosa., El Régimen Jurídico de la Acuicultura Marina, Marcial Pons, Madrid, 2002.

Chapela, Rosa, et al (2022) "Report on Current policy frameworks for aquaculture"; AquaVitae project, Deliverable 8.1 page. 25; https://aquavitaeproject.eu

Chapela, Rosa: Enabling good governance in aquaculture. Regional Aquaculture Conference, GFCM, FAO, Bari 2014.

Charria, G., Lazure, P., Le Cann, B., Serpette, A., Reverdin, G., Louazel, S., Batifoulier, F., Dumas, F., Pichon, A., Morel, Y. (2013) Surface layer circulation derived from Lagrangian drifters in the Bay of Biscay. J. Marine Sys., 109-110: S60-S76. doi.org/10.1016/j.jmarsys.2011.09.015.

Chu, Y., Wang, C., Park, J., Lader, P., 2020. Review of cage and containment tank designs for offshore fish farming. Aquaculture 734928.

Chust, G., Caballero, A., Marcos, M., Liria, P., Hernández, C., and Borja, Á. 2010. Regional scenarios of sea level rise and impacts on Basque (Bay of Biscay) coastal habitats, throughout the 21st century. Estuarine, Coastal and Shelf Science, 87: 113-124. https://doi.org/10.1016/j.ecss.2009.12.021.

Chust, G., González, M., Fontán, A., Revilla, M., Alvarez, P., Santos, M., Cotano, U., Chifflet, M., Borja, A., Muxika, I., Sagarminaga, Y., Caballero, A., de Santiago, I., Epelde, I., Liria, P., Ibaibarriaga, L., Garnier, R., Franco, J., Villarino, E., Irigoien, X., Fernandes-Salvador, J. A., Uriarte, A., Esteban, X., Orue-Echevarria, D., Figueira, T., and Uriarte, A. 2022. Climate regime shifts and biodiversity redistribution in the Bay of Biscay. Science of the Total Environment, 803: 149622. https://doi.org/10.1016/j.sctotenv.2021.149622

Ciavatta, S., Kay, S., Saux-Picart, S., Butenschön, M., and Allen, J. 2016. Decadal reanalysis of biogeochemical indicators and fluxes in the North West European shelf-sea ecosystem. Journal of Geophysical Research: Oceans, 121: 1824-1845

Cidad Maite, Peral Irene, Ramos Saioa, Basurco Bernardo, López-Francos Antonio, Muniesa Ana, Cavallo Marianna, Perez Jose, Aguilera Cristóbal, Furones Dolors, Reverté Carmen, Sanjuan-Vilaplana Anna, Edgar Brun, Dverdal Jansen Mona, Tavornpanich Saraya, Raux Pascal, Baraibar Díez Elisa, Cobo Angel, Fernández Polanco José Manuel, Llorente García Ignacio, Fernández Sánchez José Luis, Luna García Manuel, Luna Sotorrio Ladislao, Odriozola Zamanillo María, Gulzari Benan, Janssen Kasper, Komen Hans (2018). Assessment of Mediterranean Aquaculture Sustainability. Deliverable 1.2 of the Horizon 2020 project MedAID (GA number 727315), published in the project website on 21.12.2018. https://archimer.ifremer.fr/doc/00515/62630/.
Costoya, X., de Castro, M., Gómez-Gesteira, M., and Santos, F. 2015. Changes in sea surface temperature seasonality in the Bay of Biscay over the last decades (1982–2014). Journal of Marine Systems, 150: 91–101. https://doi.org/10.1016/j.jmarsys.2015.06.002.

Cranford, P. J., Duarte, P., Robinson, S. M., Fernández-Reiriz, M. J., & Labarta, U. (2014). Suspended particulate matter depletion and los modification inside mussel (Mytilus galloprovincialis) culture rafts in the Ría de Betanzos, Spain. Journal of experimental marine biology and ecology, 452, 70-81.

Cremades J., Freire O., Baamonde S., Salinas J.M. & Fuertes C. (2007) Nuevo método para el cultivo industrial de Laminaria saccharina (Laminariales, Phaeophyta) en las costas gallegas. Actas XI Congreso Nacional de Acuicultura, 1: 559-562.

Cunha ME, Quental-Ferreira H, Parejo A, Gamito S and others 2019. Understanding the individual role of fish, oyster, phytoplankton and macroalgae in the ecology of integrated production in earthen ponds. Aquaculture, 512: 734297.

Cyanopica, 2017. Boas práticas em cultivo de ostra – Algarve, APA, 50 pp.

Dai, A. 2011. Drought under global warming: a review. WIREs Climate Change, 2: 45-65. https://doi.org/10.1002/wcc.81.

Danancher D. and García-Vázquez E. (2007). Genetic effects of domestication, culture and breeding of fish and shellfish, and their impacts on wild populations. Turbot – Scophthalmus maximus. p 55-61, In: Svåsand T., Crosetti D., García-Vázquez E., Verspoor E. (eds). Genetic impact of aquaculture activities on native populations. Genimpact final scientific report (EU contract n. RICA-CT-2005-022802). http://genimpact.imr.no/.

Decree 83-228 of March 22, 1983, establishing the authorization regime for marine farming operations. [Accessed 27. October. 2023]. Available online: https://www.legifrance.gouv.fr/loda/id.

Decree 274/2003, of June 4, 2003, regulating the procedure for obtaining permits and activity concessions for aquaculture and auxiliary aquaculture establishments in the terrestrial zone. DOGA 110 (09-06-2003) Accessed 27. September. 2023]. Available online: https://vlex.es/vid/acuicultura-auxiliares-terrestre.

Decree-Law no. 151-B/2013. Environmental impact assessment (EIA). D.R. I Series. (31-10-2013) 6328-6354. [Accessed 13 October 2023]. Available online: https://diariodarepublica.pt/dr/detalhe/decreto-lei/151-b-2013-513863.

Decree-Law n.º 40/2017. Installation and operation of culture establishments in marine waters, including transitional waters, and in inland waters. D.R. I Series. 67 (04-04-2017) 1712-1724. [Accessed 22. June. 2023]. Consolidated version available online: https://diariodarepublica.pt/dr/legislacao-consolidada/decreto-lei/2017-107468888.

Directive 2001/42/EC of the European Parliament and of the Council of 27 June 2001 on the assessment of the effects of certain plans and programmes on the environment. (OJ, L197) [Accessed 27. October. 2023]. Available online: https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=celex%3A32001L0042.

de Pablo, H., Sobrinho, J., Garaboa-Paz, D., Fonteles, C., Neves, R., & Gaspar, M. B. (2022). The influence of the river discharge on residence time, exposure time and integrated water fractions for the tagus estuary (Portugal). Frontiers in Marine Science, 8, 734814. https://doi.org/10.3389/fmars.2021.734814.

Deycard, V.N., Schäfer, J., Blanc, G., Coynel, A., Petit, J.C.J., Lanceleur, L., Dutruch, L., Bossy, C., Ventura, A. (2014) Contributions and potential impacts of seven priority substances (As, Cd, Cu, Cr, Ni, Pb, and Zn) to a major European Estuary (Gironde Estuary, France) from urban wastewater. Mar. Chem., 167: 123-134. https://doi.org/10.1016/j.marchem.2014.05.005.

Diaz, R. J., and Rosenberg, R. 2008. Spreading Dead Zones and Consequences for Marine Ecosystems. Science, 321: 926-929.10.1126/science.1156401.

Dosdat Antoine, Gaignon Jean-Louis, Fuchs Jacques, Harache Yves, Lacroix Denis, Paquotte Philippe, Thouard Emmanuel (1997). La pisciculture marine en France. Note 'de synthèse DRV/RAID 97. 4'.

Duarte, C. M., Wu, J., Xiao, X., Bruhn, A., and Krause-Jensen, D. 2017. Can Seaweed Farming Play a Role in Climate Change Mitigation and Adaptation? Frontiers in Marine Science, 4.10.3389/fmars.2017.00100
Duarte, P., Azevedo, B., Ribeiro, C., Pereira, A., Falcão, M., Serpa, D., Reia, J. (2007). Management oriented mathematical modelling of Ria Formosa (South Portugal). Transitional Waters Monographs, 1(1), 13-51.

Duarte, P., Labarta, U., & Fernández-Reiriz, M. J. (2008). Modelling local food depletion effects in mussel rafts of Galician Rias. Aquaculture, 274(2-4), 300-312.

Dubert, J, Nelson DR, Spinard EJ, Kessner L, Gomez-Chiarri M, da Costa F, Prado S, Barja JL (2016a). Following the infection process of vibriosis in Manila clam (Ruditapes philippinarum) larvae through GFP-tagged pathogenic Vibrio species. J. Invertebr. Pathol. 133, 27-33. Doi: 10.1016/j.jip.2015.11.008.

Dubert, J., Barja, J. L., & Romalde, J. L. (2017). New insights into pathogenic Vibrios affecting bivalves in hatcheries: present and future prospects. *Frontiers in Microbiology, *8*, 762. https://doi.org/10.3389/fmicb.2017.00762.

Dubert, J., Osorio, C. R., Prado, S., & Barja, J. L. (2016). Persistence of antibiotic resistant Vibrio spp. in shellfish hatchery environment. *Microbial ecology, *72*, 851-860. https://doi.org/10.1007/s00248-015-0705-5.

Dubosq, N., Schmidt, S., Sudre, J., Rigaud, S., Lamarque, B., Danilo, M., Grémare, A., and Deflandre, B. 2022. First observations of seasonal bottom water deoxygenation off the Gironde estuary (Bay of Biscay, North East Atlantic). *Frontiers in Marine Science, *9*.10.3389/fmars.2022.1006453.

EC, 2000. Directive 2000/60/EC of the European Parliament and of the council of 23 October 2000 establishing a framework for community action in the field of water policy. Official Journal of the European Union, L 327, 1-72. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32000L0060.

EC, 2015. Commission implementing decision (EU) 2015/495 of 20 March 2015 establishing a watch list of substances for union-wide monitoring in the field of water policypursuant to directive 2008/105/EC of the European Parliament and of the council (notified under document C(2015) 1756). Official Journal of the European Union, L 78, 40-42. https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32015D0495.

EC, 2018. Commission implementing decision (EU) 2018/840 of 5 June 2018 establishing a watch list of substances for union-wide monitoring in the field of water policy pursuant to directive 2008/105/EC of the European Parliament and of the council and repealing commission implementing decision (EU) 2015/495 (notified under document C(2018) 3362). Official Journal of the European Union, L 141, 9-12. https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32018D0840.

EEA 2015. Spatial analysis of marine protected area networks in Europe's seas. EEA Technical report No 17/2015.

Eguiraun, H.; López-De-Ipiña, K.; Martinez, I. (2014) Application of entropy and fractal dimension analyses to the pattern recognition of contaminated fish responses in aquaculture. Entropy, 16, 6133-6151. https://doi.org/10.3390/e16116133.

Eguiraun, H.; Martinez, I. (2023a) Entropy and fractal techniques for monitoring fish behaviour and welfare in aquacultural precision fish farming—A review. Entropy, 25, 559. https://doi.org/10.3390/e25040559.

Eguiraun, H.; Martinez, I. (2023b) Non-linear analyses of fish behaviours in response to aquatic environmental pollutants—A Review. Fishes, 8, 311. https://doi.org/10.3390/fishes8060311.

Ellis, R. P., Urbina, M. A., and Wilson, R. W. 2017. Lessons from two high CO2 worlds – future oceans and intensive aquaculture. Global Change Biology, 23: 2141-2148.10.1111/gcb.13515.

EP-INE (2022). Instituto Nacional de Estatística. Estatísticas da Pesca 2021. Lisboa, Portugal. Accessed October 08, 2023, through the site: https://www.ine.pt/xportal/xmain?xpid=INE&xpgid=ine_publi-cacoes&PUBLICACOESpub_boui=280980687&PUBLICACOEStema=00&PUBLICACOESmodo=2.

European Commission (2009), Communication from the Commission to the European Parliament and the Council: Building a sustainable future for aquaculture: A new impetus for the Strategy for the Sustainable Development of European Aquaculture, Brussels, 8.4.2009, COM (2009) 162 final.
European Commission (2012). Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee of the Regions: Blue Growth opportunities for marine and maritime sustainable growth. COM/2012/0494 final.

European Commission (2017), Directorate-General for Research and Innovation, Group of Chief Scientific Advisors, Food from the Oceans, - How can more food and biomass be obtained from the oceans in a way that does not deprive future generations of their benefits; Publications Office, 2017, p. 31; https://data.europa.eu/doi/10.2777/66235.

European Commission (2017). Report on the Blue Growth Strategy: towards more sustainable growth and jobs in the blue economy. SWD (2017) 128 final.

European Commission (2018) Guidance document on aquaculture activities in the context of the Natura 2000 Network, European Commission, 2018.

European Commission (2019). The European Green Deal. Communication from the Commission to the European Parliament, the European Council, the Council, the European Economic and Social Committee and the Committee of the Regions; Brussels, 11.12.2019 COM (2019) 640 final.

European Commission (2020); Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions. *A Farm to Fork Strategy for a fair, healthy and environmentally friendly food system*. Brussels, 20.5.2020. COM (2020) 381 final.

European Commission (2024): Commission Staff Working Document Implementing the Strategic Guidelines for EU aquaculture Regulatory and administrative framework for aquaculture, SWD(2024) 95 final.

European Commission (2021): Communication on strategic guidelines for a more sustainable and competitive EU aquaculture for the period 2021-2030 – COM (2021) 236 final.

European Court of Auditors (2014): "The effectiveness of European Fisheries Fund Support for aquaculture, Special Report, num. 10, 2014.

European Court of Auditors (2023): "EU aquaculture policy: Stagnating production and unclear results despite increased EU funding" Special Report 25/2023.

European Parliament (2018) Resolution of 12 June 2018 on "Towards a sustainable and competitive European aquaculture sector: current status and future challenges"; Committee on Fisheries, 2018.

EUSeaMap 2023 Broad-Scale Predictive Habitat Map for Europe.

FAO (1995), Code of Conduct for Responsible Fisheries, Roma, FAO, 1995ICES. 2022. Workshop on the Celtic Seas Ecoregion Aquaculture Overview (WKCSAO). ICES Scientific Reports. 04:57. 126 pp. http://doi.org/10.17895/ices.pub.21221882.

FAO. 2018. Impacts of Climate Change on Fisheries and Aquaculture: Synthesis of Current Knowledge, Adaptation and Mitigation Options. 627 pp.

Faranda, D., Pascale, S., and Bulut, B. 2023. Persistent anticyclonic conditions and climate change exacerbated the exceptional 2022 European-Mediterranean drought. Environmental Research Letters, 18: 034030.10.1088/1748-9326/acbc37.

Fendall, L.S., Sewell, M.A. (2009) Contributing to marine pollution by washing your face: Microplastics in facial cleansers. Mar. Poll. Bull., 58: 1225-1228. https://doi.org/10.1016/j.marpolbul.2009.04.025.

Ferreira JG, Corner RA, Moore H, Service M, Rheault R. 2018. Ecological carrying capacity for shellfish aquaculture—sustainability of naturally occurring filter-feeders and cultivated bivalves. J. Shellfish Res. 37, 709–726.

Ferreira JG, Taylor NGH, Cubillo A, Lencart-Silva J, Pastres P, Bergh O, Guilder J. 2021. An integrated model for aquaculture production, pathogen interaction, and environmental effects. Aquaculture 536.

Ferreira, J. G., Saurel, C., e Silva, J. L., Nunes, J. P., & Vazquez, F. (2014). Modelling of interactions between inshore and offshore aquaculture. Aquaculture, 426, 154-164.
Ferreira, J. G., Saurel, C., Nunes, J. P., Ramos, L., Silva, J. D. L. E., Vazquez, F. & Rocha, M. (2012). Framework for Ria Formosa water quality, aquaculture, and resource development. ISBN: 978-972-99923-3-9.

Ferreira, J. G., Sequeira, A., Hawkins, A. J. S., Newton, A., Nickell, T. D., Pastres, R., ... & Bricker, S. B. (2009). Analysis of coastal and offshore aquaculture: application of the FARM model to multiple systems and shellfish species. Aquaculture, 289(1-2), 32-41.

Figueras et al. (2007) Biología y cultivo del mejillón (*Mytilus galloprovincialis*) en Galicia (2007). Consejo Superior de Investigaciones Científicas (España) Eds. Figueras Huerta, Antonio; Cáceres-Martínez, J. ISBN: 978-84-00-0526-1 http://hdl.handle.net/10261/104143

Filgueira, R., Comeau, L. A., Guyondet, T., McKindsey, C. W., & Byron, C. J. (2015). Modelling carrying capacity of bivalve aquaculture: a review of definitions and methods. Fisheries and Oceans Canada, Ecosystems and Oceans Science.

Flassch and Leborgne ICES 1992.

Fleury E., Petton S., Benabdelmouna A., Corporeau C., Pouvreau S. et coll. (2022) Observatoire national du cycle de vie de l'huître creuse en France. Rapport annuel 2021. Convention DPMA 2021 – Ifremer.

Fleury Elodie, Petton Sébastien, Benabdelmouna Abdellah, Pouvreau Stephane, (coord.) (2023). Observatoire national du cycle de vie de l'huître creuse en France. Rapport annuel ECOSCOPA 2022. R. INT.BREST RBE/PFOM/PI 2023-1 . https://archimer.ifremer.fr/doc/00840/95240/.

Froehlich, H. E., Gentry, R. R., and Halpern, B. S. 2018. Global change in marine aquaculture production potential under climate change. Nature Ecology & Evolution, 2: 1745-1750.10.1038/s41559-018-0669-1

FOESA (2015) Plan Estratégico Plurianual de la Acuicultura Española (2014-2020). Documento de Planificaciones Estratégicas Autonómicas. Ministerio de Agricultura y Medio Ambiente. https://www.mapa.gob.es/es/pesca/temas/acuicultura/315 PLANES_AUTONOMICS PEAE MAR 2015 tcm30-77596.pdf.

Following the infection process of vibriosis in Manila clam (*Ruditapes philippinarum*) larvae through GFP-tagged pathogenic Vibrio species. J Invertebr Pathol 133:27-33. https://doi.org/10.1016/j.jip.2015.11.008.

Fraga-Corral M., Ronza P., Garcia-Oliveira P., Pereira A.G., Losada A.P., Prieto M.A., Quiroga M.I., Simal-Gandara J. 2022. Aquaculture as a circular bio-economy model with Galicia as a study case: How to transform waste into revalorized by-products. Trends in Food Science & Technology (119): 23-35, https://doi.org/10.1016/j.tifs.2021.11.026.

Freitas, J. R., Salinas Morrondo, J. M., & Cremades Ugarte, J. (2016). Saccharina latissima (Laminariales, Ochrophyta) farming in an industrial IMTA system in Galicia (Spain). Journal of applied phycology, 28, 377-385.

Gamito S, Quental-Ferreira H, Parejo A, Aubin J, Christensen V, Cunha ME. 2020 Integrated multi-trophic aquaculture systems: energy transfers and foodweb organization in coastal earthen ponds. Aquacult Environ Interact 12: 457-470.

Gamito, S. 1997. Sustainable management of a coastal lagoonal system (Ria Formosa, Portugal): An ecological model for extensive aquaculture. International Journal of Salt Lake Research 6:145-173.

Gamito, S., & Erzini, K. 2005. Trophic foodweb and ecosystem attributes of a water reservoir of the Ria Formosa (south Portugal). Ecological Modelling, 181(4), 509-520.

Gattuso, J.-P., Magnan, A. K., Bopp, L., Cheung, W. W. L., Duarte, C. M., Hinkel, J., Mcleod, E., Micheli, F., Oschlies, A., Williamson, P., Billé, R., Chalastani, V. I., Gates, R. D., Irisson, J.-O., Middelburg, J. J., Pörtner, H.-O., and Rau, G. H. 2018. Ocean Solutions to Address Climate Change and Its Effects on Marine Ecosystems. Frontiers in Marine Science, 5.10.3389/fmars.2018.00337

Gavrilescu, M.; Demnerová, K.; Aamand, J.; Agathos, S.; Fava, F. (2015) Emerging pollutants in the environment: Present and future challenges in biomonitoring, ecological risks and bioremediation. New Biotechnol., 32, 147-156. https://doi.org/10.1016/j.nbt.2014.01.001.
Gazeau, F., Parker, L., Comeau, S., Gattuso, J.-P., O'Connor, W., Martin, S., Pörtner, H.-O., and Ross, P. 2013. Impacts of ocean acidification on marine shelled molluscs. Marine Biology, 160: 2207-2245.10.1007/s00227-013-2219-3

Gephart et al. 2021 10.1038/s41586-021-03889-2

Gobler, C. J. 2020. Climate Change and Harmful Algal Blooms: Insights and perspective. Harmful Algae, 91: 101731. https://doi.org/10.1016/j.hal.2019.101731.

Gomes M, Correia A, Pinto L, Sá C, Brotas V and Mateus M (2020) Coastal Water Quality in an Atlantic Sea Bass Farm Site (Sines, Portugal): A First Assessment. Front. Mar. Sci. 7:175. doi: 10.3389/fmars.2020.00175
Guerra-Diaz, A. 2013. Clan Production and cultivation in Galicia (NW Spain): The role of hatcheries. In: Clam fisheries and aquaculture. (ed. da Costa, F.). Nova Science Publishers. New York. 255-272.

Guimarães MHME, Cunha AH, Nzinga RL, Marques JF. 2012. The distribution of seagrass (Zostera noltii) in the Ria Formosa lagoon system and the implications of clam farming on its conservation. Journal for Nature Conservation, 20: 30-40.

Hargrave, B.T. (Ed.), 2005. Environmental Effects of Marine Finfish Aquaculture, Handbook of Environmental Chemistry. Springer-Verlag, Berlin/ Heidelberg. https://doi.org/10.1007/b12227.

Harvell, C. D., Kim, K., Burkholder, J. M., Colwell, R. R., Epstein, P. R., Grimes, D. J., Hofmann, E. E., Lipp, E. K., Osterhaus, A. D., Overstreet, R. M., Porter, J. W., Smith, G. W., and Vasta, G. R. 1999. Emerging marine diseases--climate links and anthropogenic factors. Science, 285: 1505-1510.10.1126/science.285.5433.1505.

Hobday, A. J., Alexander, L. V., Perkins, S. E., Smale, D. A., Straub, S. C., Oliver, E. C. J., Benthuysen, J. A., Burrows, M. T., Donat, M. G., Feng, M., Holbrook, N. J., Moore, P. J., Scannell, H. A., Sen Gupta, A., and Wernberg, T. 2016. A hierarchical approach to defining marine heatwaves. Progress in Oceanography, 141: 227-238. https://doi.org/10.1016/j-pocean.2015.12.014.

Holmer M., Hansen P.K., Karakassis I., Borg J.A. & Schembri P.J. (2008) Monitoring of environmental impacts of marine aquaculture. En: (Eds.), Aquaculture in the Ecosystem. Holmer M., Black K., Duarte C.M., Marbà N. & Karakassis I. Springer, pp. 47-85.

https://www.webofscience.com/wos/author/record/664046.

Hubert FN, Pellaud M, Gamito S. 2006 Environmental effects of marine fish pond culture in the Ria Formosa (Southern Portugal). Hydrobiologia, 555: 289-297.

ICES (2022) BoBIC Ecosystem Overview.

Idowu Caroline (2020): The new EU organic regulation is coming – are you ready?, Pen & Tec Consulting, August 2020, https://pentec-consulting.eu/the-new-eu-organic-regulation-is-coming-are-you-ready/.

INE & DGRM.

IPCC. 2019. IPCC Special Report on the Ocean and Cryosphere in a Changing Climate.

IPCC 2023. Summary for Policymakers. In Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, pp. 1-34. Ed. by H. Lee, and J. Romero. IPCC, Geneva, Switzerland.

IUCN Guidelines on Site Selection and Site Management on Aquaculture, 2009.

Izquierdo-Gomez, D., Fernandez-Jover, D., Sanchez-Jerez, P., Toledo-Guedes, K., Arechavala-Lopez, P., Forcada, A., & Valle-Pérez, C. (2014a). Guía de buenas prácticas para la gestión de escapes en acuicultura marina. Vol. I. Prevención.

Izquierdo-Gómez, D., Sánchez-Jerez, P., Fernández-Jover, D., Toledo-Guedes, K., Arechavala-López, P., Forcada-Almarcha, A., & Valle-Pérez, C. (2014b). Guía de buenas prácticas para la gestión de escapes en la acuicultura marina: Vol II. Mitigación. Proyecto ESCA-FEP, Fondo Europeo de Pesca. Ed. Oceanográfica, 32.
Junta de Andalucía (2014a), Localización de zonas idóneas para el desarrollo de la Acuicultura Marina en Andalucía (2014), Dirección General de Pesca y Acuicultura. Servicio de Ordenación de Recursos Pesqueros y Acuícolas, Junta de Andalucía, Sevilla, 2014. https://www.juntadeandalucia.es/servicios/publicaciones/detalle/77385.html#toc-informaci-n-general.

Junta de Andalucía (2014b), Estrategia Andaluza para el Desarrollo de la Acuicultura Marina, 2014-2020, https://www.juntadeandalucia.es/export/drupaljda/ESTRATEGIA_ANDALUZA PARA EL DESARROLLO DE LA ACUICULTURA MARINA 2014-2020.pdf.

Junta de Andalucía (2014b), Nueva Estrategia de la Acuicultura Marina en Andalucía, 2021-2030, Consejería de Agricultura, Pesca, Agua y Desarrollo Rural, 2022, https://www.juntadeandalucia.es/sites/default/files/inline-files/2023/03/Estrategia_Acuicultura_2021_2030_0.pdf.

Kermagoret, C., & Frangoudes, K. (2021). Blue growth in the face of citizen protests: analyzing the participative democracy process through four case studies in Brittany (France). Revue internationale de psychosociologie et de gestion des comportements organisationnels, (69), 91-111.

Kock et al. 2020 https://doi.org/10.1016/j.aquaculture.2020.735474.

Krause Gesche, et al., (2015). A revolution without people? Closing the people-policy gap in aquaculture development. Aquaculture, 447, 44-55. Publisher's official version: https://doi.org/10.1016/j.aquaculture.2015.02.009, Open Access version: https://archimer.ifremer.fr/doc/00252/36301/.

Kroeker, K. J., Kordas, R. L., Crim, R., Hendriks, I. E., Ramajo, L., Singh, G. S., Duarte, C. M., and Gattuso, J.-P. 2013. Impacts of ocean acidification on marine organisms: quantifying sensitivities and interaction with warming. Global Change Biology, 19: 1884-1896.10.1111/gcb.12179.

Kuhlbrodt, T., Swaminathan, R., Ceppi, P., Wilder, T. 2024. A Glimpse into the Future The 2023 Ocean Temperature and Sea Ice Extremes in the Context of Longer-Term Climate Change. American Meteorological Society. https://doi.org/10.1175/BAMS-D-23-0209.1.

Kwiatkowski, L., et al., (2020). Twenty-first century ocean warming, acidification, deoxygenation, and upper-ocean nutrient and primary production decline from CMIP6 model projections. Biogeosciences, 17: 3439-3470.10.5194/bg-17-3439-2020

Labarta, U., & Fernández-Reiriz, M. J. (2019). The Galician mussel industry: Innovation and changes in the last forty years. Ocean & coastal management, 167, 208-218.

Lafferty, K. D. 2009. The ecology of climate change and infectious diseases. Ecology, 90: 888-900. https://doi.org/10.1890/08-0079.1.

Lafferty, K. D., Harvell, C. D., Conrad, J. M., Friedman, C. S., Kent, M. L., Kuris, A. M., Powell, E. N., Rondeau, D., and Saksida, S. M. 2015. Infectious diseases affect marine fisheries and aquaculture economics. Annual Review of Marine Science, 7: 471-496.10.1146/annurev-marine-010814-015646

Laroche, J., et al., (2013) Variation patterns in individual fish responses to chemical stress among estuaries, seasons and genders: The case of the European flounder (Platichthys flesus) in the Bay of Biscay. Env. Sci. Pollut. Res. 20: 738-748. https://doi.org/10.1007/s11356-012-1276-3.

Law 23/1984. Regulation and management of marine cultures. BOE-A-1984-14431 (25-06-1984). [Accessed 27. September. 2023]. [Accessed 27. September. 2023]. Available online: https://www.boe.es/buscar/doc.php?id=BOE-A-1984-14431.

Law no. 86-2 of January 3, 1986 on coastal development, protection and enhancement. [Accessed 27. October. 2023]. Available online: https://www.legifrance.gouv.fr/loda/id/JORFTEXT000000317531.

Law 21/2013. Environmental assessment. BOE-A-2013-12913 (09-12-2013). [Accessed 27. September. 2023]. Available online: https://www.boe.es/buscar/act.php?id=BOE-A-2013-12913.

Le Gouvello, R., et Simard, F. (eds.) (2017) Durabilité des aliments pour le poisson en aquaculture : Réflexions et recommandations sur les aspects technologiques, économiques, sociaux et environnementaux. Gland, Suisse : UICN, et Paris, France : Comité français de l’UICN. 296 pp.
Lemoine Maud, Durand Gaetane, Pilven Sophie (2018). The REPHY, an outstanding monitoring network: 30 years of data. ICHA2018 - 18th International Conference on Harmful Algae "From ecosystems to socio-ecosystems". 21-26 october 2018, Nantes, France. https://archimer.ifremer.fr/doc/00472/58411/

Leung, J. Y. S., Zhang, S., and Connell, S. D. 2022. Is Ocean Acidification Really a Threat to Marine Calcifiers? A Systematic Review and Meta-Analysis of 980+ Studies Spanning Two Decades. Small, 18: 2107407.10.1002/smll.202107407.

Lillebø AL, Pita C, Garcia-Rodrigues J, Ramos S, Villasante S (2017) How can marine ecosystem services support the Blue Growth agenda? Marine Policy 81: 132-142.

Mamede, R., Santos, A., Diaz, S., da Silva, E. F., Patinha, C., Calado, R., & Ricardo, F. (2022). Elemental fingerprints of bivalve shells (Ruditapes decussatus and R. philippinarum) as natural tags to confirm their geographic origin and expose fraudulent trade practices. Food Control, 135, 108785. https://doi.org/10.1016/j.foodcont.2021.108785.

Macías JC, Aguado F, González N, Guerrero S, Estévez A, Valencia JM, Cremades J (2008) Acuicultura Integrada: desarrollo de experiencias de cultivos multitróficos en la costa española. In: Rey-Méndez M, Lodeiros C, Fernández Casal J, Guerra A (eds) Foro Ac. Rec. Mar. Rías Gal. 10, p 483-490 (in Spanish).

Masiá, P., Ardura, A., Gaitán, M., Gerber, S., Rayon-Viña, F., Garcia-Vazquez, E. (2021) Maritime ports and beach management as sources of coastal macro-, meso-, and microplastic pollution. Env. Sci. Pollut. Res., 28: 30722-30731. DOI: 10.1007/s11356-021-12821-0.

Masiá, P., Ardura, A., Garcia-Vazquez, E. (2019) Microplastics in special protected areas for migratory birds in the Bay of Biscay. Mar. Pollut. Bull., 146: 993-1001. https://doi.org/10.1016/j.marpolbul.2019.07.065.

Masiá, P., Ardura, A., Garcia-Vazquez, E. (2022) Microplastics in seafood: Relative input of Mytilus gallo-provincialis and table salt in mussel dishes. Food Res. Int., 153: 110973. https://doi.org/10.1016/j.food-res.2022.110973.

Mateus, M., Almeida D., Simonson, W., Felgueiras, M., Banza, P. Batty, L. 2016. Conflictive uses of coastal areas: A case study in a southern European coastal lagoon (Ria de Alvor, Portugal). Ocean & Coastal Management, 132: 90-100.

Matos GS, Pereira SG, Genisheva ZA, Gomes AM, Teixeira JA, Rocha CMR. Advances in Extraction Methods to Recover Added-Value Compounds from Seaweeds: Sustainability and Functionality. Foods. 2021; 10(3):516. https://doi.org/10.3390/foods10030516.

Mauffret, A., Chouvelon, T., Wessel, N., Cresson, P., Bănaru, D., Baudrier, J., Bustamante, P., Chekri, R., Jitaru, P., Le Loc'h, F., Mialet, B., Vaccher, V., Harmelin-Vivien, M. (2023) Trace elements, dioxins and PCBs in different fish species and marine regions: Importance of the taxon and regional features. Env. Res., 216: 114624. https://doi.org/10.1016/j.envres.2022.114624.

McGovern, E., Schilder, J., Artioli, Y., Birchenough, S., Dupont, S., Findlay, H., Skjelvan, I., Skogen, M. D., Álvarez, M., Büsher, J. V., Chierici, M., Aagaard Christensen, J. P., Diaz, P. L., Grage, A., Gregor, L., Humphreys, M., Järnegren, J., Knockaert, M., Krakau, M., Nogueira, M., Ólafsdóttir, S. R., von Schuckmann, K., Carreiro-Silva, M., Stiasny, M., Walsham, P., Widdicombe, S., Gehlen, M., Chau, T. T. T., Chevallier, F., Savoye, N., Clark, J., Galli, G., Hordoir, R., and C., M. 2022. Ocean Acidification.

McKindsey Christopher W., Archambault Philippe, Callier Myriam, Olivier Frederic (2011). Influence of suspended and off-bottom mussel culture on the sea bottom and benthic habitats: a review. *Canadian Journal Of Zoology-revue Canadienne De Zoologie*, 89(7), 622-646. Publisher's official version: https://doi.org/10.1139/Z11-037.

McKindsey, C. W., Thetmeyer, H., Landry, T., & Silvert, W. (2006). Review of recent carrying capacity models for bivalve culture and recommendations for research and management. Aquaculture, 261(2), 451-462.

MEA (2005) Ecosystems and Human Well-Being: Biodiversity Synthesis. World Resources Institute, Washington, DC.
Mendoza, A., Osa, J.L., Basurko, O.C., Rubio, A., Santos, M., Gago, J., Galgani, F., Peña-Rodriguez, C. (2020) Microplastics in the Bay of Biscay: An overview. Mar. Poll. Bull., 153: 110996. https://doi.org/10.1016/j.marpolbul.2020.110996.

Menéndez, D., Álvarez, A., Acle, S., Peón, P., Ardura, A., Garcia-Vazquez, E. (2022) Microplastics across biomes in diadromous species. Insights from the critically endangered Anguilla Anguilla. Env. Pollut., 305: 119277. https://doi.org/10.1016/j.envpol.2022.119277.

Mijangos, I., Ziarrusta, H., Ros, O., Kortazar, L., Fernandez, L.A., Olivares, M., Zuloaga, O., Prieto, A., Etxebarria, N. (2018) Occurrence of emerging pollutants in estuaries of the Basque Country: Analysis of sources and distribution, and assessment of the environmental risk. Water Res., 147: 152-163. https://doi.org/10.1016/j.watres.2018.09.033.

Mille, D., & Blachier, P. (2009). Les mutations conchylicoles sur la façade maritime de l'AGLIA. État des lieux et perspectives de développement. Rapport, CREAA.

Ministerio para la Transición Ecológica y el Reto Demográfico, MTERD, (2023). Planes de Ordenación del Espacio Marítimo, III. Diagnóstico: Demarcación Sudatlántica (Dirección General de la Costa y el Mar), 2023. https://www.miteco.gob.es/es/costas/temas/proteccion-medio-marino/ordenacion-del-espacio-maritimo.html.

Ministry of Agriculture, Fisheries and Food). SGP-MAPA (2022). Contribución de España a las Directrices estratégicas para una acuicultura de la UE más sostenible y competitiva 2021-2030. Secretaría General de pesca. Ministerio de Agricultura, Pesca y Alimentación, Madrid, España. 170 p.

Miranda, C., Rojas, R., Garrido, M., Geisse, J., and González, G. (2013). Role of shellfish hatchery as a reservoir of antimicrobial resistant bacteria. Mar. Pollut. Bull. 74, 334–343. doi: 10.1016/j.marpolbul.2013.06.032.

Mongruel R, Prou J, Ballé-Béganton J, Lample M, Vanhoutte-Brunier A, Réthoret H, Pérez Agúndez J, Vernier F, Bordenave P, Bacher C (2011) Modeling soft institutional change and the improvement of freshwater governance in the coastal zone. Ecol Soc 16(4):15. https://doi.org/10.5751/ES-04294-160415.

Moreno, P. et al. Surveillance of viruses in wild fish populations in areas around the Gulf of Cadiz (South Atlantic Iberian Peninsula). Appl. Environ. Microbiol. 80, 6560–6571 (2014).

Mosqueira M, Pombo A, Borges C, Brito AC, Zacarias N, Esteves R, Palma C. 2022. Potential for Coastal d Offshore Aquaculture in Portugal: Insights from Physico-Chemical and Oceanographic Conditions. Applied Sciences, 12.

MRAG (2021). Study on state-of-the-art scientific information on the impacts of aquaculture activities in Europe. Accessed October 08, 2023, through the site: https://op.europa.eu/en/publication-detail/-/publication/9dcce336-a5a5-11ec-83e1-01aa75ed71a1/language-en.

Morro, B., Davidson, K., Adams, T.P., Falconer, L., Holloway, M., Dale, A., Aleynik, D., Thies, P.R., Khalid, F., Hardwick, J., Smith, H., Gillibrand, P.A., Rey-Planellas, S., 2022. Offshore aquaculture of finfish: Big expectations at sea. Rev. Aquac. 14, 791–815. https://doi.org/10.1111/raq.12625.

National Strategic Plan for the Sustainable Development of Aquaculture (2018) (https://www.europe-en-france.gouv.fr/fr/ressources/plan-strategique-national-pour-le-developpement-des-aquacultures-du-rables-2020).

Nina Moulin. Analyse rétrospective de la gouvernance du socio-écosystème ostréicole du bassin de Marrennes-Oléron: une approche par la mémoire des acteurs. Sciences du Vivant [q-bio]. 2022. dumas-03888648.

Ottinger et al. 2006 https://doi.org/10.1016/j.ocecoaman.2015.10.015.

Peeler, E.J., & Murray, A.G. (2004). Disease interaction between farmed and wild fish populations. J. Fish Biol., 65: 321–322.

Pérez Agúndez José A., Raux Pascal, Vieira Pak Manuela, Cavallo Marianna, Lancelot Loeiza (2022). Top-level institutional policies and their implementation at regional level – A difficult equation. The example of the social acceptability of aquaculture development in Malaga, Spain. Aquaculture Reports, 25,
101227 (10p.). Publisher's official version: https://doi.org/10.1016/j.aqrep.2022.101227, Open Access version: https://archimer.ifremer.fr/doc/00780/89195/.

Pérez Camacho A., González R., Fuentes J., 1991. Mussel culture in Galicia (N.W. Spain). Aquaculture (94) 2-3: 263-278. https://doi.org/10.1016/0044-8486(91)90122-N.

Pérez R., Kaas R., Campello F., Arbault S. & Babaroux O. (1992) La culture des algues marines dans le monde. Service de la Documentation et des Plubications (SDP). Ifremer. Plouzane.

Pernet, F., and Browman, H. I. 2021. The future is now: marine aquaculture in the anthropocene. Ices Journal of Marine Science, 78: 315-322.10.1093/icesjms/fsaa248.

Peteiro C., Salinas J.M., Freire O & Fuertes C. (2006) Cultivation of the autoctonous seaweed Laminaria saccharina on the Galician Coast NW Spain): Production and features of the sporophytes for an annual and biennial harvest. Thalassas, 22: 45-53.

Petton, S., Pernet, et al., (2023). French coastal network for carbonate system monitoring: The CocoriCO2 dataset. Earth Syst. Sci. Data Discuss., 2023: 1-34.10.5194/essd-2023-445.

Pham, D.N., Clark, L., Li, M. (2021) Microplastics as hubs enriching antibiotic-resistant bacteria and pathogens in municipal activated sludge. J. Hazard. Mater. Lett., 2: 100014. https://doi.org/10.1016/j.hazl.2021.100014.

Polo, D., Varela, M. F., & Romalde, J. L. (2015). Detection and quantification of hepatitis A virus and norovirus in Spanish authorized shellfish harvesting areas. International journal of food microbiology, 193, 43-50.

Prado FD, Vera M, Hermida M, Blanco A. and others (2018) Tracing the genetic impact of farmed turbot Scophthalmus maximus on wild populations. Aquacult Environ Interact 10:447-463. https://doi.org/10.3354/aei00282.

Prado, S., Dubert, J., da Costa, F., Martínez-Patiño, D., and Barja, J. L. (2014). Vibrios in hatchery cultures of the razor clam, Solen marginatus (Pulteney). J. Fish. Dis. 37, 209-217. doi: 10.1111/jfd.12098.

Raillard O., Ménesguen A. (1994) An ecosystem box model for estimating the carrying capacity of a macro-tidal shellfish system. MEPS, 115(1-2), 117-130 *Production Carrying capacity (coupled physical and biological submodels into an ecological model)*.

Ramos, J., Lino, P. G., Caetano, M., Pereira, F., Gaspar, M., & dos Santos, M. N. (2015). Perceived impact of offshore aquaculture area on small-scale fisheries: A fuzzy logic model approach. Fisheries research, 170, 217-227. https://doi.org/10.1016/j.fishres.2015.05.030.

Ratmaya, W., Laverman, A. M., Rabouille, C., Akbarzadeh, Z., Andrieux-Loyer, F., Barillé, L., Barillé, A.-L., Le Merrer, Y., and Souchu, P. 2022. Temporal and spatial variations in benthic nitrogen cycling in a temperate macro-tidal coastal ecosystem: Observation and modeling. Continental Shelf Research, 235: 104649.

Reguera, P., Viñas, L., Gago, J. (2019) Microplastics in wild mussels (Mytilus spp.) from the north coast of spain [Microplásticos en mejillones silvestres (Mytilus spp.) de la costa del norte de España]. Sci. Mar., 83: 337-347. doi: https://doi.org/10.3989/scimar.04927.05A.

Regulation (EC) No 853/2004 of the European Parliament and of the Council of 29 April 2004 laying down specific hygiene rules for food of animal origin. (OJ, L 139) [Accessed 27. October. 2023]. Available online: https://eur-lex.europa.eu/legal-content/en/ALL/?uri=CELEX%3A32004R0853.

Regulation (EU) 2016/429 of the European Parliament and of the Council of 9 March 2016 on transmissible animal diseases and amending and repealing certain acts in the area of animal health ('Animal Health Law') (OJ, L84) [Accessed 27. October. 2023]. Available online: https://eur-lex.europa.eu/eli/reg/2016/429/oj.

Regulatory Part (Articles D111-1 to R958-33). Rural and Maritime Fishing Code. [Accessed 27. october. 2023]. Available online: https://www.legifrance.gouv.fr/codes/section_1c/LEGITEXT000006071367/LEGISCTA000006098287/2016-01-01/.
Reid, G. K., Gurney-Smith, H. J., Marcogliese, D. J., Knowler, D., Benfey, T., Garber, A. F., Forster, I., Chopin, T., Brewer-Dalton, K., Moccia, R. D., Flaherty, M., Smith, C. T., and De Silva, S. 2019. Climate change and aquaculture: considering biological response and resources. Aquaculture Environment Interactions, 11: 569-602

Relvas, P., and Barton, E. D. 2002. Mesoscale patterns in the Cape São Vicente (Iberian Peninsula) upwelling region, Journal of Geophysical Research Atmospheres, 107(C10), 3164. https://doi.org/10.1029/2000JC000456.

Ribeiro L., Soares F., Luna-Araujo R., Quental-Ferreira H., Pousão-Ferreira P., Nathan J., Cristina S., Fragoso B. (2023) Chapter 6. Microplásticos na aquacultura, o que sabemos? IN: Micro e Nanoplásticos: um Macroproblema Editores: Delminda Moura, Isabel Mendes, Jaime Aníbal, Ana Gomes. Doi: http://dx.doi.org/10.34623/tz6d-k552, Disponível em: http://hdl.handle.net/10400.1/19968Rivaud*, A., & Cazals, C. (2013). Quand la co-localisation contraint la coordination: l'apport du modèle 'exit-voice'à l'analyse des dynamiques territoriales. Revue d'économie régionale et urbaine, (4), 679-704.

Romalde, J. L., Rivadulla, E., Varela, M. F., & Barja, J. L. (2018). An overview of 20 years of studies on the prevalence of human enteric viruses in shellfish from Galicia, Spain. Journal of applied microbiology, 124(4), 943-957.

Rosas, E., Martins, F., Tosic, M., Janeiro, J., Mendonça, F., Mills, L. (2022) Pathways and Hot Spots of Floating and Submerged Microplastics in Atlantic Iberian Marine Waters: A Modelling Approach. J. Mar. Sci. Eng., 10: 1640. https://doi.org/10.3390/jmse10111640.

Royal Decree 1471/1989. General Regulations for the development and execution of Law 22/1988, of July 28, 1988, on Coasts. BOE-A-1989-29127 (01-12-1989). [Accessed 27. September. 2023]. Available online: https://www.boe.es/buscar/doc.php?id=BOE-A-1989-29127.

Rowley, A.F., Cross, M.E., Culloty, S.C., Lynch, S.A., Mackenzie, C.L., Morgan, E., O'Riordan, R.M., Robins, P.E., Smith, A.L., Thrupp, T.J., Vogan, C.L., Wootton, E.C., Malham, S.K. (2014) The potential impact of climate change on the infectious diseases of commercially important shellfish populations in the Irish Sea—a review, ICES J. Mar. Sci., 71: 741-759. https://doi.org/10.1093/icesjms/fst234.

Ruiz-Chico J, Biedma-Ferrer JM, Peña-Sánchez AR, Jiménez-García M. Social Acceptance of Aquaculture in Spain: An Instrument to Achieve Sustainability for Society. International Journal of Environmental Research and Public Health. 2020; 17(18):6628. https://doi.org/10.3390/ijerph17186628.

Ruiz de Apodaca Espinosa, Ángel: Régimen jurídico de la Evaluación de Impacto Ambiental de proyectos. Ambienta: la revista del Ministerio de Medio Ambiente, nº 123, 2018, pag. 84-97 https://www.mapa.gob.es/ministerio/pags/Biblioteca/Revistas/pdf%5FAM%2FPDF%5FAM%5FAmbiente%5F2018%5F123%5F84%5F97%2Epdf.

SAPEA, Science Advice for Policy by European Academies. (2017). Food from the oceans: how can more food and bio-mass be obtained from the oceans in a way that does not deprive future generations of their benefits? Berlin: SAPEA. doi:10.26356/foodfromtheoceans. https://scientificadvice.eu/advice/food-from-the-oceans/

Scientific, Technical and Economic Committee for Fisheries (STECF) 2013, The Economic Performance Report on the EU Aquaculture sector (STECF-13-29). 2013. Publications Office of the European Union, Luxembourg, EUR 26336 EN, JRC 86671, 383 pp.

Scientific, Technical and Economic Committee for Fisheries (STECF 2023), Economic Report on the EU aquaculture (STECF-22-17). Nielsen, R., Virtanen, J. & Guillen, J. (editors). Publications Office of the European Union, Luxembourg, 2023, doi:10.2760/51391, JRC132648.

Solaun, O., Rodríguez,J.G., Menchaca, I., López-García, E., Martínez, E., Zonja, B., Postigo, C., López de Alda, M., Barceló, D., Borja, A., Manzanos, A., Larreta, J. (2021) Contaminants of emerging concern in the Basque coast (N Spain): Occurrence and risk assessment for a better monitoring and management decisions. Sci. Tot Environ., 765: 142765. https://doi.org/10.1016/j.scitotenv.2020.142765.

Solaun, O., Rodríguez,J.G., Menchaca, I., López-García, E., Martínez, E., Zonja, B., Postigo, C., López de Alda, M., Barceló, D., Borja, A., Manzanos, A., Larreta, J. (2021) Contaminants of emerging concern in
the Basque coast (N Spain): Occurrence and risk assessment for a better monitoring and management decisions. Sci. Tot Environ., 765: 142765. https://doi.org/10.1016/j.scitotenv.2020.142765.

Sousa CAM, Cunha ME, Ribeiro L. 2020 Tracking 130 years of coastal wetland reclamation in Ria Formosa, Portugal: Opportunities for conservation and aquaculture. Land Use Policy 94.

Svåsand T., Crosetti D., García-Vázquez E., Verspoor E. (eds). (2007). Genetic impact of aquaculture activities on native populations. Genimpact final scientific report (EU contract n. RICA-CT-2005-022802). 176 p. http://genimpact.imr.no/.

Tacon A.G.J and Metian M. (2009) Fishing for Feed or Fishing for Food: Increasing Global Competition for Small Pelagic Forage Fish, Ambio, Vol. 38, No. 6 (Sep., 2009), pp. 294-302.

TEEB (2010) The Economics of Ecosystems and Biodiversity: Mainstreaming the Economics of Nature: A Synthesis of the Approach, Conclusions and Recommendations of TEEB. Available from: http://www.teebweb.org.

Tenore, K. R., Corral, J., Gonzalez, N., & Lopez-Jamar, E. (1985, July). Effects of intense mussel culture on food chain patterns and production in coastal Galicia, NW Spain. In Proceedings of the International Symposium on Utilization of Coastal Ecosystems: Planning, Pollution and Productivity. Rio Grande, Brazil (Vol. 1, pp. 321-328).

Tett, P., Portilla, E., Gillibrand, P. A., & Inall, M. (2011). Carrying and assimilative capacities: the ACExR-LESV model for sea-loch aquaculture. Aquaculture Research, 42, 51-67.

Thomas, Y., Pouvreau, S., Alunno-Bruscia, M., Barillé, L., Gohin, F., Bryère, P., and Gernez, P. 2015. Global change and climate-driven invasion of the Pacific oyster (Crassostrea gigas) along European coasts: a bioenergetics modelling approach. Journal of Biogeography.10.1111/jbi.12665.

Walton MEM, Vilas C, Canavate JP, Gonzalez-Ortegon E, Prieto A, van Bergeijk SA *et al*. (2015) A model for the future: ecosystem services provided by the aquaculture activities of Veta la Palma, Southern Spain. Aquaculture 448: 382-390.

Weitzman, J., & Filgueira, R. (2020). The evolution and application of carrying capacity in aquaculture: towards a research agenda. Reviews in Aquaculture, 12(3), 1297-1322.

Wittmann, A. C., and Pörtner, H.-O. 2013. Sensitivities of extant animal taxa to ocean acidification. Nature Climate Change, 3: 995-1001.10.1038/nclimate1982.

Yang W, Li Y, Boraschi D. (2023) Association between microorganisms and microplastics: How does it change the host-pathogen interaction and subsequent immune response? Int. J. Mol. Sci., 24:4065. doi: 10.3390/ijms24044065.

Zhulay, I., Reiss, K., Reiss, H (2015) Effects of aquaculture fallowing on the recovery of macrofauna communities, Marine Pollution Bulletin, 97: 381-390. https://doi.org/10.1016/j.marpolbul.2015.05.064.

Zorita, I., Solaun, O., Rodríguez, J.G., Larreta, J., Abad, E., Ábalos, M. (2023) Time series data (2008–2023) of polychlorinated dibenzo-p-dioxins, dibenzofurans and polychlorinated biphenyls in bivalves from Shellfish Production Areas of the Basque coast (SE Bay of Biscay). Data in Brief, 51, art. no. 109751. https://doi.org/10.1016/j.dib.2023.109751.
Annex 1: List of participants

<table><thead><tr><td>Name</td><td>INSTITUTE</td><td>Country of institute</td></tr></thead><tbody><tr><td>Myriam Callier</td><td>MARBEC, University of Montpellier, IRD, CNRS, Ifremer</td><td>France</td></tr><tr><td>Francis O'Beirn</td><td>Marine Institute</td><td>Ireland</td></tr><tr><td>Anne Cooper</td><td>ICES</td><td>Denmark</td></tr><tr><td>Ann Lisbeth Agnalt</td><td>IMR</td><td>Norway</td></tr><tr><td>Cecilia Kvaavik</td><td>ICES</td><td>Denmark</td></tr><tr><td>Bastien Sadoul</td><td>Institut Agro, DECOD Dynamique et Durabilité des Écosystèmes de la source à l'océan</td><td>France</td></tr><tr><td>Fabrice Pernet</td><td>Ifremer, Univ Brest</td><td>France</td></tr><tr><td>Fiz Da Costa</td><td>AquaCOV, Instituto Español de Oceanografía (IEO, CSIC)</td><td>Spain</td></tr><tr><td>Harkaitz Eguiraun</td><td>Department of Graphic Design & Engineering Projects, Bilbao School of Engineering, University of the Basque Country<br>Research Center for Experimental Marine Biology and Biotechnology—Plentziako itsas Estazioa (PiE), University of the Basque Country</td><td>Spain</td></tr><tr><td>Iciar Martinez</td><td>IKERBASQUE, Basque Foundation for Science<br>Research Center for Experimental Marine Biology and Biotechnology—Plentziako itsas Estazioa (PiE), University of the Basque Country<br>Department of Zoology and Animal Cell Biology, Faculty of Science and Technology, University of the Basque Country</td><td>Spain</td></tr><tr><td>Jorge Humberto Palmeira Ramos</td><td>CinTurs, University of Algarve</td><td>Portugal</td></tr><tr><td>José A. Pérez Agúndez</td><td>Ifremer, Univ Brest</td><td>France</td></tr><tr><td>Laura Ribeiro</td><td>Instituto Português do Mar e da Atmosfera</td><td>Portugal</td></tr><tr><td>Melina Kourantidou</td><td>University of Western Brittany</td><td>France</td></tr><tr><td>Montserrat Pérez Rodríguez</td><td>Centro Oceanográfico de Vigo, Instituto Español de Oceanografía (IEO, CSIC)</td><td>Spain</td></tr><tr><td>Narcisa Bandarra</td><td>Portuguese Institute for the Sea and Atmosphere (IPMA, IP)</td><td>Portugal</td></tr><tr><td>Pedro Pousão</td><td>Portuguese Institute for the Ocean and Atmosphere (IPMA)</td><td>Portugal</td></tr><tr><td>Ramon Filgueira</td><td>University of Western Brittany</td><td>France</td></tr><tr><td>Rosa Chapela Perez</td><td>CETMAR</td><td>Spain</td></tr><tr><td>Rosa Fernandez</td><td></td><td></td></tr></tbody></table>
<table><tr><td>Rui Oliveira</td><td>Directorate-General for Natural Resources, Safety and Maritime Services</td><td>Portugal</td></tr><tr><td>Sebastian Villasante</td><td>EqualSea Lab-CRETUS, University of Santiago de Compostela</td><td>Spain</td></tr><tr><td>Sofia Gamito</td><td>Faculdade de Ciências e Tecnologia, Universidade do Algarve<br>CCMAR - Centro de Ciências do Mar do Algarve, Universidade do Algarve</td><td>Portugal</td></tr><tr><td>Anaël Delorme (statistics)</td><td>SSP/SDSAFA/BSSAF, SSP BP 32688 31326 CASTANET TOLOSAN CEDEX</td><td></td></tr></table>
# Annex 2: Resolutions

**2022/WK/ASG01 Workshop on the Bay of Biscay and Iberian Coast ecoregion Aquaculture Overview (WKBoBICAO)** chaired by Myriam Callier, France*, and Francis O'Beirn, Ireland*, will be established and meet (hybrid meeting) in Sète, France (Ifremer Station) in 3–5 October 2023 to:

a) Review and discuss the data and information collected for the Bay of Biscay and Iberian Coast ecoregion aquaculture overview, identify the gaps and agree next steps to complete the draft overview;

b) Collate datasets and resources for the aquaculture overview by completing the ICES Data Profiling Tool (https://www.ices.dk/data/tools/Pages/Data-profiler.aspx); and

c) Produce a workshop report detailing the conclusions of ToRs a and b. This report will serve as the foundation for the Bay of Biscay and Iberian Coast ecoregion aquaculture overview.

WKBoBICAO will report by January 2024 for the attention of the ACOM.

## Supporting information

<table><tr><td>Priority</td><td>Aquaculture is a high-priority topic for ICES. ICES work on aquaculture is part of a wider portfolio of work that seeks to advance and share scientific understanding of marine ecosystems and the services they provide, and to use this knowledge to generate state-of-the-art advice for meeting conservation, management, and sustainability goals. The ICES Strategic Plan states: 'We will regularly publish, update, and disseminate overviews on the state of fisheries, aquaculture, and ecosystems in the ICES region, drawing as appropriate on analyses of human activities, pressures, and impacts, and incorporating social, cultural, and economic information.'</td></tr><tr><td>Scientific justification</td><td>The process of establishing ICES AOs was initiated in 2019, with: i) forming a core group consisting of representatives from ACOM leadership, SCICOM and Secretariat, and ii) agreeing on the directions and procedure of further work of the core group. The objectives AOs are to: i) synthesize regional and temporal information on aquaculture activities, practices and production of the cultured taxa; ii) consider environmental and socio-economic interactions of aquaculture activities and practices; iii) provide insights on cross-sectorial interactions of aquaculture; and, iv) consider future perspectives. The overview will have ten sections: 1) executive summary; 2) introduction; 3) description and location of marine aquaculture activities and practices; 4) production over time; 5) policy and legal foundation; 6) management frameworks; 7) ecosystem/environment interactions; 8) social and economic context; 9) interaction of environmental, economic and social drivers; and 10) future projections, and emerging threats and opportunities.</td></tr><tr><td>Resource requirements</td><td>There are already several confirmed experts (as suggested by ACOM members) from France, Spain and Portugal to agree to contribute to the work. The lead author of the Bay of Biscay and Iberian Coast ecoregion AO (Myriam Callier) has already started establishing contacts with these experts.</td></tr><tr><td>Participants</td><td>The WK will be attended by experts contributing to the Bay of Biscay and Iberian Coast ecoregion AO, as well as other interested scientists from ASG.</td></tr><tr><td>Secretariat facilities</td><td>Setting up conference calls.</td></tr><tr><td>Financial</td><td>No financial implications.</td></tr><tr><td>Linkages to advisory committees</td><td>Direct link to ACOM.</td></tr><tr><td>Linkages to other committees or groups</td><td>ASG, WGAGFA, WGECCA, WGOOA, WGPDMO, WGREIA, WGSEDA, WGSPA, WGEEL, WGSOCIAL, WGECON, SICCME, SIHD</td></tr></table>
<table><tr><td>Linkages to other organizations</td><td>DGMARE</td></tr></table>
# Annex 3: Review of ICES Scientific Reports – Workshop on the Bay of Biscay and Iberian Coast Ecoregion Aquaculture Overview

Katherine Dunlop – Institute of Marine Research, Norway. April 2024

Matt Gubbins – Marine Scotland, Scotland. April 2024

Llucia Mascorda-Cabre – University of Plymouth, UK. April 2024

## General review to overall report

Overall, the reviewers accept the report as a source of suitable and detailed information that could be used as the basis of ICES advice following the verification of some details as identified here below.

The review in its current format provides a comprehensive and informative review of the aquaculture ecoregion in focus. However, prior to publication several improvements need to be made in readability in several chapters and continuity between chapters to avoid repetition and improve the flow of the review. Of most concern is the unfished nature of some of the text in some chapters. Currently it is clear that that minimal collaboration was achieved between chapters. In some chapters, a large part of the text is given over to a review of general issues related to aquaculture globally which leaves less focus for addressing details of these aspects in the ecoregion.

It is a very long report with some very useful information and overview. However, there are some parts that I believe are not relevant to the overview and could be removed to make it more concise while others could be given a more aquaculture focus. There is a lack of references throughout the document which needs to be addressed and some updated to include more recent literature. In particular, information on effects and impacts of every type of aquaculture is lacking and that a more thorough literature review is needed to avoid biased arguments.

We appreciate that the review has involved a lot of effort from authors for which English is not a first language so as we have done our best to correct the language and improve readability. Some parts are written in note format and are unfinished and headings need to be used consistently throughout. Many paragraphs with single sentences which made the text disjointed and is not a correct writing style. Several parts of the text were difficult to understand (highlighted in yellow). Text has room for improvements in readability. Many parts read like a list and the use of tables and figures in some sections could improve this.

Section 4 is very long and rather than focusing on the ecoregion itself, is attempting to review the EU aquaculture policy thus, doing neither one or the other appropriately. Chapter 7 and 3 could be merged or structured differently to avoid so much repetition. Overall, the document needs to be thoroughly edited and some sections rewritten to improve readability and avoid repetition. Some sentences and paragraphs are unfinished which needs to be addressed.
**Executive summary:**

I believed this section is not finished as it needs to include a brief summary of the report.

A glossary of terms should be added.

**Chapter 1**

This Chapter provides some useful detail on the context of the ecoregion however, it is lacking in information compared to the Celtic Sea review. It needs more explicit linking to aquaculture making the information relevant. Particularly around the relevance of the specific oceanography which clearly lends itself to being a highly productive ecosystem suitable for farming certain shellfish species. The description of conservation areas seems quite general and lacking in details so more in-depth information on the extent to which the habitats and their protection designations are relevant to aquaculture developments is needed.

There is a lot of repetition and there is a need to be more specific to the task of the overview. Heading and sub-headings should be revised and updated. More information on emerging candidate species and production methods is needed. We provide some suggestions for improvement in text readability and the inclusion of map data. Figures need to be updated and better ones produced. References are missing and this must be addressed.

**Chapter 2**

It needs some formatting, restructuring and editing. There is specific country information missing and some better definitions needed, and the production systems and methodologies should be better described – there are some methods missing. Figures need updating in the section as well and headings and sub-headings revised as there is inconsistency issues. References are also missing, and some are too old while there are newer ones available. There is some repetition, unfinished sentences, contradictory and confusing parts, others are not relevant to the overview while other parts need more detailed information. Map figures should be improved to allow the reader to extract more information and legends with more detailed explanations are needed. All figures should be references within the text. Currently a large part of the map is of the Bay of Biscay while the aquaculture areas of interest are on the coast. For instance, some information is presented as a list and while a table of the most important species with production biomass for each country would be more appropriate.

Section 2.2 on cultivation methods is missing a lot of detail on aspects of culture such as harvesting, predator control, seeding techniques, use of hatcheries vs. wild-caught etc. None of the provided information is referenced.

Section 2.3 contains a lot of detail in text form, much of it by country. There is reference to multiple cultivation methods that are not referred to in any detail in section 2.2 and much of the information would be much better presented in the form of tables or maps. We have the impression there are some real issues disentangling some of the data from national or regional aggregates into the ecoregion, but if this could be done from the source data it would help the overall assessment.

**Chapter 3**

This Chapter starts with too much detail on production survey methodology and could just be referenced to the named survey reports. Headings and sub-headings should be checked and the order in which sections are put so the structure needs some editing. There is repetition of information from other sections but then there are sections missing and entire country/ies. Some parts are irrelevant to the overview so should be deleted to avoid confusion. This Chapter could benefit from the use of more figures and thorough editing (e.g. species in italics, consistency of terms
and units, one sentence paragraphs). It is difficult to read and seems more in note form than a finished product (it sometimes reads like a list - see page 29).

The combined production trend plots are very nice – good work by the workshop to combine the national data to the ecoregion for this. Again much of the quantitative information is provided by text when tables might be more useful. List of species produced and facilities separate from information on production in different chapters. The text could be more concise and easier to read with these sections combined. Currently keeps returning to the same topic but at a slightly different angle. While there is repetition between Chapter 2 and 3, the same level of detail in the Celtic Sea Aquaculture overview is not achieved.

## Chapter 4

This section has somehow confused the reviewers. It starts with some long text around principles and reasons for aquaculture governance and EU approach that are not particularly relevant to the ecoregion assessment. The text prior to 4.2.2 is all interesting but not really critical to an ecoregion assessment except to highlight that the same overarching European legislation applies equally to all jurisdictions in the ecoregion. If the BoBIC overview wants to include a review of EU aq strategies and policies, this section needs a lot more work to be done and a better literature review. If, on the contrary, it wants to introduce the topic of policy at EU level, to then properly explain the situation within the BoBIC ecoregion, it needs to be explicit, summarized and drastically reduced to focus on France, Spain and Portugal. In the country specific sections on legal frameworks there is some excellent relevant detail that provides the context for the authorizing environment for aquaculture in this ecoregion. The authors conclude that the complexity of this and in some countries slow pace of implementation are to blame for some of the stagnation of the sector. This is fine but the concluding recommendations should be looked at closely in the context of unsolicited ICES advice. We are nervous about such recommendations being associated with ICES advice. They are the sort of thing that might be recommended should we be asked about future changes required to strengthen a European aquaculture sector in the context of a growing Blue Economy but ICES hasn't been asked to do that. This is an overview. Instead, it might be worth highlighting these as issues experienced by the sector relevant to the ecoregion in the overview.

This Chapter's readability has improved, it is well written, organised, comprehensive and informative however, the entire section should be restructured and rewritten to focus on the ecoregion. References are needed throughout.

## Chapter 5

Useful information here but it is unevenly distributed across the jurisdictions / countries and needs bringing together for context and relevance to the assessment. In particular the section on management regimes focuses on pathogen control in Portugal and biotoxin management in France (but nothing in Spain which has some of the best biotoxin management in the world). The scope of Section 5 seems narrow; What about other management frameworks than human health and health/welfare?

The title should reflect the section. There is too much use of list format and unfinished text in some parts. Figures need to be updated and legends added. All figures and tables should be mentioned within the text. It is very short compared to chapter 4.

## Chapter 6

This section is well written but needs more work not only on the title itself but also on content. It needs tightened up with respect to linking the types of interactions discussed to the ecoregions. Where that is done it needs more attention to equitably representing the different regions in the
assessment. Some areas are notably missing such as management of enteric microorganisms (a
major issue for management) and biotoxins from section 6.2. The assessment is left without a real
understanding of whether that is an issue for the ecoregion or not. Microplastic and climate
change sections presents information that is more general to plastic impacts but less relevant to
aquaculture, the authors should consider if this is relevant here.

Terms need to standardized throughout the text. Some references should be updated to more
recent literature on the topic. There is repetition from other sections and missing information.
Some sections need to be summarized to reduce the length and at the same time, more infor-
mation on the impacts of farming is needed. This is a very long overview and needs to focus
more on the BoBIC rather than reviewing issues.

**Chapter 7**

This Chapter contains some great relevant detail but much of it should appear in earlier sections
on production detail, trends and relative importance of sectors and regions. It is well drafted and
referenced but there seems to be repetition of what has been exposed in Chapter 2 and 3. Chapter
7 and 3 could be merged or structured differently to avoid so much repetition. Headings are
different between each country. There is again parts that are not relevant. This section is well
written so could be used in the introduction.

**Chapter 8**

This Chapter is a good piece of text, well written and synthesising the issues well. It represents
a good summing of aspects of the report to date. However, there is some information missing
for certain countries. What about the positive impacts that low-trophic aquaculture can have as
habitat restoration or decreasing eutrophication? The difference between chapter 8 and 6 should
be clearer: Interactionsvs.impacts. This section could be better referenced given some of the as-
sertions in the section.

**Chapter 9**

This Chapter has clearly not been progressed, there is information missing, some threats and
opportunities have been identified but not further developed and again there is a need to focus
on the ecoregion. There is too much detail on contaminants but there are other threats and ways
to improve aq sustainability practices. Are the recommendations really what ICES wants to por-
tray? Are they already published by Angel Borja? They seem a restrictive set of recommendations
given the scope of the overview and does an EO need recommendations anyway? Where are
INNS threats and impacts addressed in the report?

This Chapter seems unfinished and still in note format in parts, there is repetition and some areas
are difficult to understand. There's no need for so many subheading levels. It needs better expla-
nation of findings from IMTA projects not just aims. IMTA has been discussed in several chapters
and continuity between text can be much improved. Presentation of most important information
should come in the earlier chapters and later chapters can refer to this.

There are a lot of references found within the text that are missing from the list.
# Annex 4: ADGAO meeting minutes

13-16 May 2024

Hybrid meeting (ICES HQ Copenhagen and Teams)

**Participants:** Dounia Hamoutene (Canada), Myriam Callier (invited expert, WKBoBICAO chair), Francis O'Beirn (invited expert, WKBoBICAO chair), Neil Ruane (Ireland), Matthew J. Gubbins (invited expert, RG chair), Reinhold Hanel (Germany), Laura Ribeiro (Portugal), Henn Ojaveer (chair, ACOM vice chair), Michala Ovens and Anne Cooper (ICES Secretariat).

**Declaration of conflict of interest:** The group was informed of the ICES code of conduct and was asked to declare perceived, potential or real conflicts of interest. None of the participants declared any types of conflict of interest.

**The ADG meeting** started with a short introductory presentation by the ADGAO chair who introduced the ICES Advisory Framework, adoption of the agenda and suggested working procedure.

RGAO chair presented the main findings from reviewers and the WKCSAO chair responded to the major points raised by reviewers.

The ADG started work on the initial draft advice prepared in advance by the ADGAO chair, which was made available for the ADG members on 29 August. The initial draft advice was prepared based on the WKBoBICA draft report.

## General comments made by the Review Group

The review in its current format provides a comprehensive and informative review of the aquaculture ecoregion in focus. However, prior to publication several improvements need to be made in readability in several chapters and continuity between chapters to avoid repetition and improve the flow of the review. Of most concern is the unfished nature of some of the text in some chapters. Currently it is clear that that minimal collaboration was achieved between chapters. In some chapters, a large part of the text is given over to a review of general issues related to aquaculture globally which leaves less focus for addressing details of these aspects in the ecoregion.

It is a very long report with some very useful information and overview. However, there are some parts that I believe are not relevant to the overview and could be removed to make it more concise while others could be given a more aquaculture focus. There is a lack of references throughout the document which needs to be addressed and some updated to include more recent literature. In particular, information on effects and impacts of every type of aquaculture is lacking and that a more thorough literature review is needed to avoid biased arguments.

We appreciate that the review has involved a lot of effort from authors for which English is not a first language so as we have done our best to correct the language and improve readability. Some parts are written in note format and are unfinished and headings need to be used consistently throughout. Many paragraphs with single sentences which made the text disjointed and is not a correct writing style. Several parts of the text were difficult to understand (highlighted in yellow). Text has room for improvements in readability. Many parts read like a list and the use of tables and figures in some sections could improve this.

Section 4 is very long and rather than focusing on the ecoregion itself, is attempting to review the EU aquaculture policy thus, doing neither one or the other appropriately. Chapter 7 and 3 could be merged or structured differently to avoid so much repetition. Overall, the document